ALBERT

Description:    Mesophotic coral reefs (30–150 m) have been assumed to be physically and biologically connected to their shallow-water counterparts, and thus may serve as refugia for important taxonomic groups such as corals, sponges, and fish. The recent invasion of the Indo–Pacific lionfish ( Pterois volitans ) onto shallow reefs of the Caribbean and Bahamas has had significant, negative, effects on shallow coral reef fish populations. In the Bahamas, lionfish have extended their habitat range into mesophotic depths down to 91 m where they have reduced the diversity of several important fish guilds, including herbivores. A phase shift to an algal dominated (〉50% benthic cover) community occurred simultaneously with the loss of herbivores to a depth of 61 m and caused a significant decline in corals and sponges at mesophotic depths. The effects of this invasive lionfish on mesophotic coral reefs and the subsequent changes in benthic community structure could not be explained by coral bleaching, overfishing, hurricanes, or disease independently or in combination. The significant ecological effects of the lionfish invasion into mesophotic depths of coral reefs casts doubt on whether these communities have the resilience to recover themselves or contribute to the recovery of their shallow water counterparts as refugia for key coral reef taxa. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0005-z Authors Michael P. Lesser, Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA Marc Slattery, Department of Pharmacognosy, University of Mississippi, Oxford, MS 38677, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The stoat ( Mustela erminea ) is a specialist predator that evolved to exploit the unstable populations of northern voles and lemmings. It was introduced to New Zealand, where it is pre-adapted to respond with a population irruption to the resource pulses that follow a heavy seedfall of southern beech ( Nothofagus spp.). Culling stoats during an irruption is necessary to reduce damaging predation on nesting endemic birds. Culling might not reduce the stoat population long term, however, if high natural mortality exceeds culling mortality in peak years. During other phases of the beech-mast cycle, culling might have a greater effect on a smaller stoat population, whether or not damage prevention is critical. We developed a 4-matrix model to predict the effects of culling on λ, the annual rate of change in the size of the stoat population, through the four annual phases of an average masting cycle, explicitly distinguishing between apparent and real culling. In the Post-seedfall phase of the cycle, large numbers of stoats are killed, but little of this extra mortality is additive; in other phases, culling removes larger proportions of smaller total numbers of stoats that would otherwise have lived. Culling throughout all phases is most effective at reducing stoat populations, but is also the most expensive option. Culling in Post-seedfall plus Seed or Crash years is somewhat less effective but better than culling in one phase only. Culling has different short-term effects on stoat age distribution depending on the phase of the cycle when culling begins. Content Type Journal Article Pages 1-17 DOI 10.1007/s10530-011-9993-y Authors Carolyn M. King, Department of Biological Sciences, Waikato University, Private Bag 3105, Hamilton, New Zealand Roger A. Powell, Department of Biology, North Carolina State University, Raleigh, NC 27695-7617, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Pine wilt disease, which can rapidly kill pines, is caused by the pine wood nematode, Bursaphelenchus xylophilus . It is expanding its range in many countries in Asia and measures are being taken at the EU level to prevent its spread from Portugal. Due to the threat to European forests, it is important to prevent additional introductions and target surveillance to the points of entry that pose the greatest risk. In this study, we present a model to identify the European ports from which the nematode can spread most rapidly across Europe. This model describes: (1) the potential spread of the pine wood nematode based on short-distance spread (the active flight of the vector beetles) and long-distance spread (primarily due to human-mediated transportation), and (2) the development of pine wilt disease based on climate suitability and the potential spread of the nematode. Separate introductions at 200 European ports were simulated under various climate change scenarios. We found that the pine wood nematode could invade 19–60% of the study area (30°00 N–72°00 N, 25°00 W–40°00 E) by 2030, with the highest spread from ports located in Eastern and Northern Europe. Based on climate change scenarios, the disease could affect 8–34% of the study area by 2030, with the highest spread from ports located in South-Eastern Europe. This study illustrates how a spread model can be used to determine the critical points of entry for invasive species, so that surveillance can be targeted more accurately and control measures prioritised. Content Type Journal Article Pages 1-15 DOI 10.1007/s10530-011-9983-0 Authors Christelle Robinet, INRA UR633 Zoologie Forestière, 2163 Avenue de la pomme de pin, CS 40001, Ardon, 45075 Orleans Cedex 2, France Nico Van Opstal, European and Mediterranean Plant Protection Organization, 21 boulevard Richard-Lenoir, 75011 Paris, France Richard Baker, The Food and Environment Research Agency, Sand Hutton, York, YO41 1LZ UK Alain Roques, INRA UR633 Zoologie Forestière, 2163 Avenue de la pomme de pin, CS 40001, Ardon, 45075 Orleans Cedex 2, France Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Rotan Perccottus glenii is one of the most widespread alien invasive freshwater fish in Eurasia. We reviewed the mechanisms of its dispersion, identified the potential range and regarded these results in the light of possible prevention of further expansion. Our analysis was based on 970 presence records and 198 absence records from both invaded and native parts of the range. Since 1916 invasion dynamics of rotan have been driven by episodic anthropogenic translocations, followed by spontaneous expansion within river networks, and secondary translocations. M axent species distribution models with independent validations showed that rotan distribution in Eurasia has climatic limitations; rotan have already invaded most areas with high climatic suitability in the Palearctic, but some regions of North Eurasia and North America, where rotan is currently absent, have high climatic suitability and may be vulnerable to invasion in the future. Rotan’s high invasiveness, lack of geographical barriers and absence of reliable methods to prevent spread present a very high risk of expansion within appropriate climate limits in Europe. Our analysis shows that the long-term invasion dynamics of an invasive freshwater species may depend on climate variables rather than on river basin borders. Species distribution models, based on large scale environmental layers, can be useful to understand the invasion risk for other freshwater species restricted to shallow aquatic habitats. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-9982-1 Authors Andrey Nikolaevich Reshetnikov, Severtsov Ecology & Evolution Institute, Leninskiy 33, 119071 Moscow, Russia Gentile Francesco Ficetola, Department of Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Habitat modification (i.e., disturbance) and resource availability have been identified as possible mechanisms that may influence the invasibility of plant communities. In the Mojave Desert, habitat disturbance has increased dramatically over the last 50 years due to increased human activities. Additionally, water availability is considered to be a main limiting resource for plant production. To elucidate the effects of soil disturbance and water availability on plant invasions, we created experimental patches where we varied the levels of soil disturbance and water availability in a fully crossed factorial experiment at five replicated field sites, and documented responses of native and non-native winter annuals. The treatments did not significantly affect the density (seedlings m −2 ) of the non-native forb, Brassica tournefortii . However, the relationship between silique production and plant height differed among treatments, with greater silique production in disturbed plots. In contrast to Brassica , density of the non-native Schismus spp. increased in soil disturbed and watered plots, and was greatest in disturbed plots during 2009 (the second year of the study). Species composition of the native annual community was not affected by treatments in 2008 but was influenced by treatments in 2009. The native forb Eriophyllum sp. was most dense on water-addition plots, while density of Chaenactis freemontii was highest in disturbed plots. Results illustrate that habitat invasibility in arid systems can be influenced by dynamics in disturbance regimes and water availability, and suggest that invasiveness can differ between non-native annual species and among native annuals in habitats undergoing changing disturbance and precipitation regimes. Understanding the mechanistic relationships between water availability and non-native plant responses will be important for understanding the effects of shifting precipitation and vegetation patterns under predicted climate change in arid ecosystems. Content Type Journal Article Pages 1-13 DOI 10.1007/s10530-011-9998-6 Authors Alexis A. Suazo, School of Environmental and Public Affairs, University of Nevada Las Vegas, Las Vegas, NV 89154-4030, USA Jessica E. Spencer, School of Environmental and Public Affairs, University of Nevada Las Vegas, Las Vegas, NV 89154-4030, USA E. Cayenne Engel, School of Environmental and Public Affairs, University of Nevada Las Vegas, Las Vegas, NV 89154-4030, USA Scott R. Abella, School of Environmental and Public Affairs, University of Nevada Las Vegas, Las Vegas, NV 89154-4030, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Plant invasions are often implicated in declines of native plant species. However, common experimental designs have received criticism questioning the assumption that invasive plants are the primary cause for ecosystem deterioration. We used a combination of field observations and a transplant experiment to investigate the influence of an exotic invasive shrub, Ligustrum sinense (Chinese Privet) on native plant species in Piedmont floodplain forests of South Carolina, USA. We conducted vegetation surveys of 12 floodplain forests documenting abundance and cover of all herbaceous and woody plant species. Additionally, we established an experimental garden to compare survival and growth of L. sinense and four common native species transplanted into a mature L. sinense stand and an adjacent uninvaded area over two growing seasons. The vegetation survey demonstrated a strong negative relationship between L. sinense presence and herbaceous vegetation. As L. sinense cover increased, herbaceous cover and height, plant abundance, and native species richness decreased. In our transplant experiment we found drastic effects of L. sinense on native plant seedling survival and growth. Survival for all native species was lower under the L. sinense canopy and native seedling growth was substantially reduced . Results from both the vegetation survey and transplant experiment show that invasion of L. sinense suppresses herbaceous understory and prevents regeneration of native species by reducing seedling survival and growth. With an approach that combines multiple field sites and local site-specific investigations our research provides strong evidence that L. sinense is an agent of change in floodplain forests. Content Type Journal Article Pages 1-12 DOI 10.1007/s10530-011-9990-1 Authors Brian T. Greene, Department of Natural Resources, Cornell University, Ithaca, NY 14853, USA Bernd Blossey, Department of Natural Resources, Cornell University, Ithaca, NY 14853, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Wetlands are subject to invasion by exotic plant species, especially during the dry season when they resemble terrestrial systems; therefore, terrestrial plants could exploit this situation to colonize this environment. We analyzed P. anserina invading Patagonian wetlands in terms of elemental ratios that would modify wetland stoichiometry due to organic matter inputs. We studied the elemental relationship (carbon/nitrogen/phosphorus) of P. anserina in comparison with native emergent macrophytes ( Eleocharis pachicarpa and Carex aematorrhyncha ). These plant species are common and dominant in the wetland. Additionally, we analyzed the presence of mycorrhizal fungi in the roots and their proportion of root infection. Our study reveals that the invasive species presented nutrient (especially phosphorus) allocation in roots and differences in mycorrhizal infection, with a predominance of arbuscular mycorrhiza, compared with native species. During flooded periods with the decay of aerial parts, P. anserina stores phosphorus in the roots and releases dissolved organic matter of high molecular weight molecules, high color, and a high C-to-nutrient ratio in comparison with native macrophytes. These results show the strategy of an invasive terrestrial plant in temporary aquatic systems, and how the elemental relationships of the invasive plant can modify the stoichiometry of the environment. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-9995-9 Authors Florencia Cuassolo, Laboratorio de Limnología, INIBIOMA-CONICET-UNComahue, Quintral 1250, 8400 Bariloche, Argentina Esteban Balseiro, Laboratorio de Limnología, INIBIOMA-CONICET-UNComahue, Quintral 1250, 8400 Bariloche, Argentina Beatriz Modenutti, Laboratorio de Limnología, INIBIOMA-CONICET-UNComahue, Quintral 1250, 8400 Bariloche, Argentina Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Mechanisms contributing to the invasive success of plants are still only partly understood. A main assumption is that an escape from specialized enemies in introduced ranges allows a reduction of chemical defences resulting in an increase in growth and reproduction and thus increased competitive ability of introduced plants. Not only variation in concentration but also variation in composition of chemical compounds between individuals may be a key advantage for plants introduced to novel areas impeding adaptation of different plant antagonists. To investigate quantitative and qualitative variation of putative defence compounds and investment of resources in growth, we conducted a common garden experiment in the native range with seeds of 13 native and 9 introduced populations of Tanacetum vulgare , an aromatic plant forming different chemotypes. After 3.5 months, plants of introduced populations had similar biomass but more stems and higher concentrations of volatile secondary compounds (mainly terpenes) than plants of native populations. Both native and invasive T. vulgare populations exhibited high chemotypic variation with nine chemotypes occurring on both continents, whereas several were found exclusively either in plants originating from the native ( n  = 10) or invasive ( n  = 2) range. Due to the known negative effects of many mono- and sesquiterpenes on various organisms, we propose that high concentrations of these secondary compounds accompanied by high chemotypic diversity may facilitate the invasion success of a plant species. Content Type Journal Article Pages 1-12 DOI 10.1007/s10530-011-0028-5 Authors Vera C. Wolf, Department of Chemical Ecology, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany Ursula Berger, StatBeCe-Statistical Consultancy Unit, Department of Chemical Ecology, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany André Gassmann, CABI Europe-Switzerland, Rue des Grillons 1, 2800 Delémont, Switzerland Caroline Müller, Department of Chemical Ecology, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Northern pike ( Esox lucius ) were introduced to the northern Susitna Basin of south-central Alaska in the 1950’s, and have since spread throughout the upper Cook Inlet Basin. Extirpations of several native fish populations have been documented in this area. It is hypothesized here that invasive pike remodel the ecology of lakes by removing vulnerable prey types and that these changes are reflected in the diet of invasive pike. Trends in pike diet suggest that pike switch to less desirable but more abundant macroinvertebrate prey as preferred fish prey are eliminated. The impacts of pike introduction were studied in detail for one species of resident fish, the threespine stickleback ( Gasterosteus aculeatus ). Stickleback abundance decreases as pike invasion progresses. Conductivity is a significant environmental predictor of stickleback abundance, with higher conductivity apparently mitigating population reduction. Higher conductivity water may lessen the physiological costs of developing more robust armor, which reduces vulnerability to predation. Maximum lake depth also appears to predict stickleback abundance, though this trend was only marginally significant. Deeper lakes may provide an open-water refuge from pike predation by allowing stickleback to exist outside of the pike inhabited littoral zone. These findings indicate the importance of diverse habitat types and certain chemical and physical characteristics to the outcome of invasion by fish predators. Content Type Journal Article Pages 1-12 DOI 10.1007/s10530-011-0029-4 Authors Stormy Haught, Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Dr., Anchorage, AK 99508-4614, USA Frank A. von Hippel, Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Dr., Anchorage, AK 99508-4614, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    In 2005, the non-native Nylanderia flavipes was first recorded from Ohio. Here, we present the results of a baseline study designed to assess the status of this exotic species in northeastern Ohio and to explore its potential impacts on local ant communities and the extent to which it has been incorporated into the diet of a native predator, the red-backed salamander. At the sites where N. flavipes occurred, we found a sixfold increase in total ant abundance, with 87% of all ants collected being N. flavipes . The high numerical dominance of N. flavipes did not lead to observable changes in the species richness and abundance of the native ant community. At baits, N. flavipes did not engage in interspecific combat and did not exhibit aggression towards native ants. Thus, aggression and interference competition are not likely factors explaining the high local abundance of N. flavipes . Red-backed salamanders have incorporated N. flavipes into their diet, but further research is needed to understand the interactions of N. flavipes within the forest-floor food web. Although we did not detect changes in the local ant communities in the presence of N. flavipes , we argue that this species’ high local abundance and ability to forage at cooler temperatures may give it a competitive advantage and thereby affect native ants through exploitative competition. Content Type Journal Article Pages 1-6 DOI 10.1007/s10530-011-0021-z Authors Kaloyan Ivanov, Cleveland Museum of Natural History, 1 Wade Oval Drive, University Circle, Cleveland, OH 44106, USA Owen M. Lockhart, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA Joe Keiper, Virginia Museum of Natural History, 21 Starling Avenue, Martinsville, VA 24112, USA B. Michael Walton, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The invasion by Indo-Pacific lionfish ( Pterois volitans and P. miles ) of the western Atlantic, Caribbean and Gulf of Mexico is emerging as a major threat to coral reef communities across the region. Comparing native and introduced populations of invasive species can reveal shifts in ecology and behaviour that can accompany successful invasions. Using standardized field surveys replicated at multiple sites in Kenya and the Bahamas, we present the first direct comparisons of lionfish density, body size, biomass and behaviour between native and invaded coral reefs. We found that lionfish occur at higher densities with larger body sizes and total biomass on invaded Bahamian coral reefs than the ecologically equivalent species ( P. miles ) does on native Kenyan reefs. However, the combined average density of the five lionfish species ( Pterois miles , P. antennata , P. radiata , Dendrochirus brachypterus and D. zebra ) on Kenyan reefs was similar to the density of invasive lionfish in the Bahamas. Understanding the ecological processes that drive these differences can help inform the management and control of invasive lionfish. Content Type Journal Article Pages 1-7 DOI 10.1007/s10530-011-0020-0 Authors Emily S. Darling, Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada Stephanie J. Green, Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada Jennifer K. O’Leary, National Centre for Ecological Analysis and Synthesis, 735 State Street, Suite 300, Santa Barbara, CA 93101, USA Isabelle M. Côté, Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Processes that promote weed invasion are often well-demonstrated, but mechanisms that facilitate ecological resistance to weed invasion in non-invaded communities, or promote weed persistence in invaded communities, are poorly understood. Yet it is these processes that must be addressed to achieve sustainable ecological restoration. We surveyed soil heterogeneity in 25 long-ungrazed, unfertilized York gum ( Eucalyptus loxophleba Benth. subsp. loxophleba )—jam ( Acacia acuminata Benth.) woodlands of the Western Australian wheatbelt to investigate differences in soil characteristics between patches locally-invaded or non-invaded by widespread exotic annuals. Based on studies in other ecosystems, we hypothesized that (1) weed persistence is associated with elevated soil resource levels, and (2) of these soil resources, phosphorus is the key contributor to weed persistence in Western Australian woodlands, that typically occur on phosphorus-impoverished soils. Our first hypothesis was partly supported, with soil nutrients associated with up to 40% of the variation in cover of exotic annuals. In particular, low concentrations of total nitrogen, nitrate and available phosphorus are likely to contribute to resistance to invasion in many non-invaded woodland patches, especially in gaps between trees. However, other non-invaded patches had comparable nutrient concentrations to invaded patches, suggesting this resistance may be weak at more productive sites or that patches have not reached a stable equilibrium. Inconsistent with our second hypothesis, exotic annuals were as strongly correlated with elevated total nitrogen and associated variables as they were with available phosphorus, probably reflecting a history of grazing without fertilization. We conclude that effectiveness of ‘bottom-up’ approaches to weed control is likely to differ among ecosystems according to interactions with disturbance history and attributes of the non-invaded community, even where the weed species or functional types are the same. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0017-8 Authors Suzanne M. Prober, CSIRO Ecosystem Sciences, Private Bag 5, PO, Wembley, WA 6913, Australia Georg Wiehl, CSIRO Ecosystem Sciences, Private Bag 5, PO, Wembley, WA 6913, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Previous island biogeography studies have quantified species richness on the scale of entire islands rather than smaller scales relevant to plant-to-plant competitive interactions. Further, they have not accounted for density compensation. Using mainland and island sites along the New England coast, we asked two questions. First, are both richness and density lower in small-scale habitats within islands than in similar mainland habitats? Second, do differences in competitor richness and density drive post-establishment trait variation in nonnative plant species? We used field surveys and individual-based rarefaction to estimate richness and density in 100-m 2 plots and demonstrated that island sites have significantly fewer species and individuals per unit area than mainland sites. We then conducted a field study in which we removed competing neighbors from nonnative plant individuals and found that when competitors were removed, individuals in low-competition environments demonstrated a lesser increase in vegetative growth but a greater increase in reproductive effort and herbivore tolerance relative to mainland individuals whose neighbors were also removed. We found that the central concept of island biogeography, i.e., that islands host fewer species than comparable mainland habitats, can be extended to smaller-scale habitats and that this difference in competitive pressure between mainland and island habitats can act as a driver of trait variation in nonnative plants. Content Type Journal Article Pages 1-9 DOI 10.1007/s10530-011-0019-6 Authors Joshua P. Atwood, Department of Natural Resources Science, University of Rhode Island, 1 Greenhouse Rd, Kingston, RI 02881, USA Laura A. Meyerson, Department of Natural Resources Science, University of Rhode Island, 1 Greenhouse Rd, Kingston, RI 02881, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The success or failure of species introductions is linked to their location, date, size, and frequency. However, reliance on synthetic works to identify and quantify these factors can lead to errors if original sources are misinterpreted or misquoted. Furthermore, information cannot be verified if authors fail to cite their sources and repetition may lead to compounded errors that have implications for studies of invasion patterns and processes. Naturalized populations of mute swans ( Cygnus olor ) in the Atlantic Flyway, for example, are repeatedly attributed to two large introductions in New York State. Tracing this belief back to original reports and using additional historical records, this inquiry investigates the first introductions of mute swans in New York State and presents evidence for three initial sites. Newspapers are also recommended as a newly searchable archive of species introduction records. Content Type Journal Article Pages 1-5 DOI 10.1007/s10530-011-0007-x Authors Chelsea L. Teale, Geography Department, The Pennsylvania State University, 302 Walker Building, University Park, PA 16801, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Invasive species are one of most significant factors in human-influenced global change. Management actions that prevent the spread and impacts of invasive species require knowledge of their ecological and genetic characteristics. The genetic characteristics of the invasive wine raspberry, Rubus phoenicolasius Maxim. (Rosaceae) and the native sawtooth blackberry, Rubus argutus Link, were examined in two forest habitats on the Maryland Coastal Plain. Using inter-simple sequence repeat (ISSR) markers we quantified the genetic diversity of both species. We analyzed genetic diversity using analysis of molecular variance (AMOVA) and found less genetic diversity in the invasive species, R. phoenicolasius, with variation between sites was 0.418 between sites and 0.075 within sites as compared to the native, R. argutus, where the variation between sites was 1.538 and 0.370 within sites. The lower genetic diversity in the invasive may be due to a history of limited introductions or frequent self-fertilization and clonal reproduction. Content Type Journal Article Pages 1-4 DOI 10.1007/s10530-011-0012-0 Authors Anne F. Innis, Department of Biology, University of Maryland, College Park, MD 20742, USA Irwin N. Forseth, Department of Biology, University of Maryland, College Park, MD 20742, USA Dennis F. Whigham, Smithsonian Environmental Research Center, Edgewater, MD 21037, USA Melissa K. McCormick, Smithsonian Environmental Research Center, Edgewater, MD 21037, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Invasive species often have dramatic negative effects that lead to the deterioration and loss of biodiversity frequently coupled with the burden of expensive biocontrol programs and subversion of socioeconomic stability. The fauna and flora of oceanic islands are particularly susceptible to invasive species and the increase of global movements of humans and their products since WW II has caused numerous anthropogenic translocations and increased the ills of human-mediated invasions. We use a multi-locus genomic dataset to identify geographic origin, pace, pattern and historical process of an invasive scincid lizard ( Carlia ) that has been inadvertently introduced to Guam, the Northern Marianas, and Palau. This lizard is of major importance as its introduction is thought to have assisted in the establishment of the invasive brown treesnake ( Boiga irregularis ) on Guam by providing a food resource. Our findings demonstrate multiple waves of introductions that appear to be concordant with movements of Allied and Imperial Japanese forces in the Pacific during World War II. Content Type Journal Article Pages 1-17 DOI 10.1007/s10530-011-0014-y Authors Christopher C. Austin, Department of Biological Sciences, Museum of Natural Science, 119 Foster Hall, Louisiana State University, Baton Rouge, LA 70803-3216, USA Eric N. Rittmeyer, Department of Biological Sciences, Museum of Natural Science, 119 Foster Hall, Louisiana State University, Baton Rouge, LA 70803-3216, USA Lauren A. Oliver, Department of Biological Sciences, Museum of Natural Science, 119 Foster Hall, Louisiana State University, Baton Rouge, LA 70803-3216, USA John O. Andermann, Department of Biological Sciences, Museum of Natural Science, 119 Foster Hall, Louisiana State University, Baton Rouge, LA 70803-3216, USA George R. Zug, Department of Vertebrate Zoology, National Museum of Natural History, Washington, DC 20013, USA Gordon H. Rodda, USGS Fort Collins Science Center, 2150 Centre Ave., Bldg. C, Fort Collins, CO 80526, USA Nathan D. Jackson, Department of Biological Sciences, Museum of Natural Science, 119 Foster Hall, Louisiana State University, Baton Rouge, LA 70803-3216, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Dispersal is critical step in plant invasions but there is limited information about human-mediated long distance seed dispersal, including in protected areas. Seed dispersal by hikers was quantified for five invasive species (the native Acaena novae - zelandiae, and the non-native weeds Rumex acetosella Anthoxanthum odoratum, Dactylis glomerata and Festuca rubra) in part of Australia’s Kosciuszko National Park . The proportion of seeds remaining attached to trousers and socks was quantified for replicated short (150 m) and long (5,000 m) distance walks. Functions were fitted for each dataset, and parameters compared among species and between trousers and socks. Dispersal data were combined with attachment rates and the number of people undertaking walks to estimate the total number of weed seeds that might be dispersed. The power exponential function gave the best fit for the majority of datasets, indicating that detachment probability decreased with distance. Seeds of all five species were more tightly attached to socks than trousers, with some seeds still present on socks at 5,000 m. Anthoxanthum and Acaena seeds were more tightly attached to clothing than the other species. Theoretically 1.9 million seeds could be dispersed on socks or 2.4 million seeds on trousers through a season but the actual numbers are likely to be much lower because of limited weed seed at the start of the walks. Because of differences in attachment and detachment rates, seeds from Acaena were more likely to be dispersed longer distances. Long distance human-mediated seed dispersal is potentially a major cause of spread of invasive weeds into protected areas that favours some invasive species over others. Content Type Journal Article Pages 1-12 DOI 10.1007/s10530-011-0006-y Authors Catherine Marina Pickering, School of Environment, International Centre for Ecotourism Research, Griffith University, Gold Coast, QLD 4222, Australia Ann Mount, School of Environment, International Centre for Ecotourism Research, Griffith University, Gold Coast, QLD 4222, Australia Matthias C. Wichmann, Centre for Ecology and Hydrology, CEH Wallingford, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB UK James M. Bullock, Centre for Ecology and Hydrology, CEH Wallingford, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB UK Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The legume Chamaecrista fasciculata attracts ants to its extrafloral nectar (EFN) which can lead to reduced herbivory and increased fecundity for the plant. In Florida, Opuntia stricta and O. humifusa , hosts of the invasive moth Cactoblastis cactorum, are often found growing in close association with C. fasciculata . We tested the hypotheses that O. stricta and O. humifusa individuals have higher ant abundance, lower levels of herbivore damage, and increased growth when growing in close association with C. fasciculata compared with individuals not growing near the plant. We also experimentally placed C. cactorum eggsticks and pupae on Opuntia individuals to see if ant predation of these stages occurred, and if so, whether predation rates were higher on individuals growing close to C. fasciculata . Opuntia plants near C. fasciculata were less likely to be attacked by C. cactorum and had higher ant abundance than plants far from C. fasciculata . Field surveys showed that Opuntia plants near C. fasciculata had a lower proportion of cladodes with C. cactorum damage of any type. Proportions of cladodes with damage from five native herbivores were not significantly different between treatments. In addition, Opuntia individuals growing near C. fasciculata added proportionately more pads during the growing season. We found evidence of ant predation on 15.9% of C. cactorum eggsticks and 17.6% of pupae. In August and October of 2008, there was significantly more evidence of predation on eggs and pupae placed on Opuntia individuals near C. fasciculata. No effect of distance to C. fasciculata was seen in November of 2008, potentially because plants were no longer producing EFN at this time. Our finding that Opuntia plants close to C. fasciculata show reduced herbivory from invasive C. cactorum , but not from the native herbivores examined, suggests that patterns of associational resistance may be influenced by the co-evolutionary history of the organisms in question. Content Type Journal Article Pages 1-13 DOI 10.1007/s10530-011-0038-3 Authors Heather Jezorek, Department of Integrative Biology, University of South Florida, Tampa, FL, USA Peter Stiling, Department of Integrative Biology, University of South Florida, Tampa, FL, USA James Carpenter, United States Department of Agriculture, Agricultural Research Service, Crop Protection and Management Research Unit, Tifton, GA, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Several freshwater mussel species represent some of the most problematic invasive species and have considerably altered ecosystems worldwide. Their invasion potential has been partially attributed to their free-living larvae, which have a high dispersal capability. We investigated the invasion potential of Anodonta ( Sinanodonta ) woodiana , a species of East Asian unionid mussel established worldwide despite having an obligatory parasitic stage (glochidium), which must encyst on host fish. The invasion success of A. woodiana has been attributed to the success of worldwide introductions of its sympatric fish hosts. We experimentally found, however, that A. woodiana is a broad host generalist, which can complete its development on all eight fish species tested, both coinvasive and native. Subsequently, we used a data on the occurrence and relative abundance of potential hosts in river habitats in the Czech Republic to project scenarios of the effect of host availability on A. woodiana invasion. We found that host availability does not constitute a major limit for A. woodiana to colonise most aquatic habitats in Central Europe. In addition, we investigated seasonal dynamics of A. woodiana reproduction and did not detect any limitations of its reproduction by ambient water temperatures typical of a Central European lowland river. Consequently, we predict that A. woodiana may further increase the speed and range of its invasion and we discuss possible consequences to native habitats and communities, especially to the endangered species of unionid mussels. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-9989-7 Authors K. Douda, Water Research Institute T.G.M., Podbabská 30, Prague, 160 00 Czech Republic M. Vrtílek, Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, Brno, 603 65 Czech Republic O. Slavík, Water Research Institute T.G.M., Podbabská 30, Prague, 160 00 Czech Republic M. Reichard, Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, Brno, 603 65 Czech Republic Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Many highly invasive plant species have fleshy fruits which are eaten by native frugivorous animals. These frugivores play an important role in long-distance seed dispersal, and may also affect germination success. The aim of this study was to determine whether generalist frugivores enhance or decrease seed germination of invasive alien species through pulp removal or seed coat abrasion, besides serving as dispersal agents. Fruits of four fleshy-fruited invasive alien plant species, namely Solanum mauritianum , Cinnamomum camphora , Lantana camara and Psidium guajava , were fed to three generalist avian frugivorous species, which have been observed feeding on these fruits in the wild. Seed retention time was recorded as this affects dispersal distance and the duration that seeds are exposed to the effects of the gut. Seeds removed from excreta, seeds from manually de-pulped fruit, and whole fruit were planted in soil trays housed in a greenhouse. Daily germination counts were done. Seed retention times differed significantly between bird species for all fruits, except those of C. camphora. However, all frugivores had a similar effect on the germination success of seeds of S. mauritianum , L. camara and P. guajava , showing that gut retention time was not important . Germination of seeds from manually de-pulped fruits did not differ from that of ingested seeds of all plant species, suggesting that seed coat abrasion was also not important. Pulp removal resulted in significantly higher germination rates, both in the two species with larger, multi-seeded fruit ( S. mauritianum and P. guajava ), and in the two species having single-seeded fruit with waxy exocarps ( C. camphora and L. camara) . Pulp removal also resulted in significantly earlier germination of L. camara and P. guajava seeds. Therefore, frugivores not only accelerate dispersal, but also greatly enhance seed germination of all fleshy-fruited invasive alien species in this study. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0013-z Authors Lorinda A. Jordaan, School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209 South Africa Steven D. Johnson, DST-NRF Centre for Invasion Biology, School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209 South Africa Colleen T. Downs, School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209 South Africa Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Mechanisms underlying invasive species impacts remain incompletely understood. We tested the hypothesis that priority resource access by an invasive biocontrol weevil, Rhinocyllus conicus , intensifies and alters the outcome of competition with native floral herbivores over flower head resources of the non-target, native host plant Cirsium canescens , specifically with the predominant, synchronous tephritid fly Paracantha culta. Four main results emerged. First, we documented strong, asymmetric competition, with R. conicus out-competing P. culta. Second, weevil priority access to floral resources accelerated competitive suppression of P. culta. Evidence for competitive suppression with increased weevil priority included decreases in both the numbers and the total biomass of native flies, plus decreases in individual P. culta fly mass and, so, potential fitness. Third, we found evidence for three concurrent mechanisms underlying the competitive suppression of P. culta by R. conicus . Prior use of a flower head by R. conicus interfered with P. culta pre-oviposition behavior. Once oviposition occurred, the weevil also reduced fly post-oviposition performance. Preemptive resource exploitation occurred, shown by the significant effect of flower head size on the total number of insects developing and in the magnitude of R. conicus effects on P. culta. Interference also occurred, shown by a spatial shift of surviving P. culta individuals away from the preferred receptacle resources as R. conicus priority increased . Finally, fourth, using an individual-based model (IBM), we found that the competitive interactions documented have the potential for imposing demographic consequences, causing a reduction in P. culta population sizes . Thus, priority resource access by an invasive insect increased competitive impact on the predominant native insect in the invaded floral guild. This study also provides the first experimental evidence for non-target effects of a weed biological control agent on an associated native insect herbivore. Content Type Journal Article Pages 1-16 DOI 10.1007/s10530-011-0036-5 Authors S. M. Louda, School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA T. A. Rand, School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA A. A. R. Kula, School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA A. E. Arnett, School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA N. M. West, School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA B. Tenhumberg, School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Complex spatial dynamics are frequent in invasive species; analyzing distribution patterns can help to understand the mechanisms driving invasions. We used different spatial regression techniques to evaluate processes determining the invasion of the red swamp crayfish Procambarus clarkii . We evaluated four a priori hypotheses on processes that may determine crayfish invasion: landscape alteration, connectivity, wetland suitability for abiotic and biotic features. We assessed the distribution of P. clarkii in 119 waterbodies in a recently invaded area. We used spatially explicit statistical techniques (spatial eigenvector mapping, generalized additive models, Bayesian intrinsic conditional autoregressive models) within an information-theoretic framework to assess the support of hypotheses; we also analyzed the pattern of spatial autocorrelation of data, model residuals, and eigenvectors. We found strong agreement between the results of spatial eigenvector mapping and Bayesian autoregressive models. Procambarus clarkii was significantly associated with the largest, permanent wetlands. Additive models suggested also association with human-dominated landscapes, but tended to overfit data. The results indicate that abiotic wetlands features and landscape alteration are major drivers of the species’ distribution. Species distribution data, residuals of ordinary least squares regression, and spatial eigenvectors all showed positive and significant spatial autocorrelation at distances up to 2,500 m; this may be caused by the dispersal ability of the species. Our analyses help to understand the processes determining the invasion and to identify the areas most at risk where screening and early management efforts can be focused. The comparison of multiple spatial techniques allows a robust assessment of factors determining complex distribution patterns. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0032-9 Authors Matteo Elio Siesa, Dipartimento di Biologia, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy Raoul Manenti, Dipartimento di Biologia, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy Emilio Padoa-Schioppa, Dipartimento di Scienze dell’Ambiente e del Territorio, Università degli Studi di Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy Fiorenza De Bernardi, Dipartimento di Biologia, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy Gentile Francesco Ficetola, Dipartimento di Scienze dell’Ambiente e del Territorio, Università degli Studi di Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Although invasion of exotic ambrosia beetles (fungus feeders) and bark beetles (phloem feeders) (Coleoptera: Curculionidae: Scolytinae) is considered a major threat to forest health worldwide, no studies have quantitatively investigated the anthropogenic and environmental factors shaping the biogeographical patterns of invasion by these insects across large spatial scales. The primary aim of this study was to assess the relative importance of international trade and several environmental variables of the recipient region on species richness of established exotic Scolytinae. As a reference, we also evaluated the relationships between the same environmental variables and species richness of native Scolytinae. Using an information - theoretic framework for model selection and hierarchical partitioning, we evaluated the relative importance of the potential drivers of species richness of native and exotic Scolytinae in 20 European countries and the 48 contiguous continental US states. Analyses were conducted separately for ambrosia and bark beetle species. Value of imports was a strong predictor of the number of exotic Scolytinae species in both regions. In addition, in the USA, warmer and wetter climate was positively linked to increased numbers of both native and exotic ambrosia beetles. Forest heterogeneity and climatic heterogeneity and secondarily forest area were key drivers in explaining patterns of species richness for native bark beetles but not for exotic species in both regions. Our findings suggest that if current infestation levels continue on imported plants and wood packaging material, increasing international trade will likely lead to more establishments of exotic Scolytinae with concomitant negative effects on forest health in both Europe and the USA. Compared to Europe the risk of invasion appears higher in the USA, especially for ambrosia beetles in the southeastern USA where the climate appears highly suitable for exotic establishment. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0039-2 Authors Lorenzo Marini, Department of Environmental Agronomy and Crop Production, University of Padova, Viale dell’Università 16, 35020 Legnaro, Padova, Italy Robert A. Haack, Northern Research Station, USDA Forest Service, 1407 S Harrison Road, East Lansing, MI 48823, USA Robert J. Rabaglia, Forest Health Protection, USDA Forest Service, 1601N Kent Street, RPC–7, Arlington, VA 22209, USA Edoardo Petrucco Toffolo, Department of Environmental Agronomy and Crop Production, University of Padova, Viale dell’Università 16, 35020 Legnaro, Padova, Italy Andrea Battisti, Department of Environmental Agronomy and Crop Production, University of Padova, Viale dell’Università 16, 35020 Legnaro, Padova, Italy Massimo Faccoli, Department of Environmental Agronomy and Crop Production, University of Padova, Viale dell’Università 16, 35020 Legnaro, Padova, Italy Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Ants are the dominant soil faunal group in many if not most terrestrial ecosystems, and play a key role in soil structure and function. This study documents the impacts of invasion by the exotic cat’s claw creeper vine, Macfadyena unguis - cati (L.) Gentry (Bignoniaceae) on surface-situated (epigaeic) and subterranean (hypogaeic) ant communities in subtropical SE Queensland Australia where it is a major environmental weed of riparian areas, rainforest communities and remnant natural vegetation, smothering standing vegetation and causing canopy collapse. Soil ants were sampled in infested and uninfested areas at eight sites spanning both riparian and non-riparian habitats in subtropical SE Queensland. Patterns of ant species composition and functional grouping in response to patch invasion status, landscape type and habitat stratum were investigated using ANOVA and non-metric multidimensional scaling ordination. The epigaeic and subterranean strata supported markedly different ant assemblages, and ant communities also differed between riparian and non-riparian habitats. However, M . unguis - cati invasion had a surprisingly limited impact. There was a tendency for ant abundance and species richness to be lower in infested patches, and overall species composition was different between infested and uninfested patches, but these differences were relatively small, and did not occur consistently across sites. There were changes in functional group composition that conformed to known functional group responses to environmental change, but these were similarly limited and inconsistent across sites. Our study has shown that ant communities are surprisingly resilient to invasion by M . unguis - cati , and serves as a warning against making assumptions about invasion impacts based on visual appearances. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0040-9 Authors Olusegun O. Osunkoya, Department of Employment, Economic Development and Innovation, Ecosciences Precinct, Invasive Plant Science Unit, Biosecurity Queensland, GPO Box 46, Brisbane, QLD 4001, Australia Claire Polo, Ecology and Phytosanitary Sciences Laboratory, Agrocampus Ouest, 65 rue de Saint-Brieuc, CS 84215, 35 042 Rennes Cedex, France Alan N. Andersen, CSIRO, Tropical Ecosystem Research Center, PMB 44, Winnellie, NT, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The wool carder bee, Anthidium manicatum , is the most widely distributed unmanaged bee in the world. It was unintentionally introduced to North America in the late 1960s from Europe, and subsequently, into South America, New Zealand and the Canary Islands. We provide information on the local distribution, seasonal abundance and sex ratio of A. manicatum from samples collected in an intensive two-year survey across Utah, USA. Anthidium manicatum was detected in 10 of the 29 Utah counties, largely in urban and suburban settings. Combining presence-only and MaxEnt background data from literature, museum databases and new records from Utah, we constructed three species distribution models to examine the potential distribution of A. manicatum in its native Eurasian range as well as invaded ranges of North and South America. The A. manicatum model based on locality and background data from the species’ native range predicted 50% of the invasive records associated with high habitat suitability (HS ≥ 0.90). The invasive North American model predicted a much broader distribution of A. manicatum (214% increase); whereas, the South American model predicted a narrower distribution (88% decrease). The poor predictive power of the latter model in estimating suitable habitats in the invasive South American range of A. manicatum suggests that the bee may still be limited by the bioclimatic constraints associated with a novel environment. Estimates of niche similarity ( D ) between the native and invasive models find that the North America bioclimatic niche is more similar to the bioclimatic niche of the native model ( D  = 0.78), whereas the bioclimatic niche of the South America invasion is relatively dissimilar ( D  = 0.69). We discuss the naturalization of A. manicatum in North America, possibly through punctuated dispersal, the probability of suitable habitats across the globe and the synanthropy exhibited by this invasive species. Content Type Journal Article Pages 1-19 DOI 10.1007/s10530-011-0030-y Authors James P. Strange, USDA-ARS Pollinating Insects - Biology, Management and Systematics Laboratory, Utah State University, 261 BNR, Logan, UT 84322-5310, USA Jonathan B. Koch, USDA-ARS Pollinating Insects - Biology, Management and Systematics Laboratory, Utah State University, 261 BNR, Logan, UT 84322-5310, USA Victor H. Gonzalez, USDA-ARS Pollinating Insects - Biology, Management and Systematics Laboratory, Utah State University, 261 BNR, Logan, UT 84322-5310, USA Lindsay Nemelka, Biology Department, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, USA Terry Griswold, USDA-ARS Pollinating Insects - Biology, Management and Systematics Laboratory, Utah State University, 261 BNR, Logan, UT 84322-5310, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Although climate change is currently affecting the distribution of many species, insects are particularly impacted because of their high sensitivity to temperature. The pine processionary moth, Thaumetopoea pityocampa , is a forest insect extending its distribution in response to climate warming. Some pioneer colonies were recently detected far beyond the main range, near Paris and in eastern France. This study tracked the origin and pathways of these pioneer colonies through a combined use of genetic markers, measurement of female flight capabilities, and comparative analyses of the natural enemy complexes. This study also aimed to determine the establishment capability beyond the main range, considering the survival rate during two recent cold periods. The larval survival rate was higher in pioneer colonies (which behave like urban heat islands) than in main range. The flight capacity of females would not have allowed them to come from the main range or the nearest established colonies, and molecular tools further showed that individuals from at least three pioneer colonies were not assigned or similar to individuals at the edge of the main range. Egg parasitoids were absent while pupal parasitoids were present in the pioneer colonies suggesting an introduction at the pupal stage. These approaches provided strong evidence that this species has been accidentally moved near Paris and to eastern France, supporting the hypothesis of human-mediated transportation over natural dispersal. This type of dispersal was unexpected because of risks from urticating hairs and the easy detection of the species. Content Type Journal Article Pages 1-13 DOI 10.1007/s10530-011-9979-9 Authors Christelle Robinet, INRA UR633 Zoologie Forestière, 2163 avenue de la pomme de pin, CS 40001 Ardon, 45075 Orléans cedex 2, France Charles-Edouard Imbert, INRA UR633 Zoologie Forestière, 2163 avenue de la pomme de pin, CS 40001 Ardon, 45075 Orléans cedex 2, France Jérôme Rousselet, INRA UR633 Zoologie Forestière, 2163 avenue de la pomme de pin, CS 40001 Ardon, 45075 Orléans cedex 2, France Daniel Sauvard, INRA UR633 Zoologie Forestière, 2163 avenue de la pomme de pin, CS 40001 Ardon, 45075 Orléans cedex 2, France Jacques Garcia, INRA UR633 Zoologie Forestière, 2163 avenue de la pomme de pin, CS 40001 Ardon, 45075 Orléans cedex 2, France Francis Goussard, INRA UR633 Zoologie Forestière, 2163 avenue de la pomme de pin, CS 40001 Ardon, 45075 Orléans cedex 2, France Alain Roques, INRA UR633 Zoologie Forestière, 2163 avenue de la pomme de pin, CS 40001 Ardon, 45075 Orléans cedex 2, France Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    As recently as 2009 the number of introductions recorded for South Africa comprised 22 marine and estuarine species. This review aims to reassess the diversity and scale of introduced marine and estuarine species in the region. Accurate taxonomic and systematic work, broad review of historical records and new sampling surveys across selected marine habitats conducted by a team of local and international experts has effectively revealed the presence of previously misidentified, overlooked, or new introductions. A total of 86 introduced and 39 cryptogenic species are recognized, increasing known numbers four and twofold respectively within 1 year, although the current assessment is far from fully comprehensive. Additional species were revealed within the historic literature (76%), from surveys conducted post-2005 (11%) and following taxonomic resolution (13%). Temporal analyses confirmed discovery rates were increasing over time. Ship fouling and ballast water were the dominant vector pathways, accounting for 48 and 38% respectively. Spatial analyses revealed patterns of bioinvasion to be significantly higher on the west coast compared to the other coastal regions. Overall, 53% of introductions were concentrated within harbour areas with only 4 open-coast invaders detected at present. Introduced species found in the cool and warm-temperate provinces of the west and south coast mainly originated from the northern hemisphere (65%). In contrast, introductions located in the sub-tropical and tropical provinces of the east coast mainly originated from the southern hemisphere (18%), with the remaining 17% of introduced species being of unknown origin. The research approach described has proven pivotal, contributing massively toward revealing the true scale and patterns of bioinvasion for a developing region within a relatively short period of time. Content Type Journal Article Pages 1-18 DOI 10.1007/s10530-011-0016-9 Authors A. Mead, Centre for Invasion Biology, Department of Zoology, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701 South Africa J. T. Carlton, Maritime Studies Program, Williams College-Mystic Seaport, P.O. Box 6000, Mystic, CT 06355, USA C. L. Griffiths, Centre for Invasion Biology, Department of Zoology, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701 South Africa M. Rius, Centre for Invasion Biology, Department of Zoology, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701 South Africa Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The association between invasive and native species varies across spatial scales and is affected by phylogenetic relatedness, but these issues have rarely been addressed in aquatic ecosystems. In this study, we used a non-native, highly invasive species of Poaceae (tropical signalgrass) to test the hypotheses that (i) tropical signalgrass success correlates negatively with success of most native species of macrophytes at fine spatial scales, but its success correlates positively or at random with natives at coarse spatial scales, and that (ii) tropical signalgrass is less associated with native species belonging to the family Poaceae than with species belonging to other families (Darwin’s naturalization hypothesis). We used a dataset obtained at fine (0.25 m 2 ) and coarse (ca. 1,000 m 2 ) scales. The presence/absence of all species was recorded at both scales, and their biomass was also measured at the fine scale. We tested the association between tropical signalgrass biomass and individual native species with logistic regressions at the fine scale, and using the T-score index between tropical signalgrass and each native species at both scales. The likelihood of the occurrence of six species (submersed and free-floating) was negatively affected by tropical signalgrass biomass at the fine scale. T-scores showed that three species were less associated with tropical signalgrass than expected by chance, but 22 species co-occurred more than expected by chance at the coarse scale. Associations between species of Poaceae and tropical signalgrass were null at the fine scale, but were positive or null at the coarse scale. In addition to showing that spatial scale affects the patterns of association among the non-native and individual native species, our results indicate that phylogeny did not explain associations between the invasive and native macrophytes, at both scales. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-0008-9 Authors Sidinei Magela Thomaz, DBI/Nupélia/PEA, Universidade Estadual de Maringá, Maringá, 87020-900 Brazil Thaisa Sala Michelan, ICB, DE, Universidade Federal de Goiás, Goiânia, GO 74001-970, Brazil Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Genetic diversities in two cultured oyster species, Crassostrea iredalei (Faustino 1932) and Crassostrea belcheri (Sowerby 1871) were assessed using a 581-nucleotide fragment of the mtDNA cytochrome oxidase subunit 1 (CO1) gene. A total of 103 C. iredalei individuals and 120 C. belcheri from 12 populations were sampled along the coast of Malaysia. Trees of unique haplotype samples generated based on Neighbor-Joining (NJ) algorithm revealed that many individuals had been misidentified and did not cluster with their presumed species based on morphological identification. BLAST results of DNA sequences showed presence of previously unreported C. madrasensis in Peninsular Malaysian waters (98% maximum identity). The true identity of the Muar ( Crassostrea sp .) and Semporna ( Saccostrea sp. ) populations were unresolved by two BLAST search and showed less than 88% identity with other species in GenBank. Repeated analysis of these two populations using 487 bp of the mitochondrial 16S gene data showed only a maximum identity less than 97%. Hence, the identity of these specimens remains unclear. Evolutionary divergences within presumed species were 0.001–0.011 and 0.034–0.313 between species. Findings from this study have important implications for aquaculture, management and monitoring of cultured populations as well as conservation of wild oyster species in Malaysia. Content Type Journal Article Pages 1-8 DOI 10.1007/s10530-011-0009-8 Authors M. Suzana, School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia A. Mohd Lutfi, School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia A. Abdul Hadi, School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia M. N. Devakie, Fisheries Research Institute, 11960 Batu Maung, Penang, Malaysia M. N. Siti Azizah, School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Predictive tools for preventing introduction of new species with high probability of becoming invasive in the U.S. must effectively distinguish non-invasive from invasive species. The Australian Weed Risk Assessment system (WRA) has been demonstrated to meet this requirement for terrestrial vascular plants. However, this system weights aquatic plants heavily toward the conclusion of invasiveness. We evaluated the accuracy of the WRA for 149 non-native aquatic species in the U.S., of which 33 are major invaders, 32 are minor invaders and 84 are non-invaders. The WRA predicted that all of the major invaders would be invasive, but also predicted that 83% of the non-invaders would be invasive. Only 1% of the non-invaders were correctly identified and 16% needed further evaluation. The resulting overall accuracy was 33%, dominated by scores for invaders. While the overall accuracy increased to 57% when the points assigned to aquatic life forms were removed, 57% of the non-invaders required further evaluation rather than were identified as having low probability of naturalizing. Discrimination between non-invaders and invaders would require an increase in the threshold score from the standard of 6 for this system to 19. That higher threshold resulted in accurate identification of 89% of the non-invaders and over 75% of the major invaders. Either further testing for definition of the optimal threshold or a separate screening system will be necessary for accurately predicting which freshwater aquatic plants are high risks for becoming invasive. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0002-2 Authors Doria R. Gordon, The Nature Conservancy and Department of Biology, University of Florida, P.O. Box 118526, Gainesville, FL 32611, USA Crysta A. Gantz, Department of Biological Sciences, University of Notre Dame, P.O. Box 369, Notre Dame, IN 46556, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description: Gerard van der Velde, Sanjeevi Rajagopal, and Abraham bij de Vaate (eds): The zebra mussel in Europe Content Type Journal Article Pages 1-2 DOI 10.1007/s10530-011-0022-y Authors Anthony Ricciardi, Redpath Museum, McGill University, Montreal, QC, Canada Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Fire regimes influence and are influenced by the structure and composition of plant communities. This complex reciprocal relationship has implications for the success of plant invasions and the subsequent impact of invasive species on native biota. Although much attention has been given to the role of invasive grasses in transforming fire regimes and native plant communities, little is known about the relationship between woody invasive species and fire regime. Despite this, prescribed burning is frequently used for managing invasive woody species. In this study we review relationships between woody exotic plant invasions and fire in invaded ecosystems worldwide. Woody invaders may increase or decrease aspects of the fire regime, including fire frequency, intensity and extent. This is in contrast to grass invaders which almost uniformly increase fire frequency. Woody plant invasion can lead to escape from a grass-fire cycle, but the resulting reduction in fire frequency can sometimes lead to a cycle of rare but more intense fires. Prescribed fires may be a useful management tool for controlling woody exotic invaders in some systems, but they are rarely sufficient to eliminate an invasive species, and a dearth of controlled experiments hampers evaluation of their benefits. Nevertheless, because some woody invaders have fuel properties that differ substantially from native species, understanding and managing the impacts of woody invaders on fire regimes and on prescribed burns should become an important component of resource and biodiversity management. Content Type Journal Article Pages 1-13 DOI 10.1007/s10530-011-0001-3 Authors Lisa Mandle, Botany Department and Ecology, Evolution and Conservation Biology Program (EECB), University of Hawai‘i at Mānoa, Honolulu, HI, USA Jennifer L. Bufford, Botany Department and Ecology, Evolution and Conservation Biology Program (EECB), University of Hawai‘i at Mānoa, Honolulu, HI, USA Isabel B. Schmidt, Botany Department and Ecology, Evolution and Conservation Biology Program (EECB), University of Hawai‘i at Mānoa, Honolulu, HI, USA Curtis C. Daehler, Botany Department and Ecology, Evolution and Conservation Biology Program (EECB), University of Hawai‘i at Mānoa, Honolulu, HI, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Marine anthropogenic structures offer novel niches for introduced species but their role in the subsequent invasion to natural habitats remains unknown. Upon arrival in new environments, invaders must overcome biotic resistance from native competitors and predators if they are to establish successfully in natural habitats. We tested the hypotheses that (1) artificial structures (e.g., suspended aquaculture installations) present a niche opportunity for invasive species by providing a refuge from native benthic predators, and (2) native predators in natural benthic habitats suppress successful colonization by invaders. A recruitment experiment showed that the ascidians Pyura chilensis (native) and Ciona intestinalis (invasive) could recruit to both suspended artificial structures and natural benthic habitats. Ciona , however, was only able to establish adult populations on artificial structures. In natural benthic habitats Ciona only recruited and grew in predator-exclusion cages, because without this protection predation prevented its establishment. In predation experiments, native invertebrate and fish predators removed all invasive ascidians (recruits and adults) in benthic habitats, which contrasted with the high adult survival of the native ascidian P. chilensis. The refuge from a number of benthic predators facilitates the establishment of large populations of invasive species on suspended structures. We present a conceptual model of the invasion processes that includes the anthropogenic structures as a transitional stepping-stone that facilitates invasion by enhancing and prolonging propagule supply to surrounding natural communities. Those established invaders might then overcome biotic resistance during time periods when populations of consumers or competitors are weakened by natural or anthropogenic disturbances. Our results suggest that the conservation of natural habitats with a high diversity of native predators can be an effective means to prevent the spread of invasive species growing on suspended structures. Content Type Journal Article Pages 1-12 DOI 10.1007/s10530-011-0018-7 Authors C. P. Dumont, Facultad Ciencias del Mar, Universidad Católica del Norte, and Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Larrondo 1281, Coquimbo, Chile C. F. Gaymer, Facultad Ciencias del Mar, Universidad Católica del Norte, and Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Larrondo 1281, Coquimbo, Chile M. Thiel, Facultad Ciencias del Mar, Universidad Católica del Norte, and Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Larrondo 1281, Coquimbo, Chile Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The primary ecological impact of invasive cane toads ( Rhinella marina ) in Australia is mediated by their powerful toxins, which are fatal to many native species. Toads use roads as invasion corridors and feeding sites, resulting in frequent road-kills. The flattened, desiccated toad carcasses remain highly toxic despite being heated daily to 〉40°C for many months during the tropical dry-season. In controlled laboratory experiments, native tadpoles ( Cyclorana australis, Litoria rothii ), fishes ( Mogurnda mogurnda ) and leeches (Family Erpobdellidae) died rapidly when we added fragments of sun-dried toad to their water, even if the native animals had no physical access to the carcass. Given the opportunity, native tadpoles and fishes strongly avoided the vicinity of dried toad fragments. Hence, long-dead toads may contaminate roadside ponds formed by early wet-season rains and induce avoidance and/or mortality of native anuran larvae, fishes and invertebrates. Our studies show that the toxicity of this invasive species does not end with the toad’s death, and that methods for disposing of toad carcasses (e.g., after culling operations) need to recognize the persistent danger posed by those carcasses. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-0031-x Authors Michael Crossland, School of Biological Sciences A08, University of Sydney, Sydney, NSW 2006, Australia Gregory Brown, School of Biological Sciences A08, University of Sydney, Sydney, NSW 2006, Australia Richard Shine, School of Biological Sciences A08, University of Sydney, Sydney, NSW 2006, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The gypsy moth is considered one of the most harmful invasive forest insects in North America. It has been suggested that gypsy moth may indirectly impact native caterpillar communities via shared parasitoids. However, the impact of gypsy moth on forest insect food webs in general remains unstudied. Here we assess such potential impacts by surveying forest insect food webs in Ontario, Canada. We systematically collected caterpillars using burlap bands at sites with and without histories of gypsy moth outbreak, and then reared these caterpillars until potential parasitoid emergence. This procedure allowed us to generate quantitative food webs describing caterpillar-parasitoid interactions. We estimated the degree of parasitoid sharing between gypsy moth and native caterpillars. We also statistically modeled the effect of gypsy moth outbreak history and current gypsy moth abundance on standard indices of quantitative food web structure and the diversity of parasitoid communities. Rates of gypsy moth parasitism were very low and gypsy moth shared very few parasitoids with native caterpillars, suggesting limited potential for indirect interactions. We did not detect any significant effects of gypsy moth on either food web structure or parasitoid diversity, and the small amount of parasitoid sharing strongly implies that this lack of significance is not merely due to low statistical power. Our study suggests that gypsy moth has limited impact on native host-parasitoid food webs, at least for species that use burlap bands. Our results emphasize that extrapolations of theoretical and experimental conclusions on the impacts of invasive species should be tested in natural settings. Content Type Journal Article Pages 1-16 DOI 10.1007/s10530-011-9999-5 Authors Laura L. Timms, Faculty of Forestry, University of Toronto, 33 Willcocks Street, Toronto, ON M5S 3B3, Canada Steven C. Walker, Département de Sciences Biologiques, Université de Montréal, P.O. Box 6128, Station Centre-Ville, Montreal, QC H3C 3J7, Canada Sandy M. Smith, Faculty of Forestry, University of Toronto, 33 Willcocks Street, Toronto, ON M5S 3B3, Canada Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    We record here the invasion of the African sharp-tooth catfish Clarias gariepinus in the South China biodiversity hotspot, an area rich in endemic and endangered fish fauna. C. gariepinus was introduced into the natural systems as escapees from aquaculture ponds. These catfishes are very large, top predators, and thus have the potential to cause serious threats to the native fish fauna. The impact of C. gariepinus needs more investigation with emphasis on developing techniques for controlling its dispersal. Content Type Journal Article Pages 1-5 DOI 10.1007/s10530-011-0004-0 Authors K. V. Radhakrishnan, Key Laboratory of Ecology and Environment Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, 510631 Guangzhou, People’s Republic of China Zhao Jun Lan, Key Laboratory of Ecology and Environment Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, 510631 Guangzhou, People’s Republic of China Jun Zhao, Key Laboratory of Ecology and Environment Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, 510631 Guangzhou, People’s Republic of China Ning Qing, Key Laboratory of Ecology and Environment Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, 510631 Guangzhou, People’s Republic of China Xio Lin Huang, Key Laboratory of Ecology and Environment Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, 510631 Guangzhou, People’s Republic of China Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Species introductions in freshwater ecosystems are often complex processes, yet an understanding of the nature of the introduction can inform management and conservation actions. The greenside darter ( Etheostoma blennioides ), until recently a species of special concern, expanded its Canadian range and is now common and widespread in the Grand River watershed (GRW). This is despite there being no evidence of greenside darter in the GRW prior to 1990. The goal of this study was to genetically characterize the GRW greenside darter introduction. Greenside darter were sampled in the GRW, the three known native watersheds in Canada, and one site from Ohio. We measured genetic diversity and population structure, and tested for population bottlenecks using eight microsatellite loci. Genotype assignment was used to identify possible introduction sources. Populations in the GRW showed similar genetic diversity to native watershed populations with no evidence for recent or historical population bottlenecks. Genotype assignment showed that one of the Canadian watersheds and the Ohio site were not potential sources of the GRW greenside darter, whereas the Thames River watershed was the most likely source. Substantial population genetic structure exists among the sample sites in the GRW. Clearly, the current widespread and abundant distribution of the greenside darter in the GRW is not the result of recent expansion of an existing native population, but rather multiple introductions into at least three sites in the GRW, followed by rapid population growth. Although the GRW E. blennioides is introduced, it harbours considerable genetic diversity and represents an important northern range extension for this species. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-9996-8 Authors Courtney L. Beneteau, Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Ave., Windsor, ON N9B 3P4, Canada Ryan P. Walter, Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Ave., Windsor, ON N9B 3P4, Canada Nicholas E. Mandrak, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, 867 Lakeshore Road, Burlington, ON L7R 4A6, Canada Daniel D. Heath, Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Ave., Windsor, ON N9B 3P4, Canada Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    We quantified the effects of exotic annual grass invasion on the ground-layer structure of grassy eucalypt woodlands, with the aim of determining if weed invasion decreased gap size and plant basal area leading to reduced spatial heterogeneity. We measured plant density, distance between plants and basal plant area in woodland sites which ranged from zero to 100% exotic plant cover in the ground-layer. The ground-layer in uninvaded woodlands was heterogeneous, with a large variation in basal plant area and distance between plants. Exotic annual grass density was positively correlated with total plant density, whereas native plant density was negatively correlated. Total plant basal area decreased as total plant density increased, with a lower total plant area in exotic dominated transects compared to native dominated. Variation in basal plant area decreased with increasing plant density. Exotic annual grasses were more closely spaced together (smaller gap size) and had a smaller basal area than the native grasses and rushes. There was also less variation in basal area and gap size with individual exotic annual grasses compared to the native grasses. Inter-plant distance was greater for both the native and exotic grasses when they had native grasses neighbouring them instead of exotic grasses. These findings show that woodlands invaded by exotic annual grasses have relatively less spatial heterogeneity in the ground-layer. These results have implications for other aspects of perennial grassy ecosystems invaded by annual grasses, including plant recruitment and restoration strategies. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-9997-7 Authors Elizabeth A. Lindsay, CSIRO Entomology, GPO BOX 1700, Canberra, ACT 2601, Australia Saul A. Cunningham, CSIRO Entomology, GPO BOX 1700, Canberra, ACT 2601, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Antarctica’s severe climate and its geographical isolation are the factors that hinder the arrival of non-native species by natural means. However, the movement of people and cargo associated with national scientific programs and tourism render Antarctica much more accessible to exotic organisms. Both the transport routes and carriers are varied. The wide range of uses to which timber is put means that it is readily freighted to Antarctic stations. However, it can harbor numerous alien organisms. All the timber materials transported to the “Arctowski” station for the 32nd Polish Antarctic Expedition in the 2007/2008 season were scanned as a potential vector for alien species. This study focuses on the non-lichenized fungi and insects which were found on the timber. Four species of perithecia-forming Ascomycota, five species of corticioid and polyporoid Basidiomycota, four unidentified basidiomycetes taxa in form of sterile mycelia, and two insects belonging to Cerambycidae, were detected. Most of these ‘hitch-hikers’ were connected with the untreated parts of the timber. Their enduring survival in harsh Antarctic conditions is regarded as highly improbable. Nevertheless, some ascocarps frequently contained vital spores, and live insect larvae and imago were found in hibernation. The results also emphasize that such organisms can be accidentally transported to Antarctica and that the elementary rules for the eventual safe transport of non-infected goods should be obeyed and respected. Content Type Journal Article Pages 1-6 DOI 10.1007/s10530-011-9991-0 Authors Piotr Osyczka, Department of Polar Research and Documentation, Institute of Botany, Jagiellonian University, Kopernika 27, 31-501 Kraków, Poland Piotr Mleczko, Department of Plant Taxonomy and Phytogeography, Institute of Botany, Jagiellonian University, Lubicz 46, 31-512 Kraków, Poland Dariusz Karasiński, Department of Mycology, W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Kraków, Poland Andrzej Chlebicki, Department of Mycology, W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Kraków, Poland Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Both invasive alien trees and agricultural conversion have major impacts on biodiversity. We studied here the comparative impact of these two types of land transformation on a wide range of surface-active arthropod species using pitfall traps, with evergreen sclerophyllous natural vegetation (fynbos) as the control. The study was in the Cape Floristic Region, a global biodiversity hotspot, where alien trees are of major concern and where vineyards replace natural fynbos vegetation. Surface-active arthropods were selected as they are species rich, relatively immobile, and occur in high abundance. We hypothesized that the impact of the two types of land cover transformation would produce similar qualitative and quantitative effects on the arthropods. We also compared the results in the transformed and natural areas with those in areas cleared of alien trees. Arthropod species richness in cleared areas was higher than in vineyards and more similar to that in natural fynbos, while alien trees had the lowest. Overall abundance scores were highest in cleared areas, closely followed by fynbos, then vineyards and lowest in alien trees. Several species were restricted to each vegetation type, including alien trees. In terms of assemblage composition, all vegetation types were significantly different, although fynbos and vineyards grouped, suggesting that vineyards have less impact on the arthropod community than do alien trees. When rare species were excluded, vineyards and cleared sites grouped, indicating some recovery but only involving those species that were common and habitat tolerant. Our results suggest that vineyards retain a greater complement of indigenous species than alien trees, but that clearing of these aliens soon encourages establishment of indigenous species. Although there were significant differences in soil moisture and litter depth within and between vegetation types, we did not record them as significantly affecting species richness or abundance, even in alien vegetation, an encouraging sign for restoration. Content Type Journal Article Pages 1-13 DOI 10.1007/s10530-011-9994-x Authors Rembu N. Magoba, Department of Conservation Ecology and Entomology, and Centre for Invasion Biology, University of Stellenbosch, P/Bag X1, Matieland, 7602 South Africa Michael J. Samways, Department of Conservation Ecology and Entomology, and Centre for Invasion Biology, University of Stellenbosch, P/Bag X1, Matieland, 7602 South Africa Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Post-establishment spread of invasive species is a major determinant of their impact, but the spatial pattern and temporal rhythm of secondary spread are often poorly known or understood. Here we examine the spread of the European rockweed Fucus serratus over 1,500 km of shoreline after its initial discovery in Pictou, Nova Scotia (Canada) in 1868. Building upon earlier periodic surveys, we document the current distribution of this invader and provide a historic analysis of the invasion, including the integration of the recently-detected multiple introductions from Europe. The initial spread was rapid in the southern Gulf of St. Lawrence (6.0 km year −1 ), likely due to both natural spread in a favorable environment and the extensive regional shipping traffic at the time which linked Pictou to several key ports in eastern Canada and northeast USA. Later spread, especially along the Atlantic coast of Nova Scotia, was slower (recently 0.9 km year −1 ), but included several major jumps (~50–500 km), undoubtedly due to human-mediated transport. Although the spatial extent of the invasion has increased over the past 140 years, it has experienced several remarkable events: apparent local extinctions of northern satellite populations, a major retraction (100–150 km) along the northwestern limits of its continuous range, and stalled invasions at several points and times during its southward progression. Distributional data suggest that this invader is excluding congeners in shallow zones and possibly kelp species in deeper zones. Genetic data from one contact zone showed hybridization with native F. distichus but no evidence for introgression in migrating F. serratus . Hybridization and several other reproductive traits likely contribute to the competitive dominance of the invader in this environment. Content Type Journal Article Pages 1-19 DOI 10.1007/s10530-011-9976-z Authors Ladd E. Johnson, Département de biologie and Québec-Océan, Université Laval, Québec, QC G1V 0A6, Canada Susan H. Brawley, School of Marine Sciences, University of Maine, Orono, ME 04469, USA Walter H. Adey, MRC-166/Botany, Smithsonian Institution, Washington, DC 20013, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The wide knowledge gaps in invasion biology research that exist in the developing world are crucial impediments to the scientific management and global policymaking on biological invasions. In an effort to fill such knowledge gaps, we present here an inventory of the alien flora of India, based on systematic reviews and rigorous analyses of research studies (ca. 190) published over the last 120 years (1890–2010 AD), and updated with field records of the last two decades. Currently, the inventory comprises of 1,599 species, belonging to 842 genera in 161 families, and constitutes 8.5% of the total Indian vascular flora. The three most species-rich families are Asteraceae (134 spp.), Papilionaceae (114 spp.) and Poaceae (106 spp.), and the three largest genera are Eucalyptus (25 spp.), Ipomoea (22 spp.), and Senna (21 spp.). The majority of these species (812) have no report of escaping from cultivation. Of the remaining subset of 787 species, which have either escaped from intentional cultivation, or spread after unintentional introduction, casuals are represented by 57 spp., casual/naturalised by 114 spp., naturalised by 257 spp., naturalised/invasive by 134 spp., and invasive by 225 spp. Biogeographically, more than one-third (35%) of the alien flora in India has its native ranges in South America, followed by Asia (21%), Africa (20%), Europe (11%), Australia (8%), North America (4%); and cryptogenic (1%). The inventory is expected to serve as the scientific baseline on plant invasions in India, with implications for conservation of global biodiversity. Content Type Journal Article Pages 1-15 DOI 10.1007/s10530-011-9981-2 Authors Anzar A. Khuroo, Department of Botany, Centre for Biodiversity and Taxonomy, University of Kashmir, Srinagar, 190 006 Jammu and Kashmir, India Zafar A. Reshi, Department of Botany, Biological Invasions Laboratory, University of Kashmir, Srinagar, 190 006 Jammu and Kashmir, India Akhtar H. Malik, Department of Botany, Centre for Biodiversity and Taxonomy, University of Kashmir, Srinagar, 190 006 Jammu and Kashmir, India Ewald Weber, Institute of Biochemistry and Biology, Biodiversity Research, University of Potsdam, Maulbeerallee 1, 14469 Potsdam, Germany Irfan Rashid, Department of Botany, Government College Baramulla, Baramulla, 193 101 Jammu and Kashmir, India G. H. Dar, Department of Botany, Centre for Biodiversity and Taxonomy, University of Kashmir, Srinagar, 190 006 Jammu and Kashmir, India Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The emerald ash borer ( Agrilus planipennis , Coleoptera: Buprestidae) is a wood-boring invasive pest devastating North American ash ( Fraxinus spp.). A. planipennis overwinters primarily as a freeze-avoiding prepupa within the outer xylem or inner bark of the host tree. The range of this species is expanding outward from its presumed introduction point in southwestern Michigan. We hypothesized that loss of cold tolerance in response to mid-winter warm spells could limit survival and northern distribution of A. planipennis . We determined whether winter-acclimatised A. planipennis prepupae reduced their cold tolerance in response to mid-winter warm periods, and whether this plasticity was reversible with subsequent cold exposure. Prepupae subjected to mid-winter warm spells of 10 and 15°C had increased supercooling points (SCPs) and thus reduced cold tolerance. This increase in SCP was accompanied by a rapid loss of haemolymph cryoprotectants and the loss of cold tolerance was not reversed when the prepupae were returned to −10°C. Exposure to temperatures fluctuating from 0 to 4°C did not reduce cold hardiness. Only extreme warming events for several days followed by extreme cold snaps may have lethal effects on overwintering A. planipennis populations. Thus, distribution in North America is likely to be limited by the presence of host trees rather than climatic factors, but we conclude that range extensions of invasive species could be halted if local climatic extremes induce unidirectional plastic responses. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-9988-8 Authors Stephanie Sobek-Swant, Department of Biology, The University of Western Ontario, London, ON, Canada Jill C. Crosthwaite, Department of Biology, The University of Western Ontario, London, ON, Canada D. Barry Lyons, Great Lakes Forestry Centre, Sault Ste., Marie, ON, Canada Brent J. Sinclair, Department of Biology, The University of Western Ontario, London, ON, Canada Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    To better understand the competitive processes involved in invasion by congeners, we examine coexistence patterns of two invasive species, Carduus nutans and C. acanthoides, at three spatial scales. A roadside survey of 5 × 5 km blocks in a previously identified overlap zone provided information about the regional scale. At smaller scales, we surveyed four fields of natural co-occurrence, quantifying the spatial patterns at the field scale by randomly placed 1 × 1 m quadrats and at the smallest scale by detailing plant position within the quadrats. The patterns observed are strikingly different at the different scales. At the regional scale, there is positive local autocorrelation in both species but negative cross-correlation between them, consistent with previous surveys. However, at the field scale, there is positive local autocorrelation in both species, and we generally see a positive association between the two species. At the plot scale, when excluding areas of joint absence, there is again a negative association between the two species. This pattern can also be seen at the field scale when excluding plots with joint absence. These results suggest that, at the scale of a field, the strongest factor determining location is aggregation in favorable habitats, which is a stronger force than the competition-induced segregation evidenced at small scales. Lottery competition for spatially aggregated safe sites thus appears to drive the patterns observed at the field scale, while the regional scale pattern may be a result of restricted natural dispersal and invasion history. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-9992-z Authors Emily S. J. Rauschert, IGDP in Ecology and Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, PA 16802, USA Katriona Shea, IGDP in Ecology and Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA Ottar N. Bjørnstad, IGDP in Ecology and Departments of Entomology and Biology, The Pennsylvania State University, University Park, PA 16802, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Garlic mustard’s ( Alliaria petiolata , Brassicaceae) invasive success is attributed in part to its release of allyl isothiocyanate (AITC) into the soil. AITC can disrupt beneficial arbuscular mycorrhizal fungi (AMF) associated with native plant roots, which limits their soil resource uptake. However, AITC and its precursor, sinigrin, have never been detected in garlic mustard-invaded forest soils. Here, we use high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC–MS) to assess the concentration and bioactivity of these putative allelochemicals in paired forest plots uninvaded or invaded by garlic mustard. Our methods detected AITC and sinigrin only where garlic mustard was present and our recovery of AITC/sinigrin coincided with adult senescence. A bioassay of in situ fungal hyphae abundance revealed significantly reduced hyphal abundance in the presence of garlic mustard relative to uninvaded soils. Finally, the lowest concentration of AITC measured in the field (~0.001 mM) is highly inhibitory to the spore germination of a forest AMF species, Glomus clarum . Together, our data provide the first direct evidence of garlic mustard-produced sinigrin and AITC in forest soils and demonstrate that even low levels of these chemicals have the potential to significantly suppress AMF growth and spore germination, strengthening their status as allelopathic novel weapons. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-9986-x Authors Aaron Cantor, Department of Biological Sciences, 4249 Fifth Avenue, University of Pittsburgh, Pittsburgh, PA 15260, USA Alison Hale, Department of Biological Sciences, 4249 Fifth Avenue, University of Pittsburgh, Pittsburgh, PA 15260, USA Justin Aaron, Department of Biological Sciences, 4249 Fifth Avenue, University of Pittsburgh, Pittsburgh, PA 15260, USA M. Brian Traw, Department of Biological Sciences, 4249 Fifth Avenue, University of Pittsburgh, Pittsburgh, PA 15260, USA Susan Kalisz, Department of Biological Sciences, 4249 Fifth Avenue, University of Pittsburgh, Pittsburgh, PA 15260, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Habitat modifying species can play crucial roles in ecosystem function. Invasive engineers may assume these roles where native engineers have been lost from the system. We compared the dynamics of the foraging pits of an invasive engineer, the European rabbit ( Oryctolagus cuniculus ) with two native mammals, the greater bilby ( Macrotis lagotis ) and the burrowing bettong ( Bettongia lesueur ). Foraging pits are small surface depressions created by animals when they forage for seeds, bulbs, roots, invertebrates and fungi. We measured foraging pit density and turnover, and density and richness of plant seedlings in pits and adjacent surfaces across three landforms representing a gradient in resource availability inside (bilbies and bettongs), and outside (rabbits only) a reserve in an arid Australian shrubland over 2 years. Pits of the native engineers contained 80% more seedlings (11.2 plants m −2 ) than rabbit pits (6.22 plants m −2 ). Further, rabbit pits supported 3.6-times fewer seedlings than equivalent non-pit surfaces outside the exclosure. Only one plant species was restricted entirely to pits. The reserve had more foraging pits and greater turnover than outside, but contrary to prediction, pit effects on seedling density were no greater in the more resource-limited dunes. There were some strong temporal and landscape effects on pit density and species composition, but generally trends were similar inside and outside the reserve. Overall, despite their functional similarities, invasive rabbits created fewer pits that were less favourable patches for seedlings than those of native engineers. Our work suggests that a suite of ecosystem processes associated with fertile patch creation has potentially been lost with the extirpation of bilbies and bettongs. Content Type Journal Article Pages 1-12 DOI 10.1007/s10530-011-9987-9 Authors Alex I. James, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia David J. Eldridge, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia Terry B. Koen, Department of Environment, Climate Change and Water, P.O. Box 455, Cowra, NSW 2794, Australia Katherine E. Moseby, Arid Recovery, P.O. Box 150, Roxby Downs, SA 5725, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Invasive plant species are often found to have advantages over native species in growth-related traits, such as photosynthetic rate, in disturbed or resource-rich environments. However, resource-use efficiency, rather than opportunistic resource capture, may confer more advantages when resources are scarce. In this study, performance and functional traits of invasive and non-invasive members of the genus Pinus were contrasted under the condition of nutrient limitations. Invasive species outperformed non-invasive congeners by growing 28% faster, on average. Invasives and non-invasives did not differ in biomass allocation traits (root-weight ratio, stem-weight ratio, leaf-weight ratio, leaf area ratio, root: shoot coefficient), but invaders had thinner and/or less dense leaves, as shown by a significantly lower leaf mass per area and leaf dry mass fraction. No differences between invasives and non-invasives were apparent in area-based leaf content of nitrogen, chlorophyll, or total protein, nor did the two groups differ in how efficiently they took up nutrients (specific absorption rate per unit root mass). The trait most strongly associated with invasives’ superior performance was photosynthetic nitrogen-use efficiency. Non-invaders were more water-use efficient. The results suggests that the relative performance of invasive and non-invasive species is context-dependent. Invaders may allocate leaf nitrogen more efficiently to maximize photosynthesis and growth in nitrogen-poor soils, while non-invaders with more heavily defended leaves may have an advantage in drier areas. Rather than searching for a suite of traits that constitutes “invasiveness”, it may be necessary to identify potential invaders by traits that are most adaptive to the local resource context. Content Type Journal Article Pages 1-10 DOI 10.1007/s10530-011-9985-y Authors Virginia Matzek, Department of Environmental Studies, California State University-Sacramento, 6000 J Street, Sacramento, CA 95819, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    A number of zooplankton invasions have been linked with the movement of plants to botanical and other public gardens. Although most of these records are historical, several recent examples indicate that aquatic fauna may still be transported by plant movements among gardens, or that there are unrecognised long-standing established populations in garden ponds around the world. We sampled 40 ponds from 10 gardens, in the United Kingdom and United States, to determine whether there is a high prevalence of non-indigenous zooplankton in garden ponds that could spread more widely if provided opportunity. No non-indigenous species were recorded from any of the gardens visited. We conclude that most well-established gardens do not pose a major threat for zooplankton invasions, mainly due to the destruction of ponds and associated populations through time, which apparently occurs commonly. In addition, ponds are regularly cleaned, insecticides are used on plants that may enter the water, and small fish are frequently added to conservatory ponds, further reducing the probability of zooplankton survival. Extirpation of populations may be occurring at a greater rate than re-introduction, due to greater restrictions on movement of plants, while the increasing focus on ex-situ conservation and science rather than aesthetics by botanical gardens means that fewer aquatic plants are being moved. Content Type Journal Article Pages 1-7 DOI 10.1007/s10530-011-9984-z Authors Ian C. Duggan, Department of Biological Sciences, Centre for Biodiversity and Ecology Research, The University of Waikato, Private Bag 3105, Hamilton, New Zealand Kathryn S. Duggan, Department of Biological Sciences, Centre for Biodiversity and Ecology Research, The University of Waikato, Private Bag 3105, Hamilton, New Zealand Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Predicting the impacts of an invasive species solely by its abundance is common, yet it ignores other potentially important moderating factors. One such factor is injury. Severe injury can lead to mortality, which can directly reduce the abundance of the invader. However, more moderate, sublethal injury can also temper the impact of invasive species. Therefore, to predict impacts, it may be useful to examine not only abundance, but also moderating factors (e.g., injury) and predictors of these factors (e.g., density, size). We documented the density, injury (i.e . , limb loss), and size of two conspicuous invaders, the European green crab ( Carcinus maenas ) and the Asian shore crab ( Hemigrapsus sanguineus ), at thirty sites from Shinnecock County Park, New York to Lubec, Maine. In addition, we used a field experiment to determine how injury influenced the consumption rate of mussels ( Mytilus edulis ) by each crab species. 31.6% of all C. maenas (1,493/4,721) and 30.7% of H. sanguineus (2,003/6,523) were missing appendage(s). Of the crabs injured, 38.4% (573/1,493) and 30.5% (611/2,003) were missing cheliped(s) for C. maenas and H. sanguineus , respectively. In our experiments, cheliped loss reduced consumption of both species on M. edulis . Injured C. maenas consumed 21% fewer mussels than uninjured crabs. Injury completely eliminated mussel consumption by H. sanguineus . Previous studies have highlighted the detrimental impacts of these two invaders on native bivalve prey. While the loss of a single cheliped can greatly reduce or even eliminate the ability of C. maenas and H. sanguineus to consume M. edulis , our results suggest that injury has a relatively minor role in reducing overall population-level impacts on prey such as mussels. However, injury on an individual-level can play a role in moderating the consumptive impacts of these invaders. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-9975-0 Authors David G. Delaney, Citizen Science Institute: Marine Invasive Species Monitoring Organization, 26 Pine Ridge Way, Carver, MA 02330, USA Blaine D. Griffen, Department of Biological Sciences and Marine Science Program, University of South Carolina, Columbia, SC 29208, USA Brian Leung, Department of Biology and School of Environment, McGill University, Montreal, QC H3A 1B1, Canada Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Biological invasions are ubiquitous ecological phenomena that often impact native ecosystems. Some introduced species have evolved traits that enhance their ability to compete and dominate in recipient communities. However, it is still unknown if introduced species can evolve traits that may enhance their species interactions to fuel invasion success. We tested whether Centaurea solstitialis (yellow starthistle) from introduced populations have greater performance than native counterparts, and whether they generate more beneficial plant-soil interactions. We used common garden and plant-soil feedback experiments with soils and seeds from native Eurasian and introduced Californian populations. We found that performance of Centaurea did not differ among source genotypes , implying that the success of this invasive species is not due to evolutionary changes. However, Centaurea grew significantly larger in soils from introduced regions than from native regions, indicating a reduction in natural enemy pressure from native populations. We conclude that species interactions, not evolution, may contribute to Centaurea ’s invasion success in introduced populations. Content Type Journal Article Pages 1-9 DOI 10.1007/s10530-011-9978-x Authors Krikor Andonian, Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95064, USA José L. Hierro, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, 6300 Santa Rosa, Argentina Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The gypsy moth, Lymantria dispar (L.), is a polyphagous defoliator introduced to Medford, Massachusetts in 1869. It has spread to over 860,000 km 2 in North America, but this still only represents ¼ of its susceptible host range in the United States. To delay defoliation in the remaining susceptible host range, the government maintains a barrier zone and a quarantine, reflecting a presumption that anthropogenic factors are important in the spread of gypsy moth. We develop a model framework that relates these factors along with biophysical characteristics to a county’s susceptibility to gypsy moth invasion. We then compile a dataset for counties within 200 km of the infested area and use trap catch data from 1999 to 2007 to estimate the probability of gypsy moth presence. As expected, gypsy moth is more likely to be found close to the population front and to traps that recorded moths in the previous year. However, when controlling for these factors, our most robust finding is that the use of wood for home heating and energy is consistently positively correlated with the presence of gypsy moth. In contrast, the movement of wood products by industry, which is actively regulated by state and federal governments, is rarely correlated with the presence of gypsy moth. This is consistent with effective regulation of the movement of goods by industry, but not by the public. Our findings provide empirical support for the importance and challenge of firewood as a vector for non-native forest insects. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0027-6 Authors Kevin M. Bigsby, Department of Forestry and Natural Resources, North Carolina State University, 3120 Jordan Hall, Raleigh, NC 27695, USA Patrick C. Tobin, United States Department of Agriculture, Forest Service, Northern Research Station, 180 Canfield Street, Morgantown, WV 26505, USA Erin O. Sills, Department of Forestry and Natural Resources, North Carolina State University, 3120 Jordan Hall, Raleigh, NC 27695, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0024-9 Authors Thomas J. Stohlgren, National Institute of Invasive Species Science, US Geological Survey, Fort Collins Science Center, Fort Collins, CO 80526, USA Petr Pyšek, Institute of Botany, Academy of Sciences of the Czech Republic Průhonice, Charles University Prague, Prague, Czech Republic John Kartesz, Biota of North America Program, 9319 Bracken Lane, Chapel Hill, NC 27516, USA Misako Nishino, Biota of North America Program, 9319 Bracken Lane, Chapel Hill, NC 27516, USA Aníbal Pauchard, Laboratorio de Invasiones Biológicas, Facultad de Ciencias Forestales, Universidad de Concepción & Institute for Ecology and Biodiversity (IEB), Casilla 160-C, Concepción, Chile Marten Winter, Department of Community Ecology, Helmholtz Centre for Environmental Research-UFZ, Theodor-Lieser-Str. 4, 06120 Halle (Saale), Germany Joan Pino, Center for Ecological Research and Forestry Applications(CREAF), Autonomous University of Barcelona, 08193 Bellaterra, Spain David M. Richardson, Department of Botany and Zoology, Centre for Invasion Biology (CIB), Stellenbosch University, Private Bag X1, Matieland, 7602 South Africa John R. U. Wilson, Department of Botany and Zoology, Centre for Invasion Biology (CIB), Stellenbosch University, Private Bag X1, Matieland, 7602 South Africa Brad R. Murray, Department of Environmental Sciences, Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, P.O. Box 123, Broadway, NSW 2007, Australia Megan L. Phillips, Department of Environmental Sciences, Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, P.O. Box 123, Broadway, NSW 2007, Australia Li Ming-yang, College of Forest Resources and Environment, Nanjing Forestry University, Nanjing, 210037 Jiangsu, China Laura Celesti-Grapow, Dipartimento di Biologia Vegetale, Università La Sapienza, Piazzale Aldo Moro, 5, 00185 Rome, Italy Xavier Font, Plant Biology Department, University of Barcelona, Diagonal 645, 08028 Barcelona, Spain Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description: T. C. Boyle: When the killing’s done Content Type Journal Article Pages 1-4 DOI 10.1007/s10530-011-0026-7 Authors Daniel Simberloff, Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    This paper quantifies the impacts of two invasive species, Rapana venosa (Gastropoda, Muricidae) and Corbicula fluminea (Bivalvia, Corbiculidae), in the food web of the Río de la Plata estuary and adjacent nearshore oceanic ecosystem. We analyzed certain functional traits of these mollusks assessed by a mass balance trophic model previously constructed for the years 2005–2007. This model incorporates 37 functional groups: three marine mammals species, one coastal bird, 17 fishes, 12 invertebrates, two zooplankton, one phytoplankton, and detritus. The model also includes 5 fishing fleets operating in the area. The results showed that the two invasive species affect multiple ecosystem components both directly and indirectly. R. venosa and the whitemouth croaker, Micropogonias furnieri, exhibited a high level of niche overlap (91%), while C. fluminea exhibited a high level of niche overlap with Mytilidae (94%), which suggests in both cases high levels of competition for similar resources. R. venosa had mixed trophic impacts but exhibited a predominantly top down effect on most bivalves. R. venosa could be a threat to natural resources in the area including to the fishing fleets. C. fluminea negatively influenced phytoplankton and detritus biomass and its positive effects on higher trophic level groups suggest a central bottom-up role in the food web as a bentho-pelagic coupler. Both species had negative impacts on the five fleets modeled, showing that the effects of these invasive species could extend to the socio-economic sector. Content Type Journal Article Pages 1-9 DOI 10.1007/s10530-011-0023-x Authors Diego Lercari, Faculty of Sciences, UNDECIMAR, Iguá 4225, Montevideo, 11400 Uruguay Leandro Bergamino, Faculty of Sciences, UNDECIMAR, Iguá 4225, Montevideo, 11400 Uruguay Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Most recorded extinctions have occurred on oceanic islands, mainly as a result of introduced mammalian predators. The impact of introduced non-mammalian competitors, however, is poorly understood. The house gecko, Hemidactylus frenatus , is one of the most successful invasive reptiles and has been implicated in the decline of endemic geckos and other taxa on a number of tropical and subtropical islands. We investigated the patterns of niche utilization between the house gecko and endemic ornate day gecko, Phelsuma ornata , in Mauritius, two species which were not believed to compete because they had different diel activity periods. The dietary and temporal niche partitioning of the two species were examined in relation to seasonal invertebrate prey abundance for three seasons. Dietary overlap between the two species was least when prey abundance was lowest and temporal overlap in activity greatest. Exploitative competition was therefore inferred, whereby changes in dietary overlap were attributed to shifts in prey selection by the day, but not the house, gecko, which was hypothesized to deplete prey. The compensatory response of the day gecko may have been to increase its tendency for cannibalism, such that the smaller house gecko was indirectly responsible for population reduction of its larger competitor. This is the first study to show how an invasive nocturnal gecko may be affecting a predominantly diurnal species. Content Type Journal Article Pages 1-13 DOI 10.1007/s10530-011-0025-8 Authors Nik C. Cole, School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG UK Stephen Harris, School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG UK Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Trees act as ecosystem engineers and invasions by exotic tree species profoundly impact recipient communities. Recently, research on invasive trees has dramatically increased, enabling the assessment of general trends in tree invasion. Analysing 90 studies dealing with 45 invasive tree species, we conducted a quantitative review and a meta-analysis to estimate the relevance of eight leading hypotheses for explaining tree invasions. We also tested whether species functional traits (growth rate, density/cover, germination, biomass and survival) equally promote tree invasiveness. Overall, our results suggest that several hypotheses, linked to invasibility or invasiveness, are pertinent to explain tree invasions. Furthermore, more than one hypothesis has been supported for a given species, which indicates that multiple factors lead to the success of invasive tree species. In addition, growth rate appears to be the most efficient predictor of invasiveness for invasive trees and could thus be used as a means to identify potential alien tree invasions. We conclude that further investigations are needed to test the consistency of some hypotheses across a broader pool of invasive tree species, whilst experimental studies with the same tree species across a larger range of sites would help to reveal the full suite of factors that affect tree invasions. Content Type Journal Article Pages 1-21 DOI 10.1007/s10530-011-0015-x Authors Laurent Jean Lamarque, Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada Sylvain Delzon, UMR BIOGECO, University of Bordeaux, INRA, Talence, France Christopher James Lortie, Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Introduced species are confronted with new environments to which they need to adapt. However, the ecological success of an introduced species is generally difficult to predict, especially when hybridizations may be involved in the invasion success. In western Europe, the lake frog Pelophylax ridibundus appears to be particularly successful. A reason for this species’ success might be the presence of the invader’s genetic material prior to the introduction in the form of a hybrid between P . ridibundus and a second indigenous water frog species. These hybrids reproduce by hybridogenesis, only transmitting the ridibundus genome to gametes and backcrossing with the indigenous species (i.e. P . lessonae ). This reproductive system allows the hybrid to be independent from P . ridibundus , and allows the ridibundus genome to be more widely spread than the species itself. Matings among hybrids produce newly formed P . ridibundus offspring (N), if the genomes are compatible. Therefore, we hypothesize that hybridogenesis increases the invasiveness of P . ridibundus (1) by enhancing propagule pressure through N individuals, and/or (2) by increasing adaptation of invaders to the native water frogs’ habitat through hybrid-derived ridibundus genomes that are locally adapted. We find support for the first hypothesis because a notable fraction of N tadpoles is viable. However, in our semi-natural experiments they did not outperform ridibundus tadpoles in the native water frogs’ habitat, nor did they differ physiologically. This does not support the second hypothesis and highlights ecological constraints on the invasion. However, we cannot rule out that these constraints may fall with ongoing selection, making a replacement of indigenous species highly probable in the future. Content Type Journal Article Pages 1-15 DOI 10.1007/s10530-011-0010-2 Authors E. Luquet, CNRS, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, 69622 France C. Vorburger, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland F. Hervant, CNRS, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, 69622 France P. Joly, CNRS, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, 69622 France B. Kaufmann, CNRS, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, 69622 France D. S. Schmeller, Station d’Ecologie Experimentale du CNRS à Moulis, 09200 Saint Girons, France J. P. Léna, CNRS, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, 69622 France O. Grolet, CNRS, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, 69622 France L. Konecny, CNRS, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, 69622 France S. Plénet, CNRS, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, 69622 France Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    In fresh waters, non-native invertebrate species preferentially spread via navigation waterways, where they often dominate assemblages. Littoral habitats in navigation waterways are regularly exposed to ship-induced waves. We conducted experiments to test the effects of artificial wave exposure on the relative performance of wide-spread native and non-native species. We compared physiological and behavioural response variables (i.e. growth rate, glycogen content, feeding and swimming activity) of two amphipods (native Gammarus roeselii and non-native Dikerogammarus villosus ) and two gastropods (native Bithynia tentaculata and non-native Physella acuta ) subject to wave and control (i.e. no wave) treatment flumes across a 6-week period. Growth, and in part glycogen content (as a measure of energy storage), were significantly reduced after exposure to waves in native invertebrates, but not in non-native invertebrates. The reduction in growth may be associated with the disturbance effects of waves, such as the higher swimming activity of G. roeselii and lower food uptake of B. tentaculata . In comparison, the effective hiding behaviour observed for D. villosus and good swimming ability of P. acuta , were identified as important traits facilitating the successful colonisation of the harsh habitat conditions of littoral waterways. Our study demonstrates that artificial wave regimes may contribute significant selective pressure, thus explaining the observed dominance of non-native species in navigational waterways. The success of non-native species under the harsh hydraulic habitat conditions of these socio-economically driven ecosystems may consequently be traced directly to behavioural and/or physiological traits. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-0003-1 Authors Friederike Gabel, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany Martin T. Pusch, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany Philippa Breyer, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany Vanessa Burmester, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany Norbert Walz, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany Xavier-François Garcia, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The absence of natural enemies being keystone to the success of invasive alien plants (IAPs) can only be accepted once all the factors governing the invader and the ecosystems it invades have been established. Few studies have attempted this approach. This study reports on the relations between the invasive alien forb Campuloclinium macrocephalum (Less.) DC. (pompom weed), herbivory and the ecology of the rangelands invaded in South Africa. Eighty invaded rangelands in Gauteng Province were studied. Pompom weed herbivory was insignificant with the greatest damage being caused by native grasshoppers. Rainfall, topography and soil texture were the primary drivers of vegetation pattern. Pompom weed exhibited disturbance-mediated invasion strategies, favouring rangelands affected by non-sustainable commercial grazing practices, abandoned agricultural fields and drained wetlands. It invaded vegetation in poor condition with sward basal cover 〈19%. Weed density was exacerbated by high fire frequency. Vegetation susceptible to pompom weed was also invaded by other alien and native pasture weeds. The absence of natural enemies could give pompom weed a competitive advantage over native pioneer cohorts in disturbed rangelands, but is unlikely to increase fitness enabling its establishment in vegetation in good condition. Grazing strategies that promote the dominance of grass species adapted to frequent non-selective defoliation appear to restrict pompom weed better than degraded rangelands that are not utilised. Biotic resistance of rangelands to pompom weed invasion will be greatest in vegetation in good condition and under good management. The low abundance of pompom weed in rangelands in communal areas and fence-line contrasts in invaded and un-invaded road reserves warrants further investigation. Content Type Journal Article Pages 1-15 DOI 10.1007/s10530-011-0035-6 Authors Jeremy Goodall, Agricultural Research Council (ARC)-Plant Protection Research Institute, Private Bag X6006, Hilton, 3245 South Africa Ed T. F. Witkowski, Restoration and Conservation Biology Research Group, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg, 2050 South Africa Craig D. Morris, ARC-Animal Production Institute, C/o University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209 South Africa Lesley Henderson, Agricultural Research Council (ARC)-Plant Protection Research Institute, Private Bag X6006, Hilton, 3245 South Africa Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    A common explanation for Centaurea solstitialis invasion in California is that it occupies an “empty niche” created by the replacement of native perennial grasses by exotic annual grasses and concomitant increases in soil water availability. This hypothesis, however, cannot explain C. solstitialis invasion into perennial-dominated grasslands of central Argentina. We assessed invasibility of annual versus perennial grass communities in these regions through parallel field experiments where we created grass plots and, after one year of establishment, measured effects on water and light, and added C. solstitialis seeds in two successive trials. Additionally, we removed vegetation around naturally occurring C. solstitialis in both regions, and examined the performance of Californian and Argentinean C. solstitialis individuals when growing under common conditions simulating climate in California and Argentina. In California, both grass types offered high resistance to C. solstitialis invasion, water was generally greater under perennials than annuals, and light was similarly low beneath both types. In Argentina, invasibility was generally greater in annual than perennial plots, water was similar between groups, and light was much greater beneath annuals. Removal experiments showed that competition from annual grasses in California and perennial grasses in Argentina greatly reduce C. solstitialis performance. Additionally, Californian and Argentinean individuals did not exhibit genetic differentiation in studied traits. Our results suggest that dominant plant functional groups in both California and Argentina offer substantial resistance to C. solstitialis invasion. The success of this species might be tightly linked to a remarkable ability to take advantage of disturbance in both regions. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-0037-4 Authors José L. Hierro, CONICET-Universidad Nacional de La Pampa, 6300 Santa Rosa, La Pampa, Argentina Christopher J. Lortie, Biology Department, York University, Toronto, ON M3J 1P3, Canada Diego Villarreal, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Santa Rosa, La Pampa, Argentina María E. Estanga-Mollica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Santa Rosa, La Pampa, Argentina Ragan M. Callaway, Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description: Response to Eichiner’s Note to McGlynn’s article “Native and invasive plant interactions in wetlands and the minimal role of invasiveness” in Biological Invasions (2009) 11:1929–1939 Content Type Journal Article Pages 1-3 DOI 10.1007/s10530-011-0041-8 Authors Catherine A. McGlynn, Northeast Illinois Invasive Plant Partnership, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Dispersal is critical step in plant invasions but there is limited information about human-mediated long distance seed dispersal, including in protected areas. Seed dispersal by hikers was quantified for five invasive species (the native Acaena novae - zelandiae, and the non-native weeds Rumex acetosella Anthoxanthum odoratum, Dactylis glomerata and Festuca rubra) in part of Australia’s Kosciuszko National Park . The proportion of seeds remaining attached to trousers and socks was quantified for replicated short (150 m) and long (5,000 m) distance walks. Functions were fitted for each dataset, and parameters compared among species and between trousers and socks. Dispersal data were combined with attachment rates and the number of people undertaking walks to estimate the total number of weed seeds that might be dispersed. The power exponential function gave the best fit for the majority of datasets, indicating that detachment probability decreased with distance. Seeds of all five species were more tightly attached to socks than trousers, with some seeds still present on socks at 5,000 m. Anthoxanthum and Acaena seeds were more tightly attached to clothing than the other species. Theoretically 1.9 million seeds could be dispersed on socks or 2.4 million seeds on trousers through a season but the actual numbers are likely to be much lower because of limited weed seed at the start of the walks. Because of differences in attachment and detachment rates, seeds from Acaena were more likely to be dispersed longer distances. Long distance human-mediated seed dispersal is potentially a major cause of spread of invasive weeds into protected areas that favours some invasive species over others. Content Type Journal Article Pages 1-12 DOI 10.1007/s10530-011-0006-y Authors Catherine Marina Pickering, School of Environment, International Centre for Ecotourism Research, Griffith University, Gold Coast, QLD 4222, Australia Ann Mount, School of Environment, International Centre for Ecotourism Research, Griffith University, Gold Coast, QLD 4222, Australia Matthias C. Wichmann, Centre for Ecology and Hydrology, CEH Wallingford, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB UK James M. Bullock, Centre for Ecology and Hydrology, CEH Wallingford, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB UK Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Previous island biogeography studies have quantified species richness on the scale of entire islands rather than smaller scales relevant to plant-to-plant competitive interactions. Further, they have not accounted for density compensation. Using mainland and island sites along the New England coast, we asked two questions. First, are both richness and density lower in small-scale habitats within islands than in similar mainland habitats? Second, do differences in competitor richness and density drive post-establishment trait variation in nonnative plant species? We used field surveys and individual-based rarefaction to estimate richness and density in 100-m 2 plots and demonstrated that island sites have significantly fewer species and individuals per unit area than mainland sites. We then conducted a field study in which we removed competing neighbors from nonnative plant individuals and found that when competitors were removed, individuals in low-competition environments demonstrated a lesser increase in vegetative growth but a greater increase in reproductive effort and herbivore tolerance relative to mainland individuals whose neighbors were also removed. We found that the central concept of island biogeography, i.e., that islands host fewer species than comparable mainland habitats, can be extended to smaller-scale habitats and that this difference in competitive pressure between mainland and island habitats can act as a driver of trait variation in nonnative plants. Content Type Journal Article Pages 1-9 DOI 10.1007/s10530-011-0019-6 Authors Joshua P. Atwood, Department of Natural Resources Science, University of Rhode Island, 1 Greenhouse Rd, Kingston, RI 02881, USA Laura A. Meyerson, Department of Natural Resources Science, University of Rhode Island, 1 Greenhouse Rd, Kingston, RI 02881, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The invasion by Indo-Pacific lionfish ( Pterois volitans and P. miles ) of the western Atlantic, Caribbean and Gulf of Mexico is emerging as a major threat to coral reef communities across the region. Comparing native and introduced populations of invasive species can reveal shifts in ecology and behaviour that can accompany successful invasions. Using standardized field surveys replicated at multiple sites in Kenya and the Bahamas, we present the first direct comparisons of lionfish density, body size, biomass and behaviour between native and invaded coral reefs. We found that lionfish occur at higher densities with larger body sizes and total biomass on invaded Bahamian coral reefs than the ecologically equivalent species ( P. miles ) does on native Kenyan reefs. However, the combined average density of the five lionfish species ( Pterois miles , P. antennata , P. radiata , Dendrochirus brachypterus and D. zebra ) on Kenyan reefs was similar to the density of invasive lionfish in the Bahamas. Understanding the ecological processes that drive these differences can help inform the management and control of invasive lionfish. Content Type Journal Article Pages 1-7 DOI 10.1007/s10530-011-0020-0 Authors Emily S. Darling, Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada Stephanie J. Green, Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada Jennifer K. O’Leary, National Centre for Ecological Analysis and Synthesis, 735 State Street, Suite 300, Santa Barbara, CA 93101, USA Isabelle M. Côté, Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    This paper quantifies the impacts of two invasive species, Rapana venosa (Gastropoda, Muricidae) and Corbicula fluminea (Bivalvia, Corbiculidae), in the food web of the Río de la Plata estuary and adjacent nearshore oceanic ecosystem. We analyzed certain functional traits of these mollusks assessed by a mass balance trophic model previously constructed for the years 2005–2007. This model incorporates 37 functional groups: three marine mammals species, one coastal bird, 17 fishes, 12 invertebrates, two zooplankton, one phytoplankton, and detritus. The model also includes 5 fishing fleets operating in the area. The results showed that the two invasive species affect multiple ecosystem components both directly and indirectly. R. venosa and the whitemouth croaker, Micropogonias furnieri, exhibited a high level of niche overlap (91%), while C. fluminea exhibited a high level of niche overlap with Mytilidae (94%), which suggests in both cases high levels of competition for similar resources. R. venosa had mixed trophic impacts but exhibited a predominantly top down effect on most bivalves. R. venosa could be a threat to natural resources in the area including to the fishing fleets. C. fluminea negatively influenced phytoplankton and detritus biomass and its positive effects on higher trophic level groups suggest a central bottom-up role in the food web as a bentho-pelagic coupler. Both species had negative impacts on the five fleets modeled, showing that the effects of these invasive species could extend to the socio-economic sector. Content Type Journal Article Pages 1-9 DOI 10.1007/s10530-011-0023-x Authors Diego Lercari, Faculty of Sciences, UNDECIMAR, Iguá 4225, Montevideo, 11400 Uruguay Leandro Bergamino, Faculty of Sciences, UNDECIMAR, Iguá 4225, Montevideo, 11400 Uruguay Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    In many mid-Atlantic forests where both native and non-native earthworms exist, it is the non-native species that are the dominant component of the soil macrofauna. Few earthworm ecology studies, however, focus attention on these forest systems in order to determine the relative ecological roles and potential interactions of the native and non-native earthworms. In a series of field samplings and experimental manipulations we collected data on the effects of earthworms on below-and aboveground ecosystem processes. Earthworm abundance and the ecological processes measured were dynamic in space and time across the range of study sites. Leaf litter decay rates doubled at sites that had abundant non-native earthworms. Earthworms also altered the abundance of soil fungi, the activity of extracellular enzymes, soil respiration, and the growth of tree seedlings but the effects varied among sites depending on differences in land-use history and forest age. Red oak seedling growth was less at sites that had abundant earthworms but tulip poplar and red maple seedlings grew equally well with and without abundant earthworms. These preliminary results suggest that non-native earthworms have significant ecosystem effects, even in forests where native earthworms still occur. Land use history, however, plays an important role in determining what those effects will be, and these effects are likely to be dynamic, depending on the abundance of non-native earthworms. Content Type Journal Article Pages 1-18 DOI 10.1007/s10530-011-9959-0 Authors Katalin Szlavecz, Department of Earth and Planetary Sciences, The Johns Hopkins University, 3400 N. Charles St, Baltimore, MD 21216, USA Melissa McCormick, Smithsonian Environmental Research Center, Edgewater, MD USA Lijun Xia, Department of Earth and Planetary Sciences, The Johns Hopkins University, 3400 N. Charles St, Baltimore, MD 21216, USA Jaclyn Saunders, Smithsonian Environmental Research Center, Edgewater, MD USA Taylan Morcol, Smithsonian Environmental Research Center, Edgewater, MD USA Dennis Whigham, Smithsonian Environmental Research Center, Edgewater, MD USA Timothy Filley, Department of Earth and Atmospheric Sciences and the Purdue Climate Change Research Center, Purdue University, West Lafayette, IN USA Csaba Csuzdi, Hungarian Natural History Museum and Systematic Zoology Research Group of HAS, Budapest, Hungary Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The first record of a lionfish larva Pterois volitans (Linnaeus 1758) collected from the ichthyoplankton in the Atlantic was found within the Yucatan current off the Western Caribbean, near Cancun, Mexico. The postflexion larva measured 8 mm standard length and was collected using a neuston net aboard the NOAA Ship Gordon Gunter on April 10, 2010. Published morphological and meristic characters were initially used for identification; genetic verification using mtDNA followed. The larva showed 3 distinct pigments beneath the parietal spines that were not included in the original larval description of the species. Ageing of sagittal otoliths exhibited 15–16 daily increments indicating a possible spawn in late March. Given that adult lionfish are established along the Mesoamerican barrier reef, oceanographic patterns suggest that the likely origin of this larva may have been from the southern coast of the Mexican Caribbean to Belize or even Honduras. The Yucatan Current is a rapid means for the potential dispersal of lionfish larvae into the Gulf of Mexico and southern Florida. Content Type Journal Article Pages 1-6 DOI 10.1007/s10530-011-9968-z Authors Lourdes Vásquez-Yeomans, Departamento de Ecología y Sistemática Acuática, El Colegio de la Frontera Sur, Avenida Centenario Km 5.5, 77014 Chetumal, Quintana Roo México Laura Carrillo, Departamento de Ecología y Sistemática Acuática, El Colegio de la Frontera Sur, Avenida Centenario Km 5.5, 77014 Chetumal, Quintana Roo México Selene Morales, Departamento de Ecología y Sistemática Acuática, El Colegio de la Frontera Sur, Avenida Centenario Km 5.5, 77014 Chetumal, Quintana Roo México Estrella Malca, Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA James A. Morris, National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science, Center for Coastal Fisheries and Habitat Research, 101 Pivers Island Road, Beaufort, NC 28516, USA Thomas Schultz, Nicholas School of the Environment, Duke University Marine Laboratory, 135 Marine Lab Road, Beaufort, NC 28516, USA John T. Lamkin, National Oceanic and Atmospheric Administration National, Marine Fisheries Service, Southeast Fisheries Science Center, 75 Virginia Beach Drive, Miami, FL 33149, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The impact of biological invasions on local biodiversity is well established, but their impact on ecosystem functioning has only been sketchily documented. However, biological invasions may impede services provided by aquatic ecosystems, such as, for example, the decomposition of organic matter, a key process in most small streams. To address this question, we experimentally quantified the leaf litter breakdown activity of native and invasive amphipod species, which are keystone species in aquatic ecosystems. The breakdown rate of each species was used to estimate the potential leaf litter recycling in the Rhône and Meurthe Rivers in sites occupied solely by native species and sites dominated by invasive species. We found that invaders were not able to compensate for the activity of native species and that the replacement of native species led to a decrease of at least 66% in the rate of leaf litter recycling. Our approach provides empirical evidence of the functional impact of non-indigenous species on leaf litter recycling, using standard protocols and literature data. Content Type Journal Article Pages 1-8 DOI 10.1007/s10530-011-9969-y Authors Christophe Piscart, UMR CNRS 5023 Laboratoire Ecologie des Hydrosystèmes Fluviaux, Université de Lyon 1, Campus de La Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne, France Florian Mermillod-Blondin, UMR CNRS 5023 Laboratoire Ecologie des Hydrosystèmes Fluviaux, Université de Lyon 1, Campus de La Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne, France Chafik Maazouzi, UMR CNRS 5023 Laboratoire Ecologie des Hydrosystèmes Fluviaux, Université de Lyon 1, Campus de La Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne, France Sylvie Merigoux, UMR CNRS 5023 Laboratoire Ecologie des Hydrosystèmes Fluviaux, Université de Lyon 1, Campus de La Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne, France Pierre Marmonier, UMR CNRS 5023 Laboratoire Ecologie des Hydrosystèmes Fluviaux, Université de Lyon 1, Campus de La Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne, France Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Introduced ecosystem engineers can severely modify the functioning on invaded systems. Species-level effects on ecosystem functioning (EF) are context dependent, but the effects of introduced ecosystem engineers are frequently assessed through single-location studies. The present work aimed to identify sources of context-dependence that can regulate the impacts of invasive ecosystem engineers on ecosystem functioning. As model systems, four locations where the bivalve Ruditapes philippinarum (Adams and Reeve) has been introduced were investigated, providing variability in habitat characteristics and community composition. As a measure of ecosystem engineering, the relative contribution of this species to community bioturbation potential was quantified at each site. The relevance of bioturbation to the local establishment of the mixing depth of marine sediments (used as a proxy for EF) was quantified in order to determine the potential for impact of the introduced species at each site. We found that R. philippinarum is one of the most important bioturbators within analysed communities, but the relative importance of this contribution at the community level depended on local species composition. The net contribution of bioturbation to the establishment of sediment mixing depths varied across sites depending on the presence of structuring vegetation, sediment granulometry and compaction. The effects of vegetation on sediment mixing were previously unreported. These findings indicate that the species composition of invaded communities, and the habitat characteristics of invaded systems, are important modulators of the impacts of introduced species on ecosystem functioning. A framework that encompasses these aspects for the prediction of the functional impacts of invasive ecosystem engineers is suggested, supporting a multi-site approach to invasive ecology studies concerned with ecosystem functioning. Content Type Journal Article Pages 1-17 DOI 10.1007/s10530-011-9948-3 Authors Ana de Moura Queirós, School of Ocean Sciences, Bangor University, Menai Bridge, Isle of Anglesey, Wales, LL59 5AB UK Jan Geert Hiddink, School of Ocean Sciences, Bangor University, Menai Bridge, Isle of Anglesey, Wales, LL59 5AB UK Gareth Johnson, School of Ocean Sciences, Bangor University, Menai Bridge, Isle of Anglesey, Wales, LL59 5AB UK Henrique Nogueira Cabral, Instituto de Oceanografia, Campo Grande, 1749-016 Lisbon, Portugal Michel Joseph Kaiser, School of Ocean Sciences, Bangor University, Menai Bridge, Isle of Anglesey, Wales, LL59 5AB UK Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Predictive tools for preventing introduction of new species with high probability of becoming invasive in the U.S. must effectively distinguish non-invasive from invasive species. The Australian Weed Risk Assessment system (WRA) has been demonstrated to meet this requirement for terrestrial vascular plants. However, this system weights aquatic plants heavily toward the conclusion of invasiveness. We evaluated the accuracy of the WRA for 149 non-native aquatic species in the U.S., of which 33 are major invaders, 32 are minor invaders and 84 are non-invaders. The WRA predicted that all of the major invaders would be invasive, but also predicted that 83% of the non-invaders would be invasive. Only 1% of the non-invaders were correctly identified and 16% needed further evaluation. The resulting overall accuracy was 33%, dominated by scores for invaders. While the overall accuracy increased to 57% when the points assigned to aquatic life forms were removed, 57% of the non-invaders required further evaluation rather than were identified as having low probability of naturalizing. Discrimination between non-invaders and invaders would require an increase in the threshold score from the standard of 6 for this system to 19. That higher threshold resulted in accurate identification of 89% of the non-invaders and over 75% of the major invaders. Either further testing for definition of the optimal threshold or a separate screening system will be necessary for accurately predicting which freshwater aquatic plants are high risks for becoming invasive. Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0002-2 Authors Doria R. Gordon, The Nature Conservancy and Department of Biology, University of Florida, P.O. Box 118526, Gainesville, FL 32611, USA Crysta A. Gantz, Department of Biological Sciences, University of Notre Dame, P.O. Box 369, Notre Dame, IN 46556, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Habitat modifying species can play crucial roles in ecosystem function. Invasive engineers may assume these roles where native engineers have been lost from the system. We compared the dynamics of the foraging pits of an invasive engineer, the European rabbit ( Oryctolagus cuniculus ) with two native mammals, the greater bilby ( Macrotis lagotis ) and the burrowing bettong ( Bettongia lesueur ). Foraging pits are small surface depressions created by animals when they forage for seeds, bulbs, roots, invertebrates and fungi. We measured foraging pit density and turnover, and density and richness of plant seedlings in pits and adjacent surfaces across three landforms representing a gradient in resource availability inside (bilbies and bettongs), and outside (rabbits only) a reserve in an arid Australian shrubland over 2 years. Pits of the native engineers contained 80% more seedlings (11.2 plants m −2 ) than rabbit pits (6.22 plants m −2 ). Further, rabbit pits supported 3.6-times fewer seedlings than equivalent non-pit surfaces outside the exclosure. Only one plant species was restricted entirely to pits. The reserve had more foraging pits and greater turnover than outside, but contrary to prediction, pit effects on seedling density were no greater in the more resource-limited dunes. There were some strong temporal and landscape effects on pit density and species composition, but generally trends were similar inside and outside the reserve. Overall, despite their functional similarities, invasive rabbits created fewer pits that were less favourable patches for seedlings than those of native engineers. Our work suggests that a suite of ecosystem processes associated with fertile patch creation has potentially been lost with the extirpation of bilbies and bettongs. Content Type Journal Article Pages 1-12 DOI 10.1007/s10530-011-9987-9 Authors Alex I. James, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia David J. Eldridge, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia Terry B. Koen, Department of Environment, Climate Change and Water, P.O. Box 455, Cowra, NSW 2794, Australia Katherine E. Moseby, Arid Recovery, P.O. Box 150, Roxby Downs, SA 5725, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Invasive species are one of most significant factors in human-influenced global change. Management actions that prevent the spread and impacts of invasive species require knowledge of their ecological and genetic characteristics. The genetic characteristics of the invasive wine raspberry, Rubus phoenicolasius Maxim. (Rosaceae) and the native sawtooth blackberry, Rubus argutus Link, were examined in two forest habitats on the Maryland Coastal Plain. Using inter-simple sequence repeat (ISSR) markers we quantified the genetic diversity of both species. We analyzed genetic diversity using analysis of molecular variance (AMOVA) and found less genetic diversity in the invasive species, R. phoenicolasius, with variation between sites was 0.418 between sites and 0.075 within sites as compared to the native, R. argutus, where the variation between sites was 1.538 and 0.370 within sites. The lower genetic diversity in the invasive may be due to a history of limited introductions or frequent self-fertilization and clonal reproduction. Content Type Journal Article Pages 1-4 DOI 10.1007/s10530-011-0012-0 Authors Anne F. Innis, Department of Biology, University of Maryland, College Park, MD 20742, USA Irwin N. Forseth, Department of Biology, University of Maryland, College Park, MD 20742, USA Dennis F. Whigham, Smithsonian Environmental Research Center, Edgewater, MD 21037, USA Melissa K. McCormick, Smithsonian Environmental Research Center, Edgewater, MD 21037, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The association between invasive and native species varies across spatial scales and is affected by phylogenetic relatedness, but these issues have rarely been addressed in aquatic ecosystems. In this study, we used a non-native, highly invasive species of Poaceae (tropical signalgrass) to test the hypotheses that (i) tropical signalgrass success correlates negatively with success of most native species of macrophytes at fine spatial scales, but its success correlates positively or at random with natives at coarse spatial scales, and that (ii) tropical signalgrass is less associated with native species belonging to the family Poaceae than with species belonging to other families (Darwin’s naturalization hypothesis). We used a dataset obtained at fine (0.25 m 2 ) and coarse (ca. 1,000 m 2 ) scales. The presence/absence of all species was recorded at both scales, and their biomass was also measured at the fine scale. We tested the association between tropical signalgrass biomass and individual native species with logistic regressions at the fine scale, and using the T-score index between tropical signalgrass and each native species at both scales. The likelihood of the occurrence of six species (submersed and free-floating) was negatively affected by tropical signalgrass biomass at the fine scale. T-scores showed that three species were less associated with tropical signalgrass than expected by chance, but 22 species co-occurred more than expected by chance at the coarse scale. Associations between species of Poaceae and tropical signalgrass were null at the fine scale, but were positive or null at the coarse scale. In addition to showing that spatial scale affects the patterns of association among the non-native and individual native species, our results indicate that phylogeny did not explain associations between the invasive and native macrophytes, at both scales. Content Type Journal Article Pages 1-11 DOI 10.1007/s10530-011-0008-9 Authors Sidinei Magela Thomaz, DBI/Nupélia/PEA, Universidade Estadual de Maringá, Maringá, 87020-900 Brazil Thaisa Sala Michelan, ICB, DE, Universidade Federal de Goiás, Goiânia, GO 74001-970, Brazil Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The success or failure of species introductions is linked to their location, date, size, and frequency. However, reliance on synthetic works to identify and quantify these factors can lead to errors if original sources are misinterpreted or misquoted. Furthermore, information cannot be verified if authors fail to cite their sources and repetition may lead to compounded errors that have implications for studies of invasion patterns and processes. Naturalized populations of mute swans ( Cygnus olor ) in the Atlantic Flyway, for example, are repeatedly attributed to two large introductions in New York State. Tracing this belief back to original reports and using additional historical records, this inquiry investigates the first introductions of mute swans in New York State and presents evidence for three initial sites. Newspapers are also recommended as a newly searchable archive of species introduction records. Content Type Journal Article Pages 1-5 DOI 10.1007/s10530-011-0007-x Authors Chelsea L. Teale, Geography Department, The Pennsylvania State University, 302 Walker Building, University Park, PA 16801, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Genetic diversities in two cultured oyster species, Crassostrea iredalei (Faustino 1932) and Crassostrea belcheri (Sowerby 1871) were assessed using a 581-nucleotide fragment of the mtDNA cytochrome oxidase subunit 1 (CO1) gene. A total of 103 C. iredalei individuals and 120 C. belcheri from 12 populations were sampled along the coast of Malaysia. Trees of unique haplotype samples generated based on Neighbor-Joining (NJ) algorithm revealed that many individuals had been misidentified and did not cluster with their presumed species based on morphological identification. BLAST results of DNA sequences showed presence of previously unreported C. madrasensis in Peninsular Malaysian waters (98% maximum identity). The true identity of the Muar ( Crassostrea sp .) and Semporna ( Saccostrea sp. ) populations were unresolved by two BLAST search and showed less than 88% identity with other species in GenBank. Repeated analysis of these two populations using 487 bp of the mitochondrial 16S gene data showed only a maximum identity less than 97%. Hence, the identity of these specimens remains unclear. Evolutionary divergences within presumed species were 0.001–0.011 and 0.034–0.313 between species. Findings from this study have important implications for aquaculture, management and monitoring of cultured populations as well as conservation of wild oyster species in Malaysia. Content Type Journal Article Pages 1-8 DOI 10.1007/s10530-011-0009-8 Authors M. Suzana, School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia A. Mohd Lutfi, School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia A. Abdul Hadi, School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia M. N. Devakie, Fisheries Research Institute, 11960 Batu Maung, Penang, Malaysia M. N. Siti Azizah, School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Hydrodynamic drift modeling was used to investigate the potential dispersion of Mnemiopsis leidyi from the Bornholm Basin in the Baltic Sea where it has been observed since 2007 further to the east and north. In the brackish surface layer dispersion is mainly driven by wind, while within the halocline dispersion is mainly controlled by the baroclinic flow field and bottom topography. Model runs showed that the natural spreading via deep water currents from the Bornholm Basin towards north and east is limited by topographic features and low advection velocities. Based on the information on ranges of salinity and temperature, which limit survival and reproduction of this ctenophore within the Baltic Sea, areas have been identified where the American comb jelly, M. leidyi could potentially survive and reproduce. While, we could show that M. leidyi might survive in vast areas of the northern Baltic Sea its reproduction is prevented by low salinity (〈10 psu) and temperature (〈12°C). Thus, due to the combined effect of low salinity and temperature, it is not probable that M. leidyi could establish permanent populations in the central or northern Baltic Sea. However, it seems that in the southern parts of the Baltic Sea environmental conditions are suitable for a successful reproduction of M. leidyi . Content Type Journal Article Pages 1-14 DOI 10.1007/s10530-011-0066-z Authors Maiju Lehtiniemi, Finnish Environment Institute, Marine Research Center, P.O. Box 140, FI-00251 Helsinki, Finland Andreas Lehmann, Leibniz Institute of Marine Sciences, Duesternbrookerweg 20, 24105 Kiel, Germany Jamileh Javidpour, Leibniz Institute of Marine Sciences, Duesternbrookerweg 20, 24105 Kiel, Germany Kai Myrberg, Finnish Environment Institute, Marine Research Center, P.O. Box 140, FI-00251 Helsinki, Finland Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Reinvasions provide prime examples of source-sink population dynamics, and are a major reason for failure of eradications of invasive rats from protected areas. Yet little is known about the origins and population structure of the replacement population compared with the original one. We eradicated eight populations of ship rats from separate podocarp-broadleaved forest fragments surrounded by open grassland (averaging 5.3 ha, scattered across 20,000 ha) in rural landscapes of Waikato, New Zealand, and monitored the- re-establishment of new populations. Rats were kill-trapped to extinction during January to April 2008, and then again after reinvasion in April–May (total n = 517). Rats carrying Rhodamine B dye (n = 94), available only in baits placed 1–2 months in advance in adjacent source areas located 170–380 m (average 228 m edge to edge) away, appeared in 7 of the 8 fragments from the first day of the first eradication. The distribution of age groups, genders and proportions of reproductively mature adults (more immature juvenile males and fewer fully mature old females) was different among marked rats compared with all other rats ( P  = 0.001, n = 509); in all rats caught on days 7+ of the first eradication compared with on days 1–6 ( P  = 0.000); and in the total sample collected in fragments by trapping to and after local extinction compared with in brief, fixed-schedule sampling of populations in continuous forests ( P  = 0.000). Genotyping of 493 carcases found no significant population-level differentiation among the 8 fragments, confirming that the rats in all fragments belonged to a single dynamic metapopulation. Marked rats of both genders travelled up to 600 m in a few days. Conservation of forest fragments is compromised by the problem that ship rats cannot be prevented from rapidly reinvading any cleared area after eradication. Content Type Journal Article Pages 1-18 DOI 10.1007/s10530-011-0051-6 Authors Carolyn M. King, Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, 3240 New Zealand John G. Innes, Landcare Research, Private Bag 3127, Hamilton, 3240 New Zealand Dianne Gleeson, Ecological Genetics Laboratory, Landcare Research, Private Bag 92170, Auckland, 1142 New Zealand Neil Fitzgerald, Landcare Research, Private Bag 3127, Hamilton, 3240 New Zealand Tom Winstanley, Ecological Genetics Laboratory, Landcare Research, Private Bag 92170, Auckland, 1142 New Zealand Barry O’Brien, Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, 3240 New Zealand Lucy Bridgman, Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, 3240 New Zealand Neil Cox, Invermay Statistics Group, AgResearch, Invermay Research Centre, Puddle Alley, Private Bag 50034, Mosgiel, New Zealand Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    When new individuals from a pest species are detected after an eradication programme, it is important to determine if these individuals are survivors from the eradication attempt or reinvaders from another population, as this enables managers to adjust and improve the methodologies for future eradications and biosecurity. Rangitoto/Motutapu Islands in the Hauraki Gulf (New Zealand) had a multispecies mammalian pest eradication conducted in 2009. A year after this eradication a single stoat was trapped on the island. Using genetic population assignment we conclude that this individual was a reinvader, which probably swam a minimum distance of 3 km from the adjacent mainland. This swimming distance is greater than any previously known stoat incursions. Our results suggest that the original population on these islands was from natural dispersal rather than anthropogenic introduction and that it had some limited ongoing mixing with the mainland population. These findings highlight the invasion/reinvasion potential of stoats across large stretches of water, and will necessitate ongoing biosecurity indefinitely for these islands. The study also highlights the utility of genetic assignment techniques for assessing reinvasion, and emphasizes the need for pre-eradication genetic sampling of all pest species to enable such analyses to be carried out. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s10530-011-0113-9 Authors A. J. Veale, Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand M. N. Clout, Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand D. M. Gleeson, Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Eradicating or controlling invasive alien species has frequently had unintended consequences, such as proliferation of other invasive species or loss of ecosystem function. We explore this problem using a case study of a highly invasive floating aquatic macrophyte, water hyacinth ( Eichhornia crassipes ), in the Sacramento-San Joaquin Delta of California. We used 5 years of remote sensing data to perform change detection analysis to study plant community dynamics contemporaneous with changes in water hyacinth cover. Our results show that as water hyacinth cover decreased, submerged aquatic plant (SAP) cover increased and vice versa. This effect was strongest in large patches of water hyacinth. We found no evidence that the native floating aquatic species, pennywort ( Hydrocotyle umbellata ), benefitted from reducing cover of water hyacinth. In most years, pennywort cover either showed no trend or followed the same trajectory as water hyacinth cover. In this study a decrease in cover of water hyacinth most often resulted in colonization by SAP species with some habitat returning to open water. Content Type Journal Article Category Original Paper Pages 1-17 DOI 10.1007/s10530-011-0112-x Authors Shruti Khanna, Center for Spatial Technologies and Remote Sensing, University of California, Davis, CA, USA Maria J. Santos, Center for Spatial Technologies and Remote Sensing, University of California, Davis, CA, USA Erin L. Hestir, Center for Spatial Technologies and Remote Sensing, University of California, Davis, CA, USA Susan L. Ustin, Center for Spatial Technologies and Remote Sensing, University of California, Davis, CA, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The impact of over-abundant exotic herbivores is well recognised, but their impact at low population densities is poorly understood. This study examined interactions between European rabbits and native herbivores, and their impact on seedling recruitment in coastal South Australia, 2 years after rabbit haemorrhagic disease (RHD) had reduced rabbit density to 4.48 rabbits ha −1 . Rabbit density was further reduced to 0.44 rabbits ha −1 in replicated experimental treatments. Rabbit control reduced total grazing pressure by 39% despite compensatory grazing increases of 〉100% for both western grey kangaroos and common wombats. Rabbit control slowed the rate of grazing and mortality for planted drooping sheoak and sweet bursaria seedlings, but few survived for 12 months: 0 and 3% of sheoak, in untreated areas and rabbit control treatments, respectively, and 3 and 11% of bursaria, respectively. Planted sheoaks survived well if protected by rabbit-proof netting (60%). Within treatments, seedling grazing and survival rates were negatively correlated with rabbit density but kangaroo and wombat density had no measurable effect. We conclude that RHD may briefly have reduced rabbit densities enough to allow recruitment of bursaria but that sheoak require much lower rabbit densities than those provided by existing biological control agents. If left unaddressed, rabbit grazing could ultimately lead to the loss of sheoaks throughout most of their current range, irrespective of other attempts to conserve them. More generally, these data show how species-specific damage caused by low-density exotic herbivore populations may occur in the presence of more abundant but less-damaging native herbivores. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s10530-011-0114-8 Authors Peter Bird, Natural Resources Management Biosecurity, Biosecurity SA, GPO Box 1671, Adelaide, SA 5001, Australia Greg Mutze, Natural Resources Management Biosecurity, Biosecurity SA, GPO Box 1671, Adelaide, SA 5001, Australia David Peacock, Natural Resources Management Biosecurity, Biosecurity SA, GPO Box 1671, Adelaide, SA 5001, Australia Scott Jennings, Department of Environment and Natural Resources, GPO Box 1047, Adelaide, SA 5001, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Invasive species can transform ecological communities. Their profound effects may alter the sources and pathways of primary production. We investigated the effects of the reef forming polychaete Ficopomatus enigmaticus invasion on the biomass and distribution of estuarine macroalgae in a SW Atlantic coastal lagoon (Mar Chiquita, 37° 40′S, 57° 23′W, Argentina). Reefs built by this species serve as substrates for macroalgal development and furnish structures that modify physical and biological conditions for the surrounding benthos. We showed that (1) the red macroalga Polysiphonia subtilissima settles and grows almost exclusively on the surface of the reef, (2) the green macroalgae Cladophora sp . and Enteromorpha intestinalis are found almost exclusively in areas without reefs attached to mollusk shells and, (3) no macroalgae occur in the sediment between reefs. Manipulative experiments show that reefs provide a complex substrate for settlement and survival and therefore benefit red macroalga. These experiments also show that the invasive reef builder has negative indirect effects on green macroalgae by increasing grazing and probably by increased sedimentation between reefs. Via these direct and indirect effects, reefs change the relative biomass contribution of each macroalgal species to the overall production in the lagoon. Knowledge of these processes is important not only for predicting net effects on primary production but also because changes in macroalgal species composition may produce effects that cascade through the food web. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s10530-011-0115-7 Authors María Cielo Bazterrica, Departamento de Biología, Laboratorio de Ecología, FCEyN, Universidad Nacional de Mar del Plata (UNMDP), Casilla de Correo 573, Correo Central, B7600WAG Mar del Plata, Argentina Florencia Botto, Departamento de Biología, Laboratorio de Ecología, FCEyN, Universidad Nacional de Mar del Plata (UNMDP), Casilla de Correo 573, Correo Central, B7600WAG Mar del Plata, Argentina Oscar Iribarne, Departamento de Biología, Laboratorio de Ecología, FCEyN, Universidad Nacional de Mar del Plata (UNMDP), Casilla de Correo 573, Correo Central, B7600WAG Mar del Plata, Argentina Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    There are often lag phases in plant invasions, seemingly dormant periods between arrival in a new range and rapid population growth. Lags impede prioritization of invasive-species control efforts: when eradication is most feasible, it is often unclear whether a species is benign or a potentially harmful “sleeper weed.” I used herbarium records to estimate lag phases for invasive or potentially invasive plant species in three regions of the upper Midwest. I tested whether factors related to species’ invasion epidemiology, traits, or the habitats they invade were correlated with lag lengths. From an initial pool of 151 species, there were sufficient records to test for lags in 76 for northern Wisconsin, 90 for southern Wisconsin, and 91 for the southern Lake Michigan region. Lags were identified in 77% (197) of these 257 datasets and ranged from 3–140 years with a mean of 47.3 ± 34.6 (SD). Lags differed by native range, introduction pathway, growth form and habit, dispersal mode, flowering phenology, pollination mode for a subset of species, and breadth, light availability, and water availability of invaded habitats. However, estimated lags were highly variable and tested factors did not have strong explanatory power. Exotic species comprised an increasing proportion of total herbarium records. Of the species with known introduction pathways, 85% were intentionally introduced, mainly as ornamentals. The long durations, high variability, and low predictability of lags, along with human culpability for an increasingly non-native flora, support a cautious approach to species introductions. Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s10530-011-0119-3 Authors Daniel J. Larkin, Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Invasive crayfish are spreading rapidly across Europe, where they are replacing the native crayfish species and impacting negatively on some other biota. Freshwater crayfish and many benthic fishes share similar habitat and food requirements and hence potentially compete for resources. In this study, we investigated impacts of the introduced signal crayfish ( Pacifastacus leniusculus ) on fish in stony littoral habitats of two large boreal lakes. We compared the littoral fish community composition and the densities of two common benthic fish species between sites with and without crayfish. To evaluate whether signal crayfish share the same food resources as benthic littoral fish or change their feeding habits, we used mixing models and trophic niche estimates based on analyses of stable isotopes of carbon and nitrogen. Both the community composition of littoral fish and the densities of benthic fish species were similar at sites with and without signal crayfish. Even though stable isotope signatures indicated strong dietary overlap between crayfish and benthic fish, the use of food sources and trophic niche widths of fish were not noticeably different between crayfish sites and non-crayfish sites. Our results suggest that, at current densities, the non-native signal crayfish does not have significant impacts on benthic fish in the stony littoral habitats of large boreal lakes. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s10530-011-0118-4 Authors Timo J. Ruokonen, Department of Biological and Environmental Science, University of Jyväskylä, Finland, Survontie 9, P.O. Box 35, 40014 Jyväskylä, Finland Juha Karjalainen, Department of Biological and Environmental Science, University of Jyväskylä, Finland, Survontie 9, P.O. Box 35, 40014 Jyväskylä, Finland Mikko Kiljunen, Department of Biological and Environmental Science, University of Jyväskylä, Finland, Survontie 9, P.O. Box 35, 40014 Jyväskylä, Finland Markku Pursiainen, Finnish Game and Fisheries Research Institute, Jyväskylä Game and Fisheries Research, Survontie 9, 40500 Jyväskylä, Finland Heikki Hämäläinen, Department of Biological and Environmental Science, University of Jyväskylä, Finland, Survontie 9, P.O. Box 35, 40014 Jyväskylä, Finland Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description: D. Rotherham and R. A. Lambert (eds): Invasive and introduced plants and animals: human perceptions, attitudes and approaches to management Content Type Journal Article Category Book Review Pages 1-3 DOI 10.1007/s10530-011-0143-3 Authors Martin A. Nuñez, Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37996-1610, USA Paula G. Nuñez, Instituto de Investigaciones en Diversidad Cultural y Procesos de Cambio, CONICET, Universidad Nacional de Río Negro, Mitre 485 5to piso, R8400BNH San Carlos de Bariloche, Argentina Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    In this study we: (1) present a quantitative spatial analysis of the macrophyte communities in Lake Chini with a focus on the biogeographical distributions of the native Nelumbo nucifera and the invasive Cabomba furcata; (2) examine the environmental changes that affect plant community composition; and (3) outline a conceptual model of the variation of ecological processes that shape the macrophyte communities. Plant species cover, biomass of C. furcata and N. nucifera, and water quality and environmental variables were measured before and after monsoonal floods in September 2009 and April 2010. Permutational multivariate analysis was used to examine the significance of the invasion of C. furcata at different spatial scales. Relationships between plant species cover and environmental variables before and after flooding were examined using principal coordinates analysis and non-parametric multivariate multiple regressions. Our findings suggest that (1) Variation in plant communities was significant at the lake scale and the distribution of plant species changed after annual floods. (2) Invasion by C. furcata significantly affected the overall plant community composition. (3) C. furcata biomass increased after the monsoonal season, which indicates that C. furcata is adapted to flooding events and that it is becoming increasingly abundant. (4) In addition to the strong monsoonal effect, total depth, nutrient concentration, and sediment type were important environmental variables that significantly affected plant community composition. The macrophyte community in Lake Chini is highly dynamic. The spatial and temporal plant community dynamics are associated with flood regime, water quality, and substrate. Human-induced changes in these parameters are likely shifting the macrophyte dominance from floating-leaved to submerged species. Content Type Journal Article Category Original Paper Pages 1-16 DOI 10.1007/s10530-011-0137-1 Authors Zati Sharip, Centre for Ecohydrology, School of Environmental Systems Engineering, The University of Western Australia, Crawley, WA 6009, Australia Shon S. Schooler, Lake Superior National Estuarine Research Reserve, University of Wisconsin-Superior, Superior, WI 54880, USA Matthew R. Hipsey, Centre for Ecohydrology, School of Environmental Systems Engineering, The University of Western Australia, Crawley, WA 6009, Australia Richard J. Hobbs, School of Plant Biology, The University of Western Australia, Crawley, WA 6009, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The effects of invasive species on community structure remain under-investigated due to the lack of long-term data. Our objectives were to examine the correlation between Lantana camara L. invasion and native species abundance, distribution, diversity, and population structure, across different forest types in a heterogeneous landscape. We examined changes in native vegetation and L. camara between 1997 and 2008. We used existing vegetation data from 134 plots spread across the 540 km 2 landscape from 1997 and re-censused these plots in 2008. We then examined the change in species richness, Shannon’s diversity, evenness, and population structure of native species from 1997 to 2008. We also examined the relationship between L. camara density and species richness, diversity, evenness, and population structure. The presence and abundance of L. camara increased dramatically from 1997 to 2008. L. camara occurred in 81% of plots by 2008, compared with only 41% of plots in 1997. Similarly, the mean density of L. camara increased almost fourfold from 1997 to 2008. This was accompanied by a change in native community structure. Species richness, diversity and evenness declined significantly in some forest types, and at the landscape scale. There were also changes in the population structure of native tree species, with reductions in the density of tree saplings, possibly due to competition with L. camara . We demonstrate the pervasive threat posed by L. camara to native vegetation at the scale of individual forest types, and at the larger landscape scale, in our study area. These changes have long-term consequences for forest structure and composition. Content Type Journal Article Category Original Paper Pages 1-15 DOI 10.1007/s10530-011-0144-2 Authors Bharath Sundaram, Ashoka Trust for Research in Ecology and the Environment (ATREE), Srirampura, Jakkur Post, Bangalore, 560064 India Ankila J. Hiremath, Ashoka Trust for Research in Ecology and the Environment (ATREE), 2nd Floor, 1, K Block Commercial Complex, Birbal Road, Jungpura Extension, New Delhi, 110014 India Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Decoupling of climate and hydrology combined with introduction of non-native species creates novel abiotic and biotic conditions along highly regulated rivers. Tamarix , a non-native shrub, dominates riparian assemblages along many waterways in the American Southwest, including the Colorado River through Grand Canyon. We conducted a tree-ring study to determine the relative influences of climate and hydrology on Tamarix establishment in Grand Canyon. Riparian vegetation was sparse and annually scoured by large floods until completion of Glen Canyon Dam, which allowed pioneer species, including Tamarix , to expand. Post-dam floods in the mid-1980s were associated with high Tamarix mortality but also initiated a large establishment event. Subsequent establishment has been low but continuous with some exceptions. From 1984 to 2006 establishment increased during years of high, late-summer flows followed by years of low precipitation. This combination provided moist surfaces for Tamarix establishment and may have caused reduced erosion of seedlings or reduced competition from native plants. Attempts to mimic pre-dam floods for ecosystem restoration through planned flood releases also have affected Tamarix establishment. Early (March 1996) and late (November 2004) restoration floods limited establishment, but a small restoration flood in May 2000 followed by steady summer flows permitted widespread establishment. Flood restoration is not expected to prevent Tamarix spread in this system because historic flood timing in May–July coincides with seed release. To decrease future Tamarix establishment, river managers should avoid floods during peak Tamarix seed release, which encompasses the historic spring and early summer flooding period. Tamarix dominance may be reduced by early spring floods that initiate asexual reproduction of clonal shrubs (e.g., Salix exigua , Pluchea sericea ). Content Type Journal Article Category Original Paper Pages 1-16 DOI 10.1007/s10530-011-0139-z Authors Susan G. Mortenson, Ecology, Evolution, and Conservation Biology Program, Department of Natural Resources and Environmental Science, University of Nevada, Reno, 1000 Valley Rd. MS 186, Reno, NV 89512, USA Peter J. Weisberg, Ecology, Evolution, and Conservation Biology Program, Department of Natural Resources and Environmental Science, University of Nevada, Reno, 1000 Valley Rd. MS 186, Reno, NV 89512, USA Lawrence E. Stevens, Biology Department, Museum of Northern Arizona, Flagstaff, AZ 86001, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    There is considerable interest in understanding how invasive species disperse across landscapes, and how they affect resident species. However, quantifying these processes using mark recapture or manipulative experiments can be time consuming and costly. A different approach is to study density changes across a broader landscape, and take advantage of naturally existing replicate locations that are imperfect, but plentiful. We documented sites of recent colonization and measured density changes in the invasive gecko Hemidactylus mabouia and the prior resident gecko Hemidactylus garnotii in Florida. We surveyed geckos at 398 locations from 19 regional sites distributed across central and southern Florida. We documented changes in abundance through repeated censuses of 56 locations in areas of sympatry between 2001 and 2009. Complete displacement occurred in 〈7 years at several locations, and overall there was a 〉10% increase in H . mabouia per year. There was evidence that H . mabouia reaches a higher carrying capacity than H . garnotii , which likely contributes to its competitive dominance. Changes in relative abundance within patches were consistent with a density dependent mechanism of displacement, suggesting the decline of H . garnotii is functionally linked to increases in H . mabouia abundance, which allows us to rule out coincidental factors not directly associated with H . mabouia . However, simulations showed that even highly asymmetric differences in carrying capacity and competitive ability were not sufficient to account for the rapid displacement we observed. We conclude that mechanisms other than resource competition must be at work to drive species displacement in this system. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s10530-011-0147-z Authors Kristen Harfmann Short, Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA Kenneth Petren, Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    New Zealand mudsnails (NZMS) have spread rapidly across the globe, but little is known about mechanisms that drive their secondary spread within invaded streams. We used a field experiment to test if upstream movement is a potential mechanism of spread and how this movement is modified by flow velocity and resource availability. We found that movement direction and rates were related to flow velocity, while resource availability influenced movement frequency. In slow-flow treatments, individuals moved upstream at rates approaching 3 m/h. In fast-flow treatments, many individuals were dislodged downstream and upstream movement rates were less than 2 m/h. In low-resource treatments, individuals were more likely to move away from their initial starting locations. We suggest that upstream movement may be important in establishing new populations within local invasions and that increases in flow velocity may be an effective means to slow upstream spread. The surprisingly fast movements that we recorded predict greater distribution of NZMS within invaded streams than has actually occurred, which suggests that factors in addition to movement rate limit population spread. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s10530-011-0149-x Authors A. J. Sepulveda, US Geological Survey, Northern Rocky Mountain Science Center, Bozeman, MT 59715, USA L. B. Marczak, Department of Ecosystem and Conservation Sciences, The University of Montana, Missoula, MT 59812, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Climate change may strongly affect the abiotic conditions in riverine ecosystems, for example by changing water temperature regimes and salinisation due to sea water intrusion and evaporation. We analysed the effects of changes in water temperature and salinity on the species pool of freshwater molluscs in the river Rhine. Species sensitivity distributions (SSDs) for maximum temperature and salinity tolerance were constructed for native and non-native species that are currently present in the river Rhine. The maximum temperature tolerance was significantly higher for non-native mollusc species than native ones. For salinity tolerance, no significant difference was found between the two groups. The SSDs were used to determine the potentially not occurring fractions (PNOFs) of each species group corresponding with the yearly maximum water temperature and salinity levels recorded in (1) different river sections for the extreme warm and dry year 2003, and (2) the river Rhine at Lobith (The Netherlands) over the period 1960–2009. Changing temperature and salinity conditions in the river Rhine over the past 50 years corresponded with a net increase in PNOF for native species. This was mainly due to rising river water temperatures, which had a larger influence than decreasing salinity levels. For non-native species no change in PNOF was found, indicating that future temperature rise will disproportionally affect native mollusc species. Validation of the PNOF estimated for Lobith with the not occurring fraction (NOF) of mollusc species derived from monitoring data revealed similar trends for native as well as non-native mollusc species richness. The increase in the PNOF accounted for 14% of the increase in the NOF. The construction and application of SSDs appeared a promising approach to address the separate and combined effects of changing abiotic conditions on native and non-native species pools. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s10530-011-0148-y Authors Laura N. H. Verbrugge, Department of Environmental Science, Institute for Water and Wetland Research, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands Aafke M. Schipper, Department of Environmental Science, Institute for Water and Wetland Research, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands Mark A. J. Huijbregts, Department of Environmental Science, Institute for Water and Wetland Research, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands Gerard Van der Velde, Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands Rob S. E. W. Leuven, Department of Environmental Science, Institute for Water and Wetland Research, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Empirical support for ‘invasional meltdown’, where the presence of one invading species facilitates another and compounds negative impacts on indigenous species, is equivocal with few convincing studies. In Ireland, the bank vole was introduced 80 years ago and now occupies a third of the island. The greater white-toothed shrew arrived more recently within the invasive range of the bank vole. We surveyed the abundance of both invasive species and two indigenous species, the wood mouse and pygmy shrew, throughout their respective ranges. The negative effects of invasive on indigenous species were strong and cumulative bringing about species replacement. The greater white-toothed shrew, the second invader, had a positive and synergistic effect on the abundance of the bank vole, the first invader, but a negative and compounding effect on the abundance of the wood mouse and occurrence of the pygmy shrew. The gradual replacement of the wood mouse by the bank vole decreased with distance from the point of the bank vole’s introduction whilst no pygmy shrews were captured where both invasive species were present. Such interactions may not be unique to invasions but characteristic of all multispecies communities. Small mammals are central in terrestrial food webs and compositional changes to this community in Ireland are likely to reverberate throughout the ecosystem. Vegetation composition and structure, invertebrate communities and the productivity of avian and mammalian predators are likely to be affected. Control of these invasive species may only be effected through landscape and habitat management. Content Type Journal Article Category Original Paper Pages 1-15 DOI 10.1007/s10530-011-0142-4 Authors W. Ian Montgomery, School of Biological Sciences, Queen’s University Belfast, Belfast, BT9 7BL Northern Ireland, UK Mathieu G. Lundy, School of Biological Sciences, Queen’s University Belfast, Belfast, BT9 7BL Northern Ireland, UK Neil Reid, School of Biological Sciences, Queen’s University Belfast, Belfast, BT9 7BL Northern Ireland, UK Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Concern over exotic invasions is fueled in part by the observation that some exotic species appear to be more abundant and have stronger impacts on other species in their non-native ranges than in their native ranges. Past studies have addressed biogeographic differences in abundance, productivity, biomass, density and demography between plants in their native and non-native ranges, but despite widespread observations of biogeographic differences in impact these have been virtually untested. In a comparison of three sites in each range, we found that the abundance of Acroptilon repens in North America where it is invasive was almost twice that in Uzbekistan where it is native. However, this difference in abundance translated to far greater differences between regions in the apparent impacts of Acroptilon on native species. The biomass of native species in Acroptilon stands was 25–30 times lower in the non-native range than in the native range. Experimental addition of native species as seeds significantly increased the abundance of natives at one North American site, but the proportion of native biomass even with seed addition remained over an order of magnitude lower than that of native species in Acroptilon stands in Uzbekistan. Experimental disturbance had no long-term effect on Acroptilon abundance or impact in North America, but Acroptilon increased slightly in abundance after disturbance in Uzbekistan. In a long-term experiment in Uzbekistan, suppression of invertebrate herbivores and pathogens did not result in either consistent increases in Acroptilon biomass across years or declines in the biomass of other native species, as one might expect if the low impact of Acroptilon in the native range was due to its strong top–down regulation by natural enemies. Our local scale measurements do not represent all patterns of Acroptilon distribution and abundance that might exist at the scale of landscapes in either range, but they do suggest the possibility of fundamental biogeographic differences in the way a highly successful invader interacts with other species, differences that are not simply related to greater biomass or reduced top–down regulation of the invader in its non-native range. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s10530-011-0145-1 Authors Ragan M. Callaway, Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA Urs Schaffner, CABI Europe—Switzerland, Rue des Grillons 1, 2800 Delémont, Switzerland Giles C. Thelen, Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA Aloviddin Khamraev, Institute of Zoology, Uzbek Academy of Sciences, 700095 Tashkent, Uzbekistan Tangirbergen Juginisov, Institute of Zoology, Uzbek Academy of Sciences, 700095 Tashkent, Uzbekistan John L. Maron, Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Continental tropical ecosystems are generally viewed as less vulnerable to biological invasions than island ones. Their apparent resistance to invasive alien species is often attributed to their higher native biota diversity and complexity. However, with the increase of human activities and disturbances and the accelerate rate of introductions of plant species, these apparently resilient continental ecosystems are now experiencing alien plant naturalization and invasion events. In order to illustrate this emergent phenomenon, we compiled a list of all known introduced and naturalized plant species in French Guiana (Guiana Shield, South America). A total of 490 alien plants were recorded, about 34% of which are currently naturalized, mainly species belonging to the Acanthaceae and Fabaceae (Faboideae) in the Eudicotyledons, and Poaceae (grasses) and Arecaceae (palms) in the Monocotyledons. The coastal dry and wet savannas appears to be vulnerable to plant invasion (with 165 naturalized species, about 34% of the alien flora), especially by Acacia mangium (Mimosaceae) and Melaleuca quinquenervia (Myrtaceae) which are forming localized but dense monotypic stands. Both tree species, intentionnally introduced for reforestation, rehabilitation, and as garden ornamentals and have the potential to spread with increasing human disturbances The number and abundance of naturalized alien plants in the relatively undisturbed tropical lowland rainforests and savannas remains still very low. Therefore, surveillance, early detection, and eradication of potential plant invaders are crucial; moreover collaboration with neighbouring countries of the Guiana Shield is essential to prevent the introduction of potentially invasive species which are still not present in French Guiana. Content Type Journal Article Category Invasion Note Pages 1-13 DOI 10.1007/s10530-011-0129-1 Authors César Delnatte, Herbier de Guyane, Institut de Recherche pour le Développement, B.P. 165, Cayenne, French Guiana Jean-Yves Meyer, Délégation à la Recherche, Gouvernement de Polynésie française, B.P. 20981, Papeete, Tahiti, French Polynesia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    The capacity of small clonal fragments to survive and grow is a major factor in the spread of clonal plants, especially aquatic species. This study of the introduced, invasive, amphibious, stoloniferous herb Alternanthera philoxeroides in China tested the effects of fragment size, of loss of the stolon apex, and of the original position of a fragment within a clone before fragmentation on the survival and growth of fragments in a greenhouse experiment. The stolon internodes of plants consisting of one stolon with 5 ramets were severed in all 16 possible patterns, generating fragments of 1–5 ramets. These 16 fragmentation treatments were crossed with removal of the stolon apex. Fragmentation and apex removal did not affect total growth of plants, but more highly fragmented plants produced smaller, more numerous ramets. The survival of fragments consisting of one original ramet was about 85%, compared to 100% survival of fragments with 5 original ramets. Fragments consisting of the youngest ramets along the original stolon grew more than fragments of the same size that consisted of older ramets. These effects of fragmentation on growth provide new evidence for clonal integration of the rate at which connected ramets produce new ramets and novel evidence that fragments produced from different portions of clones have different potential for spread. They further suggest that detachment of small groups of distal ramets along stolons in the field might be very effective in spreading the species and that a trade-off between the number and the size of new ramets produced by fragments may represent an adaptive, plastic response to disturbance. Results do not recommend intentional fragmentation of clones as a means of controlling the rate of growth of this invasive species but suggest that incidental fragmentation may not increase its growth in mass, although it may increase its rate of spread. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s10530-011-0141-5 Authors Bi-Cheng Dong, College of Nature Conservation, Beijing Forestry University, Beijing, 100083 China Peter Alpert, Biology Department, University of Massachusetts, Amherst, MA 01003-9297, USA Wei Guo, College of Nature Conservation, Beijing Forestry University, Beijing, 100083 China Fei-Hai Yu, College of Nature Conservation, Beijing Forestry University, Beijing, 100083 China Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    In analyses that attempt to estimate the costs of species invasions, it has been typical to report the costs of management and/or to multiply per-unit costs by the number affected to arrive at a total. These estimates are of limited value for most policy questions. We start our discussion by recognizing that biological pollutants such as aquatic invasive species are like conventional pollutants in important ways and appeal to the well-developed literature on conventional pollution to guide our thinking into how best to conceptualize the problem. We use a standard pollution control framework to identify the margins over which costs and benefits should be estimated to guide wise decision-making. We then use examples from the literature to illustrate how transactions in related markets can be used to estimate the benefits of management. The roles of adaptation, mitigation, and species population growth have particular relevance and are highlighted. In the final section of the paper, we think through the conditions under which investing in genetic biocontrol methods would be economically justified. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s10530-011-0134-4 Authors Frances R. Homans, Department of Applied Economics, University of Minnesota, 217G Ruttan Hall, 1994 Buford Ave., Saint Paul, MN 55108, USA David J. Smith, Department of Applied Economics, University of Minnesota, 217G Ruttan Hall, 1994 Buford Ave., Saint Paul, MN 55108, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Invasive plant species can potentially exert competitive or facilitative effects on insect pollination services of native species. Factors that influence these effects include the degree of shared pollinator species, synchronous flowering phenology, similar flower morphology and color, relatedness of invasive and natives, and showiness and densities of flowers. We investigated such plant-pollinator dynamics by comparing the invasive Lespedeza cuneata and three native congeners, all sympatric with synchronous flowering, using in situ populations over 2 years during peak floral displays. Insect visitation rates of the invasive were significantly higher per plant in both years than on the native species. The invasive exerted a competitive effect on visitation of the two native species with fewer shared pollinators, and a facilitative effect on visitation of the native species with the highest degree of shared insect visitors. Positive correlations were found between floral density and visitation rate per plant in all the native species. Although no such correlation was found for the invasive, floral density in L. cuneata was at least twenty times higher than in the native species and likely saturated the response of the pollinator community. Analyses of insect visitor taxonomic data indicated the insect communities visiting each of the Lespedeza species were generally similar though with species-specific differences. The main exception was that the common honeybee, Apis mellifera , was a primary visitor to the invasive plant species, yet was never observed on the native Lespedeza species. Content Type Journal Article Category Original Paper Pages 1-15 DOI 10.1007/s10530-011-0138-0 Authors Teresa M. Woods, Herbarium and Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506, USA Jayne L. Jonas, Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO 80523, USA Carolyn J. Ferguson, Herbarium and Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    In recent years, invasion of native grasslands by exotic woody plants has been recognized as a global problem with multiple adverse ecological and socio-economic consequences. Reasons for such expansions are numerous, including fire suppression. An important example of this problem is the native montane grassland in the Nilgiris of the Western Ghats in India, a biodiversity hotspot threatened by invasion of multiple woody species. In this study, the impacts of the highly invasive, nitrogen fixing exotic shrub Cytisus scoparius (Scotch broom) on the grassland community and ecosystem function have been quantified and the role of fire as a potential management tool evaluated. I established paired plots in uninvaded and broom-invaded grasslands that were either unburned or burned by an unplanned wildfire event. Invasion negatively impacted the grassland community structure and composition, favoring shade tolerant and weedy native plants, but did not greatly alter ecosystem function. Burning broom patches to eliminate the stands resulted in lower soil moisture and nitrogen levels 18 months after the fire. Yet, there were no notable fire effects on the grassland communities or ecosystem properties. Taken together, the results suggest that fire might be an effective tool for broom control. At the end of the study period burned-broom communities did not become more similar to uninvaded-grasslands; presumably the recovery process may be slow without additional management intervention. Content Type Journal Article Category Original Paper Pages 1-20 DOI 10.1007/s10530-011-0136-2 Authors Madhusudan P. Srinivasan, Department of Biology, University of Kentucky, 101 Morgan Building, Lexington, KY 40506, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    In 2004, the avocado lace bug (ALB) Pseudacysta perseae , was discovered in San Diego County, CA, USA. Historically, California avocado producers have relied on biological control for suppression of injurious pests. A fundamental step in identifying biological control agents is determining the source of the invasive population, thus allowing a focused search of that area for natural enemies most closely adapted to the invasive pest genotype. In an attempt to determine the geographic area of origin for ALB to assist incipient biological control efforts, mitochondrial and microsatellite markers were used to compare the genetic profile of the California population of ALB with that of populations from the pest’s known range in the US, Guatemala, Mexico and the Caribbean. Both types of marker revealed evidence for strong genetic structure among the sampled populations. Mitochondrial sequences narrowed the geographic origin of the California population, to populations in Texas and several Mexican states. This geographic range was refined further with the analysis of allele frequencies at eight microsatellite loci which identified ALB populations in the state of Nayarit, Mexico, as the most probable origin of the California population. Any effort to identify natural enemies of ALB for use in biological control in California should therefore focus on Nayarit. The strong genetic structure present among the ALB populations studied is discussed with regards to the potential influence of cytoplasmic incompatibility-inducing endosymbionts, host plant variation, and the putative native range of this pest. Content Type Journal Article Category Original Paper Pages 1-22 DOI 10.1007/s10530-011-0140-6 Authors Paul F. Rugman-Jones, Department of Entomology, University of California, Riverside, CA 92521, USA Mark S. Hoddle, Department of Entomology, University of California, Riverside, CA 92521, USA Phil A. Phillips, University of California Cooperative Extension, 669 County Square Drive, Ventura, CA 93003, USA Gilsang Jeong, Department of Agricultural Biology, National Academy of Agricultural Science, RDA, 61, Seodundong Kweonseonku, Suwon, 441-853 Republic of Korea Richard Stouthamer, Department of Entomology, University of California, Riverside, CA 92521, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Long-distance introductions of new invasive species have often been driven by socioeconomic factors, such that traditional “biological” invasion models may not be capable of estimating spread fully and reliably. In this study we present a new methodology to characterize and predict pathways of human-assisted entries of alien forest insects. We have developed a stochastic quantitative model of how these species may be moved with commodity flow through a network of international marine ports and major transportation corridors in Canada. The study makes use of a Canadian roadside survey database and data on Canadian marine imports, complemented with geo-referenced information on ports of entry, populated places and empirical observations of historical spread rates for invasive pests. The model is formulated as a probabilistic pathway matrix, and allows for quantitative characterization of likelihoods and vectors of new pest introductions from already or likely-to-be infested locations. We applied the pathway model to estimate the rates of human-assisted entry of alien forest insect species across Canada as well as cross-border transport to locations in the US. Results suggest a relatively low nationwide entry rate for Canada when compared to the US (0.338 new forest insect species per year vs. 1.89). Among Canadian urban areas, Greater Toronto and Greater Vancouver appear to have the highest alien forest insect entry potential, exhibiting species entry rates that are comparable with estimated rates at mid-size US urban metropolises. Content Type Journal Article Category Original Paper Pages 1-16 DOI 10.1007/s10530-011-0117-5 Authors Denys Yemshanov, Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, 1219 Queen Street East, Sault Ste. Marie, ON P6A 2E5, Canada Frank H. Koch, USDA Forest Service, Southern Research Station, Eastern Forest Environmental Threat Assessment Center, 3041 Cornwallis Road, Research Triangle Park, NC 27709, USA Mark Ducey, Department of Natural Resources and the Environment, University of New Hampshire, 114 James Hall, Durham, NH 03824, USA Klaus Koehler, Canadian Food Inspection Agency, 59 Camelot Drive, Ottawa, ON K1A 0Y9, USA Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547

Description:    Worldwide, we rely on introduced plants for the essentials of human life; however, intentional plant introductions for commercial benefit have resulted in invaders with negative environmental, economic or social impacts. We argue that plant species of low expected economic value should be less acceptable for introduction than species of high economic value if their other traits are similar; however, key traits such as likelihood of escape and costs of escape are often highly uncertain. Methods do not currently exist which allow decision makers to evaluate costs and benefits of introduction under uncertainty. We developed a cost-benefit analysis for determining plant introduction that incorporates probability of escape, expected economic costs after escape, expected commercial benefits, and the efficiency and cost of containment. We used a model to obtain optimal decisions for the introduction and containment of commercial plants while maximizing net benefit or avoiding losses. We also obtained conditions for robust decisions which take into account severe uncertainty in model parameters using information-gap decision theory. Optimal decisions for introduction and containment of commercial plants depended, not only on the probability of escape and subsequent costs incurred, but also on the anticipated commercial benefit, and the cost and efficiency of containment. When our objective is to maximize net benefit, increasing uncertainty in parameter values increased the likelihood of introduction; in contrast, if our objective is to avoid losses, more uncertainty decreased the likelihood of introduction. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s10530-011-0120-x Authors Hiroyuki Yokomizo, Center for Environmental Risk Research, National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, 305-8506 Japan Hugh P. Possingham, School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia Philip E. Hulme, The Bio-Protection Research Centre, Lincoln University, PO Box 84, Canterbury, New Zealand Anthony C. Grice, CSIRO Ecosystem Sciences, PO, Aitkenvale, QLD 4814, Australia Yvonne M. Buckley, CSIRO Ecosystem Sciences, EcoSciences Precinct, GPO Box 2583, Brisbane, QLD 4001, Australia Journal Biological Invasions Online ISSN 1573-1464 Print ISSN 1387-3547