Upland Species Research Articles

Assessing, mapping and quantifying the distribution of foliar biomass in Great Britain

This study has quantitatively mapped the distributions and peak above-ground foliar biomass of the 1000 most prevalent plant and tree species in Great Britain (GB) on a 1 x 1 km(2) grid. Each 1 x 1 km(2) grid cell was assigned to one of 56 land classes on the basis of environmental and land cover attributes. The mean occurrence and cover area of specific plant species within each land class was derived from the results of the Countryside Survey 1990 [Barr CJ, Bunce RGH, Clarke RT, Fuller RM, Furse MT, Gillespie MK, et al. Countryside Survey 1990 Main Report. HMSO, 1993]. Species-specific biomass conversion factors, relating above-ground living plant biomass (excluding tree timber) to a unit of ground area, were used to convert cover areas into species biomass. British totals of species cover area and biomass were then calculated. Lolium perenne (perennial rye grass), Triticum aestivurn (wheat) and Calluna vulgaris Ling (heather) covered the greatest areas of GB (26,811, 25,378 and 14,359 km(2), respectively). During summer (prior to harvest), L. perenne contributed 20% of the peak standing biomass in Britain (25.6 Mt), followed by T aestivum (18.8 Mt) and Hordeum vulgare (barley) (15.5 Mt). Picea sitchensis (Sitka spruce) was the dominant tree species in GB with the fourth highest peak foliar biomass (7.3 Mt). In total, 70 species accounted for 90% of the estimated summer biomass of GB. P. sitchensis and C. vulgaris dominated winter biomass. Predictive biomass distributions can be plotted for each species and examples of lowland and upland species are given. The predictions correspond well with known habitat preferences. Monthly variations in total biomass have also been plotted. (c) 2008 Elsevier Ltd. All rights reserved.

Evaluating two new methods for capturing large wetland birds

Waterbird research increasingly involves capturing birds to measure attributes of individuals and for attachment of telemetry devices, but there are few established techniques for capturing wading birds away from their nests. We describe the construction and testing of a new trapping technique for wading birds based on a small flip trap. Our trap was developed to capture wading birds in the Florida Everglades in water less than 30 cm deep, but could also be used to capture other waterbirds and upland species. The primary advantages of this new trap design are its ability to be easily concealed, ability to selectively capture birds, low injury rate, ease of resetting the trap after captures, minimal training requirements for operator, capacity to be fired remotely, and moderate cost. We also evaluated the effectiveness of using a net gun to capture wading birds in wetlands. Our results demonstrated that the net gun was the most effective method for capturing large numbers of wading birds, however, the modified flip trap provides a safer alternative that may be appropriate for endangered species. SINOPSIS. Evaluacide dos mpara capturar aves grandes en anegados La investigaci´ on con aves deanegadas muchas veces envuelve el capturar las aves para tomarles medidas morfomo para colocarles aparatos utilizados en radiotelemetrSin embargo, hay pocas medidas establecidas para capturar aves zancudas lejos de sus nidos. Describimos la construcciy la puesta a pruebas, de una nueva t´ para atrapar aves grandes vadeadoras, basado en una peque˜

Effect of climate fluctuations on long-term vegetation dynamics in Carolina bay wetlands

Carolina bays and similar depression wetlands of the U.S. Southeastern Coastal Plain have hydrologic regimes that are driven primarily by rainfall. Therefore, climate fluctuations such as drought cycles have the potential to shape long-term vegetation dynamics. Models suggest two potential long-term responses to hydrologic fluctuations, either cyclic change maintaining open emergent vegetation, or directional succession toward forest vegetation. In seven Carolina bay wetlands on the Savannah River Site, South Carolina, we assessed hydrologic variation and vegetation response over a 15-year period spanning two drought and reinundation cycles. Changes in pond stage (water depth) were monitored bi-weekly to monthly each year from 1989–2003. Vegetation composition was sampled in three years (1989, 1993, and 2003) and analyzed in relation to changes in hydrologic conditions. Multi-year droughts occurred prior to the 1989 and 2003 sampling years, whereas 1993 coincided with a wet period. Wetland plant species generally maintained dominance after both wet and dry conditions, but the abundances of different plant growth forms and species indicator categories shifted over the 15-year period. Decreased hydroperiods and water depths during droughts led to increased cover of grass, upland, and woody species, particularly at the shallower wetland margins. Conversely, reinundation and longer hydroperiods resulted in expansion of aquatic and emergent species and reduced the cover of flood-intolerant woody and upland species. These semi-permanent Upper Coastal Plain bays generally exhibited cyclic vegetation dynamics in response to climate fluctuation, with wet periods favoring dominance by herbaceous species. Large basin morphology and deep ponding, paired with surrounding upland forest dominated by flood-intolerant pines, were features contributing to persistence of herbaceous vegetation. Drought cycles may promote directional succession to forest in bays that are smaller, shallower, or colonized by flood-tolerant hardwoods.

Generic placement in Lobelia and revised taxonomy for New Zealand species previously in Hypsela and Isotoma (Lobeliaceae)

A taxonomic revision is presented for New Zealand plants previously included in Hypsela and Isotoma, with four species recognised. The new names and combinations formally made here are all placed in Lobelia. A single dispersal event from Australia to the South Island of New Zealand is inferred to have preceded a radiation into four New Zealand species. Importantly, the four New Zealand species differ from their Australian progenitors by the capsule that is now indehiscent due to loss of the apical valves. The first species to diverge from this lineage was L. ionantha (the new name for Hypsela rivalis), a mid‐elevation species that occupies sites east of the Alpine Fault. A new North Island endem ic L. carens is distinguished from L. ionantha by its usually hairy stems, leaves, and flower parts, and smaller flowers that lack purple‐violet markings. The two newly named South Island species that occur west of the Alpine Fault evidently evolved from a common ancestral species that is inferred to have more narrow leaves, smaller flowers, and a reduced zone of adnation for the epipetalous stamens. One species, L. fatiscens, the name for a species previously identified as the Australian Isotoma fluviatilis, primarily occupies coastal sites, and only tetraploid plants with 2n = 28 are known. The other species, L. fugax, is a newly described upland species endemic to the ephemeral and shallow margins of cirque lakes within Kahurangi National Park in North‐West Nelson. The diploid (2n = 14) L. fugax is like a diminutive version of L. fatiscens, which must have diverged from the common ancestral species before the chrom osome doubling that occurred in the evolution of L. fatiscens. The conservation status of these endemic New Zealand species is evaluated.

Flood pulsing and metacommunity dynamics in a desert riparian ecosystem

AbstractQuestions:1. Does flood pulsing drive metacommunity dynamics and provide insurance against catastrophic flooding in desert southwestern riparian ecosystems? 2. Do upland and wetland species in the floodplain differ in their dynamics?Location:Southwestern USA.Methods:We sampled vegetation and propagule banks in four communities along a floodplain hydrogradient. Plant species were classified as wetland or upland and community wetland indicator scores were calculated. ANOVA tested for differences between data categories amongst communities (extant vegetation and propagule banks) and soil depths. Sorensen's similarity coefficient was calculated to determine compositional similarity between vegetation and propagule banks.Results:Community propagule banks had high similarity indicating broad dispersal by flood waters. Wetland propagules were present in soils from channel bars to floodplain edges, despite declines in wetland vegetation with distance from channel. Wetland communities in propagule banks were dissimilar from those in vegetation except on channel bars. Upland species (vegetation and propagule banks) increased with distance from channel. Propagules of upland species were most abundant in the litter, and were compositionally similar to upland species in most communities.Conclusions:Flood pulsing is one mechanism that drives spatiotemporal metacommunity dynamics in dynamic desert riparian ecosystems. The homogenized regional propagule bank created by flood pulsing provides wetland species with a mechanism to escape local extinction by allowing for recoloni‐zation after flooding creates suitable establishment conditions. Upland species are able to germinate from in‐situ sources after small‐scale flooding or rainfall moistens soil. In fluctuating environments, these dynamics sustain biodiversity in the face of ongoing environmental change.

Impact of Irrigation Cessation on Wetland Communities within the Elk Ranch in Grand Teton National Park, Moose, Wyoming

This study began in 2006 to provide an ecologically based decision platform for Grand Teton National Park (GTNP) managers to use when evaluating the pros and cons of continuing the historic Elk Ranch irrigation operation. Ideally, this platform would also provide criteria for identifying landscapes within the irrigated hay meadows that would experience the most rapid change in vegetation community structure if the decision were to terminate irrigation operations. These criteria would aid in the identification of areas where species composition could quickly change as growing conditions shifted to the drier conditions common in surrounding undeveloped range and forestland. Once identified these sites could be closely managed to prevent invasive non-native species from disrupting site re-occupation by native upland species. To accomplish this goal the study was designed to 1) identify soil and hydrologic features associated with wetland and upland plant communities in the hayfield complex and 2) monitor shallow groundwater patterns associated with these wetland complexes. Predictive responses generated from the soil/vegetation inventories would then be compared with the recorded groundwater patterns to validate the measures as indicators of vegetation community change. If successful, these criteria will also be useful for identifying the potential for wetland mitigation and rehabilitation at other localities within Grand Teton National Park.

Landscape configuration and flood frequency influence invasive shrubs in floodplain forests of the Wisconsin River (USA)

Summary 1. Invasive species are present worldwide, yet predicting which invasive species will become problematic in which ecosystems remains an important ecological challenge. Floodplains are at particular risk for invasion, especially when subjected to anthropogenic disturbance. 2. We examined how components of flood regime, habitat quality and habitat configuration influenced the presence and abundance of three invasive shrubs in the floodplain of the Wisconsin River. Shrub taxa included two non-natives ( Lonicera spp. and Rhamnus spp.) and one native ( Zanthoxylum americanum ). Observations of taxa presence and abundance were recorded in nine forested river reaches, spanning three physiographic regions. We also compared the productivity of Z. americanum across a flood control levee in one reach. 3. Physiographic region significantly predicted the presence and abundance of these three taxa, acting as a synthetic indicator of differences in climate, geography and topography. Invasion was greatest in regions where modifications to flood regime and land use were most pronounced. Physiographic region was excluded from subsequent analyses to assess more specific predictors of shrub distributions. 4. Habitat configuration and quality both predicted shrub taxa presence and abundance. Shrub taxa were most frequently observed and most abundant in small forest patches, near roads, and in sandy soil with low nutrient content. Edge habitats have many of these characteristics. Edges appear to be favoured by avian shrub dispersers and provide conditions suitable for invasive establishment. 5. Flooding influenced non-native and native invaders differently. Non-native taxa were observed less frequently and at lower abundances in frequently flooded areas, probably because of a sensitivity to flooding. However, the presence, abundance and productivity of the native invader increased with flooding. Anthropogenic modifications to the flood regime limited hydrologic connectivity and may have reduced the competitive advantage of flood-tolerant traits, which allowed the invasion of upland species. 6. Synthesis . In the floodplain of the Wisconsin River, anthropogenic modifications that created edge habitat and altered flood regime facilitated shrub invasions, whereas unfragmented forest and intact flood regime limited invasion. Large patches of floodplain forest, less regulated flooding regimes, and lower road densities may help reduce the spread of invasive shrubs in temperate

Storage Effects on Dormancy and Germination of Native Tickseed Species

Fresh seeds of prevariety germplasms of goldenmane tickseed (Coreopsis basalis), florida tickseed (Coreopsis floridana), lanceleaf tickseed (Coreopsis lanceolata), and leavenworth's tickseed (Coreopsis leavenworthii) were harvested from cultivated plants and stored under dry conditions for 1 to 24 weeks at 15 or 32 °C to alleviate dormancy, that is, to promote after-ripening. The relative humidity (RH) was 33% for all species except lanceleaf tickseed (23% RH). Seeds were subsequently stored for 24 weeks in a commercial storage facility at 23% RH/17 to 19 °C to determine whether after-ripened seeds could be stored without loss in quality (viability, germination velocity). The only substantial after-ripening occurred with seeds of lanceleaf tickseed, although most after-ripening of lanceleaf tickseed seeds occurred during the 24 weeks of dry storage in the commercial storage facility regardless of storage conditions for the previous 24 weeks. After the 24 weeks in commercial storage, germination of lanceleaf tickseed seeds was 48% to 80%, but germination was only 2% to 15% after 24 weeks of dry storage at 15 or 32 °C, respectively. Freshly harvested seeds of the other three species were much more nondormant than seeds of lanceleaf tickseed, but after-ripening effects were still evident because there were increases in germination or germination velocity (an indicator of after-ripening). Maintenance of seed quality was species-dependent. Seed quality of the two upland species, goldenmane tickseed and lanceleaf tickseed, was maintained during the initial 24 weeks of dry storage plus the subsequent 24 weeks in the commercial storage facility. In contrast, viability of seeds of the two wetland species, florida tickseed and leavenworth's tickseed, declined to varying degrees either during the initial 24 weeks of after-ripening or during storage in the commercial facility. The greatest decline in quality occurred for florida tickseed seeds that were stored for 24 weeks at 32 °C and then for 24 weeks in the commercial storage facility.

HeightߝDiameter Equations for 12 Upland Species in the Missouri Ozark Highlands

Abstract We calibrated a model predicting total tree height as a function of tree diameter for nine tree species common to the Missouri Ozarks. Model coefficients were derived from nearly 10,000 observed trees. The calibrated model did a good job predicting the mean heightߝdiameter trend for each species (pseudo-R2 values ranged from 0.56 to 0.88), but for a given tree diameter observed tree heights were highly variable. We also present a technique for incorporating the observed variation in tree heights in the predicted values.

Relationships between soil hydrology and forest structure and composition in the southern Brazilian Amazon

AbstractQuestion: Is soil hydrology an important niche‐based driver of biodiversity in tropical forests? More specifically, we asked whether seasonal dynamics in soil water regime contributed to vegetation partitioning into distinct forest types.Location: Tropical rain forest in northwestern Mato Grosso, Brazil.Methods: We investigated the distribution of trees and lianas ≥ 1 cm DBH in ten transects that crossed distinct hydrological transitions. Soil water content and depth to water table were measured regularly over a 13‐month period.Results: A detrended correspondence analysis (DCA) of 20 dominant species and structural attributes in 10 × 10 m subplots segregated three major forest types: (1) high‐statured upland forest with intermediate stem density, (2) medium‐statured forest dominated by palms, and (3) low‐statured campinarana forest with high stem density. During the rainy season and transition into the dry season, distinct characteristics of the soil water regime (i.e. hydro‐indicators) were closely associated with each vegetation community. Stand structural attributes and hydro‐indicators were statistically different among forest types.Conclusions: Some upland species appeared intolerant of anaerobic conditions as they were not present in palm and campinarana sites, which experienced prolonged periods of saturation at the soil surface. A shallow impermeable layer restricted rooting depth in the campinarana community, which could heighten drought stress during the dry season. The only vegetation able to persist in campinarana sites were short‐statured trees that appear to be well‐adapted to the dual extremes of inundation and drought.

Relationships between soil hydrology and forest structure and composition in the southern Brazilian Amazon

Question: Is soil hydrology an important niche-based driver of biodiversity in tropical forests? More specifically, we asked whether seasonal dynamics in soil water regime contributed to vegetation partitioning into distinct forest types. Location: Tropical rain forest in northwestern Mato Grosso, Brazil. Methods: We investigated the distribution of trees and lianas ≥ 1 cm DBH in ten transects that crossed distinct hydrological transitions. Soil water content and depth to water table were measured regularly over a 13-month period. Results: A detrended correspondence analysis (DCA) of 20 dominant species and structural attributes in 10 × 10 m subplots segregated three major forest types: (1) high-statured upland forest with intermediate stem density, (2) medium-statured forest dominated by palms, and (3) low-statured campinarana forest with high stem density. During the rainy season and transition into the dry season, distinct characteristics of the soil water regime (i.e. hydro-indicators) were closely associated with each vegetation community. Stand structural attributes and hydro-indicators were statistically different among forest types. Conclusions: Some upland species appeared intolerant of anaerobic conditions as they were not present in palm and campinarana sites, which experienced prolonged periods of saturation at the soil surface. A shallow impermeable layer restricted rooting depth in the campinarana community, which could heighten drought stress during the dry season. The only vegetation able to persist in campinarana sites were short-statured trees that appear to be well-adapted to the dual extremes of inundation and drought.

Water Uptake Patterns of an Invasive Exotic Plant in Coastal Saline Habitats

Schinus terebinthifolius Raddi (Schinus) is one of the most widely found woody exotic species in South Florida. This exotic is distributed across environments with different hydrologic regimes, from upland pine forests to the edges of sawgrass marshes and into saline mangrove forests. To determine if this invasive exotic had different physiological attributes compared to native species in a coastal habitat, we measured predawn xylem water potentials (Ψ), oxygen stable isotope signatures (δ18O), and sodium (Na ) and potassium (K ) contents of sap water from plants within: (1) a transition zone (between a mangrove forest and upland pineland) and (2) an upland pineland in Southwest Florida. Under dynamic salinity and hydrologic conditions, Ψ of Schinus appeared less subject to fluctuations caused by seasonality when compared with native species. Although stem water δ18O values could not be used to distinguish the depth of Schinus and native species' water uptake in the transition zone, Ψ and sap Na /K patterns showed that Schinus was less of a salt excluder relative to the native upland species during the dry season. This exotic also exhibited Na /K ratios similar to the mangrove species, indicating some salinity tolerance. In the upland pineland, Schinus water uptake patterns were not significantly different from those of native species. Differences between Schinus and native upland species, however, may provide this exotic an advantage over native species within mangrove transition zones.

Multi-scale factors and long-term responses of Chihuahuan Desert grasses to drought

Factors with variation at broad (e.g., climate) and fine scales (e.g., soil texture) that influence local processes at the plant scale (e.g., competition) have often been used to infer controls on spatial patterns and temporal trends in vegetation. However, these factors can be insufficient to explain spatial and temporal variation in grass cover for arid and semiarid grasslands during an extreme drought that promotes woody plant encroachment. Transport of materials among patches may also be important to this variation. We used long-term cover data (1915–2001) combined with recently collected field data and spatial databases from a site in the northern Chihuahuan Desert to assess temporal trends in cover and the relative importance of factors at three scales (plant, patch, landscape unit) in explaining spatial variation in grass cover. We examined cover of five important grass species from two topographic positions before, during, and after the extreme drought of the 1950s. Our results show that dynamics before, during, and after the drought varied by species rather than by topographic position. Different factors were related to cover of each species in each time period. Factors at the landscape unit scale (rainfall, stocking rate) were related to grass cover in the pre- and post-drought periods whereas only the plant-scale factor of soil texture was significantly related to cover of two upland species during the drought. Patch-scale factors associated with the redistribution of water (microtopography) were important for different species in the pre- and post-drought period. Another patch-scale factor, distance from historic shrub populations, was important to the persistence of the dominant grass in uplands (Bouteloua eriopoda) through time. Our results suggest the importance of local processes during the drought, and transport processes before and after the drought with different relationships for different species. Disentangling the relative importance of factors at different spatial scales to spatial patterns and long-term trends in grass cover can provide new insights into the key processes driving these historic patterns, and can be used to improve forecasts of vegetation change in arid and semiarid areas.

Responses of twelve tree species common in Everglades tree islands to simulated hydrologic regimes

Twelve tree species common in Everglades tree islands were subjected to three hydrologic regimes under controlled conditions for 25 weeks and assessed for growth and physiological responses. Treatments representing high, low, and no flood were maintained in pools of water to mimic seasonal variation in water depths at different positions in tree islands. Soil inundation under the high flood treatment resulted in reduced tree growth (height, basal diameter, crown volume) that was more pronounced and occurred earlier in mesic forest species than in swamp forest species. Physiological responses differed less among species, although stomatal conductance was a better predictor of the effects of flood stress on growth than either relative water content or chlorophyll fluorescence (Fv/Fm). Some swamp species appeared to be better adapted to rising water levels than others; Annona glabra, Morella cerifera, and Salix caroliniana responded more positively to flooding, while Magnolia virginiana, Persea borbonia, Chrysobalanus icaco, and Ilex cassine were less flood-tolerant. The highest mortalities and lowest growth were observed in the five upland species: Bursera simaruba, Coccoloba diversifolia, Eugenia axillaris, Sideroxylon foetidissimum, and Simarouba glauca. Of these, Sideroxylon and Simarouba did not survive to the end of the study under the high flood treatment. The moist soil conditions simulated by the low flood treatment resulted in greater growth in all species compared to soil inundation under high flood, except for the most flood-tolerant (Annona, Morella, Salix). The arrangement of species according to their responses to experimental flooding roughly paralleled their spatial distribution in the tree islands. The gradient in species responses demonstrated in this experiment may help guide responsible water management and tree island restoration in the Everglades.

To graze or not to graze? Sheep, voles, forestry and nature conservation in the British uplands

Summary The British uplands are internationally important for their unique plant and bird communities. They have considerable economic, nature conservation, landscape, aesthetic and tourism‐related value and as a result are under a variety of different pressures, most notably from sheep farming, shooting interests, commercial forestry and conservation interests. In order to optimize biodiversity in the uplands, the challenge is to find how to balance the different land‐use pressures. One key upland species that is potentially affected by livestock grazing, and is of considerable interest to both foresters and nature conservationists, is the field vole Microtus agrestis. Relaxation of livestock grazing can result in an increase in vole numbers. This in turn could have both positive and negative implications for biodiversity as (i) field voles are a major source of prey for other species and (ii) they are a cause of damage to newly planted trees and potentially damaging in areas of native woodland regeneration. A replicated, randomized block experiment, consisting of six replicates of four livestock grazing treatments, was established in 2003 (with baseline data collected in 2002). This enabled us to examine the effects of livestock grazing on field vole abundance. We have demonstrated experimentally for the first time that livestock grazing pressure affects the abundance of field voles (as measured by a vole sign index) in the uplands. In the first year of the experiment, immediate treatment effects were detectable, with a lower abundance of voles in the conventionally grazed treatment compared with those in the ungrazed treatment, and with intermediate vole abundances in the lightly grazed treatments. The significant treatment effects became more apparent in 2004, with a higher abundance of voles in the extensively grazed mixed treatment (i.e. sheep and cattle) than in the extensively grazed treatment that contained only sheep. Synthesis and applications. In order to maximize biodiversity in the uplands, our results suggest that low intensity livestock grazing, used in a novel ways, could be a useful management tool to reduce vole abundance (and hence subsequent tree damage) compared with excluding livestock from young plantations completely. Furthermore, vole abundance would be higher at low grazing intensity compared with conventional stocking rates, thus still providing food for raptors and other vole‐eating vertebrates. Indeed, low‐intensity sheep and mixed livestock grazing might improve prey availability as a direct consequence of increased heterogeneity in vegetation structure. Our results suggest that it may be possible to maintain the open character of moorland habitats, and benefit key upland species generally, by reducing sheep grazing pressure and introducing low‐intensity mixed livestock grazing throughout the uplands.

Phylogenetic relationships based on morphology among the Diospyros (Ebenaceae) species endemic to the Mascarene Islands

The Diospyros (Ebenaceae) species which colonized the Mascarene Islands, namely Mauritius, Reunion and Rodrigues, have been decimated over the years by human settlements. Of the 14 endemic species that have been described and collected for herbaria, Diospyros angulata is now believed to be extinct in Mauritius. The phylogenetic relationships of the 14 Diospyros species were determined using maximum parsimony analysis of 35 morphological characters. This analysis separated the Mascarene Diospyros into two major clades, with D. revaughanii , D. egrettarum and D. leucomelas grouped in the same strongly supported most basal clade while the rest of the species formed the other major clade. High bootstrap values were obtained for the sister species D. angulata and D. boutonania , and the clade clustering the upland species D. neraudii , D. nodosa and D. pterocalyx . There was also relatively strong support for the clade comprising D. hemiteles and D. melanida , which are located in mid altitude regions. These results indicate that Diospyros species most probably colonized the coastal areas of Mauritius and then moved to mid altitude habitats before finally reaching the upland regions. There are also strong indications that D. borbonica and D. diversifolia , endemic to Reunion and Rodrigues, respectively, resulted from migrations from Mauritius. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 307‐313.

Birds in depressional forested wetlands: Area and habitat requirements and model uncertainty

Forested wetlands are important habitat for many bird species, but data about area and habitat relationships of birds in depressional (i.e., non-riverine) deciduous forested wetlands are scarce. Depressional forested wetlands are often surrounded by larger, continuous patches of upland forest, and it is not clear whether this surrounding forest should be considered part of the forested wetland. To contribute regional data to this question, we sampled birds and vegetation in depressional forested wetlands in southern Michigan, USA. Results indicated that the wetland per se should not be considered separate from the surrounding forest because forest area and forest characteristics were the most important predictors of richness and abundance of wetland-associated birds. Conversely, wetland area and wetland characteristics were important for some upland species. Because spatial clustering and model selection uncertainty are often encountered by wetland scientists, we describe analytical methods used to deal with these problems.

Linking hydroperiod and vegetation response in Carolina bay wetlands

Hydrology filters propagule bank expression in herbaceous Carolina bays, but the strength of this filter’s effects on community composition at different points along the hydrologic gradient of these southeastern U.S. depressional wetlands is unknown. We used an experimental approach to determine the pattern of vegetation expression from propagule banks of Carolina bays exposed to different hydrologic conditions and gradients. Propagule banks of sediment cores collected from six Carolina bays were placed in bins, each of which was allocated to one of three hydrologic treatments: moist soil (MS), mid-summer drawdown (DD), or flooded (FL). After one season of vegetation development (1995) in the hydrologic treatments, half of the bins were left flat and the remaining were sloped to produce a finer moisture gradient within each bin. We compared taxa richness, community composition based on cover, and cover patterns of eight abundant species that developed in bins over the season (1996) after sloping. Species richness was significantly higher in the moist soil treatment and in sloped bins. Community composition, however, was affected by the hydrologic treatment only and not the finer-scale flooding gradient produced by sloping. Under flooded conditions, floating-leaved and submerged aquatics had higher cover; vegetation converged on simpler, less variable communities dominated by obligate wetland species, with species exhibiting different patterns of abundance over small changes in water depth. Emergent species typically had higher cover in moist soil and drawdown treatments. These results confirm a tight mechanistic link between hydrology and vegetation patterns within Carolina bays, but suggest that the strength of this link is not uniform across the gradient. The linkage weakens with drier conditions as both facultative wetland and upland species recruit into the standing vegetation.

Ecological traits of declining amphibians in upland areas of eastern Australia

AbstractCatastrophic declines of amphibian populations have been reported from upland areas around the world, yet within regions not all species have been affected. Herein, we examine the relationships between conservation status and ecological traits for over 60 amphibian species from upland areas of eastern Australia. Among the 24 phylogenetic groups examined, eight groups contained only declining species, eight groups contained both declining and non‐declining species and eight groups had no declining species, suggesting species declines are influenced by their evolutionary history. Declines have been reported for only one species (Philoria frosti) of 20 species (i.e. from genera Assa, Cophixalus, Austrochaperina and remaining Philoria/Kyaranus) with direct development in the terrestrial environment. Of the remaining 40 species that include an aquatic stage in the life history, species‐specific traits associated with declines suggest species with stream‐dwelling tadpoles are more likely to be declining than species that breed in ephemeral and isolated ponds. However, low ovarian clutch size is the most important ecological trait significantly associated with the tendency for a species to be declining (independent of phylogeny). Species with restricted geographic ranges are also more likely to be declining than widespread species (independent of phylogeny). While ovarian clutch size and geographic range are correlated they are both good predictors for the likelihood of decline for upland species independent of their phylogenetic history. We propose that low ovarian clutch size is an index of low fecundity, and indicates a reduction in population resilience, making those species more susceptible to population declines and extinction than highly fecund species. This provides the first ecological explanation for why some species are declining while other sympatric species are not. Geographic range provides an easily applied tool that can be used to predict the likelihood of species decline in other regions. These results support the hypothesis that a causal factor may be affecting all species of frogs, yet only those species with naturally low population resilience are susceptible to declines.

Independence of the Central Asian Faunistic Region (According to the Distribution of Lizards (Reptilia, Sauria))

Central Asian area above 2000 m was studied to test the independence of the Central Asian Mountain region in the herpetogeographical map of the Palearctic Region and the neighboring Sahara-Gobi Desert region. According to the range and origin similarity, all species inhabiting this area were assigned to several groups: mountain Central Asian species (the bulk of the range lies within the studied area), Western Asian upland species (the bulk of the range lies in the Near Eastern uplands), plain desert species (the bulk of the range is below 2000 m), Indo-Malayan species (the bulk of the range lies within the Indo-Malayan Kingdom), European species (the bulk of the range lies in the forest and steppe zones of Europe and West Siberia), and mountain desert species (equal parts of the range lie in the deserts and mountains of Central Asia). The distribution of species density was mapped by range superposition for each group. The dominance (over 50% of the total number of species) of mountain Central Asian or other species groups allowed us to assign the studied area to either the Central Asian mountain region or Sahara-Gobi desert region. The areas where neither of the specified groups exceeded the 50% threshold were recognized as transitional. Considering a large number of endemic species (28% of the total fauna), the Central Asian mountain area should be recognized as an independent region rather than a subregion of the Sahara-Gobi Desert region.