ALBERT

Notes: The depth distribution of submersed aquatic vegetation (SAV) was studied in Lake Pontchartrain, Louisiana, to develop a model to predict changes in SAV abundance from changes in environmental quality. We conducted annual line-intercept surveys from 1997 through 2001 and monitored monthly photosynthetically active radiation at four sites with different shoreface slopes. The following relationships between SAV distribution and environmental factors were used as model parameters: (1) water clarity controls SAV colonization depth; (2) fluctuation in annual mean water level and wave mixing determines SAV minimum colonization depth; and (3) site differences in SAV areal coverage under the comparable water quality conditions are due to shoreface slope differences. These parameters expressed as mathematical components of the model are as follows: mean water clarity determines SAV colonization depth (Zmax= 2.3/Kd); mean water level and wave mixing controls SAV minimum depth (Zmin= 0.3 m); and shoreface slope angle (θ) determines the distance from Zmin to Zmax. The equation developed for the potential SAV habitat (PSAV) model is PSAV = (2.3 − 0.3 ×Kd)/(sinθ×Kd). The model was validated by comparing empirical values from the dataset to values predicted by the model. Although the model was developed to predict the PSAV in Lake Pontchartrain, it can be applied to other coastal habitats if local SAV light requirements are substituted for Lake Pontchartrain values. This model is a useful tool in selecting potential restoration sites and in predicting the extent of SAV habitat gain after restoration.

Notes: Assessing the community-level consequences of ecological restoration treatments is essential to guide future restoration efforts. We compared the vegetation composition and species richness of restored sites that received a range of restoration treatments and those of unrestored sites that experienced varying levels of disturbance. Our study was conducted in the industrially degraded landscape surrounding Sudbury, Ontario, Canada. The Great Lakes–St. Lawrence Forest once present in this area was degraded through logging, mining, and smelting activities beginning in the late 1800s until restoration of the most visibly degraded areas began in 1974. Restoration treatments ranged from simple abiotic enhancements to complex, multistage revegetation treatments using native and non-native species, which included fertilizing, spreading of ground dolomitic limestone, understory seeding, and tree planting. Canonical correspondence analysis was used to determine which restoration treatments explained differences in the community structure among sites. We found that native understory vascular species richness was similar in restored sites that received more complex restoration treatments and unrestored sites that were mildly disturbed; however, the role of planted trees and non-native species in the restored communities remains unclear. Understory vascular seeding played a key role in determining community composition of vascular understory and overstory communities, but the time since restoration commenced was a more important factor for nonvascular communities because they received no direct biotic enhancements. The use of non-native species in the vascular seed mix seems to be slowly encouraging the colonization of native species, but non-natives continue to dominate restored sites 25 years after restoration began.

Notes: Grasslands dominated by exotic annual grasses have replaced native perennial vegetation types in vast areas of California. Prescribed spring fires can cause a temporary replacement of exotic annual grasses by native and non-native forbs, but generally do not lead to recovery of native perennials, especially where these have been entirely displaced for many years. Successful reintroduction of perennial species after fire depends on establishment in the postfire environment. We studied the effects of vegetation changes after an April fire on competition for soil moisture, a key factor in exotic annual grass dominance. As an alternative to fire, solarization effectively kills seeds of most plant species but with a high labor investment per area. We compared the burn to solarization in a study of establishment and growth of seeds and transplants of the native perennial grass Purple needlegrass (Nassella pulchra) and coastal sage species California sagebrush (Artemisia californica). After the fire, initial seed bank and seedling densities and regular percent cover and soil moisture (0–20 cm) data were collected in burned and unburned areas. Burned areas had 96% fewer viable seeds of the dominant annual grass, Ripgut brome (Bromus diandrus), leading to replacement by forbs from the seed bank, especially non-native Black mustard (Brassica nigra). In the early growing season, B. diandrus dominating unburned areas consistently depleted soil moisture to a greater extent between rains than forbs in burned areas. However, B. diandrus senesced early, leaving more moisture available in unburned areas after late-season rains. Nassella pulchra and A. californica established better on plots treated with fire and/or solarization than on untreated plots. We conclude that both spring burns and solarization can produce conditions where native perennials can establish in annual grasslands. However, the relative contribution of these treatments to restoration appears to depend on the native species being reintroduced, and the long-term success of these initial restoration experiments remains to be determined.

Notes: This study assesses the risks in ecological restoration arising from transplanting into soil containing glyphosate residues. Four Australian restoration species were grown for 60 days in nonadsorbing media treated continuously with glyphosate to establish threshold concentrations for damage. Visual signs of injury were observed in three species, and severe effects on root growth in all species, at solution concentrations as low as 18 mg/L. Only the perennial grass Themeda sp. died at this concentration, with other species surviving at concentrations in the range 36–360 mg/L, beyond which all plants died. Fourteen days exposure followed by removal of glyphosate from root media produced similar effects. Field and glasshouse experiments with the relatively tolerant tree species Angophora costata showed that application rates in the range 10–50 L/ha of herbicide product (360 g/L) would be needed to sustain damage to young plants transplanted into soil typical of local restoration sites. The volume of spray delivered using a hand-operated sprayer varied between operators by 5- and 10-fold to complete the same tasks, at the high end presenting a potential risk to the most tolerant species under field conditions, even when spray concentrations follow label instructions. For all but the most sensitive species, the risk of glyphosate residues in ecological restoration should be minimized by training operators of unregulated applicators to deliver controlled volumes of herbicide when spot spraying prior to transplanting.

Notes: Restoring habitat structure that existed before active and inadvertent fire suppression is thought to be critical to maintaining populations of some rare plants in fire-suppressed habitats. Nevertheless, the impacts of habitat restoration on most endangered plants are poorly understood. Current theory predicts and empirical studies have shown that the reduction of shade or competition (frequently a goal of many habitat restoration projects in degraded fire-dependent ecosystems) benefits plants adapted to nutrient-poor soils by increasing the benefit-to-cost ratio of adaptations for enhanced nutrient capture. Here, I examined how experimental reduction of neighboring plants in a wet longleaf pine community dominated in the ground cover by shrubs and stump sprouts influenced the growth, the reproduction, the carnivorous effort, and the benefits of carnivory in a U.S. federally endangered species, Sarracenia rubra ssp. alabamensis. Two years of data showed no significant effects of neighbor reduction or prey exclusion on any of several indicators of plant performance, nor was there any evidence of a hypothesized morphological trade-off between shade avoidance and prey capture. These results were unexpected. Inadequate replication and atypical precipitation patterns were ruled out as possible explanations. The population studied here (unlike that of a different, but morphologically similar, species growing in a fire-maintained pine grass–sedge savanna) did not exhibit the ability to respond to variation in competition from neighboring plants.

Notes: In Ohio and elsewhere, recent grassland plantings in the federal Conservation Reserve Program (CRP) have become much more extensive than native prairie remnants. The seed source for CRP grasslands in Ohio often comes from as far away as Missouri or Texas, which may be undesirable from the standpoint of conservation genetics. The goal of this study was to examine the potential for gene flow from large, recently introduced populations of Big bluestem (Andropogon gerardii, Poaceae) to small local populations of this outcrossing perennial species. We examined the potential for cross-pollination between three local populations and three introduced CRP populations by comparing flowering phenologies. Flowering times overlapped extensively, indicating that cross-pollination is possible where local and introduced genotypes co-occur. To compare genetic variation in local and CRP populations, we analyzed variation at 68 RAPD loci in six populations of each type. Somewhat surprisingly, we found no significant differences in the genetic diversity or composition between the two groups (local vs. CRP). In summary, we found that local and introduced populations of Big bluestem have the potential to interbreed, based on their flowering periods, but further research is needed to determine whether local genotypes harbor unique genetic variation that could be jeopardized by hybridization with introduced genotypes.

Notes: Coastal protection remains a global priority. Protection and maintenance of shoreline integrity is often a goal of many coastal protection programs. Typically, shorelines are protected by armoring them with hard, non-native, and nonsustainable materials such as limestone. This study investigated the potential shoreline protection role of created, three-dimensional Eastern oyster (Crassostrea virginica) shell reefs fringing eroding marsh shorelines in Louisiana. Experimental reefs (25 × 1.0 × 0.7 m; intertidal) were created in June 2002 at both high and low wave energy shorelines. Six 25-m study sites (three cultched and three control noncultched) were established at each shoreline in June 2002, for a total of 12 sites. Shoreline retreat was reduced in cultched low-energy shorelines as compared to the control low-energy shorelines (analysis of variance; p 〈 0.001) but was not significantly different between cultched and noncultched sites in high-energy environments. Spat set increased from 0.5 ± 0.1 spat/shell in July 2002 to a peak of 9.5 ± 0.4 spat/shell in October 2002. On average, oyster spat grew at a rate of 0.05 mm/day through the duration of the study. Recruitment and growth rates of oyster spat suggested potential reef sustainability over time. Small fringing reefs may be a useful tool in protecting shorelines in low-energy environments. However, their usefulness may be limited in high-energy environments.

Notes: The Araucaria forest is Brazil's highly threatened subtropical forest ecosystem that has been disappearing in recent decades. Restoration programs involving this forest type are scarce, and there is a lack of scientific information on how ecological processes such as competition, facilitation, and seed dispersal influence natural forest restoration. This work aims to investigate how use of perches to attract seed dispersers and the influence of pioneer vegetation and soil fertilization could affect the colonization of woody species in a degraded area. An experiment was conducted in an abandoned field where the natural establishment of seeds and seedlings of woody species was monitored under factorial combinations of the following treatments: (1) pioneer vegetation (presence and absence); (2) soil fertility (addition of NPK and control); and (3) perches (presence and absence). Seed and seedling abundance, seed and seedling species richness, and seedling mortality were recorded monthly during 12 months. Seed abundance and species richness were significantly greater in places with perches than in control plots. These results were consistent over the year and more pronounced when the surrounding forest produced a higher amount of fruit. Species richness and abundance of seedlings were significantly greater in places with perches than in control plots, and in places with vegetation than without. Soil fertility did not influence seedling establishment. Facilitation and seed dispersal are important factors affecting the colonization of woody species in this subtropical area. Nutrient availability neither regulates the facilitation process nor influences species replacement during the early stages of Araucaria forest succession.

Notes: We investigate the scenario in which some amount of higher quality habitat is destroyed and is then replaced by some undetermined amount of lower quality habitat. We examined how much low-quality habitat would need to be created to maintain the equilibrium population abundance in the entire geographic area. Using a source–sink model, we find that (1) the number of hectares of created habitat per hectare of destroyed habitat must equal the ratio of the high-quality habitat's productivity to the low-quality habitat's productivity, however, (2) if the created habitat is a sink, then there is a threshold fraction of destroyed high-quality habitat below which the initial population abundance cannot be maintained through the creation of habitat. We illustrate these results using data on Red-winged Blackbirds (Agelaius phoeniceus) in two different regions where high-quality habitat is being replaced by or converted into lower quality habitat.

Notes: Introduced grasses have displaced Hawaiian Pili grass (Heteropogon contortus) in most dry, leeward habitats of the Hawaiian Islands. The purpose of this study was to assess the feasibility of restoring an indigenous Heteropogon grassland at the Puukohola Heiau National Historic Site, where introduced Buffel grass (Cenchrus ciliaris) is now dominant. Heteropogon seeds (50 seedlings/m2) were added to replicate plots within a Cenchrus grassland. Some plots were subjected to one-time herbicide or hand-pulling treatments to remove established Cenchrus. Because Hawaiians historically used fire to promote Heteropogon grasslands, the plots were burned biennially. Plots were also subjected to two levels of water supplementation. Heteropogon establishment was monitored over 2 and 4 years in the higher- and lower-water plots, respectively. In treatments containing established Cenchrus, Heteropogon establishment was consistently poor (〈10% cover). But in the burned plots where established Cenchrus had been removed, as many as 31 Heteropogon seedlings per square meter were recorded, and Heteropogon became the dominant cover, averaging 34% absolute cover (81% relative cover) after 4 years in the lower-water plot and 34% absolute cover (60% relative cover) after 2 years in the higher-water plot. Few Cenchrus grass seedlings survived, possibly due to insufficient water. Water supplementation promoted growth of other alien grasses from the seed bank (Digitaria insularis and Eragrostis spp.); however, these grasses quickly declined after supplemental watering was terminated. Although initial suppression of Cenchrus was required, Heteropogon expanded quickly when seeds and fire were reintroduced, demonstrating that a Heteropogon-dominated grassland can be reestablished in 2–4 years.

Notes: Human activities have degraded riparian systems in numerous ways, including homogenization of the floodplain landscape and minimization of extreme flows. We analyzed the effects of changes in these and other factors for extinction–colonization dynamics of a threatened Bank Swallow population along the upper Sacramento River, California, U.S.A. We monitored Bank Swallow distributions along a 160-km stretch of the river from 1986–1992 and 1996–2003 and tested whether site extinctions and colonizations corresponded with changes in maximum river discharge, surrounding land cover, estimated colony size, temperature, and precipitation. Colonization probabilities increased with maximum discharge. Extinction probabilities decreased with proximity to the nearest grassland, decreased with colony size, and increased with maximum discharge. To explore the implications for restoration, we incorporated the statistically estimated effects of distance to grassland and maximum discharge into simple metapopulation models. Under current conditions, the Bank Swallow metapopulation appears to be in continued decline, although stable or increasing numbers cannot be ruled out with the existing data. Maximum likelihood parameters from these regression models suggest that the Sacramento River metapopulation could be restored to 45 colonies through moderate amounts of grassland restoration, large increases in discharge, or direct restoration of nesting habitat by removing approximately 10% of existing bank protection (riprap) from suitable areas. Our results highlight the importance of grassland restoration, mixed benefits of restoring high spring discharge, and the importance of within-colony dynamics as areas for future research.

Notes: Spatial heterogeneity of resources can influence plant community composition and diversity in natural communities. We manipulated soil depth (two levels) and nutrient availability (three levels) to create four heterogeneity treatments (no heterogeneity, depth heterogeneity, nutrient heterogeneity, and depth + nutrient heterogeneity) replicated in an agricultural field seeded to native prairie species. Our objective was to determine whether resource heterogeneity influences species diversity and the trajectory of community development during grassland restoration. The treatments significantly increased heterogeneity of available inorganic nitrogen (N), soil water content, and light penetration. Plant diversity was indirectly related to resource heterogeneity through positive relationships with variability in productivity and cover established by the belowground manipulations. Diversity was inversely correlated with the average cover of the dominant grass, Switchgrass (Panicum virgatum), which increased over time in all heterogeneity treatments and resulted in community convergence among the heterogeneity treatments over time. The success of this cultivar across the wide range of resource availability was attributed to net photosynthesis rates equivalent to or higher than those of the native prairie plants in the presence of lower foliar N content. Our results suggest that resource heterogeneity alone may not increase diversity in restorations where a dominant species can successfully establish across the range of resource availability. This is consistent with theory regarding the role of ecological filters on community assembly in that the establishment of one species best adapted for the physical and biological conditions can play an inordinately important role in determining community structure.

Notes: High erosion potential of dewatered kimberlite mine tailings after diamond extraction has prompted research at the Ekati Diamond Mine in the Canadian subarctic heath tundra ecosystem. Greenhouse and field studies aimed at establishing a permanent vegetation cover on these dewatered tailings began in spring 2000. Coarse texture, no organic component, lack of available macronutrients, and a serpentine chemistry are the principal limitations of kimberlite tailings to plant colonization. Structure-improving (peat moss, lake sediment, and sewage sludge) and nutrient-providing (fertilizer, rock phosphate, calcium carbonate, and gypsum) amendments were tested to ameliorate these conditions, facilitating the establishment of a permanent vegetation cover, which stabilizes surface materials and promotes natural colonization by the surrounding tundra vegetation. Seven native grass species (Arctagrostis latifolia, Calamagrostis canadensis, Poa glauca, Poa alpina, Deschampsia beringensis, Deschampsia caespitosa, and Festuca rubra) were used to measure amendment success. With the addition of structure-improving and nutrient-providing amendments, plant growth on these kimberlite tailings under field conditions was significantly improved over unamended tailings material. Tailings properties, including cation exchange capacity, organic carbon, and macronutrient availability, were also improved with amendment addition.

Notes: Reclaimed landscapes after oil sands mining have saline soils; yet, they are required to have similar biodiversity and productivity as the predisturbance nonsaline landscape. Given that many species in the boreal forest are not tolerant of salinity, we studied the effects of soil salinity on plant communities in natural saline landscapes to understand potential plant responses during the reclamation process. Vegetation–soil relationships were measured along transects from flooded wetlands to upland forest vegetation in strongly saline, slightly saline, nonsaline, and reclaimed boreal landscapes. In strongly saline landscapes, surface soil salinity was high (〉10 dS/m) in flooded, wet-meadow, and dry-meadow vegetation zones as compared to slightly saline (〈5 dS/m) and nonsaline (〈2 dS/m) landscapes. Plant communities in these vegetation zones were quite different from nonsaline boreal landscapes and were dominated by halophytes common to saline habitats of the Great Plains. In the shrub and forest vegetation zones, surface soil salinity was similar between saline and nonsaline landscapes, resulting in similar plant communities. In strongly saline landscapes, soils remained saline at depth through the shrub and forest vegetation zones (〉10 dS/m), suggesting that forest vegetation can establish over saline soils as long as the salts are below the rooting zone. The reclaimed landscape was intermediate between slightly saline and nonsaline landscapes in terms of soil salinity but more similar to nonsaline habitats with respect to species composition. Results from this study suggest it may be unrealistic to expect that plant communities similar to those found on the predisturbance landscape can be established on all reclaimed landscapes after oil sands mining.

Notes: High coral cover and topographic complexity are favorable qualities of a healthy coral reef. Because coral reef restoration is expensive and coral growth is naturally slow, there is a need to strategically arrange coral transplants to maximize coral cover and topographic complexity. Similarly, it is important to understand how differences in the life history characteristics of coral transplants can influence changes in the structural attributes of coral reefs. This study utilizes agent-based computer modeling to explore the different spatial scenarios of coral transplantation using corals with contrasting r- and K-selected life histories. Spatial indexes are used to compare coral cover and topographic complexity at incremental time scales, within which disturbance events are of minor importance in spatial structuring. The outcomes of the model suggest that even-spaced grided transplanting arrangements provide the fastest increase in coral cover and three-dimensional habitat space (topographic complexity) across large temporal scales (〈30 years) for corals with r-selected life history strategies.

Notes: A commonly cited mechanism for invasion resistance is more complete resource use by diverse plant assemblages with maximum niche complementarity. We investigated the invasion resistance of several plant functional groups against the nonindigenous forb Spotted knapweed (Centaurea maculosa). The study consisted of a factorial combination of seven functional group removals (groups singularly or in combination) and two C. maculosa treatments (addition vs. no addition) applied in a randomized complete block design replicated four times at each of two sites. We quantified aboveground plant material nutrient concentration and uptake (concentration × biomass) by indigenous functional groups: grasses, shallow-rooted forbs, deep-rooted forbs, spikemoss, and the nonindigenous invader C. maculosa. In 2001, C. maculosa density depended upon which functional groups were removed. The highest C. maculosa densities occurred where all vegetation or all forbs were removed. Centaurea maculosa densities were the lowest in plots where nothing, shallow-rooted forbs, deep-rooted forbs, grasses, or spikemoss were removed. Functional group biomass was also collected and analyzed for nitrogen, phosphorus, potassium, and sulphur. Based on covariate analyses, postremoval indigenous plot biomass did not relate to invasion by C. maculosa. Analysis of variance indicated that C. maculosa tissue nutrient percentage and net nutrient uptake were most similar to indigenous forb functional groups. Our study suggests that establishing and maintaining a diversity of plant functional groups within the plant community enhances resistance to invasion. Indigenous plants of functionally similar groups as an invader may be particularly important in invasion resistance.

Notes: Effects of flooding on survival and growth of three different types of Nuttall oak (Quercus texana Buckl.) seedlings were observed at the end of third and fifth growing seasons at Yazoo National Wildlife Refuge, Mississippi, U.S.A. Three types of seedlings were planted in January 1995 in a split-plot design, with four replications at each of two elevations on floodprone, former cropland in Sharkey clay soil. The lower of the two planting elevations was inundated for 21 days during the first growing season, whereas the higher elevation did not flood during the 5-year period of this study. The three types of 1-0 seedlings were bareroot seedlings, seedlings grown in containers (3.8 × 21–cm plastic seedling cones), and container-grown seedlings inoculated with vegetative mycelia of Pisolithus tinctorius (Pers.) Coker. Survival of all the three seedling types was greatest at the lower, intermittently flooded elevation, indicating that drought and related effects on plant competition were more limiting to seedling survival than flooding. At the lower elevation, survival of mycorrhizal-inoculated container seedlings was greater than that of noninoculated container seedlings. Survival among bareroot seedlings and inoculated container seedlings was not significantly different at either elevation. At the higher, nonflooded elevation, however, bareroot seedling survival was greater than the survival of container seedlings without inoculation. Differences were significant among the inoculated and the noninoculated container seedlings, with higher survival of inoculated seedlings at both elevations, though differences were only significant in year 3. At the end of the fifth year, height of bareroot seedlings was significantly greater than the heights of both types of container-grown seedlings at both planting elevations. Because seedlings grown in the plastic seedlings cones did not survive better than the bareroot seedlings at either planting elevation, the bareroot stock appear to be the economically superior choice for regeneration in Sharkey soil.

Notes: To restore diversity of native vegetation, we must understand factors responsible for diversity in targeted communities. These factors operate at different spatial scales and may affect the number and relative abundances of species differently. We measured diversity of plant species and functional groups of species in replicated plots within paired restored and remnant (relic) tallgrass prairies at three locations in central Texas, U.S.A. To determine the contributions of species abundances and of spatial patterns of diversity to differences between prairie types, we separated diversity into richness and evenness (relative biomass) and into within-plot (α), among-plot (β), and prairie (γ) components. Species diversity was greater in remnant than in restored prairies at all spatial scales. At the γ scale, both species richness and species evenness were greater in remnants because of greater spatial variation in species composition. At the α scale, remnants were more diverse because of greater richness alone. Mean α richness correlated positively with the size of the species pool in restored prairies only, implying that in remnants, α richness was influenced more by colonization dynamics than by the number of species available for colonization. Plots in remnant prairies contained more functional groups and fewer species per group than did plots in restored prairies, suggesting that resource partitioning was greater in relic prairies. Our results are consistent with the interpretation that local ecological processes, like resource partitioning and limitations on seed dispersal, contribute to the greater diversity of remnant than restored prairies in central Texas. Restoration practices that limit abundances of competitive dominants, increase the number of species in seed mixtures, and increase the proximity of plants of different functional groups thus may be required to better simulate the plant diversity of tallgrass prairies.

Notes: Microtopography is a characteristic feature of many natural wetlands that is commonly lacking in restored wetlands (RWs). Consequently, it has been suggested that microtopography must be reestablished in RWs to accelerate the development of wetland function. The objective of this research was to examine responses of hydrology, soils, and vegetation to microtopographic reestablishment at a 3-year-old RW site in North Carolina. Microtopography was reestablished by configuring hummocks (mounds) and hollows (depressions), on otherwise level terrain (flats) of intermediate elevation. For most of the 2003 growing season, mean water table depths were below the soil surface in the flats and 10 cm above the soil surface in the hollows. Analysis of variance revealed significant microtopography by time interactions for soil temperature (p 〈 0.05) and moisture (p 〈 0.001), indicating that differences between zones were not consistent throughout the growing season. Hummocks had significantly higher nitrate (p 〈 0.0001) and ammonium (p= 0.001) than flats and hollows for most of the growing season. Differences in microbial biomass carbon and denitrification enzyme activity across the microtopographic zones were not detected. Plant species richness was significantly different (p 〈 0.001) across the microtopographic zones, with hummocks 〈 hollows 〈 flats. Flats supported the greatest numbers of wetland species. Aboveground biomass differed significantly (p 〈 0.001) across the microtopographic zones and followed a different pattern than richness: hummocks 〈 flats 〈 hollows, owing to the growth of emergent wetland herbs in hollows.

Notes: Biologically rich savannas and woodlands dominated by Pinus palustris once dominated the southeastern U.S. landscape. With European settlement, fire suppression, and landscape fragmentation, this ecosystem has been reduced in area by 97%. Half of remnant forests are not burned with sufficient frequency, leading to declines in plant and animal species richness. For these fire-suppressed ecosystems a major regional conservation goal has been ecological restoration, primarily through the reinitiation of historic fire regimes. Unfortunately, fire reintroduction in long-unburned Longleaf pine stands can have novel, undesirable effects. We review case studies of Longleaf pine ecosystem restoration, highlighting novel fire behavior, patterns of tree mortality, and unintended outcomes resulting from reintroduction of fire. Many of these pineland restoration efforts have resulted in excessive overstory pine mortality (often 〉50%) and produced substantial quantities of noxious smoke. The most compelling mechanisms of high tree mortality after reintroduction of fire are related to smoldering combustion of surface layers of organic matter (duff) around the bases of old pines. Development of effective methods to reduce fuels and competing vegetation while encouraging native vegetation is a restoration challenge common to fire-prone ecosystems worldwide that will require understanding of the responses of altered ecosystems to the resumption of historically natural disturbances.

Notes: Recurrent fires are integral to the function of many ecosystems worldwide. The management of fire-frequented ecosystems requires the application of fire at the appropriate frequency and seasonality, but establishing the natural fire regime for an ecosystem can be problematic. Historical records of fires are often not available, and surrogates for past fires may not exist. We suggest that the relationship between climate and fire can provide an alternative means for inferring past fire regimes in some ecosystems.

Notes: Prescribed burning is an important tool for managing and restoring prairies and other ecosystems. One effect of fire is plant litter removal, which can influence seedling establishment. Four experimental treatments (burned, clipped and raked to remove litter, burned with litter reapplied, and unmanipulated) were applied to 2 × 2.5–m plots in three western Oregon, United States, upland prairies to determine how burning affects seedling establishment. Seeds of common exotic and native prairie species were sowed into the experimental plots after treatments. Seedlings were censused the following spring. The experiment was repeated on each of the three sites, representing three common types of prairie vegetation: an Annual Exotic Grass site, a Perennial Exotic Grass site, and a Native Bunchgrass site. In both the Annual Exotic Grass and the Perennial Exotic Grass sites, burning significantly improved native, but not exotic, seedling establishment over those on unburned plots. Litter removal was a significant component of this burn effect, particularly on the Perennial Exotic Grass site. In these winter-moist systems, the net effect of litter is to inhibit seedling establishment. Burning treatments on the Native Bunchgrass site significantly increased seedling establishment only of short-lived exotic species. These results suggest that in prairie ecosystems similar to the Annual and Perennial Exotic Grass sites, prescribed burning followed by sowing native seeds can be an effective restoration technique. Burning alone or sowing alone would be counter-productive, in the first case because increased establishment would come from exotic species and in the second case because establishment rates are low in unburned plots.

Notes: Food web management is a frequently used lake restoration method, which aims to reduce phytoplankton biomass by strengthening herbivorous zooplankton through reduction of planktivorous fish. However, in clay-turbid lakes several factors may reduce the effectivity of food web management. Increasing turbidity reduces the effectivity of fish predation and weakens the link between zooplankton and phytoplankton. Therefore, the effects of fish stock manipulations may not cascade to lower trophic levels as expected. Additionally, in clay-turbid conditions invertebrate predators may coexist in high densities with planktivorous fish and negate the effects of fish reductions. For instance, in the stratifying regions of the clay-turbid Lake Hiidenvesi, Chaoborus flavicans is the main regulator of cladocerans and occupies the water column throughout the day, although planktivorous Osmerus eperlanus is very abundant. The coexistence of chaoborids and fish is facilitated by a metalimnetic turbidity peak, which prevents efficient predation by fish. In the shallow parts of the lake, chaoborids are absent despite high water turbidity. We suggest that, generally, the importance of invertebrate predators in relation to vertebrate predators may change along turbidity and depth gradients. The importance of fish predation is highest in shallow waters with low turbidity. When water depth increases, the importance of fish in the top-down regulation of zooplankton declines, whereas that of chaoborids increases, the change along the depth gradient being moderate in clear-water lakes and steep in highly turbid lakes. Thus, especially deep clay-turbid lakes may be problematic for implementing food web management as a restoration tool.

Notes: The rehabilitation of disturbed ecosystems through ecological succession should lead to the recovery of indigenous biological assemblages typical of a region. However, rehabilitation may give rise to unusual successional pathways and lead to atypical assemblages. We compared millipede assemblages along a chronosequence of habitats developing in response to a post-mining coastal dune forest rehabilitation program with those developing spontaneously in the same area. Our comparison suggests that active rehabilitation mimics and even surpasses spontaneous successional development. On both chronosequences, the total number of species, as well as the mean density, diversity, and species richness increased, and dominance decreased, with habitat regeneration age. Moreover, the similarity of millipede assemblages on the two chronosequences to those on three sets of reference sites (mature forests) increased with regeneration age, but this recovery of community composition occurred faster on the rehabilitating chronosequence than on the spontaneously regenerating chronosequence. This suggests that successional processes are leading to a recovery of the predisturbed state, but factors like protection from further disturbances, which occur on the spontaneously regenerating chronosequence, is probably important to ensure success. The distance between a regenerating site and a colonization source area apparently affects the direction of community recovery—assemblages on the rehabilitating chronosequence converged faster onto assemblages on closer reference sites than onto those on reference sites farther away.

Notes: Ozark glades are gaps in forested areas that are dominated by grasses and forbs growing in rocky, nutrient-poor soil. Historically, these open, patchy habitats were maintained by natural and anthropogenic fire cycles that prohibited tree encroachment. However, because of decades of fire suppression, glades have become overgrown by fire-intolerant species such as Eastern red cedar (Juniperus virginiana). Current restoration practices include cutting down invasive cedars and burning brush piles, which represent habitat for Northern fence lizards (Sceloporus undulatus). Because Sceloporus actively consumes herbivores, we hypothesized that the presence of these lizards in and around brush piles might result in a trophic cascade, whereby damage on native plants is reduced. Field surveys across six Missouri glades indicated that lizard activity was minimal beyond 1 m from habitat structures. This activity pattern reduced grasshopper abundance by 75% and plant damage by over 66% on Echinacea paradoxa and Rudbeckia missouriensis near structures with lizards. A field transplant experiment demonstrated similar reductions in grasshopper abundance and damage on two other glade endemic species, Aster oblongifolius and Schizachyrium scoparium. These results demonstrate that future glade restoration efforts might benefit from considering top-down effects of predators in facilitating native plant establishment.

Notes: We initiated a study of the effects of mycorrhizal fungal community composition on the restoration of tropical dry seasonal forest trees. Tree seedlings were planted in a severely burned experimental site (1995 fire) during the growing season of 1998 at the El Edén Ecological Reserve, in north Quintana Roo, Mexico. Seedlings of Leucaena leucocephala, Guazuma ulmifolia, Caesalpinia violacea, Piscidia piscipula, Gliricidia sepium, and Cochlospermum vitifolium were germinated in steam-sterilized soil and either remained uninoculated (nonmycorrhizal at transplanting) or were inoculated with mycorrhizal fungi in soils from early-seral (recently burned) or late-seral (mature forest) inoculum. Inoculum from the early-seral soil was largely Glomus spp., whereas a diverse community of arbuscular mycorrhizal fungi were reintroduced from the mature forest including species of Scutellospora, Gigaspora, Glomus, Sclerocystis, and Acaulospora. Plants grew better when associated with the mature forest inoculum, unlike a previous experiment in which plants grew taller with the early-seral inoculum. Reasons for the different responses include a less-intense burn resulting in more residual organic matter. In addition to mycorrhizal responses, plants were severely affected by deer browsing. One tree species, C. vitifolium found in the region but not in the reserve, was eliminated by a resident fungal facultative pathogen. Several practical conclusions for restoration can be made. The common nursery practice of soil sterilization may be detrimental because it eliminates beneficial mycorrhizal fungi; species not native to the site may not survive because they may not be adapted to the local pathogens; and herbivory can be severe depending on the landscape context of the restoration.

Notes: Many wetland restoration projects occur on former agricultural soils that have a history of disturbance and fertilization, making them prone to phosphorus (P) release upon flooding. To study the relationship between P release and hydrologic regime, we collected soil cores from three restoration wetlands and three undisturbed wetlands around Upper Klamath Lake in southern Oregon, U.S.A. Soil cores were subjected to one of three hydrologic regimes—flooded, moist, and dry—for 7.5 weeks, and P fluxes were measured upon reflooding. Soils from restoration wetlands released P upon reflooding regardless of the hydrologic regime, with the greatest releases coming from soils that had been flooded or dried. Undisturbed wetland soils released P only after drying. Patterns in P release can be explained by a combination of physical and biological processes, including the release of iron-bound P due to anoxia in the flooded treatment and the mineralization of organic P under aerobic conditions in the dry treatment. Higher rates of soil P release from restoration wetland soils, particularly under flooded conditions, were associated with higher total P concentrations compared with undisturbed wetland soils. We conclude that maintaining moist soil is the means to minimize P release from recently flooded wetland soils. Alternatively, prolonged flooding provides a means of liberating excess labile P from former agricultural soils while minimizing continued organic P mineralization and soil subsidence.

Notes: Aspen is considered a keystone species, and aspen communities are critical for maintaining biodiversity in western landscapes. Inventories of aspen stand health across the Eagle Lake Ranger District (ELRD), Lassen National Forest, California, U.S.A., indicate that 77% of stands are in decline and at risk of loss as defined by almost complete loss of mature aspen with little or no regeneration. This decline is due to competition from conifers establishing within aspen stands as a result of modification of natural fire regimes coupled with excessive browsing by livestock. Restoration treatments were implemented in four aspen stands in 1999 using mechanical equipment to remove competing conifers to enhance the growth environment for aspen. Recruitment and establishment of aspen stems were measured in treated stands (removal of competing conifers) and non-treated stands (control) immediately prior to treatment and 2 and 4 years post-treatment. There was a significant increase in total aspen stem density and in two of three aspen regeneration size classes for treated stands compared to controls. Pre-treatment total aspen density was positively associated with total aspen density and density in all size classes of aspen (p 〈 0.001). The results demonstrate that mechanical removal of conifers is an effective treatment for restoring aspen.

Notes: High erosion potential of dewatered kimberlite mine tailings after diamond extraction has prompted research at the Ekati Diamond Mine in the Canadian subarctic heath tundra ecosystem. Coarse texture, no organic component, lack of available macronutrients, and a serpentine chemistry are the principal limitations of these kimberlite tailings to plant colonization. Structure-improving (peat moss, lake sediment, sewage sludge, Agri-Boost, and composted papermill sludge) and nutrient-providing (fertilizer, calcium carbonate, gypsum, and rock phosphate) amendments were tested in the greenhouse to ameliorate these limitations, thereby facilitating the field establishment of a permanent vegetation cover, which would stabilize the surface materials and promote natural colonization by the surrounding tundra vegetation. Seven native grass species (Arctagrostis latifolia, Calamagrostis canadensis, Poa glauca, Poa alpina, Deschampsia beringensis, Deschampsia caespitosa, and Festuca rubra) were used to measure amendment success. With the addition of structure-improving and nutrient-providing amendments, plant growth on kimberlite tailings was significantly enhanced. Tailings properties, including cation exchange capacity, percentage of organic carbon, and macronutrient availability, were also improved by amendment addition.

Notes: Mechanical, biological, and chemical attempts to control invasive plants can be expensive, ecologically damaging, and frequently unsuccessful. This study proposes using the intrinsic biological attributes of the threatened plant community by artificially increasing the density of competitive native species to selectively suppress the growth of the invasive. Evidence from agricultural weed control suggests that oversowing infested areas with species with biological traits similar to those of the invasive species not only reduces productivity of the invasive species but also may eliminate environmental damage associated with standard control techniques. Annual bastard cabbage (Rapistrum rugosum), a Eurasian exotic, is an invader of native plant communities in the continental United States. Control with herbicides has been problematic due to high mortality of adjacent native species and subsequent perpetuation of a disturbed state that facilitates further regeneration of R. rugosum from the seed bank. In a randomized field experiment, sowing native Indian blanket (Gaillardia pulchella) over established seedling colonies of R. rugosum resulted in significant reduction of R. rugosum productivity (F= 3.43; p 〈 0.05). The highest sowing rate of G. pulchella resulted in a 72% reduction in aboveground productivity of R. rugosum that translated to an estimated 83% decrease in seed set, without significant suppression of adjacent native species. It is proposed that enriching threatened or infested plant communities with selected native species with matching phenologies and competitive characteristics has advantages over conventional control methods in that (1) it reduces the threat to nontarget organisms; (2) once installed, the species could self-regenerate; and (3) it does not perpetuate a disturbed (early-successional) state that might aggravate the problem. This may serve as an alternative technique to protect and restore native plant communities.

Notes: Land application of municipal biosolids on coal mine spoils can benefit vegetation establishment in mine reclamation. However, the application of biosolids leads to domination by early-successional species, such as grasses, and low establishment of woody and volunteer species, thus reducing potential for forestry as a postmining land use. In this experiment, tree seedlings were planted in strips (0.6-, 1-, and 4-m wide) that were not seeded with grasses, and the effects of unseeded strip width on seedling growth and species richness were assessed. Planted seedling mortality was high; therefore, the effect of unseeded strip width on seedling growth could not be determined. However, it was found that natural plant invasion and species richness were highest in the 4-m unseeded strips. The practice of leaving 4-m-wide unseeded strips in mine reclamation with biosolids in the eastern United States, along with the improvement of tree seedling planting practices and planting stock, would help promote a more species-rich plant community that could be utilized for forestry or a variety of other postmining land uses.

Notes: Grassy woodlands dominated by Eucalyptus species such as E. albens Benth., E. melliodora A. Cunn. ex Schauer, and E. microcarpa Maiden are poorly conserved in Australia, owing to widespread agricultural development. Understorey restoration is vitally important to enhance degraded remnants but no reliable techniques are available to restore herbaceous understorey species over large areas. Reestablishment of dominant native grasses such as Kangaroo grass (Themeda triandra Forssk.) is particularly important. This study compared Themeda establishment using a variety of sowing techniques across a range of landscape positions in degraded woodlands in central New South Wales. Four localities were sampled at three landscape positions (upper, mid-, and lower slopes). Existing vegetative cover was sprayed with herbicide and removed by mowing. A randomized block experiment was established at each site with five replicates of five seedbed treatments: all four factorial combinations of soil disturbance (disturbed, nondisturbed) and weed control (atrazine, nonatrazine), plus topsoil scalping followed by soil disturbance. After 117 days, all plots were subject to a common herbicide (atrazine) treatment to control weeds. Themeda establishment was not significantly affected by landscape position, despite significant differences in the cover of exotic species among landscape positions. The scalped/disturbed treatment resulted in significantly better establishment at 400 days (18% or 3.9 plants/m2) than the control (8% or 1.8 plants/m2). All other treatments did not differ significantly from the control suggesting that seedbed treatments are not critical to successful Themeda establishment. These results suggest that Themeda swards can be reestablished in degraded woodlands relatively simply. The similarity in outcomes across all landscape positions suggests that general recommendations for “best-bet” establishment methods may prove robust under a wide range of environmental and seasonal conditions.

Notes: The criteria of restoration success should be clearly established to evaluate restoration projects. Recently, the Society of Ecological Restoration International (SER) has produced a Primer that includes ecosystem attributes that should be considered when evaluating restoration success. To determine how restoration success has been evaluated in restoration projects, we reviewed articles published in Restoration Ecology (Vols. 1[1]–11[4]). Specifically, we addressed the following questions: (1) what measures of ecosystem attributes are assessed and (2) how are these measures used to determine restoration success. No study has measured all the SER Primer attributes, but most studies did include at least one measure in each of three general categories of the ecosystem attributes: diversity, vegetation structure, and ecological processes. Most of the reviewed studies are using multiple measures to evaluate restoration success, but we would encourage future projects to include: (1) at least two variables within each of the three ecosystem attributes that clearly related to ecosystem functioning and (2) at least two reference sites to capture the variation that exist in ecosystems.

Notes: The restoration potential of Sweetgrass (Anthoxanthum nitens (Weber) Y. Schouten & Veldkamp) was evaluated through a field experiment conducted on Kanatsiohareke, a Mohawk farm, and at the LaFayette Experiment Station near Syracuse, New York. The effects of competition reduction and two cover crops on Sweetgrass reestablishment success were examined. Sweetgrass was planted under four treatments: Sweetgrass alone; with existing, old-field vegetation; with a cover crop of Hairy vetch (Vicia villosa); and with a cover crop of Annual (Italian) ryegrass (Lolium multiflorum). The experiment consisted of five replicates of the four treatments at both LaFayette and Kanatsiohareke. Sweetgrass biomass, height, reproduction rate, and survivorship were greatest in plots that were weeded to eliminate competition and in plots with Hairy vetch as a cover crop. A cover crop of Annual ryegrass resulted in reduced Sweetgrass growth and reproduction. The results of this field experiment indicate that there is great restoration potential for Sweetgrass because it is easily transplanted and reproduces vigorously. For 2.25-m2 plots, Hairy vetch is an effective cover crop for Sweetgrass. Planting the Sweetgrass with Hairy vetch generated properties of the grass that are desired by basketmakers, such as abundance and tall blades. This technique also allowed for a relatively non–labor intensive method of cultivation. Reestablishment of Sweetgrass offers the members and visitors of Kanatsiohareke the means to continue to use the plant, strengthen traditional practices associated with Sweetgrass, and benefit economically by selling baskets and medicine made with Sweetgrass.

Notes: Whether restoration programs successfully reinstate ecological interactions remains a contentious and largely untested issue. We investigated plant and pollinator interactions on two old and two restored hay meadows, with the aim of evaluating if quantitative patterns of insect visitation and pollen transport were comparable among old and restored meadows. In terms of structural diversity, few species of plants and insects were shared among the webs. In all four meadows, Diptera and Hymenoptera dominated the visitor community in terms of both species richness and abundance. Coleoptera, Hemiptera, and Lepidoptera comprised the remainder of the flower visitors. No significant difference was found between restored and old sites in plant or insect species richness or in plant and insect abundance. In terms of function, the meadows appeared more similar, although a slightly higher proportion of the potential links between plants and insects was realized for old meadows. No difference was found in the proportion of plant species visited, and visited plant species were generalized, with all having more than a single species of insect visitor. We also sampled approximately 400,000 pollen grains from the flower-visiting insects. There were no differences between old and restored sites in the amount of pollen being transported or in the average number of pollen grains per insect. At both types of meadows, Hymenoptera carried most pollen, followed by Diptera. Again, generalization was the norm, with all plants having more than a single species of pollen carrier. No difference was observed in the connectance of pollen transport webs between old and restored sites. Overall, although the four meadows showed considerable structural variation, they showed similarity with regard to the functional processes we studied. Because structural variation is expected among localities, we conclude that the two restoration projects have been successful.

Notes: Current restoration measures of degraded, acidified heathland ecosystems have not always been successful in the Netherlands. Positive effects of a restored hydrology are often counteracted by acidification of the soil and the local groundwater system. Liming of the heathlands in the catchment of moorland pools might contribute to the restoration of both habitats. Experimental catchment liming was carried out in two degraded Dutch heathlands, with doses varying between 2 and 6 tons/ha. Catchment liming resulted in increased pH and base cation concentrations in the highest elevated limed parts, as well as in the lower situated, nonlimed heath areas and moorland pools. Generally, catchment liming created suitable conditions for the return of heathland target species, and the positive effects lasted for at least 6 years. The response of the heathland vegetation to the liming has, however, been slow because only a small number of endangered plant species increased in abundance. In contrast, four Red List soft-water macrophytes strongly increased in abundance in the moorland pool. Our results show that, even with the slow return of Red List plant species, catchment liming can be a successful management tool for the restoration of the acidified heathland landscape.

Notes: Phalaris arundinacea L. is an aggressive species that can dominate wetlands by producing monotypic stands that suppress native vegetation. In this study invasion windows were created for native species in monotypic stands of P. arundinacea with either fire or herbicide. Three native species groups, herbaceous plants, herbaceous seeds, and woody shrubs, were planted into plots burned or treated with herbicide in the early spring. Fire did not create an effective invasion window for native species; there was no difference in P. arundinacea root and shoot biomass or cover between burned and control plots (p≥ 0.998). Herbicide treatment created an invasion window for native species by reducing P. arundinacea root and shoot biomass for two growing seasons, but that invasion window was fast closing by the end of the second growing season because P. arundinacea shoot biomass had nearly reached the shoot biomass levels in the control plots (p= 0.053). Transplant mortality, frost, and animal herbivory prevented the herbaceous species and woody seedlings from becoming fully established in the plots treated with herbicide during the first year of the experiment. Transplanted monocots had a greater survival than dicots. By the second growing season the herbaceous group had the greatest mean areal cover (5%), compared to the woody seedlings (3%) and seed group (0%). Long-term monitoring of the plots will determine whether the herbaceous transplants will compete effectively with P. arundinacea and whether the woody species will survive, shade the P. arundinacea, and accelerate forest succession.

Notes: Invasive plants are one of the most serious threats to native species assemblages and have been responsible for the degradation of natural habitats worldwide. As a result, removal of invasive species and reestablishment of natural vegetation have been attempted in order to restore biodiversity and ecosystem function. This study examined how native arthropod assemblages, an abundant and functionally important group of organisms in many ecosystems, are affected by the incursion of the invasive wetland plant Phragmites australis and if the restoration of the native vegetation in brackish Spartina alterniflora marshes results in the reestablishment of the arthropod community. The invasion of Phragmites into a coastal Spartina marsh in southern New Jersey seriously altered arthropod assemblages and trophic structure by changing the abundance of trophic groups (detritivores, herbivores, carnivores) and their taxonomic composition. Herbivore assemblages shifted from the dominance of external free-living specialists (e.g., planthoppers) in Spartina to concealed feeders in Phragmites (stem-feeding cecidomyiids). Moreover, free-living arthropods in Phragmites became dominated by detritivores such as Collembola and chironomids. The dominant marsh spiders, web-building linyphiids, were significantly reduced in Phragmites habitats, likely caused by differences in the physical environment of the invaded habitats (e.g., lower stem densities). Thus, trophic structure of arthropod assemblages in Phragmites, as seen in the large shifts in feeding guilds, was significantly different from that in Spartina. Removal of Phragmites with the herbicide glyphosate resulted in the rapid return of Spartina (≤5 yrs). Moreover, return of the dominant vegetation was accompanied by the recovery of most original habitat characteristics (e.g., live and dead plant biomass, water flow rate). The arthropod assemblage associated with Spartina also quickly returned to its preinvasion state and was not distinguishable from that in uninvaded Spartina reference sites. This study provides evidence that the reestablishment of native vegetation in areas previously altered by an invasive plant can result in the rapid recovery of the native arthropod assemblage associated with the restored habitat.

Notes: Habitat restoration resulting in changes in plant community composition or species dominance can affect the spatial pattern and variability of soil nutrients. Questions about how these changes in soil spatial heterogeneity develop over time at restoration sites, however, remain unaddressed. In this study, a geostatistical approach was used to quantify changes over time in the spatial heterogeneity of soil organic matter (SOM) across a 26-year chronosequence of tallgrass prairie restoration sites at FermiLab, outside of Chicago, Illinois. We used total soil N and C as an index of the quantity of SOM. We also examined changes in C:N ratio, which can influence the turnover of SOM. Specifically, the spatial structure of total N, total C, and C:N ratio in the top 10 cm of soil was quantified at a macroscale (minimum spacing of 1.5 m) and a microscale (minimum spacing of 0.2 m). The magnitude of spatial heterogeneity (MSH) was characterized as the proportion of total sample variation explained by spatially structured variation. At the macroscale, the MSH for total N decreased with time since restoration (r2= 0.99, p 〈 0.001). The decrease in spatial heterogeneity over time corresponded with a significant increase in the dominance of the C4 grasses. At the microscale, there was significant spatial structure for total N at the 4-year-old, 16-year-old, and 26-year-old sites, and significant spatial structure for total C at the 16-year-old and 26-year-old sites. These results suggest that an increase in dominance of C4 grasses across the chronosequence is homogenizing organic matter variability at the field scale while creating fine-scale patterns associated with the spacing of vegetation. Areas of higher soil moisture were associated with higher soil N and C at the two oldest restoration sites and at the native prairie site, potentially suggesting patches of increased belowground productivity in areas of higher soil moisture. This study is one of the first to report significant changes over time in the spatial structure of organic matter in response to successional changes initiated by restoration.

Notes: One of the proximate results of forest fragmentation, and a cause of continued microenvironmental change and exacerbation of ecological problems, is increased invasions by weedy plant species. One such example is Alliaria petiolata (Brassicaceae), a serious pest threatening much of eastern North America. Alliaria petiolata impedes mitigation of fragmentation and restoration efforts because it tends to outcompete and possibly extirpate much of the native understory species on localized scales. As part of a strategy to address the problems of fragmented habitats, an experiment was conducted to determine whether Sanguinaria canadensis (Papaveraceae) could outcompete A. petiolata. Using an additive design, I transplanted S. canadensis at densities of 0, 1, 2, 3, 5, 7, 9, 11, 15, and 20 ramets/m2 in 1997 and allowed them to interact with initial A. petiolata densities of 128 seedlings and 31 rosettes/m2. As of 2000, multivariate analyses of variance with repeated measures and simple analyses of variance indicated that initial S. canadensis densities of as little as 5 ramets/m2 suppressed A. petiolata. Initial S. canadensis densities of 9 and 11 ramets/m2 resulted in the lowest numbers of late-spring seedlings, numbers and sizes of year 1 and 2 rosettes, numbers and gross areas of stem leaves, numbers of flowering individuals, number of flowers, number of fruits (siliques), and height at flowering. While it remains to be tested whether this will continue and if the reestablishment of S. canadensis will help reassemble forest ecosystems, the experiments indicated that transplanting S. canadensis was effective at mitigating the spread of A. petiolata.

Notes: Canebrakes are dense stands of Arundinaria gigantea (Walt.) Muhl. that covered large areas of the southeastern North America. With agricultural development, canebrakes were quickly converted to crop and pastureland and now occur only in small, isolated patches. There is growing interest in the use of A. gigantea and other temperate bamboo species in riparian and floodplain revegetation in North America, but lack of detailed information on propagation and management of woody perennial grasses hinders reestablishment activities. Our study assesses the influence of nutrient and woodchip mulch amendments on survival and growth of A. gigantea transplanted as part of a riparian restoration project in central Kentucky. After two growing seasons, culm number (aboveground stems) increased 4-fold and extent of transplanted clumps expanded 26-fold. The survival rate of transplanted cane clumps was 98%. Hardwood chip mulch significantly increased the emergence of new culms, culm height growth, and clump area. Composted manure, applied at a rate that contributed a similar mass of organic matter as the hardwood mulch, also significantly increased new culm number and clump area. Our findings demonstrate that addition of manure or hardwood mulch can significantly enhance aboveground production of A. gigantea transplants. However, survival and initial growth of untreated clumps were also adequate in this study. It appears that careful site selection, transplantation, and site maintenance may be sufficient to ensure A. gigantea establishment on many sites. Practitioners should assess soil drainage, water stress, and fertility along with herbaceous competition and incidence of overbank flooding before determining the necessity of organic amendments to supplement establishment of A. gigantea or other woody grasses for riparian restoration.

Notes: Constraints to grassland and open forest restoration (e.g., poor seed sources, yearly variation in establishment, and the persistence of weeds) necessitate the development of innovative methods to restore bunchgrass communities. We assessed the use of two native bunchgrass transplants, Bluebunch wheatgrass (Pseudoroegneria spicata) and Spreading needlegrass (Achnatherum richardsonii), for restoration within thinned montane forest communities of southeastern British Columbia, Canada. Fall and spring plantings were examined, either with or without glyphosate treatments to Pinegrass (Calamagrostis rubescens) neighbors. Calamagrostis rubescens is abundant in grassland affected by tree encroachment and may limit transplant establishment. Bunchgrass survival was positively associated (p 〈 0.05) with transplant size. Although P. spicata survival was greater (p 〈 0.01) with fall (81%) than with spring (44%) planting, survival of A. richardsonii was greater (p 〈 0.01) when planted in the spring (68 vs. 23%). Reduction of C. rubescens led to a relatively small but significant increase (p 〈 0.05) in bunchgrass survival by 7%. The summer after planting, changes in transplant tiller number varied by bunchgrass species, planting season, and treatment of neighboring C. rubescens. Removal of neighboring C. rubescens generally increased the number of tillers (or reduced tiller loss) but only within fall-planted A. richardsonii and spring-planted P. spicata. Both A. richardsonii and P. spicata transplants have potential for understory restoration within thinned montane forests, particularly using larger individuals, although to maximize survival, these species should be planted in the spring and fall, respectively. Reduction of C. rubescens may also enhance transplant survival and in some cases growth.

Notes: Carolina bays are depression wetlands of high conservation value that occur across the Southeastern Coastal Plain of the United States. Venus flytrap (Dionaea muscipula) is one rare carnivorous plant that grows in open habitats on the rims of Carolina bays. Without frequent burning, vegetation on bay rims becomes dominated by evergreen shrubs and Venus flytrap populations decline. This project examined the utility of mechanical mowing, soil clearing, transplanting, and seeding as an approach to restoring populations of Venus flytraps when fire is precluded. Mowing of patches on bay rims produced open sites with little ground-layer vegetation. After two growing seasons, adult Venus flytraps transplanted to mowed patches showed high survivorship and relatively high leaf number/plant. Suppressed Venus flytraps existing on-site quickly initiated growth in response to mowing. These volunteers and the transplants had higher flowering percentages than plants in reference populations. Seeds of Venus flytraps were scattered in mowed and cleared plots. Seedling establishment was low, but seedlings persisted into the second growing season. Mowing created suitable habitat for growth and flowering of adult Venus flytraps and facilitated establishment of two other carnivorous species, Sundew (Drosera capillaris) and Bladderwort (Utricularia subulata). But, mowing and clearing also facilitated invasion by four species of grasses and rushes; evergreen shrubs resprouted quickly after mowing. Maintaining persistent openings by mowing the rims of Carolina bays will be an ongoing challenge due to availability of potential invaders and rapid regrowth of shrubs.

Notes: Native plant establishment is limited by harsh environmental conditions in areas affected by tephra deposition following volcanic eruptions. Late-successional species might be lacking even decades after the disturbance. We assessed the effectiveness of pine-bark mulch, a by-product of sustainable timber production in the study area, in promoting the establishment and survival of a late-successional species (Pinus pseudostrobus) and a nitrogen-fixing legume (Lupinus elegans). We established a factorial experiment in areas covered with tephra during the eruption of the Paricutín volcano in the state of Michoacán, Mexico. After 1 year, P. pseudostrobus survival was significantly higher (p 〈 0.001) in plots with pine-bark mulching (46.5%) than in plots without mulching (21.8%). After 2 years, surviving pines with mulching were significantly taller (p= 0.03) than pines without mulching (45.3 ± 3.8 cm and 31.2 ± 3.7 cm, respectively). Lupinus elegans plants survived longer when grown in plots with pine-bark mulching than without mulching. Mulching reduced tephra temperatures during the dry season (when temperatures can reach up to 58°C 4 cm below the surface of bare tephra). Lupinus elegans plants were affected by herbivory by small rodents, run-off, and frost at the end of the growing season. Our results suggest that mulching can ameliorate harsh environmental conditions on sites covered with tephra while incorporating a by-product of sustainable forestry into restoration practice.

Notes: Bracken (Pteridium aquilinum) is a major weed of seminatural vegetation in Great Britain, as in many other countries. As a consequence, large areas have been subject to control with the intention of restoring the former vegetation. The use of aerial spraying with asulam, a narrow spectrum, carbamate herbicide, has become a common method of control. However, its long-term efficacy has not been assessed in terms of either controlling the bracken or in producing suitable restored habitats. This study undertook such an assessment by comparing the results of a 2002 survey of the sites subject to bracken control by aerial spraying of asulam with previous (1990/1991 and 1994) surveys of the same sites. This showed that a single application of asulam was effective in eradicating bracken (〈1% cover remaining) on a third of sites. However, on 10% of the sites, the bracken had regenerated completely (cover 〉80%) and on the remainder it was still present in patches (〉20% of quadrats), often at high density. More than half the sprayed sites had seen good recovery of moorland vegetation, the target of the restoration, because they were now classified as having upland heathland vegetation within the National Vegetation Classification. Considerable amounts of bracken control are grant aided as part of agri-environment schemes. These schemes should be adapted to encourage good practice, namely, intensive follow-up treatment by spraying any emerging fronds, and to encourage treatment of previously sprayed areas rather than spraying of new areas in order to protect previous investment of grant aid.

Notes: Invasions of North American grasslands by Spotted knapweed (Centaurea maculosa Lam.) are mediated in part by Spotted knapweed root exudation of (±)-catechin, a potent phytotoxin. Residual soil (±)-catechin may interfere with reestablishment of native grassland species even after Spotted knapweed populations are controlled. Grassland species that are resistant to (±)-catechin may be more successful for restoration of areas infested by Spotted knapweed. We evaluated the (±)-catechin resistance of 23 grassland species by measuring the effects of seven (±)-catechin concentrations (0–4.0 mg/mL) on seed germination, seedling root and shoot elongation, and seedling mortality. (±)-Catechin treatments were chosen to reflect the range of observed Spotted knapweed field soil (±)-catechin concentrations. Inhibition of root elongation was the strongest and most common effect of (±)-catechin treatment. High (±)-catechin concentrations reduced mean root lengths of 5 of the species by more than 75% and another 10 species by more than 55%. Experimentally derived concentrations needed to reduce root length by 50% (EC50), an indicator of (±)-catechin resistance, ranged from 0.43 mg/mL ± 0.30 SE to greater than 4.0 mg/mL among species. Eight species with EC50s greater than 3.0 mg/mL were identified as resistant to (±)-catechin and are likely suitable for revegetation of Spotted knapweed–infested areas. (±)-Catechin resistance was positively correlated with mean seed mass, suggesting that seed carbohydrate reserves may allow seedlings to detoxify (±)-catechin, develop barriers to (±)-catechin exposure, or sustain a positive growth rate, despite (±)-catechin-induced cell death. Future efforts to identify allelochemical-resistant grassland species should focus on large-seeded species.

Notes: In plant conservation, restoration (the augmentation or reestablishment of an extinct population or community) is a valuable tool to mitigate the loss of habitat. However, restoration efforts can result in the introduction of novel genes and genotypes into populations when plant materials used are not of local origin. This movement is potentially important because many plant species are subdivided into populations that are adapted to local environmental conditions. Here we focus on genetic concerns arising from ongoing restoration efforts, where often little is known about “How local is local?” (i.e., the geographic or environmental scale over which plant species are adapted). We review the major issues regarding gene flow and local adaptation in the restoration of natural plant populations. Finally, we offer some practical, commonsense guidelines for the consideration of genetic structure when restoring natural plant populations.

Notes: Ecological restoration often relies on the use of expert opinion to make management decisions in the face of uncertainty. The quantification of expert opinion can be difficult, especially when more than one expert is consulted and experts are not in agreement. Decision analysis can provide a framework to systematically deconstruct a complex problem and provide greater objectivity to restoration decisions. We utilized decision analysis techniques to identify restoration objectives and to quantify expert opinions to prioritize restoration activities at 112 prairie openings in the Edge of Appalachia Preserve in southern Ohio, U.S.A. We first created an objectives hierarchy to model how decision-makers decide which prairies to manage. We then determined how to measure each component of the hierarchy and sampled all prairies for percent woody cover, geology, indicator species index (an index of plant species richness), slope, aspect, and distance to nearest prairie. We modeled seven different experts’ preferences for managing prairies with varying values for each of these ecological measures. We then interviewed the same decision-makers to determine relative weights for each component of the objectives hierarchy using trade-off analysis. By combining the weights, preference relationships, and sampling data, we were able to rank each prairie and management unit based on its management priority. Experts had similar preferences except for the measure of distance to nearest prairie. We found that decision-makers gave different weights to each of the different components of the hierarchy. Generally, experts weighted percent woody cover, indicator species index, and geology more highly than slope, aspect, and distance to nearest prairie. Despite these differences, priorities for management, once all factors were weighted and combined, were similar.

Notes: The Karner blue butterfly (KBB) (Lycaeides melissa samuelis), a federally listed species, has historically been a component of barren and savannah ecosystems in the northeastern and midwestern United States. In New York, it now occurs primarily on managed, early-successional sites such as power line corridors (utility rights-of-way) from Albany to Glens Falls. Blue lupine (Lupinus perennis), the exclusive larval food source of the KBB, has been suggested to be the most limiting factor for the butterfly within the eastern portion of its range. Power line corridor management maintains early-successional habitats by suppressing the regrowth of woody species, creating potentially important habitat for the conservation and restoration of the KBB complex. This research compared the effects of several vegetation-clearing methods on Blue lupine populations and associated communities of nectar species for KBB over an 8-year period. Methods evaluated differed in intensity (annual, 4-, or 8-year intervals) and type (herbicide or mechanical). Blue lupine and plant community responses did not significantly differ among the treatment types applied to the power line corridors. However, Blue lupine cover, clump size, and density of stems per clump increased following the application of treatments in general. The number and cover of nectar species, total herbaceous cover, and species richness also responded positively to treatment overall. The percentage of non-native species temporarily increased following treatment but declined to near pre-treatment levels again as woody cover increased. Temporal changes in plant community composition were not related to management methods. The management tools assessed, mowing and herbicide application, will accomplish the goal of halting or reversing succession, maintaining critical habitat for the KBB in a landscape that provides little other suitable habitat.

Notes: Replacement of perennial grasses with non-native annual grasses in California's Central Valley grasslands and foothills has increased deep soil water availability. Yellow starthistle (Centaurea solstitialis), a deep-rooted invasive thistle, can use this water to invade annual grasslands. Native perennial bunchgrasses, such as Purple needlegrass (Nassella pulchra), also use deep soil water, so there is an overlap in resource use between N. pulchra and C. solstitialis. Restoration of N. pulchra to annual grasslands could result in strong competitive interactions between N. pulchra and C. solstitialis, which may reduce survival, growth, and reproduction of the invader. The strength of this competitive interaction can increase as N. pulchra plants mature, increase in size, and develop more extensive root systems. We studied how the size of N. pulchra affected the success of C. solstitialis invasion over 2 years. We allowed C. solstitialis seed to fall naturally into plots containing N. pulchra plants. For each plot, we measured the number of C. solstitialis seedlings and mature plants, as well as C. solstitialis biomass and seedhead production. In both years of the study, C. solstitialis number, biomass, and seedhead production declined significantly as N. pulchra size increased. However, even C. solstitialis grown with the largest N. pulchra plants produced some seed, especially during the higher rainfall year. We conclude that restoration plantings with larger, established N. pulchra plants will be more resistant to invasion by C. solstitialis than young N. pulchra plantings, but site management must continue as long as a C. solstitialis seed source is present.

Notes: A study was conducted to evaluate the long-term effects of biosolids amendment on restoration of disturbed sagebrush steppe habitat in northwestern Colorado. Twenty-four years after biosolids amendment, soil fertility and plant community development were studied in replicated plots receiving various biosolids amendments on two different substrates. The two substrates used were a subsoil, determined to have low initial fertility, and a topsoil over retorted shale substrate, determined to have relatively high initial fertility. Results suggest that biosolids amendments have long-lasting effects on soil fertility and plant community composition, but these effects vary between the two substrates that were utilized. Within the plots established on subsoil, the long-term effect of biosolids was a reduction in plant species diversity and dominance by perennial grasses. On the topsoil substrate, there was a decrease in perennial grasses and an increase in shrub dominance with increasing biosolids. Results demonstrate the importance of considering initial soil conditions, seed mixture, and biosolids application rate when using biosolids for restoration of disturbed sagebrush steppe habitat. The long-term effects of the biosolids treatments at this site demonstrate the need to consider restoration treatment effects over longer and more ecologically meaningful time frames.

Notes: Non-native fish generally cause native fish decline, and once non-natives are established, control or elimination is usually problematic. Because non-native fish colonization has been greatest in anthropogenically altered habitats, restoring habitat similar to predisturbance conditions may offer a viable means of non-native fish control. In this investigation we identified habitats favoring native over non-native fish in a Mojave Desert oasis (Ash Meadows) and used this information to restore one of its major warm water spring systems (Kings Pool Spring). Prior to restoration, native fishes predominated in warm water (25–32°C) stream and spring-pool habitat, whereas non-natives predominated in cool water (≤23°C) spring-pool and marsh/slack water habitat. Native Amargosa pupfish (Cyprinodon nevadensis) and Ash Meadows speckled dace (Rhinichthys osculus nevadensis) inhabited significantly faster mean water column velocities (MWCV) and greater total depth (TD) than non-native Sailfin molly (Poecilia latipinna) and Mosquitofish (Gambusia affinis) in warm water stream habitat, and Ash Meadows speckled dace inhabited significantly faster water than non-natives in cool water stream habitat. Modification of the outflow of Kings Pool Spring from marsh to warm water stream, with MWCV, TD, and temperature favoring native fish, changed the fish composition from predominantly non-native Sailfin molly and Mosquitofish to predominantly Ash Meadows pupfish. This result supports the hypothesis that restoring spring systems to a semblance of predisturbance conditions would promote recolonization of native fishes and deter non-native fish invasion and proliferation.

Notes: Rainforest fragmentation and creek degradation are major problems on the Atherton Tablelands in North Queensland. Lake Barrine and Wooroonooran National Parks are separated by a 1.5-km length of Toohey's Creek which has been cleared except for small remnant rainforest patches. The creek has been fenced and replanted to create a corridor between the two national parks. The aim of this study was to monitor the success of the corridor in providing habitat for rainforest birds. Avian communities were monitored in the corridor and in adjacent rainforest sites using point counts over the period of reestablishment of a continuous rainforest canopy. In terms of bird community composition, within 3 years of planting, the replanted sites were on a trajectory toward the rainforest sites. Although specialist rainforest species were not yet found in the plantings, after 3 years those species which mainly inhabit rainforest but also utilize edges and riparian strips were found in similar numbers in the plantings and in the small remnant patches along the corridor. Frugivorous species were quite abundant even in the youngest plantings. Thus, replanting of rainforest trees along Toohey's Creek has begun to provide habitat for some rainforest birds. It also shows good potential to act as a corridor to connect the previously isolated patches of rainforest for these species and to develop in habitat complexity as the frugivorous birds bring in rainforest plant species from nearby areas.

Notes: Many semiarid rangelands in the Great Basin, U.S.A., are shifting dominance to woody species as a consequence of land degradation including intense livestock grazing and fire suppression. Whereas past rehabilitation efforts in Big sagebrush (Artemisia tridentata) steppes removed the shrub and added introduced forage grasses to successfully shift communities from shrublands to grasslands, current consensus is that native species should be included in restoration projects and that retention of some woody plants is desirable. We examined the potential for interseeding grasses into dense shrub communities as a precursor to thinning shrubs and releasing grasses from shrub interference. We compared seedling establishment of the native grass, Bluebunch wheatgrass (Pseudoroegneria spicata), with that of the Eurasia grass, Crested wheatgrass (Agropyron desertorum), in dense Ar. tridentata stands. Shrubs may play an important role as nurse plants for seedling establishment (reduced solar radiation, “island of fertility” effect) but result in highly contrasting light environments and root interference for seedlings. In experimental plots, we examined effects of Ar. tridentata shade levels (0, 40, 70, and 90% reduction of solar radiation) and initial root exclusion (present/absent) on the establishment and growth of P. spicata and Ag. desertorum seedlings. With this design we evaluated the interference effects of Ar. tridentata on the two grasses and identified the most beneficial microsites for grass restoration in Ar. tridentata–dominated communities. We predicted seedling survival and growth to be greater under moderate shade (40% reduction) and limited root competition than under no or strong shade conditions (0 and 90%) and unrestricted root interactions. Fifty to 85% of the P. spicata and Ag. desertorum seedlings survived the dry summer months of 1995 and 1996 and the intervening winter. Neither shading nor root exclusion from Ar. tridentata affected final seedling survival of either species. Seedling biomass of both grass species was negatively affected by initial root interactions with Ar. tridentata. However, the analysis of seedling biomass variability (coefficient of variation) indicated that in all shade and root-exclusion treatments, some seedlings of both species developed to large individuals to survive in Ar. tridentata–dominated rangelands. Thus, the use of interseeding techniques shows promise for restoring herbaceous species in dense Ar. tridentata stands and should be given further consideration when shrub retention is an important consideration.

Notes: Preventing and controlling exotic plants remains a key challenge in any ecological restoration, and most efforts are currently aimed at local scales. We combined local- and landscape-scale approaches to identify factors that were most closely associated with invasion of riparian forests by exotic shrubs (Amur honeysuckle [Lonicera maackii] and Tatarian honeysuckle [L. tatarica]) in Ohio, U.S.A. Twenty sites were selected in mature riparian forests along a rural–urban gradient (〈1–47% urban land cover). Within each site, we measured percent cover of Lonicera spp. and native trees and shrubs, percent canopy cover, and facing edge aspect. We then developed 10 a priori models based on local- and landscape-level variables that we hypothesized would influence percent cover of Lonicera spp. within 25 m of the forest edge. To determine which of these models best fit the data, we used an information-theoretic approach and Akaike's information criterion. Percent cover of Lonicera was best explained by the proportion of urban land cover within 1 km of riparian forests. In particular, percent cover of Lonicera was greater in forests within more urban landscapes than in forests within rural landscapes. Results suggest that surrounding land uses influence invasion by exotic shrubs, and explicit consideration of land uses may improve our ability to predict or limit invasion. Moreover, identifying land uses that increase the risk of invasion may inform restoration efforts.

Notes: The extent of impairment to some Appalachian watersheds from acid precipitation is so extreme that watershed scale analytical tools are needed to help guide cost-effective management decisions. The objective of this study was to develop a measure of the functional value of streams as potential areas for juvenile Brook trout recruitment. This measure, which we term “weighted potential recruitment area” (WPRA), is a function of the expected Brook trout spawning intensity and juvenile survivorship. Estimates of WPRA for each stream segment were then used to identify restoration priorities and optimal restoration programs in the upper Shavers Fork watershed in West Virginia, U.S.A. Using this approach, we determined that the watershed has lost nearly 80% of its historic juvenile recruitment potential as a result of acid precipitation. We also determined that of the 145 stream segments in the watershed, eight critical stream segments account for nearly 20% of the loss. The costs and ecological benefits of a series of five alternative restoration programs were then assessed using an ArcGIS model (Environmental Systems Research Institute, Redlands, CA, U.S.A.). This approach identified two “optimal” alternatives: (1) a low-cost, moderate-benefit approach that would use existing rail access to treat acidification in three critical headwater locations and (2) a high-cost, high-benefit approach that would use aerial limestone application to treat numerous acidic tributaries near their source. The measure of stream ecological value that we developed was effective in identifying critical restoration priorities and optimal restoration strategies in this watershed. A similar procedure could be used to guide watershed restoration decisions throughout the Appalachian region.

Notes: Leaf litter is an important source of organic matter as nutrients for aquatic and terrestrial microbial communities. Biogenic decomposition of leaf litter contributes substantially to atmospheric CO2, possibly producing global warming, and comprises an important part of the terrestrial carbon cycle. Small-scale variability in terrestrial protozoan communities may be attributed to localized variations in leaf matter. This study examined the effect of aqueous leaf extracts from four trees (beech, maple, red oak, and white oak) on the abundance and diversity of protozoa in laboratory aquatic and soil cultures. Beech leaf extract was the most productive followed in the descending order by white oak, red oak, and maple in both aquatic and soil microcosm cultures. Dilution experiments indicated that concentration-related inhibitory substance(s) in the maple and red oak leaves contribute to lower productivity. Removal of tannins by treatment with activated charcoal (Norit®) improved productivity especially for red oak leaf extracts, suggesting that tannins may contribute to the inhibition of protozoan standing stock. To determine if the lower productivity was mainly due to the inhibition of protozoan excystment, aliquots of thoroughly dried soil were inoculated into maple and red oak leaf extracts. A comparable growth of protozoa occurred in these treatments as in aliquots from moist soil indicating that inhibition of excystment is not a likely explanation for reduced productivity of the protozoan communities.

Notes: The stalked ciliate, Vorticella convallaria, is a good model system to study mechanochemical motility because its contractile organelles (spasmoneme and myonemes) use a mode of contraction that differs from most other eukaryotic motile systems. Since calcium triggers this contraction, we have undertaken the molecular characterization of the calcium-binding proteins associated with these organelles. We have isolated and identified seven unique centrin-like cDNAs from V. convallaria. Each encodes an acidic protein of approximately 20-kDa, containing a unique N-terminus and four potential calcium-binding domains. We predict that each centrin has a distinct function within the cell. To define these functions, we have initiated immunofluorescence localization studies utilizing various anti-centrin antibodies. Western analysis indicates that each antibody recognizes a distinct protein or subset of proteins in Vorticella. Using these antibodies, we have localized centrin to various structures within the cell; myonemes, spasmoneme, and the oral apparatus. Because each of these antibodies recognizes a different protein on Westerern analysis, we conclude that a number of calcium-binding proteins are associated with the contractile organelles. To further characterize this gene family, we have initiated immunolocalization at the ultrastructural level. This will permit subcellular localization of all Vorticella centrins and enable us to dissect the function of this multi-gene family.

Notes: A previous survey of Euplotes genes available in GenBank indicated that 〉5% required a +1 translational frameshift for expression, much higher than observed in other organisms. Because this sample of sequences was non-random and biased towards highly expressed genes, we have randomly selected and sequenced 25 Euplotes crassus macronuclear DNA molecules to more accurately assess the frequency of frameshifting. Three new +1 frameshift genes were identified, and all have sequence features similar to the previously postulated frameshift sites. The results indicate that the frequency of Euplotes+1 frameshift genes is indeed high, and likely 〉10%. We have also examined the evolution of one of two frameshift sites present in the telomerase reverse transcriptase (TERT) genes of E. crassus. TERT gene segments were isolated from five additional Euplotes species. FS2 was found only in E. crassus and the closely related E. vannus, and phylogenetic analyses indicate that the site arose late in the evolution of the Euplotes group. Moreover, a novel frameshift site (FS3) was identified solely in the TERT gene of E. minuta. These results indicate that frameshift sites have arisen within genes during the recent history of Euplotes, and that it may be an ongoing process. Overall, the data suggest to us that the appearance of a frameshift site in a Euplotes gene is selectively neutral, or near-neutral. This would require an efficient mechanism of frameshifting in Euplotes. A model will be presented linking frequent frameshifting to a second unusual genetic feature of Euplotes, stop codon reassignment.

Notes: Control of protozoal pathogens in water and food destined for human use employs chemical and physical agents for inactivation of trophozoites and cysts. γ radiation, when given in certain doses, damages DNA as well as other cell components. Previously, we characterized damage in irradiated Giardia lamblia trophozoites by using Nomarski interference and scanning electron microscopy. To further examine cellular damage, irradiated trophozoites were viewed with transmission electron microscopy. Degranulation of cytoplasm at higher irradiation doses was observed, however, axonemes, adhesive discs, and peripheral vesicles appeared morphologically similar in treated as well as control cells. In order to determine damage to the DNA, the comet assay was employed. The comet assay is a single cell gel electrophoresis assay that measures the number of single and double strand breaks in DNA. This was achieved by embedment of live cells in low melting point agarose, lysis of cells, and then addition of an alkali solution to allow the DNA to unwind. After ample time for unwinding, the cells were electrophoresed, thus pulling the smaller broken strands away from the supercoiled DNA. We used Sybr GreenR, a DNA specific fluorescent dye, and a signal-enhancing camera to visualize the DNA. Lengths of comet tails (corresponding to number of strand breaks) were measured for quantification of damage.

Notes: Karenia brevis (Davis) is a unicellular dinoflagellate responsible for nearly annual “red tides” in the Gulf of Mexico. Insight into the molecular mechanisms that control growth, toxicity, and adaptive mechanisms in K. brevis is critical to understanding the formation and persistence of these toxic blooms. However, little information is available on the molecular biology K. brevis. Therefore, we constructed a cDNA library from which to gain insight into its expressed genome and to develop tools for studying gene expression. Large-scale sequencing of 9728 clones yielded 7001 high-quality expressed sequence tags (ESTs) for further analysis. The highest expressed gene accounts for only 1% of the total ESTs. Approximately 29% of ESTs were found to have homology to known sequences in other organisms after BLASTx similarity comparisons to the Genbank nonredundant database (p〈10−4). Using a minimum identity of 95% within a 50-bp region of overlap, the 7001 ESTs were assembled into 5054 contigs. Of the 5054 contigs, 4399 contained only a single sequence. Of those containing 〉2 ESTs, approximately 40% displayed single nucleotide polymorphisms, suggesting the presence of multiple gene copies in this haploid organism. Gene-specific 60-mer oligonucleotides were then designed for each of the 5054 contigs using a Parcel clustering package, version 2.2.8 (Agilent). The resulting oligonucleotides and controls were printed on glass slides to yield an 8000 feature array using inkjet printing technology (Agilent). The 8000 features included 5054 unique features and 2946 secondary probes. Validation experiments to assess system noise, reproducibility, log ratio accuracy, and differential gene expression are underway using Agilent Feature Extraction tools and Rosetta Luminator Gene Expression Analysis software.

Notes: Apostome ciliates are exclusively symbionts, typically of crustaceans. Their life cycles are complex, but show remarkable similarities to ophyroglenines and to other symbiotic oligohymenophoreans, particularly those that undergo microstome–macrostome transformations. The highly modified structures around the cytostome—the rosette and x, y, and z kineties—have made the assessment of homologies to other groups of ciliates difficult. A description of the apostome somatic kinetids with well-developed overlapping kinetodesmal fibrils suggested affinities with hymenostomes (Bradbury 1966. J. Protozool., 13:591). Further analysis of the ultrastructural features of the oral region of the tomite of Hyalophysa demonstrated homologies to the paroral and adoral ciliature of hymenostomes, confirming these affinities (Bradbury 1989. J. Protozool., 36:95). To test this hypothesis, we proposed to sequence the small subunit rRNA (SSrRNA) genes of apostomes. Specimens of Gymnodinioides sp. were collected from molts of the amphipod Marinogammarus obtusatus collected off the coast of Eastport, ME. Seawater was decanted from the substrate upon which tomonts had settled, and the dish was flooded with 70% ethanol. The ethanol-fixed ciliates were collected by a micropipette, rinsed with distilled water, and DNA was extracted using the modified Chelex® protocol. The SSrRNA genes were amplified by PCR, and sequences obtained in both directions. Initial BLAST searches of the GenBank databases clearly demonstrated affinities with oligohymenophorean ciliates, particularly scuticociliates. In preliminary phylogenetic analyses which use likelihood, distance and parsimony methods, this relationship was confirmed. However, the apostome sequence diverged basal to the Subclasses Astomatia and Scuticociliatia consistent with the assignment of a Subclass Apostomatia within the Class Oligohymenophorea. We have made collections of Hyalophysa chattoni and anticipate that the SSrRNA gene sequences of this genus will confirm the relationship of apostomes to the oligohymenophoreans.Funded by NSERC Canada Discovery Grant to D. H. L.

Notes: Our laboratory studies how the contractile cytoskeleton contributes to the process of phagocytosis. Because of its larger size and ease of manipulation, we chose the macrostomal cell of Tetrahymena vorax as our model for analysis of the distribution of proteins of prominent filamentous structures within the large oral apparatus (OA). Previous work in our laboratory identified centrin as a component of the fine filamentous reticulum (FFR) and actin and tetrin as colocalizing components of the coarse filamentous reticulum (CFR) and cross-connectives (CC) (J. Eukaryot. Microbiol., 51:253–257). Our new data also show that actin coimmunoprecipitates with tetrin proteins, confirming our actin–tetrin colocalization results. Because of its positioning around the cytostome, the actin-containing CFR/CC is a logical candidate for involvement in phagosome “pinch-off” following prey ingestion. We have analyzed this process by employing an assay that uses the addition of calcium to induce phagosome formation. We show that inhibitors of actin are able to block this event, indicating that actin is necessary for phagosome “pinch-off”. The OA also contains precisely arranged arrays of microtubules. We have examined the spatial relationship of the microtubular arrays to the distribution patterns of centrin, actin and tetrin, and found that tubulin and centrin fluorescences overlap in the region of the undulating membrane (UM). Tubulin fluorescence overlaps with actin and tetrin labeling at the inner edge of the CFR, where the CFR and UM converge. In addition to ciliary and oral rib labeling, tubulin antibodies also recognize the outer microtubule bundle (OMB), which delineates the right and posterior boundary of the OA.

Notes: This mini-review examines the maximum growth rate and threshold levels (the food level where growth rate is zero) of marine planktonic ciliates and heterotrophic dinoflagellates. There are strong indications that ciliates will out-compete dinoflagellates, as they have higher maximum growth rates, lower threshold levels and are able to rapidly exploit both harmful and non-harmful dinoflagellates as prey. I suggest that ciliates are neither the tortoise (slow and steady) nor the hare (fast and foolish), but the best combination of both. To some extent, this argument is raised as a “straw-man” to be knocked down by discussion; the session is intended to serve as a platform for evaluating the relative importance of ciliates and heterotrophic dinoflagellates in marine ecosystems.

Notes: In endemic areas, clinical manifestations of Plasmodium falciparum infection range from asymptomatic parasitaemia to life-threatening severe syndromes. Immune differences that could account for this disparity are poorly understood. Using tight criteria to classify patients into non-overlapping clinical categories, we showed that cerebral malaria and severe anaemia were distinct immunological syndromes and that a proper quantitative description of cytokine profiles in the various clinical groups is essential to the understanding of the activation of immunocompetent cells.Due to the limited size of paediatric blood samples, we chose to measure cytokine mRNA using real-time RT-PCR. We showed that RT efficiency displayed intra-and intergenic variations that have to be taken into consideration for reliable absolute RNA quantification when comparing clinical cases. We thus developed a SYBR Green I-based real-time RT-PCR method using synthetic external RNA standards specific for each gene. Absolute RNA quantification is achieved by reverse transcribing known copy numbers of this RNA standard in parallel with cellular RNA. Strictly specific primers were designed to allow the quantification of any RNA in the same thermocycling parameters for future automation. Our method gave similar results for a lower cost when compared with TaqMan, and led to reproducible and reliable absolute RNA quantification. We validated it in vitro on naïve PBMC stimulated by LPS and ex vivo on PBMC from malaria patients. This new method raises the unprecedented possibility to compare cytokine mRNA levels between different clinical groups and is a powerful tool to further study the inflammation processes associated to malaria.

Notes: Intestinal microsporidiosis caused by Enterocytozoon bieneusi and Encephalitozoon intestinalis are opportunistic infections occurring in severely immuno-depressed patients, and may cause severe chronic diarrhea. Due to the extent of the HIV pandemic, microsporidia could pose a serious threat to public health in Africa. This study was conducted in Libreville, Gabon, central Africa, among HIV-positive patients between September 2002 and December 2003. Criteria for inclusion were being HIV positive (HIV1 and/or HIV2), regardless of the CD4 cell count, stage of the disease or gastrointestinal symptoms. Nine hundred and ninety-tree stool samples from 836 patients (mean age 38 years, range 18 months-74 years) were screened for microsporidia by immunofluorescence using species-specific monoclonal antibodies and confirmed by PCR. Twenty seven cases of E. bieneusi infection were found in the cohort, a prevalence of 2.7%. These patients were in the most severely immuno-depressed group, 84% had a CD4 cell count below 200/mm3 compared to 57% of the cohort (mean=55 CD4+cells/mm3 compared to a mean of 88/mm3 for the microsporidia negative patients with less than 200 CD4/mm3).The ribosomal DNA ITS sequence has been determined for several E. bieneusi isolates. A very high diversity of genotypes wasfound: eight different sequences were found from only 12 samples. This is surprisingly high since in previous studies conducted in Europe and America only 15 of the 49 E. bieneusi genotypes described have been found to infect humans. Only three genotypes from our samples have already been described: type K (two specimens). previously reported in human and cat, type D (one specimen) in human, pig and rhesus monkey, type E (1 specimen) in man, pig, racoon and muskrat. The five other genotypes are new and have been named Gabon-1 to 5. The phylogenetic analysis of the sequences shows that genotypes Gabon-1,2,3 and 4 (one specimen each) are close to types E, WL12, D and K, respectively, which belong to a group comprising most genotypes described so far. However, the Gabon-5 genotype (four specimens) is only distantly related to this group and is most apparent to the group of genotypes (WL1-3) recently described from racoons in North America. It was thus suggested that this group could represent another species or subspecies of E. bieneusi which are host-adapted and do not infect humans. However, the finding of genotype Gabon-5 shows that even distantly related genotypes infect severely immuno-depressed humans.This work was supported by the French National Agency for AIDS Research (ANRS-1264).

Notes: While the Plasmodium falciparum fully annotated genome has now been released, functional analysis of its expected about 5300 genes remains to be carried out to understand their roles during the parasite development, in particular for about 60% of genes devoid of significant similarities in other species. Here, a suppression subtractive hybridisation (SSH) screen was used to identify genes coding for proteins expressed during merozoite morphogenesis. The resulting library yielded clones with cDNA inserts ranging from a few hundreds to about a thousand base pairs. We report here the analysis of 50 independent cDNA clones and of the corresponding 40 P. falciparum genes. While 27.5% of them turned out to be previously described genes, all known to code for proteins expressed in schizont/merozoite stages (EBA-175, MSP-1, MSP-3, MSP-6, ABRA/MSP-9, coronin, myosin A and the CLAG/RhopH1 protein), the remaining 72.5% were “putative” and “hypothetical” genes, coding for a variety of proteins among which we found several protease orthologs and orthologs of cytoskeleton-associated and/or actin-interacting proteins such as dynamin and formin-2 as well as other rhoptry proteins. In addition to providing experimental evidence for their expression in schizont/merozoite stages, we discuss how these genes represent original candidates to investigate the molecular events required to elaborate infective merozoites.

Notes: Toroidal DNA condensates have attracted the attention of biophysicists, biochemists, and polymer physicists for more than thirty years. In the biological community, the quest to understand DNA toroid formation has been motivated by its relevance to gene packing in certain viruses and by the potential use of DNA toroids in artificial gene delivery (e.g., gene therapy). In the physical sciences, DNA toroids are appreciated as a superb model system for studying particle formation by the collapse of a semiflexible, polyelectrolyte polymer. This review focuses on experimental studies from the past few years that have significantly increased our understanding of DNA toroid structure and the mechanism of their formation. Highlights include structural studies that show the DNA strands within toroids to be packed in an ideal hexagonal lattice, and also in regions with a nonhexagonal lattice that are required by the topological constraints associated with winding DNA into a toroid. Recent studies of DNA toroid formation have also revealed that toroid size limits result from a complex interplay between kinetic and thermodynamic factors that govern both toroid nucleation and growth. The work discussed in this review indicates that it will ultimately be possible to obtain substantial control over DNA toroid dimensions.

Notes: With genome sequencing nearing completion for the model organisms used in biomedical research, there is a rapidly growing appreciation that proteomics, the study of covalent modification to proteins, and transcriptional regulation will likely dominate the research headlines in the next decade. Protein methylation plays a central role in both of these fields, as several different residues (Arg, Lys, Gln) are methylated in cells and methylation plays a central role in the "histone code" that regulates chromatin structure and impacts transcription. In some cases, a single lysine can be mono-, di-, or trimethylated, with different functional consequences for each of the three forms. This review describes structural aspects of methylation of histone lysine residues by two enzyme families with entirely different structural scaffolding (the SET proteins and Dot1p) and methylation of protein arginine residues by PRMTs.

Notes: Potassium (K+) channels are tetrameric membrane-spanning proteins that provide a selective pore for the conductance of K+ across the cell membranes. These channels are most remarkable in their ability to discriminate K+ from Na+ by more than a thousandfold and conduct at a throughput rate near diffusion limit. The recent progress in the structural characterization of K+ channel provides us with a unique opportunity to understand their function at the atomic level. With their ability to go beyond static structures, molecular dynamics simulations based on atomic models can play an important role in shaping our view of how ion channels carry out their function. The purpose of this review is to summarize the most important findings from experiments and computations and to highlight a number of fundamental mechanistic questions about ion conduction and selectivity that will require further work.

Notes: Proteins have become accessible targets for chemical synthesis. The basic strategy is to use native chemical ligation, Staudinger ligation, or other orthogonal chemical reactions to couple synthetic peptides. The ligation reactions are compatible with a variety of solvents and proceed in solution or on a solid support. Chemical synthesis enables a level of control on protein composition that greatly exceeds that attainable with ribosome-mediated biosynthesis. Accordingly, the chemical synthesis of proteins is providing previously unattainable insight into the structure and function of proteins.

Notes: A powerful approach to understanding protein enzyme catalysis is to examine the structural context of essential amino acid side chains whose deletion or modification negatively impacts catalysis. In principle, this approach can be even more powerful for RNA enzymes, given the wide variety and subtlety of functionally modified nucleotides now available. Numerous recent success stories confirm the utility of this approach to understanding ribozyme function. An anomaly, however, is the hammerhead ribozyme, for which the structural and functional data do not agree well, preventing a unifying view of its catalytic mechanism from emerging. To delineate the hammerhead structure-function comparison, we have evaluated and distilled the large body of biochemical data into a consensus set of functional groups unambiguously required for hammerhead catalysis. By examining the context of these functional groups within available structures, we have established a concise set of disagreements between the structural and functional data. The number and relative distribution of these inconsistencies throughout the hammerhead reaffirms that an extensive conformational rearrangement from the fold observed in the crystal structure must be necessary for cleavage to occur. The nature and energetic driving force of this conformational isomerization are discussed.

Notes: The development of single-molecule detection and manipulation has allowed us to monitor the behavior of individual biological molecules and molecular complexes in real time. This approach significantly expands our capability to characterize complex dynamics of biological processes, allowing transient intermediate states and parallel kinetic pathways to be directly observed. Exploring this capability to elucidate complex dynamics, recent single-molecule experiments on RNA folding and catalysis have improved our understanding of the folding energy landscape of RNA and allowed us to better dissect complex RNA catalytic reactions, including translation by the ribosome.

Notes: Water plays a central role in the structures and properties of biomoleculesĐ??proteins, nucleic acids, and membranesĐ??and in their interactions with ligands and drugs. Over the past half century, our understanding of water has been advanced significantly owing to theoretical and computational modeling. However, like the blind men and the elephant, different models describe different aspects of water's behavior. The trend in water modeling has been toward finer-scale properties and increasing structural detail, at increasing computational expense. Recently, our labs and others have moved in the opposite direction, toward simpler physical models, focusing on more global propertiesĐ??water's thermodynamics, phase diagram, and solvation properties, for exampleĐ??and toward less computational expense. Simplified models can guide a better understanding of water in ways that complement what we learn from more complex models. One ultimate goal is more tractable models for computer simulations of biomolecules. This review gives a perspective from simple models on how the physical properties of waterĐ??as a pure liquid and as a solventĐ??derive from the geometric and hydrogen bonding properties of water.

Notes: Structural data on protein-DNA complexes provide clues for understanding the mechanism of protein-DNA recognition. Although the structures of a large number of protein-DNA complexes are known, the mechanisms underlying their specific binding are still only poorly understood. Analysis of these structures has shown that there is no simple one-to-one correspondence between bases and amino acids within protein-DNA complexes; nevertheless, the observed patterns of interaction carry important information on the mechanisms of protein-DNA recognition. In this review, we show how the patterns of interaction, either observed in known structures or derived from computer simulations, confer recognition specificity, and how they can be used to examine the relationship between structure and specificity and to predict target DNA sequences used by regulatory proteins.

Notes: The field of lymphatic research has been recently invigorated by the identification of genes and mechanisms that control various aspects of lymphatic development. We are beginning to understand how, starting from a subgroup of embryonic venous endothelial cells, the whole lymphatic system forms in a stepwise manner. The generation of genetically engineered mice with defects in different steps of the lymphangiogenic program has provided models that are increasing our understanding of the lymphatic system in health and disease. This knowledge, in turn, should lead to the development of better diagnostic methods and treatments of lymphatic disorders and tumor metastasis.

Notes: Mixed mating, in which hermaphrodite plant species reproduce by both self- and cross-fertilization, presents a challenging problem for evolutionary biologists. Theory suggests that inbreeding depression, the main selective factor opposing the evolution of selfing, can be purged with self-fertilization, a process that is expected to yield pure strategies of either outcrossing or selfing. Here we present updated evidence suggesting that mixed mating systems are frequent in seed plants. We outline the floral and pollination mechanisms that can lead to intermediate outcrossing, review the theoretical models that address the stability of intermediate outcrossing, and examine relevant empirical evidence. A comparative analysis of estimated inbreeding coefficients and outcrossing rates suggests that mixed mating often evolves despite strong inbreeding depression. The adaptive significance of mixed mating has yet to be fully explained for any species. Recent theoretical and empirical work suggests that future progress will come from a better integration of studies of floral mechanisms, genetics, and ecology, and recognition of how selective pressures vary in space and time.

Notes: We explore empirical and theoretical evidence for the functional significance of plant-litter diversity and the extraordinary high diversity of decomposer organisms in the process of litter decomposition and the consequences for biogeochemical cycles. Potential mechanisms for the frequently observed litter-diversity effects on mass loss and nitrogen dynamics include fungi-driven nutrient transfer among litter species, inhibition or stimulation of microorganisms by specific litter compounds, and positive feedback of soil fauna due to greater habitat and food diversity. Theory predicts positive effects of microbial diversity that result from functional niche complementarity, but the few existing experiments provide conflicting results. Microbial succession with shifting enzymatic capabilities enhances decomposition, whereas antagonistic interactions among fungi that compete for similar resources slow litter decay. Soil-fauna diversity manipulations indicate that the number of trophic levels, species identity, and the presence of keystone species have a strong impact on decomposition, whereas the importance of diversity within functional groups is not clear at present. In conclusion, litter species and decomposer diversity can significantly influence carbon and nutrient turnover rates; however, no general or predictable pattern has emerged. Proposed mechanisms for diversity effects need confirmation and a link to functional traits for a comprehensive understanding of how biodiversity interacts with decomposition processes and the consequences of ongoing biodiversity loss for ecosystem functioning.

Notes: Investigation into model selection has a long history in the statistical literature. As model-based approaches begin dominating systematic biology, increased attention has focused on how models should be selected for distance-based, likelihood, and Bayesian phylogenetics. Here, we review issues that render model-based approaches necessary, briefly review nucleotide-based models that attempt to capture relevant features of evolutionary processes, and review methods that have been applied to model selection in phylogenetics: likelihood-ratio tests, AIC, BIC, and performance-based approaches.

Notes: One of the greatest mass extinctions in Earth's history occurred at the end of the Cretaceous era, sixty-five million years (Myr) ago. Considerable evidence indicates that the impact of a large asteroid or comet was the ultimate cause of this extraordinary event. At the time of mass extinction, the organic flux to the deep sea collapsed, and production of calcium carbonate by marine plankton radically declined. These biogeochemical processes did not fully recover for a few million years. The drastic decline and long lag in final recovery of these processes are most simply explained as consequences of open-ocean ecosystem alteration by the mass extinction. If this explanation is correct, the extent and timing of marine biogeochemical recovery from the end-Cretaceous event was ultimately contingent on the extent and timing of open-ocean ecosystem recovery. The biogeochemical recovery may in turn have created new evolutionary opportunities for a diverse array of marine organisms.

Notes: Variation in the subtle differences between right and left sides of bilateral characters, or fluctuating asymmetry (FA), has long been considered to be primarily environmental in origin, and this has promoted its use as a measure of developmental instability (DI) in populations. There is little evidence for specific genes that govern FA per se. Numerous studies show that FA levels in various characters are influenced by dominance and especially epistatic interactions among genes. An epistatic genetic basis for FA may complicate its primary use in comparisons of DI levels in outbred or wild populations subjected or not subjected to various environmental stressors. Although the heritability of FA typically is very low or zero, epistasis can generate additive genetic variation for FA that may allow it to evolve especially in populations subjected to bottlenecks, hybridizations, or periods of rapid environmental changes caused by various stresses.

Notes: Understanding and predicting the dynamics of multispecies systems generally require estimates of interaction strength among species. Measuring interaction strength is difficult because of the large number of interactions in any natural system, long-term feedback, multiple pathways of effects between species pairs, and possible nonlinearities in interaction-strength functions. Presently, the few studies that extensively estimate interaction strength suggest that distributions of interaction strength tend to be skewed toward few strong and many weak interactions. Modeling studies indicate that such skewed patterns tend to promote system stability and arise during assembly of persistent communities. Methods for estimating interaction strength efficiently from traits of organisms, such as allometric relationships, show some promise. Methods for estimating community response to environmental perturbations without an estimate of interaction strength may also be of use. Spatial and temporal scale may affect patterns of interaction strength, but these effects require further investigation and new multispecies modeling frameworks. Future progress will be aided by development of long-term multispecies time series of natural communities, by experimental tests of different methods for estimating interaction strength, and by increased understanding of nonlinear functional forms.

Notes: Oysters have been introduced worldwide to 73 countries, but the ecological consequences of the introductions are not fully understood. Economically, introduced oysters compose a majority of oyster harvests in many areas. Oysters are ecosystem engineers that influence many ecological processes, such as maintenance of biodiversity, population and food web dynamics, and nutrient cycling. Consequently, both their loss, through interaction of overharvest, habitat degradation, disease, poor water quality, and detrimental species interactions, and their gain, through introductions, can cause complex changes in coastal ecosystems. Introductions can greatly enhance oyster population abundance and production, as well as populations of associated native species. However, introduced oysters are also vectors for non-native species, including disease-causing organisms. Thus, substantial population, community, and habitat changes have accompanied new oysters. In contrast, ecosystem-level consequences of oyster introductions, such as impacts on flow patterns, sediment and nutrient dynamics, and native bioengineering species, are not well understood. Ecological risk assessments for future introductions must emphasize probabilities of establishment, spread, and impacts on vulnerable species, communities, and ecosystem properties. Many characteristics of oysters lead to predictions that they would be successful, high-impact members of recipient ecosystems. This conclusion leaves open the discussion of whether such impacts are desirable in terms of restoration of coastal ecosystems, especially where restoration of native oysters is possible.

Notes: The multi-gene family that encodes ribosomal RNA (the rDNA) has been the subject of numerous review articles examining its structure and function, as well as its use as a molecular systematic marker. The purpose of this review is to integrate information about structural and functional aspects of rDNA that impact the ecology and evolution of organisms. We examine current understanding of the impact of length heterogeneity and copy number in the rDNA on fitness and the evolutionary ecology of organisms. We also examine the role that elemental ratios (biological stoichiometry) play in mediating the impact of rDNA variation in natural populations and ecosystems. The body of work examined suggests that there are strong reciprocal feedbacks between rDNA and the ecology of all organisms, from microbes to metazoans, mediated through increased phosphorus demand in organisms with high rRNA content.

Notes: Two consequences of terrestrial ectothermy (low energy needs and behavioral control of body temperatures) have had major consequences for the evolution of reptile life-history traits. For example, reproducing females can manipulate incubation temperatures and thus phenotypic traits of their offspring by retaining developing eggs in utero. This ability has resulted in multiple evolutionary transitions from oviparity to viviparity in cool-climate reptile populations. The spatial and temporal heterogeneity of operative temperatures in terrestrial habitats also has favored careful nest-site selection and a matching of embryonic reaction norms to thermal regimes during incubation (e.g., via temperature-dependent sex determination). Many of the life-history features in which reptiles differ from endothermic vertebratesĐ??such as their small offspring sizes, large litter sizes, and infrequent reproductionĐ??are direct consequences of ectothermy, reflecting freedom from heat-conserving constraints on body size and energy storage. Ectothermy confers immense flexibility, enabling a dynamic matching of life-history traits to local circumstances. This flexibility has generated massive spatial and temporal variation in life-history traits via phenotypic plasticity as well as adaptation. The diversity of life histories in reptiles can best be interpreted within a conceptual framework that views reptiles as low-energy, variable-temperature systems.

Notes: The continuous flow of genomic data is creating unprecedented opportunities for the reconstruction of molecular phylogenies. Access to whole-genome data means that phylogenetic analysis can now be performed at different genomic levels, such as primary sequences and gene order, allowing for reciprocal corroboration of the results. We critically review the different kinds of phylogenomic methods currently available, paying particular attention to method reliability. Our emphasis is on methods for the analysis of primary sequences because these are the most advanced. We discuss the important issue of statistical inconsistency and show how failing to fully capture the process of sequence evolution in the underlying models leads to tree reconstruction artifacts. We suggest strategies for detecting and potentially overcoming these problems. These strategies involve the development of better models, the use of an improved taxon sampling, and the exclusion of phylogenetically misleading data.

Notes: It has often been argued that conserving biodiversity is necessary for maintaining ecosystem functioning. We critically evaluate the current evidence for this argument. Although there is substantial evidence that diversity is able to affect function, particularly for plant communities, it is unclear if these patterns will hold for realistic scenarios of extinctions, multitrophic communities, or larger spatial scales. Experiments are conducted at small spatial scales, the very scales at which diversity tends to increase owing to exotics. Stressors may affect function by many pathways, and diversity-mediated effects on function may be a minor pathway, except in the case of multiple-stressor insurance effects. In general, the conservation case is stronger for stability measures of function than stock and flux measures, in part because it is easier to attribute value unambiguously to stability and in part because stock and flux measures of functions are anticipated to be more affected by multitrophic dynamics. Nor is biodiversity-ecosystem function theory likely to help conservation managers in practical decisions, except in the particular case of restoration. We give recommendations for increasing the relevance of this area of research for conservation.

Notes: The diversity and composition of herbivore assemblages was a favored theme for community ecology in the 1970s and culminated in 1984 with Insects on Plants by Strong, Lawton and Southwood. We scrutinize findings since then, considering analyses of country-wide insect-host catalogs, field studies of local herbivore communities, and comparative studies at different spatial scales. Studies in tropical forests have advanced significantly and offer new insights into stratification and host specialization of herbivores. Comparative and long-term data sets are still scarce, which limits assessment of general patterns in herbivore richness and assemblage structure. Methods of community phylogenetic analysis, complex networks, spatial and among-host diversity partitioning, and metacommunity models represent promising approaches for future work.