ALBERT

Description: Clonal plants benefit from the ability to translocate resources among interconnected ramets through clonal integration to colonise ubiquitous heterogeneous habitats, which may contribute to the invasiveness of exotic clonal plants. To test this hypothesis, a greenhouse experiment was conducted to investigate the effects of clonal integration on a non-native clonal plant, Myriophyllum aquaticum , subjected to spatial and temporal heterogeneity of water supply. The daughter ramets were grown with stolon connections either severed from or connected to the mother plant and subjected to different amounts or frequencies of water supply. Clonal integration significantly improved growth and photosynthetic performance of daughter ramets that were exposed to spatial and temporal heterogeneity of water supply. Biomass allocation to roots of offspring ramets changed with water supply to enhance the capacity for water uptake. The decrease of the maximum quantum yield of photosystem II ( F v / F m ) as a function of reduced water supply was greatly alleviated by stolon connection. Moreover, clonal integration facilitated stabilisation of foliar N concentration and C/N ratio to support healthy growth of the ramets. These results suggest that clonal integration may facilitate invasion of M. aquaticum when subjected to heterogeneity in resource supply under ever-changing environments.

Description: Streams receiving agricultural runoff are typically enriched with nutrients, which variously impact stream communities. We examined the effects of phosphate and nitrate enrichment on leaf litter breakdown, microbial biomass and the nutrition of an invertebrate shredder to determine how nutrients are transferred through the stream detrital food web. Using artificial streams, individuals of Anisocentropus kirramus (Trichoptera: Calamoceratidae) were fed leaves of Apodytes brachystylus (Icacinaceae) under different nutrient regimes. We measured the amount of leaf material consumed or decomposed and the microbial biomass colonising the leaves. The dry mass, and protein, lipid and carbohydrate composition of A. kirramus larvae were determined after 28-day feeding on the leaves. Supplements of phosphorus, but not nitrogen, enhanced leaf breakdown, microbial growth and growth of larvae. Microbial biomass and dry mass of larvae increased with nutrient enrichment and they were significantly correlated. Thus, the phosphorus supplement was transmitted through the detrital food web via the microbial pathway, resulting in higher nutritional quality of leaves and enhanced physiological condition of the shredder. Understanding such subtle relationships is important in determining the impacts of anthropogenic contaminants on freshwater ecosystems.

Description: Assessing ammonium (NH 4 + ) availability in aquatic systems requires accurate concentration and turnover rate data. Water column NH 4 + regeneration, potential NH 4 + uptake, and nitrogen (N) fixation rates were measured in Missisquoi Bay, Lake Champlain, to help constrain internal N dynamics affecting phytoplankton community structure and cyanobacteria (Cy) blooms. Cyanobacteria dominated phytoplankton biomass during occasional summer bloom periods, but low or undetectable N 2 fixation rates and low heterocyte abundances suggested that N fixing cyanobacteria did not rely on atmospheric N 2 . Light/dark incubations revealed that photosynthetic and dark NH 4 + uptake generally were balanced, highlighting the importance of bacterial uptake. Our results suggest that phytoplankton were not controlled by nutrients from the “bottom-up”; rather, water column N dynamics responded to phytoplankton patterns. Basin-scale water column NH 4 + regeneration rates were about 700,000 mol N day −1 (9.8 t N day −1 ), which is almost twice the estimated N load from tributaries, and suggests a primary role for water column N regeneration in supporting primary production. Comparisons of basin-scale NH 4 + regeneration and demand imply that primary production is not sustained fully by combined water column regeneration and tributary N inputs; thus, future research should constrain additional sources and sinks affecting N balance in this and other aquatic systems.

Description: The reconstructed Lake Karla, Greece, has been undergoing its water-filling period since November 2009. In this paper, we aimed at investigating whether the unicellular eukaryotes, including the toxic/parasitic ones, that have been found during mass fish kills in the lake (March–April 2010), persist during the first warm period of the lake (May, August, November 2010). Given that microscopic characterization of some of these eukaryotes is not adequate for their identification, we analysed the 18S rRNA gene diversity of plankton samples. All the found phylotypes belonged to the phyla of Mesomycetazoa, Chlorophyta, Fungi, Alveolata, Cercozoa, Cryptophyta and Stramenopiles. Some members of these groups seem to persist in Lake Karla as they have been found in early spring as well. These microscopic eukaryotes are either ichthyotoxic/parasitic (e.g. Pfiesteria sp./ Pseudopfiesteria shumwayae , some Fungi, Mesomycetazoa, Lagenidium sp., Cercozoa) or indicative of hyper-eutrophic conditions (e.g. Oocystis sp., Scenedesmus spp.) and were rather abundant during the first spring–autumn period of the lake’s refilling process. These complex microscopic communities are expected to shape highly dynamic and variable food webs with the risk of repeated fish kills.

Description: Subfossil chironomid and sediment geochemistry data from Lugu Lake, a large high-elevation lake in southwest China, were used to assess the influences of climate warming and direct human impacts on the lake through time. A 95-year-long sediment record was recovered from the lake. Principal components analysis (PCA) and redundancy analysis of fossil chironomid data were performed to determine the controlling factors on the chironomid community. The four prominent environmental controls were summer air temperature, organic matter C:N ratio (C org :N), dry mass accumulation rate (DMAR), and total nitrogen. C org :N proved to be the most important controlling factor through time. However, C org :N and summer air temperature were highly co-linear, possibly due to temperature directly impacting lake productivity (and thus C:N ratios) through increased stratification and a longer growing season. PCA Axis 1 scores were a strong predictor of summer temperatures even after DMAR was factored out to account for direct human influences. The strong temperature–chironomid relationship over the last 50 years could be due to the lake becoming more responsive to climate warming after cultural eutrophication of the 1950s, as lakes with higher nutrient loads are shown to be more responsive to the effects of climate warming.

Description: The impacts of climate change on Microcystis blooms in San Francisco Estuary are uncertain because factors associated with the abundance and distribution of Microcystis blooms since their inception in 1999 are poorly understood. Discrete and continuous data collected between 2004 and 2008 were used to assess what factors controlled bloom initiation and persistence, if there was an impact of the bloom on mesozooplankton abundance and toxicity or dissolved organic carbon concentration, and how these might vary with climate change. Microcystis abundance was greater in dry years than wet years and both total microcystins concentration and the microcystins content of mesozooplankton tissue increased with abundance. The bloom began in the upstream portions of the estuary and spread farther west during dry years. Bloom initiation required water temperature above 19°C and surface irradiance in the visible range above 100 W m −2 . The bloom persisted during a wide range of water quality conditions but was closely correlated with low turbidity. The intensity of Microcystis blooms will likely increase with climate change due to increased water temperature and low streamflow during droughts. Elevated water temperature earlier in the spring could also extend the duration of Microcystis blooms by up to 3 months.

Description: In pike E. lucius L., evidence on maternal effect on reproductive output is mixed. We studied whether older and larger pike females produce eggs and larvae of higher quality (weight, starvation resistance) in three forest lakes in southern Finland. Later, the study lakes were subjected to intensive experimental pike fishing, which we assumed would increase resource availability and lead to higher maternal investment (larger egg size). Length of female pike was positively correlated with the dry weight of eggs and larvae but this relation was dependent on female age. In old females, the effect of female length on egg weight was lower or even negative. Survival analysis showed a positive effect of female length on larval survival time indicating that larvae from larger females are less vulnerable to starvation during the early stage of life. After the intensive pike fishing, the positive effect of female length on egg weight was stronger in all age classes probably due to the released resources. Based on the high quality and amount of reproductive products in large (but not very old) females, they are important for the reproduction of pike populations. This should be considered in fisheries management.

Description: Freshwater predatory insects can exert strong effects on prey, although how multiple similar predators may coexist is not well understood. Larval predaceous diving beetles are often numerically and taxonomically abundant predators in lentic systems, but the proximate mechanisms that explain their high abundance remain unknown. Field surveys were conducted twice in June in ponds in Alberta, Canada to assess the associations between larvae of two genera ( Graphoderus , Rhantus ), their spatial locations, and correlations with potential prey. Both larvae were common and positively correlated within wetlands although neither varied with pond depth nor distance from edge. Laboratory trials indicated that Graphoderus consumed more prey (corixids) at the surface, whereas Rhantus killed benthic prey (chironomids) and corixids at an equal rate; damselflies were the least consumed prey. Predation also varied with depth, with both larvae feeding at higher rates in the shallowest environments compared to Graphoderus at an intermediate depth. Predator–prey correlations from ponds were mostly congruent with predation trials; Graphoderus was positively correlated with corixids, Rhantus was positively correlated with corixids and chironomids; beetles were uncorrelated with damselflies. Reliance on different prey in different microhabitats may be an important mechanism for the maintenance of high abundance of dytiscid larvae.

Description: In Chile, mediterranean climate conditions only occur in the Central Zone (ChMZ). Despite its small area, this mediterranean climate region (med-region) has been recognised as a hotspot for biodiversity. However, in contrast to the rivers of other med-regions, the rivers in the ChMZ have been studied infrequently, and knowledge of their freshwater biodiversity is scarce and fragmented. We gathered information on the freshwater biodiversity of ChMZ, and present a review of the current knowledge of the principal floral and faunal groups. Existing knowledge indicates that the ChMZ has high levels of endemism, with many primitive species being of Gondwanan origin. Although detailed information is available on most floral groups, most faunal groups remain poorly known. In addition, numerous rivers in the ChMZ remain completely unexplored. Taxonomic specialists are scarce, and the information available on freshwater biodiversity has resulted from studies with objectives that did not directly address biodiversity issues. Research funding in this med-region has a strong applied character and is not focused on the knowledge of natural systems and their biodiversity. Species conservation policies are urgently required in this highly diverse med-region, which is also the most severely impacted and most populated region of the country.

Description: Freshwater species worldwide are experiencing dramatic declines partly attributable to ongoing climate change. It is expected that the future effects of climate change could be particularly severe in mediterranean climate (med-) regions, which host many endemic species already under great stress from the high level of human development. In this article, we review the climate and climate-induced changes in streams of med-regions and the responses of stream biota, focusing on both observed and anticipated ecological responses. We also discuss current knowledge gaps and conservation challenges. Expected climate alterations have already been observed in the last decades, and include: increased annual average air temperatures; decreased annual average precipitation; hydrologic alterations; and an increase in frequency, intensity and duration of extreme events, such as floods, droughts and fires. Recent observations, which are concordant with forecasts built, show stream biota of med-regions when facing climate changes tend to be displaced towards higher elevations and upper latitudes, communities tend to change their composition and homogenize, while some life-history traits seem to provide biota with resilience and resistance to adapt to the new conditions (as being short-lived, small, and resistant to low streamflow and desiccation). Nevertheless, such responses may be insufficient to cope with current and future environmental changes. Accurate forecasts of biotic changes and possible adaptations are difficult to obtain in med-regions mainly because of the difficulty of distinguishing disturbances due to natural variability from the effects of climate change, particularly regarding hydrology. Long-term studies are needed to disentangle such variability and improve knowledge regarding the ecological responses and the detection of early warning signals to climate change. Investments should focus on taxa beyond fish and macroinvertebrates, and in covering the less studied regions of Chile and South Africa. Scientists, policy makers and water managers must be involved in the climate change dialogue because the freshwater conservation concerns are huge.

Description: Streams and rivers in mediterranean-climate regions (med-rivers) are subjected to sequential, yet contrasting hydrologic disturbances of drying and flooding. Although seasonally predictable, these disturbances can vary in intensity and duration within and among mediterranean-climate regions (med-regions). Consequently, med-rivers differ in the permanence of their aquatic habitats. To persist, species have acquired matched resistance and resilience adaptations. They gain resistance either by enduring the stress or avoiding it. Community recovery (or resilience) is achieved with cessation of hydrologic stress that permits maximization of re-colonization and reproduction. Endurance strategies are usually disturbance-specific, but avoidance enables organisms to cope with both drying and flooding, and is the prevalent resistance strategy. Correspondingly, community persistence depends to a large extent on the integrity of refuges, an aspect that has so far been little explored. Existing information suggests that seasonal community succession becomes more pronounced with increasing aridity and declining water permanence. The invertebrate community in semi-arid med-rivers can therefore undergo succession through three to four identifiable assemblages, whereas in perennial streams the difference between wet and dry period assemblages is smaller. Community turnover is influenced by the intensity of the hydrologic disturbances and varies between wet and drought years.

Description: Southwestern Australia is recognised as a global biodiversity hotspot, characterised by high diversity and endemism of vascular terrestrial plants. However, the significance of its freshwater biodiversity is not well understood. This review provides an updated account of species richness in rivers in the Mediterranean region (med-region) of southwestern Australia. Taxonomic knowledge of many aquatic invertebrate groups in this region has improved significantly in the last two decades as a result of ecological surveys and government funding for taxonomic research. Of the 662 species of plants and animals surveyed, 43% were found to be endemic to the region, yet when taxonomic groups were considered separately, levels of endemism were varied. To date, few aquatic species from the med-region are listed as threatened; however, many more species would be expected to be included if assessed against appropriate criteria. Conservation efforts are focussed on climate change mitigation and managing the impacts of broad scale land clearing for agriculture. Reserve design and location of important nature reserves on the extreme south coast, limits the ability for species’ movement to cooler, wetter regions. This will necessitate supporting restoration which leads to increased resilience in freshwater ecosystems to withstand the combined effects of climate change and land use.

Description: Rivers in mediterranean regions are subject to hydrological extremes. They range from highly stable, perennial ground- or snow-fed systems to highly ephemeral, unpredictable ones in semi-arid environments. Spatial and temporal complexity inherent in these systems presents challenges for ecological status assessment and defining reference conditions, particularly as many areas have been extensively transformed through anthropogenic activities. Temporal variability driven by sequential and predictable, seasonal events of flooding and drying accentuates the need to take season and/or hydrological period into account. Intermittent streams, which are common in mediterranean regions (med-regions) and which have aquatic communities distinct from perennial streams, are often not incorporated in bioassessment and present distinct challenges. Med-regions are also known for their high biodiversity and rates of endemism, as well as large numbers of introduced species. Med-regions are expected to be among the most affected by global climate change and, in these systems, climate change is an additional driver influencing ecosystems that are already stressed. From this review it is evident that an understanding of responses of indices, metrics, and models to climate change in comparison to existing stresses, and the development of thermally specific bioassessment tools are needed for this region.

Description: Refuges protect plant and animal populations from disturbance. Knowledge of refuges from disturbance in mediterranean climate rivers (med-rivers) has increased the last decade. We review disturbance processes and their relationship to refuges in streams in mediterranean climate regions (med-regions). Med-river fauna show high endemicity and their populations are often exposed to disturbance; hence the critical importance of refuges during (both seasonal and supraseasonal) disturbances. Disturbance pressures are increasing in med-regions, in particular from climatic change, salinisation, sedimentation, water extraction, hydropower generation, supraseasonal drought, and wildfire. Med-rivers show annual cycles of constrained precipitation and predictable seasonal drying, causing the biota to depend on seasonal refuges, in particular, those that are spatially predictable. This creates a spatial and temporal mosaic of inundation that determines habitat extent and refuge function. Refuges of sufficient size and duration to maintain populations, such as perennially flowing reaches, sustain biodiversity and may harbour relict populations, particularly during increasing aridification, where little other suitable habitat remains in landscapes. Therefore, disturbances that threaten perennial flows potentially cascade disproportionately to reduce regional scale biodiversity in med-regions. Conservation approaches for med-river systems need to conserve both refuges and refuge connectivity, reduce the impact of anthropogenic disturbances and sustain predictable, seasonal flow patterns.

Description: River and stream biofilms in mediterranean fluvial ecosystems face both extreme seasonality as well as arrhythmic fluctuations. The hydrological extremes (droughts and floods) impose direct changes in water availability but also in the quantity and quality of organic matter and nutrients that sustain the microbial growth. This review analyzes how these ecological pulses might determine unique properties of biofilms developing in mediterranean streams. The paper brings together data from heterotrophic and autotrophic community structure, and extracellular enzyme activities in biofilms in mediterranean streams. Mediterranean stream biofilms show higher use of peptides during the favorable period for epilithic algae development (spring), and preferential use of cellulose and hemicellulose in autumn as a response to allochthonous input. The drying process causes the reduction in bacterial production and chlorophyll biomass, but the rapid recovery of both autotrophs and heterotrophs with rewetting indicates their adaptability to fluctuations. Bacteria surviving the drought are mainly associated with sediment and leaf litter which serve as “humid refuges”. Some algae and cyanobacteria show resistant strategies to cope with the drought stress. The resistance to these fluctuations is strongly linked to the streambed characteristics (e.g., sediment grain size, organic matter accumulation, nutrient content).

Description: Mediterranean climate ecosystems are among the most fire-prone in the world; however, little is known about the effects of fire on mediterranean streams (med-streams). Fire impacts on med-streams are associated with increased runoff and erosion from severely burned landscapes during storms, particularly the first intense rains. Increased inputs of water, solutes, nutrients, sediment, organic matter, and ash to streams after fires are usually observed for months to up to 4 years. Return to pre-fire conditions is associated with vegetation recovery. Benthic algae, invertebrates, and fish are reduced to low levels by scouring floods after wildfire. If riparian zones are burned, benthic algae increase, and invertebrate communities become dominated by r -strategist species. Fishes are eradicated from reaches affected by intense wildfire and often do not re-colonize quickly because of downstream barriers. In general, med-stream communities appear to be more resilient to fire compared to streams in other ecosystems because of the rapid recovery of mediterranean upland and riparian vegetation and geomorphological conditions (1–4 years in med-streams vs 5–10 years in non-med streams). However, drought or mass sediment movements after fire can prolong fire effects. Studies of the long-term effects of fire and the consequences of fire management practices are still needed.

Description: Although the California mediterranean climate region is widely considered a biodiversity hotspot for terrestrial plants and vertebrates, freshwater biodiversity in this region is generally not well known. Using information from museum specimen databases, published literature, biological assessment surveys, and specialist’s knowledge, we review freshwater biodiversity for several groups of stream organisms in the med-climate region of California, which includes 2,220 species in 292 families. The groups with the highest diversity of lotic species are aquatic insects and diatoms, which comprise 39 and 36 % of species in our lists, respectively. Sequential floods and drying periods limit the overall biodiversity of many stream organisms in California mediterranean rivers, and continued climate and land-use change may cause disproportionate biodiversity declines in the region. However, only 4 % of lotic species have been evaluated in the IUCN Red List of Threatened Species, and many assessments are outdated. Future development of online databases for botanical and zoological collections will significantly enhance biodiversity and distribution knowledge. This information will enable us to more accurately and efficiently assess the effects of global change on biodiversity of freshwater organisms, to evaluate conservation status of individual taxa, and to set conservation priorities for stream ecosystems.

Description: The occurrence of picocyanobacteria, the smallest cell-size fraction of cyanobacteria, in low-pH waters, is still poorly studied. In this study, we tested the hypothesis that picocyanobacteria found occasionally in low-pH environments are adapted to such water conditions. We isolated picocyanobacteria by means of the cytometric method from two humic lakes with pH ≤5. We obtained two strains belonging to two cosmopolitan phylogenetic clades of picocyanobacteria: Cyanobium gracile cluster and Subalpine cluster I. Experiments on filtered lake water from low-pH (≤5) and slightly alkaline (pH 8.2) lakes, and with an acidified cyanobacterium medium (pH 4.5) were conducted to test the growth of the isolated picocyanobacteria in various pH conditions. The experimental results of this study showed that some picocyanobacteria strains were acid tolerant, achieving higher growth rates and reaching higher maximum numbers in humic, naturally acidic waters rather than in alkaline waters. We show that despite a close phylogenetic relationship, strains of picocyanobacteria exhibit significant physiological and ecological diversity and that at least some picocyanobacteria have the evolutionary potential to cope with low pH. Characterization of the genetic basis of acid tolerance in picocyanobacteria is important to understand how these microorganisms function in aquatic ecosystems and how their communities may respond to a changing environment.

Description: This paper summarises key issues from papers included in a special issue about the impacts of climate change on Australian wetlands. The papers covered: the assessment of wetlands under climate change, adaptation and engineering responses to climate change, and restoring wetlands under a changing climate. The key issues from these papers were used to indicate areas where the Ramsar Convention could develop guidance as part of its’ Handbooks for the Wise Use of Wetlands. These included: (i) assessing changes in the distribution of species and whether these constitute a change in the ecological character of the wetland; (ii) assessing the usefulness of models of wetland response to climate change; (iii) assessing the value in allocating water to protected sites where restoration would be contingent on reallocation of larger volumes of water; (iv) assessing the efficacy of engineering responses with the potential to deliver more water-efficient environmental outcomes for wetlands and (v) determining if the description of the ecological character of a Ramsar site at the time of listing is a suitable reference for management purposes. With these issues in mind it is recommended that further attention is directed towards determining and responding to the ecological consequences of climate change.

Description: A review of stratigraphic, radiocarbon, pollen, and aerial photographic data on the Swan Coastal Plain, south-western Australia, allows interpretation of long-term changes in climate and its effects on wetlands during the Holocene, whereas monitoring wetland hydrology and vegetation provides a measure of shorter-term changes. The information provides models for basin wetland response to changing climate. Drying climates shift wetlands to drier conditions, turning lakes into seasonally inundated or waterlogged basins, or resulting in an overall loss of wetlands, and favours more saline conditions, and development of carbonate deposits. Wetter conditions results in more frequent inundation, shifting damplands to sumplands or lakes, and resulting in fresher water conditions, and development of peat and/or organic matter enriched deposits. Examples of wetland basin responses to climate change across the Swan Coastal Plain show differential responses depending on setting, spatial distribution, hydrology, hydrochemistry and geochemistry, different temporal frameworks, and biological resilience.

Description: In Neotropical mangroves the crabs Ucides cordatus and Goniopsis cruentata have been considered the most significant propagule consumers, but their relative importance has not been investigated. The aim of this study was to compare the magnitude of predation by these crabs on three mangrove species propagules: Avicennia schaueriana , Laguncularia racemosa and Rhizophora mangle . We found that G. cruentata is a more important predator than U. cordatus in both natural and restored areas. We also tested the hypothesis that Ucides and Goniopsis have antagonistic effects on propagules predation using a cage experiment where the presence/absence of these species was manipulated in a 2 × 2 factorial design. The effects of Goniopsis were stronger in the absence of Ucides due to negative interactions between these predator species. Moreover, we found that Goniopsis preference for A. schaueriana and L. racemosa can favor the dominance of R. mangle in Neotropical mangroves. This study suggests that propagule predation by Goniopsis should be controlled in mangrove restoration programs at abandoned shrimp farms and destroyed areas, if dominance by R. mangle is undesirable relative to mixed species communities.

Description: We investigated the emergence of Daphnia pulicaria from resting eggs in Río Seco, an alpine lake in which the zooplankton growing period is short. In situ studies were carried out using sediment emergence traps and plankton sampling, and the sediment egg bank was analyzed. A laboratory experiment was performed to explore the role of photoperiod and temperature as hatching cues for D. pulicaria . We hypothesized that the time window for emergence would be short and that hatching cues would be linked to the variable ice-break period. In the field, D.   pulicaria showed a highly synchronized emergence in both years. The hatching period was restricted to 3 weeks during and immediately after the thaw. In the laboratory experiment, no hatchings were observed in the dark treatment and neither photoperiod nor temperature affected hatching rates. Therefore, the presence of light, which corresponds with the period of ice-break, was essential for triggering dormancy termination of D. pulicaria . Our results show that the period when the ice-break occurs is a key event for Daphnia population development. The longer ice-free periods predicted by climate change in the alpine lakes could therefore have important effects on the crustacean population dynamics of these systems.

Description: The objective of this research was to determine if the highly invasive round goby ( Neogobius melanostomus ) experiences lower predation risk during early stages of invasion. We compared round goby predation rates between a recently invaded area (occupied for ≈1 year) and a longer established area (≈7 years) of the Trent River, Ontario, Canada. Tethering trials were conducted in three habitat types, and comparable habitats in the two areas were similar in water temperature, velocity and depth. Predation rates of tethered round gobies were on average 27% lower in the recently invaded area. Reduced predation in the recently invaded area may be due to the short duration of round goby occupancy and/or differences in predator communities between the two study areas. Data before the round goby invasion suggest that predator communities were similar between the two range areas, but differences in predator abundance cannot be ruled out as a potential mechanism. Other possible mechanisms include a numerical or learned response by predators over time to a novel prey item. Reduced predation rate during the initial stages of invasion may contribute to the fitness of individuals that migrate into areas not previously occupied, and thus facilitate successful range expansion.

Description: Wetland managers are faced with an array of challenges when restoring ecosystems at risk from changing climate and human impacts, especially as many of these processes have been operating over decadal–millennial timescales. Variations in the level and salinity of the large crater lakes of western Victoria, as revealed over millennia by the physical, chemical and biological evidence archived in sediments, attest to extended periods of positive rainfall balance and others of rainfall deficit. The recent declines in the depth of these lakes have been attributed to a 15% decline in effective rainfall since AD 1859. Whilst some sites reveal state shifts following past droughts, the response of most wetlands to millennial-scale climatic variations is muted. Regional wetland condition has changed comprehensively, however, since European settlement, on account of extensive catchment modifications. These modifications appear to have reduced the resilience of wetlands limiting their capacity to recover from the recent ‘big dry’. These sedimentary archives reveal most modern wetlands to be outside their historical range of variability. This approach provides a longer-term context when assessing wetland condition and better establishes the restoration challenge posed by the impact of climate change and variability and human impacts.

Description: Globally, rain-fed wetlands provide critical habitat for a wide range of amphibian species, however, information on the use of rain-fed wetlands by Australian frog species is extremely limited. This study examined the distribution of frog breeding in rain-fed wetlands following the first significant rain event after a period of severe drought (2002–2009) in order to predict how frog communities may be affected in the future by changed climate. Tadpole communities along with vegetation and water quality variables were described in 35 rain-fed wetlands across the South West Slopes and Riverina bioregions of inland south-eastern Australia. In addition, weekly tadpole surveys were conducted in a subset of these wetlands to describe temporal patterns of occupancy. Despite the protracted dry period prior to this study 50% of the rain-fed wetlands surveyed contained tadpoles. However, frog communities were species poor with only five species recorded. The majority of wetlands were dominated be a single species, Limnodynastes tasmaniensis which is also common within permanent waterbodies such as farm dams and irrigation infrastructure in both bioregions. Tadpoles of two burrowing species L. interioris and Neobatrachus sudelli were restricted to a small number of wetlands mostly in the South West Slopes. The composition of tadpole communities changed over time, and Crinia parinsignifera was the only species that continued to breed over winter. The dominance of generalist species within rain-fed wetlands indicates that characteristics such as dispersal capability, flexibility in breeding times and the ability to utilise created habitats may be more important than burrowing ability and longevity when predicting vulnerability to climate change.

Description: Competing demands for water have resulted in many wetlands becoming either more permanently flooded or more permanently dry. It has been stated that such changes may lead to a loss of diversity in wetland communities; yet to date, this has not been tested experimentally. In this study, we experimentally test the hypothesis that increasing the hydrologic stability of wetlands results in reduced abundance, richness and diversity of aquatic biota emerging from wetland sediments. Sediment was collected from 19 wetlands that were divided into five groups (permanently flooded and wetlands that had been dry for 2, 7, 11 and 30 years). Aquatic plant communities germinating from the sediment of wetlands that had been permanently inundated and those that had been dry for 30 years had lower species richness and number of individuals than wetlands with intermediate flooding histories. For microfaunal communities, significantly less individuals but more taxa hatched from wetlands that had been permanently flooded or dry for 2 years than the other wetland groups. These results provide evidence of reduced biotic diversity as hydrological stability is increased under the common management scenarios of making wetlands more permanently wet or dry.

Description: Stoichiometric theory predicts that organisms should experience dietary imbalances not only when nutrients (e.g., phosphorus, P) are limiting relative to carbon (C), but also when nutrients are in excess (i.e., well above somatic demand). Nevertheless, few experiments have elucidated the response of consumers in such low C:P conditions. We assessed the growth, tissue stoichiometry, and nutrient excretion of the invasive primary consumer, zebra mussel (ZM), Dreissena polymorpha , under three dietary C:P conditions (C:P = 20, 45, 380) in the laboratory. The two low C:P conditions represent increasingly common eutrophic systems, while the high C:P treatment is representative of oligotrophic systems. Growth rates and condition were lower when ZMs were fed a low C:P (20 and 45) diet, compared to the C:P = 380 treatment, wherein ZMs grew rapidly and exhibited lower somatic C:P. Furthermore, ZMs in the C:P = 20 and C:P = 45 treatments excreted more ammonia indicative of protein catabolism. These results clearly show that hypereutrophic conditions invoke significant shifts in physiology, growth, and condition of ZMs. Together, these results are consistent with stoichiometric theory that predicts costs associated with the intake of excess dietary P.

Description: Despite over 100 years of phytoplankton research in the Baltic Sea, little is known about how the species composition has changed during this period, characterised by severe anthropogenic eutrophication. We investigated the phytoplankton communities in the northern Baltic Sea using data from 1903 to 1911 and 1993 to 2005; to minimise effects of methodological differences we focused on occurrence frequencies. We found that the historical and modern communities differed regarding both species composition and the relative importance of taxonomical groups. The most obvious differences were the increase of dinoflagellates and decrease in the diatom to dinoflagellate ratio in all seasons. Contrary to the widely held view that cyanophytes have gained significance, our results indicate that in terms of occurrence the group has not increased in summer, and has lost ground in both spring and autumn. Several shifts in the occurrence frequency and seasonality of individual taxa transpired. Examining our results in relation to environmental conditions we found that some changes may be symptomatic of climate change related pressures. However, statistical analyses revealed that an undefined ‘period effect’ was the most important factor separating the historical and modern phytoplankton communities. We interpret this ‘period effect’ as evidence for the direct and/or indirect influence of eutrophication.

Description: In Australia’s Murray–Darling Basin, small-scale engineering works called ‘environmental works and measures’ have been implemented as a basis for river and other wetland conservation. While implementing these, governments seem to have embraced the beguiling notion that scarce water supplies can be divided further, while conserving the environment and maintaining agricultural production. The difficulties in doing this are expected to increase in the face of extreme climate variability. With this scenario as a backdrop, the $280 million (Monetary values ($) in this paper are in Australian dollars (AUD). At the time of writing AUD $1.00 = ~USD $1.02.) Living Murray and related programmes are assessed to see whether microengineering works to manage the hydrology of wetlands make for effective adaptation to water scarcity and climate change or whether it amounts to an overly narrow adaptation or maladaptation. Some measures were found to be substantially beneficial, such as the construction of fishways. However, under these programmes, only 0.6% of the Basin’s wetlands would be inundated and there are significant risks including desiccation of non-target wetlands and further reductions in water allocations for the environment. It is recommended that trade-offs between alternative strategies are assessed as the basis for minimising perverse impacts under changing climatic and hydrological conditions.

Description: The purpose of this microcosm experiment was to determine whether the freshwater snail Bellamya aeruginosa affected phytoplankton community and water quality. Three treatments of different snail densities (low, medium, and high) and a control (no snails) were set up in twelve enclosures. Chlorophyll a (chl a ), transparency (SD), water temperature (WT), dissolved oxygen (DO), pH, nutrients, and abundance of phytoplankton were determined on days 0, 3, 7, 11, 15, 23, 31, 46, and 61. The total chl a concentration decreased and SD increased in the treatments, whereas the proportion of cyanobacteria chl a increased. Bellamya seemed to result indirectly in a decrease of DO, by reducing the algal biomass rather than by respiration. A significant decrease in nitrogen–phosphorus ratios was observed in the treatments. In the enclosed system the abundance of colonial green algae decreased over time whereas that of cyanobacteria and flagellates increased. Principal response curves showed that both phytoplankton community and water quality in the medium and high-density treatments were consistently different from in the control. These results indicate that the presence of snails resulted in a significant change of water physicochemical properties and phytoplankton community.

Description: Brown trout is a cold-adapted freshwater species with restricted distribution to headwater streams in rivers of the South European peninsulas, where populations are highly vulnerable because Mediterranean regions are highly sensitive to the global climatic warming. Moreover, these populations are endangered due to the introgressive hybridization with cultured stocks. Individuals from six remnant populations in Western Mediterranean rivers were sequenced for the complete mitochondrial DNA control region and genotyped for 11 nuclear markers. Three different brown trout lineages were present in the studied region. Significant genetic divergence was observed among locations and a strong effect of genetic drift was suggested. An important stocking impact (close to 25%) was detected in the zone. Significant correlations between mitochondrial-based rates of hatchery introgression and water flow variation suggested a higher impact of stocked females in unstable habitats. In spite of hatchery introgression, all populations remained highly differentiated, suggesting that native genetic resources are still abundant. However, climatic predictions indicated that suitable habitats for the species in these rivers will be reduced and hence trout populations are highly endangered and vulnerable. Thus, management policies should take into account these predictions to design upstream refuge areas to protect remnant native trout in the region.

Description: A rapid method to estimate the three-dimensional (3D) surface area (SA) of marine gorgonians and sponges from field measurements of colony height, diameter, and morphology was developed as an indicator of habitat availability for fish and invertebrates. Colony characteristics for sponges and gorgonians were compiled from field measurements, expert judgment, and taxonomic literature, and employed to generate 3D images using computer-aided design software. The images were used to test various statistical models and geometric surrogates that best estimated SA using only height and diameter measurements. A morphological classification system was devised using shapes and relative proportions of sponges and gorgonians which are commonly found in shallow waters (〈25 m depth) of the Central Western Atlantic Ocean. Regression models (linear, quadratic, or cubic) were found to be more robust than geometric surrogates, exhibiting greater accuracy at range extremes. Statistical models explained over 90% of the variation in SA and forecast errors of less than 20%. The best models for estimating SA are presented for eight sponge and nine gorgonian morphologies. Application of these methods with existing estimators for stony corals SA can be used as an indicator of structural habitat availability, which is an important ecosystem service of coral reefs.

Description: The common and routine procedure for the quantification of chlorophyll a (chl a ) in aquatic studies has a series of steps. Here, we sought to find optimal conditions for phytoplankton cell harvesting, chl a extraction, and chl a measurement and calculation, to find an effective, cost-saving, safe, and environment-friendly procedure for determining phytoplankton chl a concentration. We replaced the traditional GF/C filters with inorganic polymer flocculants (IPFs) and clay for phytoplankton harvesting, and then various solvents (acetone, ethanol, DMF, and DMSO), IPFs (PAC, PFS, and PAFS) and clay were tested for their suitability for chl a extraction, with or without homogenization at different temperatures for different extraction durations. About 0.3–1.0 g l −1 of PAC or PFSA combined with 1.0–2.5 g l −1 clay were found to provide optimal conditions in terms of yield and cost for phytoplankton cell harvesting from water samples. Based on our results, we recommend flocculation and centrifugation instead of glass-fiber membrane filtration for harvesting phytoplankton cells from environmental water samples, 95% ethanol for chl a extraction without homogenization and heating, and spectrophotometry to determine chl a concentration.

Description: Geomorphic research across the semi-arid and wet-dry tropics of northern Australia has highlighted the role of the regions’ estuaries as a “canary in the coalmine” for climate variations, with dramatic structural shifts over the Holocene. This behaviour highlights the region’s potential sensitivity to climate change and suggests the need for careful identification and interpretation of dynamics in the tropical and sub-tropical regions. However, analysis of change in these regions requires care, as a number of the basic tools applied to interpreting estuarine change in temperate regions are obscured, invalid or simply unavailable when applied in lower latitudes. This study provides a synthesis from a range of investigations across northern Australia and identifies characteristics to be considered when interpreting or predicting sub-millennial estuarine change in these regions.

Description: Zooplankton are potentially powerful proxies for the assessments of biologic integrity. The paleolimnological perspective and use of fossil Cladocera also provide the means to reconstruct reference conditions and natural long-term community dynamics. Unfortunately, the use of zooplankton in lake quality assessments is currently underexploited. We studied a surface sediment dataset of 41 lakes in Finland to examine the relationship between Cladocera remains and environmental variables. Of the examined environmental variables, total phosphorus availability was found to be the most important variable in explaining the Cladocera community composition. Following the tests on species environment relations, we selected a lake trophic typology as the most suitable environmental variable for developing a new tool for limnoecological quality assessments. A test of the model on a modern and historic sample from a eutrophied lake showed that the test lake has proceeded from “mesotrophic/poor” to “eutrophic/bad” limnoecological state in agreement with previous independent evidence. The model developed here showed favorable performance that can be used to provide reliable estimates of ecological and environmental state of lakes.

Description: Nutrient enrichment may alter population dynamics of species in different ways depending on their life strategies. The aim of this study was to test the effect of different nutrient concentrations on the population development of two bacterivorous freshwater nematodes, Bursilla monhystera and Plectus aquatilis . Microcosms with autoclaved natural sand from a pristine stream (Fuirosos, NE of Spain) were enriched with different levels of phosphate, nitrate and ammonia as inorganic nutrients and glucose as a biodegradable dissolved organic carbon source. Although leaching of carbon and nutrients from the detritus fraction in the sediment initially may have overruled differences between treatments, later samplings revealed bottom-up control, with Bursilla monhystera abundances positively correlated to bacterial abundances at high nutrient concentrations. Nevertheless, there were several indications that nematodes in turn affected microbial abundance, most likely through excretion of ammonia and through grazing. In contrast to B. monhystera , Plectus aquatilis at high nutrient concentrations showed a unimodal abundance curve, while not increasing in abundance at low nutrient concentrations. Glucose enrichment did not have any stimulatory effect on either microbial or nematode abundances, probably as a result of unfavourable C:N:P stoichiometry. P enrichment, by contrast, stimulated microbial and Bursilla abundances. Our results indicate that episodic nutrient enrichment may affect populations of bacterial-feeding nematodes in the short term. Their longer-term dynamics may, however, be more dependent on leaching of carbon and nutrients from the pools of sediment-bound detritus.

Description: This study investigates the dynamics of protozoan community in biofilms formed on inert artificial surfaces suspended in various freshwater environments. The results also test the hypothesis that the dynamics of protozoan and microalgal communities in biofilms are interdependent because the latter form one of the major food items of benthic protozoa. Cleaned glass slides were suspended in surface waters at four sampling locations to collect biofilm communities. The glass slides after retrieval were observed under a microscope for diatom and protozoan density and their generic composition. Members of protozoa belonging to phylum Sarcomastigophora dominated the protozoan community followed by phylum Ciliophora in all sampling locations. The variation of protozoan feeding groups showed an initial abundance of autotrophs/holophytes which gave way to heterotrophs, predators, and bacterivores towards the end of the study. The density and generic composition of protozoa varied significantly with the age of biofilm and sampling location. The density variation of protozoa followed that of diatoms in all four sampling locations and this has resulted in a significant positive correlation between diatom and protozoan densities. This suggests the dependency and/or food web connectedness of these two communities in natural biofilms.

Description: Nutrient ratios have been related to nutrient limitation of algal growth in lakes. Retention of nutrients in lakes, by sedimentation and by denitrification, reduces the nutrient concentrations in the water column, thereby enhancing nutrient limitation. Differential retention of nitrogen and phosphorus alters their ratios in lakes and thereby contributes to determine whether nitrogen or phosphorus limits algal growth. We examined the relationships between differential nutrient retention, nutrient ratios, and nutrient limitation in Lake Brunner, a deep oligotrophic lake. The observed retention of nitrogen (20%) and phosphorus (47%) agreed with predictions by empirical equations from literature. As a result of differential retention with a much larger proportion of phosphorus retained than that of nitrogen, the nitrogen:phosphorus ratio was higher in the lake (69) than in the inflows (46). While the mean ratio in the inflows suggested no or only moderate phosphorus limitation, the lake appeared to be severely phosphorus limited. Combining empirical equations from literature that predict nitrogen and phosphorus retention suggests that the nitrogen:phosphorus ratio is enhanced by greater retention of phosphorus compared to nitrogen only in deep lakes with relatively short residence times, such as Lake Brunner. In contrast, in most lakes differential retention is expected to result in lower nitrogen:phosphorus ratios.

Description: Using a large pan-European dataset, we compared least disturbed sites to sites impacted by human pressures across broad river types to assess which aspects of bio-ecological traits of the fish assemblage are most sensitive to alterations of the river ecosystem. To control for variation across river types and large-scale environmental gradients, we began by clustering the least disturbed sites ( n  = 716) into four homogenous fish assemblage types (FATs) differing by four fish metrics, i.e., lithophilic, rheophilic, omnivorous, and potamodromous fish. We predicted these FATs (headwater streams, medium gradient rivers, lowland rivers, and Mediterranean streams) using environmental variables, i.e., altitude, river slope, temperature, precipitation, latitude, and longitude for impacted sites in our dataset ( n  = 2,389). Using tests of sensitivity and intensity, 17 fish metrics showed a clear reaction to human pressures. However, 12 metrics responded exclusively within only one of the four FATs. Hence we observed a divergent reaction of fish metrics to human pressures in, e.g., headwater versus lowland rivers. Type-specific reactions are useful in customizing impact assessment for particular river types. It is of primary importance to understand the comparative sensitivity and efficiency of fish-based indicators of water quality for detecting human-induced degradation of river ecosystems.

Description: To elucidate the effects of scallop mariculture on the macrobenthic community in a moderate energy system, bimonthly samples from four transects along a distance gradient in Sishili Bay, the northern Yellow Sea of China, were investigated. Differences in macrobenthic community structure along the distance gradient were evaluated using univariate and multivariate analyses. The AZTI’s Marine Biotic Index (AMBI) and multivariate-AMBI analyses indicated that the macrobenthic community suffered little disturbance from the scallop culture. Consistently, the results of two-way analysis of similarities demonstrated that macrobenthic communities showed no difference along the distance gradient, but were significantly affected by the sampling months and transects. This conclusion was also confirmed by other univariate and multivariate analyses. The concentration of total organic carbon was 17.27 ± 6.05 mg g −1 , which is below the dangerous threshold of 35 mg g −1 toxic to benthic fauna. Combined results revealed that no detectable effects on the macrobenthic community were caused by intensive and long-term scallop culture in this moderate energy system. This is likely due to the influence of local hydrodynamics and it is recommended that intensive scallop farming be located in areas with strong tidal or current flows.

Description: Southwestern Australia has already undergone significant climatic warming and drying and water temperatures are increasing particularly in small streams where riparian vegetation has been cleared. The ability to predict how freshwater fauna may respond to these changes requires understanding of their thermal tolerances. A review of relevant literature and laboratory testing of four aquatic species from southwestern Australia were used to compare upper thermal tolerance (UTT) among key taxonomic groups. UTT for selected species determined by LT 50 tests were similar to that of species tested elsewhere. Mean UTT, based on relevant literature and LT 50 experiments, ranged from 22.3°C for Ephemeroptera to 43.4°C for Coleoptera. Mean UTT for both Coleoptera and Odonata (41.9°C) were significantly higher than those for all the other groups (22.3–31.5°C) with the exception of Planaria. The mean UTT value of 22.3°C for Ephemeroptera was significantly lower than for Decapoda (29.6°C), Trichoptera (30.1°C) and Mollusca (31.5°C). For three insect orders tested, eurytherms had significantly higher UTT values than stenotherms. The variation in UTT among taxa suggests that additional thermal shifts, caused by riparian disturbance and/or climate change, are likely to create novel assemblages due to the replacement of temperature-sensitive taxa by more tolerant taxa. This has implications for the sustainability of regionally important endemic cool water species.

Description: The effects of stream urbanization on fishes have been well studied in general. Yet despite the wealth of knowledge available for streams in many different ecoregions, relatively little is known of the effects of urbanization on prairie stream fishes. Management of urban stormwater through impoundment has the potential to fragment streams, and habitat fragmentation on nonurban streams has been documented to relate to declines in small-bodied mobile minnow species. We asked whether urban habitat fragmentation through stormwater impoundment would relate to a similar decline in small-bodied fishes in Cottonwood Creek, a stream system partially managed by stormwater impoundment in central Oklahoma. Analyses with basic metrics of ecological tolerance, richness, community structure, and multivariate ordination found negative relationships between cyprinid richness and abundance and a metric of urban habitat fragmentation, as well as between Lepomis humilis , a small-bodied sunfish, and the metric of urban habitat fragmentation. We review potential hypotheses for these biological patterns in fragmented urban streams, including predation, lack of successful reproduction, and lack of ability to recolonize above barriers.

Description: While numerous reports exist on the results of lake restoration initiatives in temperate regions, only a few exist from subtropical lakes. We present results of the lake restoration of shallow, subtropical Lake Wuli, China, conducted between 1999 and 2010. After restoration, annual average concentrations of total nitrogen, total phosphorus (TP), and chlorophyll a and the chemical oxygen demand declined significantly, though summer TP remained high. Suspended solids increased significantly over the years, whereas transparency decreased, though not significantly so. The contribution of cryptophytes to total phytoplankton biomass decreased, while the proportion of cyanobacteria, especially potentially N 2 -fixing species, increased. Rotifers were superseded by crustaceans as the dominant taxon of the zooplankton community. Enhanced abundance of Daphnia spp., appearance of Leptodora kindti , and increased biomass ratios of zooplankton to phytoplankton, calanoids to cyclopoids, and nauplii to copepods in the post-restoration period indicate reduced fish predation and stronger top-down control of phytoplankton. However, the increase in non-algal turbidity, probably caused by the higher biomass of benthivorous fish, apparently prevented the re-establishment of submerged macrophyte communities. We conclude that removal of fish, particularly benthivorous species, will further improve water quality in this and other subtropical shallow lakes.

Description: Agricultural and urban runoffs result in increased nitrogen and phosphorus inputs in rivers and are the cause of eutrophication. Headwater streams are less frequently affected by these impairments because of the low-to-moderate human activities there. Eutrophication can affect the structure and function of benthic communities in headwater streams, stimulating the activity of heterotrophic microorganisms and macroinvertebrates on a pivotal process such as leaf-litter decomposition. In this study, we monitored the breakdown of alder leaves in six headwater streams that constitute a moderate nutrient enrichment gradient. Breakdown experiments were conducted in autumn–winter and leaf carbon, nitrogen and phosphorus, and associated aquatic hyphomycetes and macroinvertebrates were determined. The increase in nutrient availability in the stream water enhanced leaf-litter quality and led to an increase in the hyphomycete assemblage evenness and a reduction of shredder densities. However, contrary to our expectations, dissolved nutrient availability did not explain the breakdown rates. Thus, the absence of a clear effect of nutrient enrichment of stream water on the leaf breakdown rate highlights the difficulties of predicting the response of this ecosystem process to slight levels of eutrophication in headwater streams.

Description:    Millions of fish ascend through fishways in South America every year, but there is no evidence that downstream passage is occurring in large dams. Based on this concern, this study monitored the fish ladder at Lajeado Dam, Tocantins River, a large Amazonian tributary. To investigate the extent of downstream movements through the fishway, ascending and descending movements were quantified between November 2007 and October 2008. Monitoring showed that the ladder is restrictive to many species in both directions, but downstream passage was much more limited: almost all fish captured in the ladder (99.5%) were ascending the facility. Consequently, the numerical ratio between ascending and descending fish (ind./m 2 ) showed high positive values throughout the year (1508:1 on average); migratory species showed higher ratios. All results showed that downstream passage through the ladder is very limited, and that the facility allows only one-way movements (i.e., upstream). This is the first empirical evidence showing that a ladder is critically deficient for downstream passage of fishes in South America. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0787-0 Authors Carlos Sérgio Agostinho, Núcleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Rua 3, Quadra 17, Jardim dos Ipês, Porto Nacional, TO 77500-000, Brazil Fernando Mayer Pelicice, Núcleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Rua 3, Quadra 17, Jardim dos Ipês, Porto Nacional, TO 77500-000, Brazil Elineide Eugênio Marques, Núcleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Rua 3, Quadra 17, Jardim dos Ipês, Porto Nacional, TO 77500-000, Brazil Anderson Brito Soares, Núcleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Rua 3, Quadra 17, Jardim dos Ipês, Porto Nacional, TO 77500-000, Brazil Deusimar Augusto Alves de Almeida, Investco S.A., Miracema do Tocantins, TO, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Marine sponges of the class Hexactinellida (glass sponges) are among the most understudied groups of Porifera, and molecular approaches to investigating their evolution have only recently emerged. Although these first results appeared reliable as they largely corroborated morphology-based hypotheses, they were almost exclusively based on ribosomal RNA genes (rDNA) and should, therefore, be further tested with independent types of genetic data, such as protein-coding genes. To this end, we established the mitochondrial-encoded cytochrome oxidase subunit I gene (COI) as an additional marker, and conducted phylogenetic analyses on DNA- and amino-acid level, as well as a supermatrix analysis based on combined COI DNA and rDNA alignments. Furthermore, we increased taxon sampling compared to previous studies by adding seven additional species. The COI-based phylogenies were largely congruent with the rDNA-based phylogeny but suffered from poor bootstrap support for many nodes. However, addition of the COI sequences to the rDNA data set increased resolution of the overall molecular phylogeny. Thus, although obtaining COI sequences from glass sponges turned out to be quite challenging, this gene appears to be a valuable supplement to rDNA data for molecular evolutionary studies of this group. Some implications of our extended phylogeny for the evolution and systematics of Hexactinellida are discussed. Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0727-z Authors Martin Dohrmann, Department of Earth & Environmental Sciences, Palaeontology & Geobiology, LMU Munich, Richard-Wagner-Straße 10, 80333 Munich, Germany Karri M. Haen, Department of Ecology, Evolution & Organismal Biology, Iowa State University, 253 Bessey Hall, Ames, IA 50011, USA Dennis V. Lavrov, Department of Ecology, Evolution & Organismal Biology, Iowa State University, 253 Bessey Hall, Ames, IA 50011, USA Gert Wörheide, Department of Earth & Environmental Sciences, Palaeontology & Geobiology, LMU Munich, Richard-Wagner-Straße 10, 80333 Munich, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Two sympatric and divergent adaptive ecotypes of Littorina saxatilis (RB and SU) are known to hybridize showing partial premating isolation in the wild. Previous studies have revealed that morphological intermediate forms (presumably hybrids) present fitness (viability, sexual selection and fecundity) similar to that from pure ecotypes at the mid-shore. However, the absence of postzygotic isolation due to genetic incompatibility cannot be ruled out unless it is measured directly on true F 1 hybrids. In this study, we overcome this problem and present data on 56 individual crosses including the four possible mating combinations (RB/RB, RB/SU, SU/RB and SU/SU) to compare fertilization and fecundity rates (including young progeny viability) between the four type crosses. Pooled RB female crosses showed apparently larger fertility and fecundity than pooled SU female crosses, probably because of differences in fecundity and laboratory survivorship between ecotypes. However, similar fertilization and fecundity rates were found for both RB and SU females when mated with different male types, supporting the idea that genetic-incompatibility-based postzygotic isolation can be ignored as a major determinant of this polymorphism in nature. Content Type Journal Article Pages 1-6 DOI 10.1007/s10750-011-0788-z Authors M. Saura, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain M. Martínez-Fernández, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain M. J. Rivas, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain A. Caballero, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain E. Rolán-Alvarez, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Rewetting can strongly affect the matter balance of peatlands. Owing to evidence of increasing CH 4 emissions and P mobilisation after rewetting, the effects of peatland restoration on climate, eutrophication risks and related controversies are discussed. Our study focuses on the role of helophytes in the carbon and nutrient balance of rewetted fen grasslands of NE Germany. We hypothesise that the helophytes Carex riparia , Glyceria maxima , Phalaris arundinacea , Phragmites australis and Typha latifolia differ in biomass production and nutrient standing stock according to site conditions and harvest time. We analysed the helophyte biomass three times a year and continuously measured water levels and quality. Biomass production, nutrient standing stock and litter accumulation were highly species specific and depended on nutrient availability, mean water levels and harvesting time. We conclude that helophytes store considerable amounts of carbon and temporarily improve the water quality by withdrawing high amounts of nutrients from the top soil during the growing season, and by reducing nutrient discharges. Restoring peatlands as effective nutrient and carbon sinks in the landscape should favour highly productive potentially peat-forming helophytes as Phragmites australis by establishing adequate water levels. If nutrients are to be removed from the degraded peatland, then management can combine the restoration of helophyte stands by rewetting with harvesting measures. Content Type Journal Article Pages 1-16 DOI 10.1007/s10750-011-0782-5 Authors Karsten Schulz, Institute of Botany and Landscape Ecology, University of Greifswald, Grimmer Str. 88, 17487 Greifswald, Germany Tiemo Timmermann, Institute of Botany and Landscape Ecology, University of Greifswald, Grimmer Str. 88, 17487 Greifswald, Germany Peggy Steffenhagen, LUP—Luftbild Umwelt Planung GmbH, Große Weinmeisterstraße 3a, 14469 Potsdam, Germany Stefan Zerbe, Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano, Italy Michael Succow, Michael Succow Foundation, Institute of Botany and Landscape Ecology, Grimmer Str. 88, 17487 Greifswald, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Ecologically specialized species may be more susceptible to anthropogenic impacts than generalist species. Japan’s native bitterlings (subfamily Acheilognathinae), which are specialized to spawn on the gills of certain freshwater mussels, have been declining dramatically during the last few decades. To identify factors affecting the local occurrence of the threatened bitterling species Tanakia lanceolata , we measured its presence and absence, along with several environmental factors, at 68 sites within agricultural canal networks in the Lake Mikata basin, Fukui Prefecture, Japan. Based on the theoretical information approach of Akaike’s information criterion, generalized linear mixed models were constructed. These revealed that the species’ occurrence is strongly affected by five major factors: the presence of freshwater mussels Anodonta sp., water depth, floating plants coverage, the presence of bullfrogs, and submerged plants coverage. The probability of the presence of T. lanceolata was higher at shallower sites with lower floating plants coverage, located within channels containing mussel beds. These results suggest that mussel-containing channel systems are high-priority conservation zones for T. lanceolata . Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0790-5 Authors Akira Terui, Department of Ecosystem Studies, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan Shin-ichiro S. Matsuzaki, National Institute for Environmental Studies, Tsukuba-shi, Ibaraki 305-8506, Japan Kohji Kodama, Fukui Prefectural Fisheries Experimental Station, Urazoko, Tsuruga-shi, Fukui 914-0843, Japan Masamitsu Tada, Fukui Prefectural Coastal Nature Center, 18-2 Sekumi, Mikatakaminaka-gun, Fukui 919-1464, Japan Izumi Washitani, Department of Ecosystem Studies, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Daphnia subfossils from lake sediments are useful for exploring the impacts of environmental stressors on aquatic ecosystems. Unfortunately, taxonomic resolution of Daphnia remains is coarse, as only a small portion of the animal is preserved, and so the identification of daphniid subfossils typically relies upon postabdominal claws. Daphniid claws can be assigned to one of two species complexes: D. longispina or D. pulex . Both complexes contain species with differing environmental optima, and therefore improved taxonomic resolution of subfossil daphniid claws would aid paleolimnological analyses. To identify morphological features that may be used to help differentiate between species within complexes, we used species presence/absence data from net tows to select lakes in central Ontario (Canada) containing only a single species from a particular complex, then used remains preserved in surface sediments of these lakes to isolate four Daphnia species: D.   ambigua and D.   mendotae from the D. longispina complex, and D. pulicaria and D. catawba from the D. pulex complex. Our analyses demonstrate that, within the D.   longispina complex, postabdominal claw length (PCL) and spinule length can be used to distinguish D. mendotae from D. ambigua . In addition, within the D. pulex complex, there are differences between D. pulicaria and D. catawba in the relative lengths of the proximal and middle combs on the postabdominal claw. However, the number of stout spines on the middle comb is an unreliable character for differentiating species. Overall, our data demonstrate that greater resolution within Daphnia species complexes is possible using postabdominal claws; however, the process is arduous, and applicability will likely decrease with the number of taxa present. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0779-0 Authors Jennifer B. Korosi, Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada Adam Jeziorski, Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada John P. Smol, Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The European Union’s Water Framework Directive has set a target of achieving good ecological status for all aquatic environments in Europe by 2015. In order to determine the quality of aquatic environments, biological indicators such as diatoms are often used. However, biotic diatom indices can be difficult and time consuming to use because of complexity of species determination. We investigated whether the biological traits of diatoms in rivers (life-forms, size classes and ecological guilds) could be used to assess organic pollution and trophic level. We worked on a data set comprising 315 diatom species, determined at 328 river stations of south-east France and a variety of parameters. The abundances of some biological traits differed significantly between the different organic pollution and trophic levels, particularly stalked diatoms, and the motile and low-profile guilds. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0786-1 Authors Vincent Berthon, INRA, UMR CARRTEL, 75 av. de Corzent, BP 511, 74203 Thonon-les-Bains Cedex, France Agnès Bouchez, INRA, UMR CARRTEL, 75 av. de Corzent, BP 511, 74203 Thonon-les-Bains Cedex, France Frédéric Rimet, INRA, UMR CARRTEL, 75 av. de Corzent, BP 511, 74203 Thonon-les-Bains Cedex, France Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Quantitative genetic studies in natural populations are of growing interest to speciation research since divergence is often believed to arise through micro-evolutionary change, caused by natural selection on functional morphological traits. The species flock of cichlid fishes in Africa’s oldest lake, Lake Tanganyika, offers a rare opportunity to study this process. Using the cichlid species Tropheus moorii , we assessed the potential for microevolution in a set of morphological traits by estimating their quantitative genetic basis of variation. Two approaches were employed: (1) estimation of trait heritabilities ( h 2 ) in situ from a sample of wild caught fish, and (2) estimation of h 2 from first generation offspring produced in a semi-natural breeding experiment. In both cases, microsatellite data were used to infer pedigree structure among the sampled individuals and estimates of h 2 were made using an animal model approach. Although power was limited by the pedigree structures estimated (particularly in the wild caught sample), we nonetheless demonstrate the presence of significant additive genetic variance for aspects of morphology that, in the cichlid species Tropheus moorii , are expected to be functionally and ecologically important, and therefore likely targets of natural selection. We hypothesize that traits showing significant additive genetic variance, such as the mouth position have most likely played a key role in the adaptive evolution of the cichlid fish Tropheus moorii . Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0785-2 Authors Martin Koch, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Alastair J. Wilson, Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT UK Michaela Kerschbaumer, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Thomas Wiedl, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Christian Sturmbauer, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Genetic variability within and among Bulinus truncatus of the Albertine Rift freshwater bodies were assessed to investigate the degree of inbreeding and gene flow in the snail populations. The effect of ploidy on the genetic structuring of B.   truncatus is also described. We characterized the genetic structure of seven B.   truncatus populations from Lake Albert, Lake Kivu, and Katosho swamp in Tanzania using five polymorphic microsatellite loci. Genetic differentiation was quantified using pairwise FST values and Nei’s standard genetic distances. Different alleles were observed across all loci and genetic diversity was low although it varied greatly across populations; observed heterozygosity was, however, higher than the expected heterozygosity in three of the populations studied. Significant heterozygote deficiencies were observed coupled with significant linkage disequilibria in five populations for all the five loci examined in this study. We found significant genetic differentiation among the seven freshwater bodies; private alleles were observed across all loci indicating restricted or absence of gene flow between populations. Limited snail dispersal and the reproductive biology of B.   truncatus are the major forces shaping the genetic variation observed. Low genetic variation within B.   truncatus populations exposes them to a high parasite infection risk as predicted in the Red Queen hypothesis. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0749-6 Authors Allen Nalugwa, Molecular Biology Laboratory, Makerere University, College of Agricultural and Environmental Sciences, P.O. Box 7298, Kampala, Uganda Aslak Jørgensen, Laboratory of Molecular Systematics, The Natural History Museum of Denmark, Sølvgade 83, 1307 Copenhagen K, Denmark Silvester Nyakaana, Molecular Biology Laboratory, Makerere University, College of Agricultural and Environmental Sciences, P.O. Box 7298, Kampala, Uganda Thomas K. Kristensen, The Mandahl-Barth Research Centre for Biodiversity and Health, DBL-Parasitology, Health and Development, Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 57, 1871 Frederiksberg C, Denmark Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Previous phylogenetic investigations on the mayfly Baetis rhodani Pictet from several European countries, excluding Italy, strongly suggested the presence of cryptic species. Our paper reports a DNA-taxonomy phylogenetic analysis of B. rhodani with additional populations coming from Italian and UK sites, and aims to identify potential cryptic species with a coalescent-based method (GMYC model) and to understand the mechanisms of local coexistence of cryptic species. Twenty-five haplotypes of Italian samples and five haplotypes of UK samples were identified and added to a large European dataset. A total of 11 potential cryptic species have been recognised, and three of them co-occured in one Italian area. Such cryptic species seem to be phylogenetically over-dispersed on the tree and temporally segregated, and the seasonal substitution pattern of cryptic species could explain the apparently widespread distribution of the B. rhodani complex and its ability to adapt to different temperatures and food resources, justifying some of the differences observed in the relationship between water temperature, growth rates and phenology documented from field studies. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0778-1 Authors Livia Lucentini, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Manuela Rebora, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Maria Elena Puletti, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Lilia Gigliarelli, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Diego Fontaneto, Division of Biology, Imperial College London, Silwood Park Campus, SL5 7PY Ascot, Berkshire, UK Elda Gaino, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Fausto Panara, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description: Preface: Restoration, biogeochemistry and ecological services of wetlands Content Type Journal Article Pages 1-4 DOI 10.1007/s10750-011-0783-4 Authors Dominik Zak, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Central Chemical Laboratory, Müggelseedamm 301, 12587 Berlin, Germany Robert McInnes, Bioscan (UK) Ltd., The Old Parlour, Little Baldon Farm, Oxford, OX44 9PU UK Jörg Gelbrecht, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Central Chemical Laboratory, Müggelseedamm 301, 12587 Berlin, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We compared land cover, riparian vegetation, and instream habitat characteristics with stream macroinvertebrate assemblages in 25 catchments in the Carpathian Mountains in Central Europe. This study area was particularly selected because of its diverse history of forest and agricultural ecosystems linked to geopolitical dynamic, which provide a suite of unique landscape scale, land cover settings in one ecoregion. Canonical Correspondence Analysis (CCA) showed that variation in composition and structure of macroinvertebrate assemblages was primarily related to four land cover types, and not to riparian or instream habitat. These were the portions in the catchment areas of (1) broadleaved forest, (2) fine-grained agricultural landscape mosaic with scattered trees (e.g., pre-industrial cultural landscape), (3) mixed forest, and (4) natural grassland without trees. Principal Component Analysis (PCA) suggested that land cover types and stream channel substrates co-varied. The PCA also showed that chemical variables, including organic carbon, had higher values in the agricultural landscape compared to natural forests. The major source of variation among taxa in streams was higher abundance of Diptera in agricultural landscapes and of Plecoptera, Coleoptera, Trichoptera, and Amphipoda in forests. Gastropoda and Oligochaeta were more abundant in open, fine-grained agricultural landscape mosaics with scattered trees. Ephemeroptera taxa were quite indifferent to these gradients in catchment land cover, but showed a tendency of being more abundant in the pre-industrial cultural landscape. Our findings suggest that land cover can be used as a proxy of the composition and structure of macroinvertebrate assemblages. This means that land use management at the catchment scale is needed for efficient conservation and recovery of stream invertebrate communities. Content Type Journal Article Pages 1-16 DOI 10.1007/s10750-011-0769-2 Authors J. Törnblom, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, 739 21 Skinnskatteberg, Sweden P. Angelstam, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, 739 21 Skinnskatteberg, Sweden E. Degerman, National Board of Fisheries, 702 15 Örebro, Sweden L. Henrikson, Freshwater Program, WWF, Ulriksdals Slott, 170 81 Solna, Sweden T. Edman, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, 739 21 Skinnskatteberg, Sweden J. Temnerud, Department of Natural Sciences, Man-Technology-Environment Research Centre, Örebro University, Örebro, Sweden Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Different groups of marine benthic organisms show contrasting latitudinal patterns of biodiversity. The widely accepted paradigm of increasing biodiversity towards the tropics does not seem to be valid for macroalgal floras of the Southern Hemisphere. We compiled a database summarizing the distributional ranges of macroalgae along the coast of Argentina to test whether biodiversity decreases towards lower latitudes, as in the Pacific coast of South America, and whether breaking points in the geographical distribution can be recognized in one or more areas of the Southwest Atlantic south of 36°S. We found a clear trend of decreasing biodiversity with decreasing latitude. The interpretation of some biodiversity declines is confounded by changes in the intensity of the sampling effort. A 51% reduction in algal species richness between 42 and 41°S coincides with the boundary between the Argentine and Magellanic Zoogeographic Provinces. This sharp breaking point is related to a thermal anomaly caused by long residence times of water masses within San Matías Gulf, suggesting an upper thermal tolerance limit for most Antarctic/sub-Antarctic seaweeds. A further reduction occurs at 38–37°S. This breaking point can be explained by the disappearance of suitable hard substrata, since rocky outcrops give place to wide extensions of sandy beaches. The impoverished algal assemblage inhabiting the northern coast of Argentina is mainly related to the reduction or disappearance of the Antarctic/sub-Antarctic floristic component. This area is characterised by a predominance of widely distributed species, Chlorophytes and opportunistic filamentous or foliose algae. Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0780-7 Authors María G. Liuzzi, Museo Argentino de Ciencias Naturales, Av. Ángel Gallardo 470, C1405DJR Buenos Aires, Argentina Juan López Gappa, Museo Argentino de Ciencias Naturales, Av. Ángel Gallardo 470, C1405DJR Buenos Aires, Argentina María L. Piriz, Morgan 2455, U9120AFM Puerto Madryn, Chubut, Argentina Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Transposable elements play a vital role in genome evolution and may have been important for the formation of the early metazoan genome, but only little is known about transposons at this interface between unicellular opisthokonts and Metazoa. Here, we describe the first miniature transposable elements (MITEs, Queen1 and Queen2 ) in sponges. Queen1 and Queen2 are probably derived from Tc1/mariner-like MITE families and are represented in more than 3,800 and 1,700 copies, respectively, in the Amphimedon queenslandica genome. Queen elements are located in intergenic regions as well as in introns, providing the potential to induce new splicing sites and termination signals in the genes. Further possible impacts of MITEs on the evolution of the metazoan genome are discussed. Content Type Journal Article Pages 1-5 DOI 10.1007/s10750-011-0775-4 Authors Dirk Erpenbeck, Department of Earth- and Environmental Sciences & GeoBio-CenterLMU, Ludwig-Maximilians Universität, Richard-Wagner-Str. 10, 80333 München, Germany Jürgen Schmitz, Institute of Experimental Pathology, ZMBE, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany Gennady Churakov, Institute of Experimental Pathology, ZMBE, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany Dorothée Huchon, Department of Zoology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978 Israel Gert Wörheide, Department of Earth- and Environmental Sciences & GeoBio-CenterLMU, Ludwig-Maximilians Universität, Richard-Wagner-Str. 10, 80333 München, Germany Bernard M. Degnan, School of Biological Sciences, University of Queensland, Brisbane, 4072 Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    High-resolution biostratigraphy has been established on the basis of fossil ostracodes from cores of the Cretaceous Continental Scientific Drilling borehole-Songke 1 (south) (SK1(s)) in the Songliao Basin, northeast China. More than 80 species belonging to 13 genera have been identified and 15 ostracode assemblage zones have been recognized. On the basis of ostracode paleoecological analysis, paleoenvironments, for example lake levels and salinity, have been reconstructed. Two inferred deep-water phases occurred during the deposition of the lower Qingshankou and lower Nenjiang formations, whereas shallower water phases probably occurred during deposition of the upper Quantou and uppermost Qingshankou to Yaojia formations. The salinity of paleo-Songliao lake is interpreted as predominantly freshwater to oligohaline. Oligohaline to mesohaline water environments may have occurred during the first and middle third members of the Qingshankou formation and the lower first and lower second members of the Nenjiang formation. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0765-6 Authors Dangpeng Xi, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Shun Li, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Xiaoqiao Wan, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Xia Jing, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Qinghua Huang, Daqing Oilfield, Daqing, Heilongjiang, People’s Republic of China Jean-Paul Colin, Impassse des Biroulayres, 33610 Cestas, France Zhuo Wang, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Weiming Si, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Jenynsia multidentata is one of the most abundant freshwater fishes in the subtropical region of South America and when abundant it appears to have a major impact on lake ecosystems function. We studied the life-history traits and population structure of J. multidentata in a shallow lake in Uruguay, and collected literature data along a subtropical to tropical freshwater gradient in South America. Our general focus was on reproductive strategy, particularly on sexual differences in growth, size and abundance. In Lake Blanca, we found strong reverse size dimorphism (RSD) and a feminized sex ratio. Both are attributed to sexual differences in growth patterns and longevity. RSD and a feminized sex ratio seem to characterise J. multidentata regardless of latitude, and together with other life traits such as small size, rapid growth, low age of maturity, the capacity of the females to keep sperm alive to fertilize several successive litters, high natural mortality and fertility, resistance to extreme environmental conditions and omnivory, they are indicative of high productivity to biomass ratio. The very high population growth rate helps to explain why fish removal, aiming to promote an increase in the zooplankton grazing pressure on phytoplankton, may not be a useful tool in eutrophic-turbid subtropical South American lakes. We also found that the duration of the breeding season deviated markedly with latitude, increasing towards the tropics, which may have major consequences for population growth rates and differential impact of this species on lake ecosystems in the different climate zones. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0784-3 Authors G. Goyenola, Ecología y Rehabilitación de Sistemas Acuáticos, Departamento de Ecología y Evolución, Centro Universitario Regional Este/Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay C. Iglesias, Ecología y Rehabilitación de Sistemas Acuáticos, Departamento de Ecología y Evolución, Centro Universitario Regional Este/Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay N. Mazzeo, Ecología y Rehabilitación de Sistemas Acuáticos, Departamento de Ecología y Evolución, Centro Universitario Regional Este/Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay E. Jeppesen, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Diatom-based indices are increasingly becoming important tools for the assessment of ecological conditions in lotic systems. The applicability of regional and foreign diatom-based water quality assessment indices to streams around São Carlos-SP, Brazil, is discussed. The relationship between measured water quality variables and diatom index scores was assessed. The indices, when compared to chemical analyses, proved useful in providing an indication of the quality of the investigated waters. Though all borrowed indices were applicable to the study area because many widely distributed diatom species have similar environmental tolerances to those recorded for these species elsewhere, ecological requirements of some diatom species from Brazil need to be clarified and incorporated in a diatom-based water quality assessment protocol unique to the region. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0772-7 Authors Taurai Bere, Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, São Carlos, São Paulo, Brazil José Galizia Tundisi, Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, São Carlos, São Paulo, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Sponges are an important component of the benthic community, especially on coral reefs, but demographic data such as growth, recruitment or mortality are notably limited. This study examined the growth of the elephant ear sponge Ianthella basta , the largest and in some areas one of the dominating sponge species on Guam and other pacific reefs. We measured growth rates of the natural population on Guam over the course of one year and identified intra-individual growth patterns. Initial sponge sizes ranged from 200 to 35,000 cm 2 . Specific growth rates ranged from 0.08 to 6.08 with a mean specific growth rate of 1.43 ± 1.29 (SD) year −1 . Furthermore, specific growth decreased with sponge size. The age estimate for the largest sponge (1.7 m height × 9.5 m circumference) was ~8 years. Intra-individual growth was mostly apical. This study demonstrated high growth rates, which has notable implications for environmental assessments, management and potential biomedical applications. Content Type Journal Article Pages 1-8 DOI 10.1007/s10750-011-0774-5 Authors Sven Rohde, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstr. 1, 26382 Wilhelmshaven, Germany Peter J. Schupp, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstr. 1, 26382 Wilhelmshaven, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Copper poses a risk to the integrity of the Thames Estuary and Marshes special protection area (SPA) as bioaccumulation within the food chain takes place. This article describes some of the investigations carried out for the Habitats Directive Review of Consents including a review of the methods used to analyse copper samples; analysis of the long-term data sets gathered by the Environment Agency; and modelling work. Mean dissolved copper levels for 2002–2006 are below the 5 μg/l Environmental Quality Standard. Catchment modelling was used to establish total copper budgets both for sources discharging directly to the Tideway and for sources throughout the Thames catchment including sewage treatment works (STWs), industries, non-urban, and urban runoff. The total copper load to the Tideway was estimated to be 36 tonnes/year with 52% of this attributed to STWs. Modelling was used to explore the mixing, transport and fate of copper throughout the estuary taking account of partitioning and the interaction with sediments. The modelling showed how the fourth Water Industry Asset Management Programme (AMP4) improvements to the main London STWs would affect copper concentrations throughout the estuary. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0756-7 Authors Donna Murray, WRc plc, Frankland Road, Blagrove, Swindon, SN5 8YF UK Paul Dempsey, WRc plc, Frankland Road, Blagrove, Swindon, SN5 8YF UK Peter Lloyd, Environment Agency, Rivers House, Crossness STW, Belvedere Road, Abbey Wood, London, SE2 9AQ UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Restoration of drained peatlands has been promoted to reduce gaseous and aquatic carbon losses; however, there are conflicting reports as to its effectiveness. Here we report “hotspots” of organic matter decomposition as a result of rewetting a drained peatland in Wales, at the field-scale, in the medium/long-term with implications for water quality and greenhouse gas emissions. Low soil moisture levels, that characterise these hotspots before rewetting, regenerate electron acceptors and provide carbon and nutrients which stimulate phenol oxidase-mediated release of phenolic compounds from the peat matrix upon waterlogging. Electron acceptors are then consumed sequentially, eventually favouring CH 4 production and rising pH, despite accumulating SO 4 levels. The latter two processes promote positive feedback to increased phenol oxidase activities and the release of even more dissolved organic carbon (DOC) and CH 4 from the peat matrix. Hotspot formation therefore represents an inextricably linked physico-chemical and biological positive feedback mechanism. Such hotspots account for a large proportion of the mean increase in carbon loss due to rewetting of this naturally drained peatland (e.g. at maximum mean DOC concentrations: with hotspot 997%; without hotspot 102%) and are not “outliers” but important drivers of biogeochemical fluxes that should be included in budgets for carbon and other elements (e.g. sulphur). As such, understanding hotspot formation should allow improved management strategies for restoration, carbon stocks, drinking water quality and even future geo-engineering options in the face of changes in climate and atmospheric chemistry. Content Type Journal Article Pages 1-16 DOI 10.1007/s10750-011-0733-1 Authors Nathalie Fenner, School of Biological Sciences, Bangor University, Bangor, LL57 2UW UK Robert Williams, School of Biological Sciences, Bangor University, Bangor, LL57 2UW UK Hannah Toberman, School of Biological Sciences, Bangor University, Bangor, LL57 2UW UK Steve Hughes, Centre for Ecology & Hydrology (CEH), Bangor, LL57 2UW UK Brian Reynolds, Centre for Ecology & Hydrology (CEH), Bangor, LL57 2UW UK Chris Freeman, School of Biological Sciences, Bangor University, Bangor, LL57 2UW UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    In this article, the variability of physical settings of anchialine systems in Indonesia is discussed together with the consequences these settings have for the environment and biota within the systems. Exploration in two karstic areas (Berau, East Kalimantan and Raja Ampat, West Papua) has resulted in the discovery of 20 previously unknown anchialine systems in Indonesia. Based on parameters such as bathymetry, size, coastline, salinity, water temperature, pH, degree of connection to the sea, and the presence-absence of selected key taxa we distinguish three types of (non-cave) anchialine systems in the Indo-Pacific: (1) Marine lakes with large and deep basins containing brackish to almost fully marine waters. Marine lakes show a range in the degree of connection to the sea with the result that the higher the connection the more the lake resembles a lagoon in both water chemistry and biota, while the more isolated lakes have brackish water and contain unique species that are rarely found in the adjacent sea. (2) Anchialine pools with small and shallow basins containing brackish water and low diversity of macrofauna. (3) Blue pools in chasms that contain water with a clear halocline and are possibly connected to anchialine caves. Study of the many unique features of anchialine systems will enhance our understanding of the physical and ecological processes responsible for diversification in tropical shallow marine environments. Content Type Journal Article Pages 1-17 DOI 10.1007/s10750-011-0742-0 Authors Leontine E. Becking, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Willem Renema, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Nadiezhda K. Santodomingo, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Bert W. Hoeksema, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Yosephine Tuti, Indonesian Institute of Sciences, Research Centre for Oceanography, P.O. Box 4801/JKTF, Jakarta, 11048 Indonesia Nicole J. de Voogd, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Chemical defenses are an effective mode of predator deterrence across benthic marine organisms, but their production may come with associated costs to the organism as limited resources are diverted away from primary processes like growth and reproduction. Organisms concentrating ecologically relevant levels of these defenses in tissues most at risk to predator attack may alleviate this cost while deterring predators. We addressed this hypothesis by investigating the deterrence of chemical extracts from the inner and outer regions of the sponges Aplysina fulva , Ircinia felix , and I. campana from a temperate hard-bottom reef in the South Atlantic Bight. Assays were conducted using natural fish assemblages and sea urchins. Although, A. fulva and I. felix have higher concentrations of defensive metabolites in the outer and inner regions, respectively, extracts from these regions did not display enhanced deterrency against fish or mobile invertebrate predators. Likewise, extracts from both regions of the sponge Ircinia campana , which has a uniform distribution of defensive chemicals throughout, did not differ in their ability to deter either group of predators. Since chemical defenses were effective deterrents at lower concentrations, secondary metabolite allocation patterns observed among these sponges are likely not driven by predation pressure from generalist fish and mobile invertebrate predators on these reefs. Alternatively, these patterns may be driven by other ecological stressors, another suite of predators, or may be more effective at deterring predators when combined with structural defenses. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0792-3 Authors Christopher J. Freeman, Department of Biology, University of Alabama at Birmingham, 1300 University Boulevard, Campbell Hall Room 464, Birmingham, AL 35294, USA Daniel F. Gleason, Department of Biology, Georgia Southern University, P.O. Box 8042, Statesboro, GA 30460, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Early to late Pliocene sedimentary strata present across the northern Bass Strait hinterland, southeastern Australia yield extensive fossil proxy data relevant to the interpretation of high sea level coastal palaeomorphology. Within the Pliocene Whalers Bluff Formation exposed in coastal cliffs near the township of Portland, Victoria, marine microfossil faunas delineate two broad cycles of deposition. Both these sedimentary cycles are bound below by unconformity surfaces. Within the lower sedimentary cycle, a basal stress-tolerant (low diversity) marginal marine microfossil fauna devoid of ostracods and suggestive of bottom-water hypoxia, is succeeded by a diverse shallow marine ostracod fauna dominated by stenohaline species indicative of a sheltered (but open) oceanic embayment. This lower sedimentary cycle has an early Pliocene (Zanclean) age. Equivalent shallow marine (e.g. coastal embayment) deposits occur broadly across the coastal hinterland of southeastern Australia—reflecting the generally higher global sea levels of this time. The upper cycle in the cliff exposures at Portland is late Pliocene (Piacenzian) in age. Equivalent deposits across the Bass Strait hinterland are restricted to former incised river valley settings. Euryhaline estuarine/coastal lagoon Ostracoda are present throughout the upper cycle in the Portland cliffs. These are associated with a low diversity microfauna at the base of the upper cycle and a high diversity microfauna towards the top of the cycle. Early Pliocene coastal marine deposits can be distinguished from late Pliocene coastal marine deposits across the northern Bass Strait hinterland on the basis of the presence or absence of certain open marine (‘stenohaline’) ostracod species. Content Type Journal Article Pages 1-20 DOI 10.1007/s10750-011-0777-2 Authors Mark T. Warne, School of Life and Environmental Sciences, Deakin University (Melbourne Campus), 221 Burwood Highway, Burwood, VIC 3135, Australia Brent Soutar, School of Life and Environmental Sciences, Deakin University (Melbourne Campus), 221 Burwood Highway, Burwood, VIC 3135, Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The Three Gorges Dam was built in 2005 with a storage capacity of 39.3 billion m 3 , ranking 22nd in the world. However, since the impoundment of the reservoir, serious blooms of phytoplankton have occurred. Rotifers, having a key role in the freshwater aquatic food web, are important grazers of phytoplankton and an essential food resource to higher trophic consumers. To explore the impacts of phytoplankton blooms on the rotifer community, daily and vertical surveys of rotifers were conducted in a bay of the Three Gorges Reservoir (Xiangxi Bay). Altogether 46 rotifer species were registered, and Synchaeta tremula , Polyarthra vulgaris , and Brachionus calyciflorus were the most abundant species accounting for 36, 26, and 16% of the mean rotifer densities, respectively. Although these dominant species always prevailed in the rotifer community, their proportions changed significantly from non-bloom phase to bloom phase, e.g., the significance of S. tremula deceased from 46.8 to 33.2%, while P. vulgaris and B. calyciflorus increased from 23.9 and 13.9% to 26.2 and 16.2%, respectively. In the vertical water column, all the rotifer following phytoplankton displayed an aggregated distribution, concentrating at the upper layers (0.5–5 m), especially during the bloom phase. From the non-bloom phase to the bloom phase, rotifer densities, the dominant rotifers, Shannon–Wiener and Margalef’s diversity increased significantly, while the evenness displayed the opposite trend. Non-metric multidimensional scaling analysis (NMDS) revealed that the samples in the non-bloom phase were well separated from those in the bloom phase. This means that the outbreak of the diatom bloom in the Xiangxi Bay had significant impacts on the rotifer community. Further investigations are needed to address the impacts of the changes of rotifer community on higher trophic levels. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0793-2 Authors Shuchan Zhou, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 People’s Republic of China Qinghua Cai, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 People’s Republic of China Yaoyang Xu, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 People’s Republic of China Xinqin Han, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 People’s Republic of China Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The complete mitochondrial DNA (mtDNA) genome of the Eunapius subterraneu s (Porifera, Demospongiae), a unique stygobitic sponge, was analyzed and compared with previously published mitochondrial genomes from this group. The 24,850 bp long mtDNA genome is circular with the same gene composition as found in other metazoans. Intergenic regions (IGRs) comprise 24.7% of mtDNA and are abundant with direct and inverted repeats and palindromic elements as well as with open reading fames (ORFs) whose distribution and homology was compared with other available mt genomes with a special focus on freshwater sponges. Phylogenetic analyses based on concatenated amino acid sequences from 12 mt protein genes placed E.   subterraneus in a well-supported monophyletic clade with the freshwater sponges, Ephydatia muelleri and Lubomirskia baicalensis . Our study showed high homology of mtDNA genomes among freshwater sponges, implying their recent split. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0789-y Authors Bruna Pleše, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Lada Lukić-Bilela, Institute for Genetic Engineering and Biotechnology, Gajev trg 4, 71 000 Sarajevo, Bosnia and Herzegovina Branka Bruvo-Mađarić, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Matija Harcet, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Mirna Imešek, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Helena Bilandžija, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Helena Ćetković, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    A survey was conducted for the presence of cyanobacteria toxins in Lake Kotokel due to a few cases of Haff disease registered in 2008–2009 caused by consumption of fish from Lake Kotokel, and wildlife mortality including large fish kill. The aims of this study were to determine what cyanotoxins (if any) were present in the lake, to describe phytoplankton composition including morphology, density, and species diversity of cyanobacteria, as well as to evaluate the trophic state of the lake. Samples were collected from both nearshore and central sites in August of 2009. Aphanocapsa holsatica dominated the phytoplankton. The presence of toxigenic genotypes of Microcystis spp. and Anabaena lemmermannii was detected by sequencing of PCR-amplified aminotransferase domain of microcystin synthetase gene. LR, RR, and YR microcystin (MC) variants were detected with liquid chromatography-UV mass spectrometry. The data do not shed light on the etiology of Haff disease in Lake Kotokel region, nevertheless taking into account the recreational importance of the lake and its direct connection to Lake Baikal, a necessity to monitor cyanobacteria in these water bodies is evident. This is the first report on simultaneous detection of MC-producing genotypes and MCs in the Lake Baikal region. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0724-2 Authors Olga I. Belykh, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Ekaterina G. Sorokovikova, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Galina A. Fedorova, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Oksana V. Kaluzhnaya, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Evgeniya S. Korneva, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Maria V. Sakirko, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Tatyana A. Sherbakova, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Currently, the distribution of the European native white-clawed crayfish ( Austropotamobius pallipes ) is restricted, fragmented and mainly located in headwater streams. Many European countries have active programmes for its conservation and some also have reintroduction programmes. Here, we used the ephemeropteran communities as a bioindicator of A. pallipes presence. Results from 36 brooks showed that the ephemeropteran richness is statistically higher in sites with crayfish compared to sites without crayfish. We propose using two Leptophlebiidae species ( Habrophlebia lauta and Paraleptophlebia submarginata ) as bioindicators of crayfish presence. Content Type Journal Article Pages 1-6 DOI 10.1007/s10750-011-0717-1 Authors Frédéric Grandjean, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Joelle Jandry, Laboratoire de Chimie de l’Eau et de l’Environnement, Université de Poitiers, UMR-CNRS 6008, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Elodie Bardon, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Aurore Coignet, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Marie-Cécile Trouilhé, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Bernard Parinet, Laboratoire de Chimie de l’Eau et de l’Environnement, Université de Poitiers, UMR-CNRS 6008, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Catherine Souty-Grosset, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Michel Brulin, OPIE-benthos, La Minière, B.P. 30, 78041 Guyancourt cedex, France Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The anchovy/sardine complex is an important fishery resource in some of the largest upwelling systems in the world. Synchronous, but out of phase, fluctuations of the two species in distant parts of the oceans have prompted a number of studies dedicated to determining the phenomena, atmospheric and oceanic, responsible for the observed synchronicity and the biological mechanisms behind the population changes of the two species. Anchovy and sardine are of high commercial value for the fishing sector in Greece; this study investigates the impact of large-scale climatic indices on the anchovy/sardine complex in the Greek seas using fishery catches as a proxy for fish productivity. Time series of catches for both species were analysed for relationships with teleconnection indices and local environmental variability. The connection between the teleconnection indices and local weather/oceanic variation was also examined in an effort to describe physical mechanisms that link large-scale atmospheric patterns with anchovy and sardine. The West African Summer Monsoon, East Atlantic Jet and Pacific–North American (PNA) pattern exhibit coherent relationships with the catches of the two species. The first two aforementioned patterns are prominent atmospheric modes of variability during the summer months when sardine is spawning and anchovy juveniles are growing. PNA is related with El Niño Southern Oscillation events. Sea Surface Temperature (SST) appears as a significant link between atmospheric and biological variability either because higher temperatures seem to be favouring sardine growth or because lower temperatures, characteristic of productivity-enhancing oceanic features, exert a positive influence on both species. However at a local scale, other parameters such as wind and mesoscale circulation describe air–sea variability affecting the anchovy/sardine complex. These relationships are non-linear and in agreement with results of previous studies stressing the importance of optimal environmental windows. The results also show differences in the response of the two species to environmental forcing and possible interactions between the two species. The nature of these phenomena, e.g., if the species interactions are direct through competition or indirect through the food web, remains to be examined. Content Type Journal Article Pages 1-17 DOI 10.1007/s10750-011-0693-5 Authors Isidora Katara, School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, AB24 2TZ Aberdeen, UK Graham J. Pierce, School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, AB24 2TZ Aberdeen, UK Janine Illian, School of Mathematics and Statistics, The Observatory, University of St. Andrews, Buchanan Gardens, KY16 9LZ St. Andrews, UK Beth E. Scott, School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, AB24 2TZ Aberdeen, UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    This study evaluated whether the alpha and beta diversity of fishes in vegetated littoral zones of floodplain lakes in the Pantanal are randomly distributed on three different spatial scales: within the lake, among lakes, and between regions. Three alternative hypotheses were contrasted: (1) that regional diversity is generated at local scale, depending on the internal environmental heterogeneity of lakes, (2) that the diversity of fishes in floodplain lakes is produced at intermediate spatial scales, depending on structural differences and on the landscape matrix between lakes, and (3) that the diversity of fishes in the littoral zone is generated at regional scale, due to regional differences in land-use pattern and the presence of a geographical barrier represented by the river. Our results indicate that the regional diversity of fishes in the vegetated littoral zone of lakes in the northern Pantanal is a consequence of high diversity at the local level ( α ) and the wide differences in species composition among lakes and between regions. This suggests that we need to maintain environmental heterogeneity, represented by the structural differences among the lakes and their landscape matrix as well as regional differences in the flood pattern, if we hope to preserve the diversity of fishes in the region. Besides, it is necessary to establish new conservation units at the different Pantanal subregions, which should incorporate a set of lakes with different landscape features such as size, shape, and distance from and degree of connection to rivers. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0697-1 Authors Alexandro Cezar Florentino, Programa de Pós-Graduação em Biologia de Água Doce e Pesca Interior, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Petrópolis, Manaus, AM CEP 69060-001, Brazil Jerry Penha, Laboratório de Ecologia de Populações, Instituto de Biociências, Universidade Federal de Mato Grosso, Av. Fernando Correa da Costa s/n, Coxipó, Cuiabá, Mato Grosso 78060-900, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Synurophytes are planktonic protists whose cells are covered with silica scales. According to the temperature-size rule, protists decrease in size with increasing temperature. Here, we showed that inorganic silica scales responded to increasing temperature in the same way as the cells did. Two species, Mallomonas tonsurata and Synura petersenii , were cultivated at five temperature levels (5, 10, 15, 20 and 25°C) and the methods of geometric morphometrics were applied for scale size and shape data analyses. We observed that the shape of the scales was significantly affected by the cultivation temperature. The overall shape change from rounded, circular scales to oval or more elongated scales seemed to be a general feature in synurophytes and may be considered a consequence of rising temperature. Moreover, the difference in shape remained significant even if the effect of size (allometric effect) was separated. Finally, we compared the level of the scales’ morphological variation among all temperature treatments. The results indicated that the cultivation temperature of 25°C negatively affected cellular processes involved in scale biogenesis. The use of the scale shape data has potential in palaeoecological research. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0743-z Authors Martina Pichrtová, Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Praha 2, 128 01 Czech Republic Yvonne Němcová, Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Praha 2, 128 01 Czech Republic Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Nodularia spumigena , like many cyanobacteria, produces specialised reproductive structures, known as akinetes, which are believed to allow survival under unfavourable conditions. This study investigated the effects of salinity, nitrogen and phosphorus concentration at two irradiances on akinete differentiation in a N. spumigena isolate from the Gippsland Lakes, Victoria, Australia. A computer image analysis program was used to photograph filaments and assess production of akinetes over time in separate experiments for each environmental parameter. Heterocyst production and cell morphology were also examined. The results suggest that akinete production increases over time. Production of akinetes is further increased at low and high salinities and with the addition of nitrate. Higher irradiance increases akinete differentiation, although in combination with different phosphorus concentrations causes varied effects. The development and sedimentation of akinetes may provide an inoculum for reoccurring blooms. Heterocysts were only observed during experiments with varying salinity and nitrogen exposures. Light quantity appeared to play a large role in heterocyst production. The ability of N. spumigena to produce akinetes and heterocysts is likely to be part of the reason for its success and continual occurrence in estuarine environments low in nitrogen, such as the Gippsland Lakes, Victoria, Australia. Factors known to reduce heterocyst and akinete production will provide new insight to possible management controls for this species. Content Type Journal Article Pages 1-16 DOI 10.1007/s10750-011-0714-4 Authors Jackie H. Myers, School of Biological Sciences, Monash University (Clayton Campus), Clayton, VIC 3800, Australia John Beardall, School of Biological Sciences, Monash University (Clayton Campus), Clayton, VIC 3800, Australia Graeme Allinson, Centre Aquatic Pollution Identification Management (CAPIM), Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, VIC 3025, Australia Scott Salzman, School of Information Systems, Deakin University (Warrnambool Campus), 423, Warrnambool, VIC 3280, Australia Simon Robertson, Fish Ageing Services Pty Ltd, 396, Portarlington, VIC 3223, Australia Leanne Gunthorpe, Department of Primary Industries, Fisheries Victoria, DPI Queenscliff Centre, 114, Queenscliff, VIC 3225, Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Some plants have high ability to absorb heavy metals in high concentrations. In this study, Spartina maritima was tested in conjunction with low molecular weight organic acids (LMWOA), in order to evaluate the possible use of this plant in phytoremediation processes in salt marshes. Three different LMWOA (citric acid, malic acid and acetic acid) were applied to contaminated intact cores of S. maritima colonized sediment and several heavy metals (Cd, Zn, Pb, Cu, Cr and Ni) were analyzed in sediment and plant parts. Acetic acid application proved to be the most efficient, enhancing greatly the uptake of all metals analyzed. Citric acid also showed good results, while malic acid proved to be very inefficient in most of the cases. The highest enhancement was observed for Cr with a 10-fold increase of the uptake upon application of acetic acid, while improving the Pb uptake proved to be the most difficult, probably due to its low solubility. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0731-3 Authors B. Duarte, Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisbon, Portugal J. Freitas, Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisbon, Portugal I. Caçador, Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisbon, Portugal Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    A constructed wetland (2.1 ha; 2% of catchment area) in southeast Sweden, in a catchment with 35% arable land on clay soils, was investigated with respect to phosphorus (P) retention, focusing on particulate P (PP) and sediment accretion. The aims were to (i) estimate P retention and identify the dominating retention processes; (ii) investigate how well estimates of P retention based on inflow-outflow measurements compared with the amount of P accumulated in the sediment. In- and outflow of P was measured during 4 years with continuous flow measurements and flow-proportional weekly composite samples. P in the accumulated sediment was estimated based on core samples and analyzed using sequential fractionation. Total P load during 4 years was 65 kg ha −1 and intensive sampling events detected 69% as PP. Based on inflow-outflow estimates the mean P retention was 2.8 kg ha −1  year −1 , or 17%, but the amount of P accumulated in the inlet zone equated 78% of the TP load. This discrepancy showed the need to add studies of sediment accumulation to inflow-outflow estimates for an improved understanding of the P retention. The dominating P forms in the sediment were organic P (38%) and P associated with iron or aluminum (39%), i.e., potentially mobile forms. In areas colonized by Typha latifolia , the amount of P in the upper sediment layer (390 kg) was more than double the total P load of 136 kg. Cycling and release in those areas is a potential source of P that deserves further attention. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0728-y Authors Karin M. Johannesson, IFM Biology, section Ecology, Linköping University, 581 83 Linköping, Sweden Jonas L. Andersson, WRS Uppsala AB, 753 22 Uppsala, Sweden Karin S. Tonderski, IFM Biology, section Ecology, Linköping University, 581 83 Linköping, Sweden Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Despite the growing concern about the importance of silicon (Si) in controlling ecological processes in aquatic ecosystems, little is known about its processing in riparian vegetation, especially compared to nitrogen (N) and phosphorus (P). We present experimental evidence that relative plant uptake of N and P compared to Si in riparian vegetation is dependent on mowing practices, water-logging and species composition. Results are obtained from a controlled and replicated mesocosm experiment, with a full-factorial design of soil water logging and mowing management. In our experiments, the Si excluding species Plantago lanceolata was dominant in the mown and non-waterlogged treatments, while Si accumulating meadow grasses and Phalaris arundinacea dominated the waterlogged treatments. Although species composition, management and soil moisture interacted strongly in their effect on relative Si:N and Si:P uptake ratios, the uptake of N to P remained virtually unchanged over the different treatments. Our study sheds new light on the impact of riparian wetland ecosystems on nutrient transport to rivers. It indicates that it is essential to include Si in future studies of the impact of riparian vegetation on nutrient transport, as these are often implemented as a measure to moderate excessive N and P inputs. Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0737-x Authors Eric Struyf, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Wiktor Kotowski, Department of Plant Ecology and Environmental Conservation, University of Warsaw, Warsaw, Poland Sander Jacobs, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Stefan Van Damme, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Kris Bal, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Wout Opdekamp, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Hans Backx, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Dimitri Van Pelt, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Patrick Meire, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Environmental flows are applied to regulated rivers, predominantly with the aim of benefiting native fauna. However, the outcomes for biodiversity and the mechanisms that underpin changes due to these manipulations are poorly understood. We examined the effects of elevated water release, of the magnitude used for riffle maintenance, on the movement and habitat use of the locally-threatened two-spined blackfish, Gadopsis bispinosus , in the Cotter River, a regulated upland stream in south-eastern Australia. We compared the behaviour of radio-tagged individuals during baseline flow conditions (0.12 m 3  s −1 ) and during elevated flow releases (1.74 m 3  s −1 ). Eight individuals (196 ± 8 mm TL) were radio-tracked at one site over 22 days, and six individuals (180 ± 5 mm TL) were monitored by fixed telemetry stations at a second site for 1 month. At both the sites, two-spined blackfish were nocturnal and occupied small linear ranges (23 ± 6 m). They preferentially used pools, but also used runs and riffles. Elevated discharge did not significantly affect movement, activity or dispersal of two-spined blackfish. Two individuals utilised inundated vegetation during high flow. Despite a small number of behavioural changes, there was no response to elevated flow at the population level. It is likely that the benthic nature of this species precludes its behaviour being affected by a 15-fold increase in-stream discharge. However, the indirect effects of flows of this magnitude on two-spined blackfish, and their responses to discharges of greater magnitude, remain to be investigated. Content Type Journal Article Pages 1-15 DOI 10.1007/s10750-011-0750-0 Authors B. T. Broadhurst, Parks, Conservation & Lands, Territory & Municipal Services, GPO Box 158, Canberra, ACT 2601, Australia J. G. Dyer, Department of Environmental Management and Ecology, La Trobe University, Wodonga, VIC 3690, Australia B. C. Ebner, Parks, Conservation & Lands, Territory & Municipal Services, GPO Box 158, Canberra, ACT 2601, Australia J. D. Thiem, Parks, Conservation & Lands, Territory & Municipal Services, GPO Box 158, Canberra, ACT 2601, Australia P. A. Pridmore, Department of Environmental Management and Ecology, La Trobe University, Wodonga, VIC 3690, Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Phytoplankton biomass–nutrient relationship is widely used by lake managers to assess the eutrophication impact and to set the nutrient targets. Submerged vegetation and large zooplankton grazing have long been identified as factors weakening the relationship by decoupling phytoplankton from nutrients. Proving this decoupling unambiguously is difficult because, in natural systems, many factors act together, blurring each other’s effect. In this article, we present the results of continuous monitoring of 13 ponds where the effects of submerged vegetation and zooplankton grazing were enhanced by biomanipulation (fish removal). The monitoring allowed these effects to be assessed and compared with the pre-biomanipulation situations when phytoplankton biomass was mainly nutrient driven. The comparison showed a strong weakening effect of submerged vegetation and large zooplankton grazing on the chlorophyll a –total phosphorus relationship suggesting that a considerable degree of ecological quality of ponds affected by eutrophication can be restored even when nutrient-loading reduction is not feasible. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0726-0 Authors Samuel Teissier, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Anatoly Peretyatko, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Sylvia De Backer, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Ludwig Triest, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Sampling benthic macroinvertebrates in large rivers has several limitations, arising not only from the selectivity of traditional sampling gears but also from difficulty in capturing organisms that inhabit the deeper zones and high current velocities. Considering the importance of benthic macroinvertebrates as a food resource for fishes, the sampling restrictions in sediment collection done by dredges, and the importance of surveying benthos biodiversity, the objective of this study was to evaluate the stomach contents of five commonly-occurring invertivorous fish species as a means of complementing a benthic macroinvertebrate inventory. Three sampling campaigns (fish and benthic macroinvertebrate) were conducted in a reach of the Araguari River (Minas Gerais, Brazil), approximately 9 km long and 90 m wide. Astyanax altiparanae Garutti & Britski 2000, Leporinus friderici (Bloch 1794), Leporinus amblyrhynchus Garavello & Britski 1987, Iheringichthys labrosus (Lütken 1874) and Pimelodus maculatus Lacepède 1803 were the fish species collected and studied. To determine benthic macroinvertebrate taxonomic richness, a total of 54 Van Veen sediment samples were obtained. We compared lists of the benthic taxa found in fish stomachs with those from the sediment samples. The differences in the taxonomic composition of the benthic macroinvertebrate communities between the sediment samples and each fish species stomachs contents were assessed through NMDS and ANOSIM analyses, using a Sorensen similarity index with the presence/absence of taxa data. Independent of sampling period, additional benthic macroinvertebrate families or classes were provided by identifying fish stomach contents. We found a total of 30 taxa in this study, including 5 unique taxa (or 17% of the total) in the sediment samples, 9 unique taxa (30%) in the stomach samples, and 16 taxa (53%) common to both. The NMDS and ANOSIM analyses showed a significant separation between Van Veen sediment samples and two fish species stomach contents— L. amblyrhynchus and P. maculatus . These results indicate that fish can be used as additional samplers and are an efficient method to complement the benthic taxonomic inventory obtained through traditional sediment sampling techniques in large areas, as river segments and catchments. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0747-8 Authors Daniel M. Maroneze, Laboratório de Ecologia de Bentos, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, C.P. 486, Pampulha, CEP 30161-970 Belo Horizonte, MG, Brazil Taynan H. Tupinambás, Laboratório de Ecologia de Bentos, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, C.P. 486, Pampulha, CEP 30161-970 Belo Horizonte, MG, Brazil Carlos B. M. Alves, Nuvelhas/Projeto Manuelzão, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, CEP 31270-901 Belo Horizonte, MG, Brazil Fábio Vieira, Centro de Transposição de Peixes, Universidade Federal de Minas Gerais, Agência Shopping Del Rey, C. P. 4011, CEP 31250-970 Belo Horizonte, MG, Brazil Paulo S. Pompeu, Nuvelhas/Projeto Manuelzão, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, CEP 31270-901 Belo Horizonte, MG, Brazil Marcos Callisto, Laboratório de Ecologia de Bentos, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, C.P. 486, Pampulha, CEP 30161-970 Belo Horizonte, MG, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    New habitats are an interesting tool to monitor colonization processes in the light of changes in genetic structure and evolutionary potential of populations. Cladocerans are cyclical parthenogens that offer the possibility to track genetic changes during the colonization process due to the alternation of sexual and asexual phases. The locally called “malladas” are shallow and temporary peridunal ponds in Eastern Spain that were silted in the 1960s and have been recently dug to their original basin. We here describe the colonization process in two of these newly restored ponds by the cladoceran Daphnia magna during their first 3 years. This colonization process followed three critical steps: population founding by the initial colonists, arrival of secondary immigrants and consolidation of the population structure. We found a low number of genotype colonists followed by the establishment of secondary immigrants and a slight decrease in gene flow with time. We discuss the importance of dispersal, founder effects, natural selection, inbreeding depression and genetic drift during the colonization process in the light of the most recent literature. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0741-1 Authors Raquel Ortells, Departament de Microbiologia i Ecologia, Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, c/ Dr. José Beltrán nº 2, 46980 Paterna, Valencia, Spain Carla Olmo, Departament de Microbiologia i Ecologia, Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, c/ Dr. José Beltrán nº 2, 46980 Paterna, Valencia, Spain Xavier Armengol, Departament de Microbiologia i Ecologia, Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, c/ Dr. José Beltrán nº 2, 46980 Paterna, Valencia, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    In aquatic sciences, the agreement between laboratory and field observations remains a challenge. Using kinetic modeling, this research aims to compare the decomposition in laboratory and in situ conditions. In the in situ incubations, the mass decreases of the aquatic macrophytes ( Echinodorus tenellus , Hydrocotyle verticillata , Najas microcarpa and Pontederia parviflora ) were described using a litter bag technique and in the laboratory their decomposition was maintained under controlled conditions. The plants and water samples were collected from a tropical reservoir (Brazil). To describe the particulate organic carbon (POC) decay we adopted a two stage kinetic model that considered the heterogeneity of resources. The released organic carbon (i.e., losses related to mineralization, dissolution and sedimentation of smaller particles than the litter bag mesh) were used to compare the results derived from the field and laboratory incubations. Despite the methodological differences, the results show equivalence among the POC decay. The decomposition measured by litter bags method was 1.32 faster, owing to the effects of losses by sedimentation of the smaller particles, abrasion, action of decomposer organisms (e.g., fragmentation and enzymatic attack) and synergy among these factors. From a mathematical modeling approach, the results validate the use of decomposition data obtained under controlled conditions providing estimations of energy and matter fluxes within aquatic ecosystems. However, it is necessary to adopt a coefficient to acquire the similarity (e.g., 1.32). Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0625-4 Authors D. S. Silva, Programa de Pós-Graduação em Ecologia de Ecótonos, Universidade Federal de Tocantins (UFT), Av. NS 15, ALCNO 14, Bloco IV, 109 Norte, Palmas, TO 77001-090, Brazil M. B. Cunha-Santino, Departamento Hidrobiologia, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235, São Carlos, SP Brazil E. E. Marques, Programa de Pós-Graduação em Ecologia de Ecótonos, Universidade Federal de Tocantins (UFT), Av. NS 15, ALCNO 14, Bloco IV, 109 Norte, Palmas, TO 77001-090, Brazil I. Bianchini, Departamento Hidrobiologia, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235, São Carlos, SP Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We investigated the population dynamics of the rotifer Brachionus rotundiformis fed with the alga Isochrysis galbana at two food concentrations (3 × 10 4 and 40 × 10 4  cells ml −1 ) and four salinity levels (5, 10, 20, and 30) in the presence and absence of two copepod species, Pseudodiaptomus annandalei and Apocyclops royi and one cladoceran, Diaphanosoma aspinosum . Both the density and population growth rate of B. rotundiformis increased at higher food concentration and at salinity levels of 10 and 20. Among the microcrustaceans, only P. annandalei had a significant negative effect on the growth rate of the rotifer population because of its efficient predation. In contrast, the presence of both A. royi and D. aspinosum did not affect the growth rates at any of the salinity and food levels. Brachionus rotundiformis had significantly larger size during the log-phase, particularly if P. annandalei was present. Thus, B. rotundiformis grows better at higher food level and medium salinity levels. Unlike the larger calanoid, P. annandalei , B. rotundiformis can definitely coexist with relatively small cyclopoid copepods ( A. royi ) and cladocerans ( D. aspinosum ), because of the absence of interference. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0615-6 Authors Shin-Hong Cheng, Tungkang Biotechnology Research Center, Fisheries Research Institute, Tungkang, Pingtung, 928 Taiwan Samba Kâ, Institute of Marine Biology, National Taiwan Ocean University, Keelung, 202 Taiwan Ram Kumar, Ecosystem Research Laboratory, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi, 110019 India Chung-Su Kuo, Institute of Marine Biology, National Taiwan Ocean University, Keelung, 202 Taiwan Jiang-Shiou Hwang, Institute of Marine Biology, National Taiwan Ocean University, Keelung, 202 Taiwan Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We hypothesised that (i) a summer heat wave would increase the thermal stability of lakes and (ii) the size and trophic state differences would modify the lakes’ responses to heating. Within 2 years, 2008 and 2009, we studied the thermal and optical regimes of two adjacent stratified lakes in northern Italy, the oligo-mesotrophic Lake Monate (2.5 km 2 , max. depth 34 m) and the eutrophic Lake Varese (14.8 km 2 , 26 m). After the cold winter 2008–2009, a heat wave starting in May turned the whole year 2009 the second hottest after 2003. The particular sequence of meteorological events resulted in extreme vertical temperature gradients and unusually high thermal stability of both lakes. All calculated thermal parameters showed the highest values in 2009 while also the values for 2008 exceeded considerably those published for these lakes in the past. Due to the large wind exposed surface, wind mixing was supposedly the dominating mechanism of heat transfer in the shallower eutrophic Lake Varese where, due to low water transparency, large amount of solar energy trapped in the upper layers markedly increased the thermal stability. In the deeper and more transparent Lake Monate, the deeper penetrating solar irradiance contributed to better energy dissipation within the water column and smaller interannual differences in thermal stability. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0691-7 Authors Peeter Nõges, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Tiina Nõges, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Michela Ghiani, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Bruno Paracchini, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Joaquin Pinto Grande, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Fabrizio Sena, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Recent submarine caves are inhabited by endemic faunas adapted to oligotrophism, darkness and a tranquil environment. Many of their representatives are archaic types of animals resembling fossils from very early times in evolution. This article compares fossil fauna from Jurassic neptunian dykes (originally sea bed clefts) from the Western Carpathians with the Recent cave-dwelling fauna. The ostracods Pokornyopsis feifeli are particularly important. In the Western Carpathians, these were exclusively found in the Middle/Late Jurassic fissure fillings, but in the non-Tethyan Germanic Jurassic this species was found in deep-marine claystones. They are phylogenetic forerunners of the recent genus Danielopolina inhabiting both anchialine caves and deep seas. This indicates a Jurassic migration of deep-marine fauna to cryptic habitats. Other examples of cryptic communities include the Upper Jurassic cavity-dwelling fauna dominated by serpulids and scleractinian corals. Associated suspension feeders include thecideidine brachiopods, oysters, bryozoans, sponges, crinoids and sessile foraminifers. Serpulid-dominated bioconstructions have recent analogies in the Mediterranean and Carribean seas. Different type of dyke communities represent the Late Jurassic fauna of small sized ammonites which originated from both Tethyan and Boreal paleobioprovinces. It has not been established whether these amonites were juvenile, dwarfed specimens adapted to limited cave space or size-sorted adult specimens. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0687-3 Authors Roman Aubrecht, Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynská dolina-G, 842 15 Bratislava, Slovakia Ján Schlögl, Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynská dolina-G, 842 15 Bratislava, Slovakia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description: Erratum to: Distribution and ecology of Hemimysis anomala , the latest invader of the Great Lakes basin Content Type Journal Article Pages 1-1 DOI 10.1007/s10750-011-0692-6 Authors Jérôme Marty, St. Lawrence River Institute, 2, Belmont Street, Cornwall, ON K6H 4Z1, Canada Kelly Bowen, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, 867 Lakeshore Road, Burlington, ON L7R 4A6, Canada Marten A. Koops, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, 867 Lakeshore Road, Burlington, ON L7R 4A6, Canada Michael Power, Biology Department, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 1G3, Canada Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Baited underwater camera (BUC) systems to estimate demersal fish abundance are becoming increasingly considered as an alternative to traditional survey methods, particularly in environments that contain sensitive habitats or protected species. Based on 27 replicate deployments of BUCs at 100 m depth in the northern North Sea, in rank order of abundance, hagfish ( Myxine glutinosa ), flatfish mainly dabs ( Limanda limanda ), whiting ( Merlangius merlangus ) and haddock ( Melanogramus aeglefinus ) were observed consistently at baits. Higher maximum numbers ( N max ) occurred during daytime in all species with the most significant effect in flatfish, 18 in daytime and 5 at night-time. Bottom current had no significant effect on numbers of whiting, flatfish or haddock. The N max of hagfish was strongly related to current speed in a non-linear way with an increase in numbers up to 10 cm s −1 and then decrease in N max at higher water speeds. Understanding and accounting for such species-specific influences is important in the design of long term monitoring surveys using baited cameras. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0672-x Authors Iñigo Martinez, Marine Scotland-Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB UK Emma G. Jones, Marine Scotland-Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB UK Sarah L. Davie, Marine Scotland-Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB UK Francis C. Neat, Marine Scotland-Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB UK Ben D. Wigham, Dove Marine Laboratory, Newcastle University, Cullercoats, North Shields, NE30 4PZ UK Imants G. Priede, University of Aberdeen, Oceanlab, Newburgh, Aberdeen, AB11 6AA UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We tested the hypothesis that species composition and persistence of phytoplankton communities in nutrient rich lowland rivers depends mainly on physical factors. The study aimed to analyse the effects of water discharge, temperature and chemistry on phytoplankton dynamic and species composition in the lowland reach of the eutrophic Po river (Italy). Both taxonomical and morpho-functional methods were used. True planktonic and tychoplanktic (i.e. detached taxa of benthic origin that remain in suspension) species were found, among which only a few taxa and functional groups prevailed. Diatoms were the most abundant, with a clear dominance of species either sensitive to the onset of water stratification or well adapted to turbid waters. Phytoplankton abundance, biomass and chlorophyll- a followed similar trends, attaining the highest values in summer, at low discharge rates. Correlation and multivariate analysis revealed that the development of a stable phytoplankton community was mainly controlled by water discharge rates. Namely, changes in water flow rates induced major variations in the community structure. The seasonal succession of phytoplankton assemblages was also related to water temperature and dissolved reactive silica availability to some extent overlapping flow effects. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0688-2 Authors Silvia Tavernini, Department of Environmental Sciences, University of Parma, Viale G.P. Usberti, 11/A, 43100 Parma, Italy Enrica Pierobon, Department of Environmental Sciences, University of Parma, Viale G.P. Usberti, 11/A, 43100 Parma, Italy Pierluigi Viaroli, Department of Environmental Sciences, University of Parma, Viale G.P. Usberti, 11/A, 43100 Parma, Italy Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Despite iodine being one of the most abundant of the minor elements in oxic seawater, the principal processes controlling its interconversion from iodate to iodide and vice versa, are still either elusive or largely unknown. The two major hypotheses for iodate reduction involve either phytoplankton growth in primary production, or bacteria during regeneration. An earlier study intended to exploit the unusual nature of anchialine environments revealed that iodide is oxidised to iodate in the bottom of such caves, whereas reduction of iodate occurs in the shallower parts of the water column. This investigation was made on the hypothesis that study of the nitrogen and phosphorus nutrient systems within the caves might offer a bridge between the iodine chemistry and the marine bacteria which are assumed to be the agent of change of the iodine in the caves. Accordingly, the hydrography, the nutrient chemistry, and some further iodine studies were made of two anchialine caves on the east coast of the Adriatic Sea in Croatia. Iodate and iodide were determined by differential pulse voltammetry and cathodic stripping square-wave voltammetry, respectively. Total iodine was determined indirectly, as iodate, after oxidation of reduced iodine species with UV irradiation and strong chemical oxidants. Nutrient concentrations were measured by spectrophotometry. Nutrient profiles within the well stratified water columns indicate a relatively short-lived surface source of nitrate and phosphate to the caves, with a more conventional, mid-water, nutrient regeneration system. The latter involves nitrite and ammonium at the bottom of the halocline, suggestive of both autotrophic and heterotrophic microbial activity. High iodate/low iodide deep water, and conservative behaviour of total inorganic iodine were confirmed in both systems. Iodate is reduced to iodide in the hypoxic region where nutrient regeneration occurs. The concentrations of organic iodine were surprisingly high in both systems, generally increasing toward the surface, where it comprised almost 80% of total iodine. As with alkalinity and silica, the results suggest that this refractive iodine component is liberated during dissolution of the surrounding karst rock. A major, natural flushing of one of the caves with fresh water was confirmed, showing that the cave systems offer the opportunity to re-start investigations periodically. Content Type Journal Article Pages 1-20 DOI 10.1007/s10750-011-0686-4 Authors Vesna Žic, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička 54, 10001 Zagreb, Croatia Victor W. Truesdale, School of Life Sciences, Oxford Brookes University, Headington, Oxford, OX3 0BP UK Vlado Cuculić, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička 54, 10001 Zagreb, Croatia Neven Cukrov, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička 54, 10001 Zagreb, Croatia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Total nitrogen (TN) in Lake Okeechobee, a large, shallow, turbid lake in south Florida, has averaged between 90 and 150 μM on an annual basis since 1983. No TN trends are evident, despite major storm events, droughts, and nutrient management changes in the watershed. To understand the relative stability of TN, this study evaluates nitrogen (N) dynamics at three temporal/spatial levels: (1) annual whole lake N budgets, (2) monthly in-lake water quality measurements in offshore and nearshore areas, and (3) isotope addition experiments lasting 3 days and using 15 N-ammonium ( 15 NH 4 + ) and 15 N-nitrate ( 15 NO 3 − ) at two offshore locations. Budgets indicate that the lake is a net sink for N. TN concentrations were less variable than net N loads, suggesting that in-lake processes moderate these net loads. Monthly NO 3 − concentrations were higher in the offshore area and higher in winter for both offshore and nearshore areas. Negative relationships between the percentage of samples classified as algal blooms (defined as chlorophyll a  〉 40 μg l −1 ) and inorganic N concentrations suggest N-limitation. Continuous-flow experiments over intact sediment cores measured net fluxes (μmol N m −2  h −1 ) between 0 and 25 released from sediments for NH 4 + , 0–60 removed by sediments for NO 3 − , and 63–68 transformed by denitrification. Uptake rates in the water column (μmol N m −2  h −1 ) determined by isotope dilution experiments and normalized for water depth were 1,090–1,970 for NH 4 + and 59–119 for NO 3 − . These fluxes are similar to previously reported results. Our work suggests that external N inputs are balanced in Lake Okeechobee by denitrification. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0683-7 Authors R. Thomas James, Water Quality Treatment Technologies Division, South Florida Water Management District, West Palm Beach, FL USA Wayne S. Gardner, Marine Science Institute, The University of Texas at Austin, Port Aransas, TX USA Mark J. McCarthy, Marine Science Institute, The University of Texas at Austin, Port Aransas, TX USA Stephen A. Carini, Marine Science Institute, The University of Texas at Austin, Port Aransas, TX USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    To address the question whether the abundance of an invasive species can be explained by physical and chemical properties of the invaded ecosystems, we gathered density data of invasive zebra mussels and the physical and chemical data of ecosystems they invaded. We assembled published data from 55 European and 13 North American lakes and developed a model for zebra mussel density using a generalized additive model (GAM) approach. Our model revealed that the joint effect of surface area, total phosphorus and calcium concentrations explained 62% of the variation in Dreissena density. Our study indicates that large and less productive North American lakes can support larger local populations of zebra mussels. Our results suggest that the proliferation of an exotic species in an area can partially be explained by physical and chemical properties of the recipient environment. Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0689-1 Authors Rahmat Naddafi, Department of Ecology and Evolution/Erken Laboratory, Evolutionary Biology Centre, Uppsala University, Norr Malma 4200, 76173 Norrtälje, Sweden Thorsten Blenckner, Baltic Nest Institute, Stockholm Resilience Centre, Stockholm University, 10691 Stockholm, Sweden Peter Eklöv, Department of Ecology and Evolution/Limnology, Evolutionary Biology Centre, Uppsala University, Box 573, SE-751 23 Uppsala, Sweden Kurt Pettersson, Department of Ecology and Evolution/Erken Laboratory, Evolutionary Biology Centre, Uppsala University, Norr Malma 4200, 76173 Norrtälje, Sweden Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Accurate prediction of species distributions based on sampling and environmental data is essential for further scientific analysis, such as stock assessment, detection of abundance fluctuation due to climate change or overexploitation, and to underpin management and legislation processes. The evolution of computer science and statistics has allowed the development of sophisticated and well-established modelling techniques as well as a variety of promising innovative approaches for modelling species distribution. The appropriate selection of modelling approach is crucial to the quality of predictions about species distribution. In this study, modelling techniques based on different approaches are compared and evaluated in relation to their predictive performance, utilizing fish density acoustic data. Generalized additive models and mixed models amongst the regression models, associative neural networks (ANNs) and artificial neural networks ensemble amongst the artificial neural networks and ordinary kriging amongst the geostatistical techniques are applied and evaluated. A verification dataset is used for estimating the predictive performance of these models. A combination of outputs from the different models is applied for prediction optimization to exploit the ability of each model to explain certain aspects of variation in species acoustic density. Neural networks and especially ANNs appear to provide more accurate results in fitting the training dataset while generalized additive models appear more flexible in predicting the verification dataset. The efficiency of each technique in relation to certain sampling and output strategies is also discussed. Content Type Journal Article Pages 1-24 DOI 10.1007/s10750-011-0676-6 Authors A. Palialexis, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece S. Georgakarakos, Department of Marine Sciences, University of the Aegean, University Hill, 81 100 Mytilini, Lesvos, Greece I. Karakassis, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece K. Lika, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece V. D. Valavanis, Marine GIS Lab, Hellenic Centre for Marine Research, Thalassocosmos, 71 003 Heraklion, Crete, Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Particulate organic matter (POM) plays an important role in nutrient dynamics in river ecosystems, but little is known about changes in the origin and quality of POM in relation to physical and seasonal changes along rivers. Using stable isotope and stoichiometric analyses, we investigated the changes in origin and quality of POM of three different size fractions (fine [FPOM], 1.2–100 μm; medium [MPOM], 100–250 μm; and coarse [CPOM], 250–1,000 μm) at 14 sites along a gravel-bed river over four seasons. FPOM and MPOM accounted for 90% of all POM at all study sites. At each site, the δ 13 C level was lower for FPOM (range: −29.0 to −21.1‰) than for MPOM (−26.9 to −17.2‰) and CPOM (−27.5 to −16.3‰). The C:N ratio was lower for FPOM (6.9–15.6) than for MPOM (6.3–17.4) and CPOM (5.7–27.1). The contribution of periphyton to POM of all size fractions had a tendency to increase downstream, though the trend was less clear and varied seasonally for MPOM and CPOM between sites in middle and downstream reaches. Contrastively, the C:N ratio in all size fractions of POM consistently decreased downstream. The downstream decrease in the C:N ratio of POM can be partly explained by the increase in the contribution of periphyton, which seems to be associated with increased discharge and enhanced periphyton dislodgement, especially in winter. In addition, an increase in bacterial biomass associated with the greater nutrient availability in pool areas is another possible reason for the decrease in the C:N ratio of POM downstream. Content Type Journal Article Pages 1-15 DOI 10.1007/s10750-011-0682-8 Authors Fumikazu Akamatsu, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Sohei Kobayashi, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Kunihiko Amano, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Satoru Nakanishi, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Yurika Oshima, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The bluemouth, Helicolenus dactylopterus , is a deep-sea scorpionfish widely distributed in the Atlantic Ocean and the Mediterranean. It is a common by-catch associated to many demersal fisheries. However, there is little information about the stock structure, stock dynamics and life history parameters of the bluemouth. From the perspective of stock identification, it is important to study growth in fish populations to better understand the possible morphological differences among populations and when and why do they arise. Thus, the aim of this study was to determine the growth (allometric) trajectories of shape for several bluemouth populations in Northeast Atlantic and Mediterranean using landmark-based geometric morphometric techniques. In this study, ontogenetic allometry was present in all of the bluemouth samples. Ontogenetic shape changes were most evident in the head and pectoral area, affecting the position of the snout, preopercular spines and pectoral fins, but changes in body depth and length were also important. However, the degree to which these ontogenetic shape changes were present in bluemouth from each of the studied areas was different, indicating that their growth trajectories are not homogeneous. The importance of this finding for size-correction of the shape variables in morphometric studies for stock identification is also discussed. Content Type Journal Article Pages 1-18 DOI 10.1007/s10750-011-0675-7 Authors Rebeca Rodríguez-Mendoza, Instituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, 36208 Vigo, Spain Marta Muñoz, Departament de Ciències Ambientals, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain Fran Saborido-Rey, Instituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, 36208 Vigo, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The accurate representation of species distribution derived from sampled data is essential for management purposes and to underpin population modelling. Additionally, the prediction of species distribution for an expanded area, beyond the sampling area can reduce sampling costs. Here, several well-established and recently developed habitat modelling techniques are investigated in order to identify the most suitable approach to use with presence–absence acoustic data. The fitting efficiency of the modelling techniques are initially tested on the training dataset while their predictive capacity is evaluated using a verification set. For the comparison among models, Receiver Operating Characteristics (ROC), Kappa statistics, correlation and confusion matrices are used. Boosted Regression Trees (BRT) and Associative Neural Networks (ASNN), which are both within the machine learning category, outperformed the other modelling approaches tested. Content Type Journal Article Pages 1-26 DOI 10.1007/s10750-011-0673-9 Authors A. Palialexis, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece S. Georgakarakos, Department of Marine Sciences, University of the Aegean, University Hill, 81 100 Mytilini, Lesvos, Greece I. Karakassis, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece K. Lika, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece V. D. Valavanis, Marine GIS Lab, Hellenic Centre for Marine Research, P.O. Box 2214, 71 003 Heraklion, Crete, Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The bottom trawl fishery developed on the slope off Balearic Islands (western Mediterranean) has been analysed from different sources of information: (i) data obtained during experimental bottom trawl surveys developed annually since 2001; (ii) daily sale bills from the bottom trawl fleet, available since 2000. Considering both hydrographical and geomorphologic conditions, the study area was divided in four geographical sectors. Multivariate techniques were applied to identify assemblages and their main species, and to investigate the influence of environmental variables in the slope communities. Fishery-independent and fishery-dependent indicators were calculated, both at specific and community level, for the assemblages identified. In all cases, they were summarised using the Traffic Light approach. Three assemblages have been identified in the slope trawl fishing grounds off the Balearic Islands: (1) the almost unexploited shelf break, where teleosts predominate; (2) the upper slope, where teleosts still predominate but crustaceans are also very important (with Nephrops norvegicus as target species); (3) and the middle slope, where crustaceans predominate (with Aristeus antennatus as target species). Depth was the main factor affecting the species composition of the assemblages, although other factors such as area, year and effort level also affect. Indicators estimated from both sets of data suggested an improvement in the state of N. norvegicus , although the results suggest the influence of other factors than fishing impact in the state of this resource. For A. antennatus , marked differences have been found depending on the data source. In the upper slope, indicators suggested an improvement in the state of this assemblage, which can be related to a decreasing trend found in the fishing effort exerted in this depth range. Indicators from the middle slope showed differences for both sets of data. The characteristics of both data sources and of the species analysed are discussed as responsible of these differences. Content Type Journal Article Pages 1-19 DOI 10.1007/s10750-011-0670-z Authors Beatriz Guijarro, Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Moll de Ponent s/n, 07015 Palma, Spain George Tserpes, Hellenic Centre for Marine Research (HCMR), Institute of Marine Biological Resources, P.O. Box 2214, 71003 Poros, Heraklion, Greece Joan Moranta, Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Moll de Ponent s/n, 07015 Palma, Spain Enric Massutí, Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Moll de Ponent s/n, 07015 Palma, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The relation of macrobenthic species turnover (beta diversity) and species plylogenetic variation with functional diversity patterns, across an environmental gradient induced by an aquaculture unit, in a coastal area of the island of Lesvos (NE Aegean) has been investigated in this study. The contribution of rare species response and species dispersal ability in the variation of functional diversity patterns along the environmental gradient, on a spatio-temporal scale, has been also examined. Our results revealed that benthic functional diversity was decreasing monotonically with increasing species turnover rate and hence with increasing spatial variability along the environmental gradient. Increased environmental stress which was detected in the immediate vicinity of the fish cages resulted to low species functional redundancy, since different species didn’t perform the same functional role at the most disturbed part of the established gradient. Functional diversity patterns were found to be correlated with species population size, whereas a strong linear relationship was also detected with phylogenetic diversity patterns, thus supporting the claim that wider local taxonomic trees can support a wider range of species functions even in small spatial scales. Rare species loss seemed to be one of the dominant factors ruling functional diversity variation. Species with the minimum possible dispersal ability, which were mostly rare, tend to diminish both in species number and population size faster than species with wider dispersal ability towards the most disturbed areas. The aforementioned results indicate that rare species variation and endemic species loss are critical factors in determining functional diversity loss across a human-induced environmental gradient in soft bottom benthic communities. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0668-6 Authors Charalampos Dimitriadis, Department of Marine Sciences, Faculty of Environment, University of the Aegean, Lesvos Island, 81100 Greece Drosos Koutsoubas, Department of Marine Sciences, Faculty of Environment, University of the Aegean, Lesvos Island, 81100 Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Marine protected areas (MPAs) are attracting widespread attention worldwide as a tool for fishery management and marine ecosystem conservation. The establishment of MPAs has increased greatly in recent years mostly due to international commitments to the establishment of a global network of MPAs by 2012. MPAs have the potential to strongly affect the fishing industry, and their success depends, at least partly, on fishers’ attitudes towards this management measure. However, research on MPAs tends to focus on the ecological and conservation aspects of this management approach and not on its human dimensions. Studies in attitudes, perceptions, beliefs and preferences related to MPA issues have been identified as priority social science topics in need of research. We present a ‘rapid review’, conducted systematically, of the literature published up to September 2009 and aimed at identifying the most investigated topics related to commercial fishers’ attitudes towards MPAs, describing the main findings from these studies, and analysing the implications for management. Most published work focuses on fishers’ attitudes towards issues of governance, conservation of biodiversity and the environment, and the impact of MPAs on fishing activity. Despite the recent increase in the literature on the human dimensions of MPAs, the present review reveals that little of this literature originates from empirical studies. Hence, given the forthcoming increase in the implementation of MPAs in the near future, research on fishers’ attitudes towards these management measures is critically needed. Content Type Journal Article Pages 1-18 DOI 10.1007/s10750-011-0665-9 Authors Cristina Pita, Business School, Department of Economics, University of Aberdeen, Edward Wright Building, Dunbar Street, Aberdeen, AB24 3QY UK Graham J. Pierce, Institute of Biological and Environmental Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ UK Ioannis Theodossiou, Business School, Department of Economics, University of Aberdeen, Edward Wright Building, Dunbar Street, Aberdeen, AB24 3QY UK Karen Macpherson, NHS Quality Improvement Scotland, Delta House, 50 West Nile Street, Glasgow, G1 2NP UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The distribution of the common octopus ( Octopus vulgaris ) in the Mediterranean and Eastern Atlantic waters is evaluated using two presence-only analyses: The maximum entropy model (Maxent) and the ecological niche factor analysis (ENFA). Maxent predicts those geographical areas that satisfy the environmental or abiotic requirements of a species while ENFA explores the niche and habitat preferences of O. vulgaris . The analyses were implemented recovering the spatial information from 213 octopus presence data collected from surveys and bibliographical records. Together, these analyses provided reasonable estimates of the species distribution and the octopus habitat. Among the gathered set of explanatory environmental variables, sea bottom temperature, sea bottom salinity, surface dissolved oxygen and sea surface chlorophyll-α appear as the main variables involved in O. vulgaris distribution. These results were confronted with the available literature. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0671-y Authors Consuelo Hermosilla, Department of Ecology and Animal Biology, Campus As Lagoas Marcosende, University of Vigo, 36310 Vigo, Spain Francisco Rocha, Department of Ecology and Animal Biology, Campus As Lagoas Marcosende, University of Vigo, 36310 Vigo, Spain Vasilis D. Valavanis, Marine GIS Laboratory, Institute of Marine Biological Resources, Hellenic Centre for Marine Research, Thalassocosmos, 71003 Heraklion Crete, Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158