Biodiversity impacts of an invasive grass: ant community responses to <Emphasis Type="Italic">Cenchrus ciliaris</Emphasis> in arid Australia

Buffel grass (Cenchrus ciliaris) is a highly invasive species that thrives in semi-arid environments and has the capacity to transform native vegetation outside its native range. However, there is limited information on the effects of buffel grass invasion on native fauna. We used an experimental approach to investigate the impact of buffel grass on the native ant fauna near Alice Springs in semi-arid central Australia. A series of plots where buffel grass was removed and native vegetation had regenerated (B?), paired with adjacent control plots heavily invaded by buffel grass (B+), were used to assess the impact of buffel grass on ant diversity and composition, and on rates of seed dispersal by ants. Differences in ant diversity were also compared between two microhabitat types: bare ground and under cover, to examine the extent to which any impacts were a simple function of change in vegetation cover. Ant abundance and richness were approximately 50 % higher in B? compared with B+ plots, and higher abundance was especially pronounced for the very thermophilic Hot-Climate Specialists. Ant species composition varied significantly between plot types. B? plots supported more species and individuals in both bare and covered microhabitats, which suggests that the differences in ant diversity was not simply through changes in vegetation cover. Rates of seed removal by ants were marginally higher in B? plots. Our findings indicate that buffel grass has a major impact on a dominant faunal group of arid Australia, and possibly reduces the delivery of an important ecosystem service. In addition, our study demonstrates the potential for ecosystem recovery following effective buffel grass management.     

Herpetofaunal Richness and Community Structure of Offshore Islands of Sulawesi,Indonesia1

We examined the distribution and broad habitat associations of the herpetofauna on three offshore islands of southeast Sulawesi, Indonesia. A total of 74 amphibian and reptile taxa were recorded, comprising 13 frogs, 29 lizards, 29 snakes, 1 freshwater turtle, and 1 crocodile. Of the total taxa, 38 percent were endemic to Sulawesi, 13 were new undescribed taxa. Range extensions were also recorded for one taxon previously not known from Sulawesi. Herpetofauna of these islands is largely derived from that of mainland Sulawesi, and as for Sulawesi generally, is depauperate compared with herpetofaunal assemblages in Borneo, Java, and Thailand. Taxon richness was much higher in minimally disturbed forest and forest habitats with only moderate disturbance levels than in highly modified or disturbed habitats, such as secondary forests, plantations, and villages. Disturbed habitats were characterized by widespread, habitat generalists and human commensals. Forests were characterized by endemic and habitat‐specialist taxa. Little discrimination of taxon composition or endemism was found between minimally and moderately disturbed forest habitats. These results reaffirm the need for more general biological survey and research in this region. Taxa most likely to be displaced by human impacts tend to be endemic taxa, for which there exists little or no ecological information. The similarity in the herpetofaunal community structure between habitats with minimal and moderate disturbance levels has important implications for our understanding of ecological resilience in tropical herpetofaunal communities.     

Ecogeography of the herpetofauna of a northern California watershed: linking species patterns to landscape processes

Ecosystems are rapidly being altered and destabilized on a global scale, threatening native biota and compromising vital services provided to human society. We need to better understand the processes that can undermine ecosystem integrity (resistance‐resilience) in order to devise strategies to ameliorate this trend. We used a herpetofaunal assemblage to first assess spatial patterns of biodiversity and then to discover the underlying landscape processes likely responsible for these patterns. Reptiles and amphibians are a phylogenetically diverse set of species with documented sensitivity to environmental perturbations. We examined ecogeographic patterns of these taxa in aquatic and riparian environments across the landscape mosaic of the Mattole River watershed of northern California, USA. We analyzed species distributions relative to three primary vegetation types (grassland, second‐growth forest, late‐seral forest) and two hydrologic regimes (perennial vs intermittent). We sought evidence for the processes behind these patterns by modeling animal distributions relative to multi‐scale compositional, structural, and physical attributes of the vegetation or hydrologic type. Total herpetofaunal diversity was higher along perennial streams, with reptile diversity higher in mixed grassland. Amphibian and reptile richness, and reptile evenness, varied significantly among the three vegetations. Evidence indicated that distinct assemblages were associated with each end of a seral continuum. Four amphibians were more abundant in late‐seral forest, while two amphibians and two reptiles were more abundant in second‐growth forest, or mixed grassland, or both. Two amphibians were more abundant along intermittent streams. Models for predicting reptile richness, or abundances of the two amphibian assemblages, indicated water temperature was the best predictor variable. Based on these results and the physiological limits of several sensitive species, we determined the primary processes influencing faunal assemblage patterns on this landscape have been vegetation changes resulting from the harvesting of late‐seral forests and the clearing of forest for pasture. Comparing past with present landscape mosaics indicated that these changes have transformed the dominant amphibian and reptile species assemblage from a mostly cold‐water and cool forest‐associated assemblage to one now dominated by warm‐water and mixed grassland/woodland species.     

Reptile and Amphibian Responses to Restoration of Fire‐Maintained Pine Woodlands

Fire‐maintained woodlands and savannas are important ecosystems for vertebrates in many regions of the world. These ecosystems are being restored by forest managers, but little information exists on herpetofaunal responses to this restoration in areas dominated by shortleaf pine (Pinus echinata). We compared habitat characteristics and herpetofaunal communities in restored pine woodlands to relatively unmanaged, second‐growth forests in the Ouachita Mountains of western Arkansas, USA. We found woodland restoration with periodic burning affected species differently; some species benefited, some species appeared negatively affected, but most species did not respond clearly either way. Overall reptile captures were significantly (p = 0.041) greater in pine‐woodlands than in unrestored forest; one species of snake and three species of lizards were captured more often in woodlands than unrestored forests. Among anurans, we found no significant difference in captures between woodlands and unrestored forests for any species. Among salamanders, we captured western slimy salamanders (Plethodon albagula) almost exclusively in unrestored forest, but captures of other species did not differ between the two treatments. Historically, the Ouachita region likely consisted of a mosaic that included both fire‐maintained habitats (woodlands, savannas, and prairies) and areas of denser forest on mesic sites that were less likely to burn. Consequently, landscapes that retain both open woodlands and denser, less‐intensely burned forest (in the form of unharvested greenbelts or separate stands) would likely promote and maintain a greater diversity of herpetofauna.     

Ranking buffel: Comparative risk and mitigation costs of key environmental and socio‐cultural threats in central Australia

Changed fire regimes and the introduction of rabbits, cats, foxes, and large exotic herbivores have driven widespread ecological catastrophe in Australian arid and semi‐arid zones, which encompass over two‐thirds of the continent. These threats have caused the highest global mammal extinction rates in the last 200 years, as well as significantly undermining social, economic, and cultural practices of Aboriginal peoples of this region. However, a new and potentially more serious threat is emerging. Buffel grass (Cenchrus ciliaris L.) is a globally significant invader now widespread across central Australia, but the threat this ecological transformer species poses to biodiversity, ecosystem function, and culture has received relatively little attention. Our analyses suggest threats from buffel grass in arid and semi‐arid areas of Australia are at least equivalent in magnitude to those posed by invasive animals and possibly higher, because unlike these more recognized threats, buffel has yet to occupy its potential distribution. Buffel infestation also increases the intensity and frequency of wildfires that affect biodiversity, cultural pursuits, and productivity. We compare the logistical and financial challenges of creating and maintaining areas free of buffel for the protection of biodiversity and cultural values, with the creation and maintenance of refuges from introduced mammals or from large‐scale fire in natural habitats. The scale and expense of projected buffel management costs highlight the urgent policy, research, and financing initiatives essential to safeguard threatened species, ecosystems, and cultural values of Aboriginal people in central Australia.     

Influence of landscape and vegetation characteristics on herpetofaunal assemblages in Gulf Coastal Plain pine forests

Longleaf pine (Pinus palustris) savanna characterized by open-canopy, diverse herbaceous vegetation, and high amounts of bare soil once covered much of the southeastern United States Coastal Plain. The unique structural and vegetative conditions of this ecosystem support endemic reptiles and amphibians that have declined as longleaf pine forests have been lost or degraded. Private working pine (Pinus spp.) forests managed for timber production now occur throughout the southeastern United States and have replaced much of the historical longleaf pine savanna. The examination of herpetofaunal (reptile, amphibian) communities in private working loblolly pine (P. taeda) landscapes, particularly in the western Gulf Coastal Plain is lacking. Using repeated field surveys and hierarchical community occupancy models, we examined occupancy and species richness of herpetofauna across 81 sites spanning gradients of management practices, vegetative conditions, and soil composition in northwestern Louisiana, USA, 2017–2019. Young pine stands (<6 yr) exhibited structural characteristics most similar to mature longleaf pine reference sites (>30 yr), while mid-aged stands (13–26 yr) often featured closed canopy and dense midstory. Vegetation conditions varied widely depending on landscape characteristics and site-specific disturbance regimes. We documented 43 species of herpetofauna, including 9 open-pine-associated species. Occupancy of open-pine-associated herpetofauna was positively associated with open-canopy and understory conditions, and sandy soil area. Sites providing open-canopy conditions were often occupied by open-pine-associated species regardless of overstory type and disturbance method. Overall richness of herpetofauna was greatest at sites with moderate canopy cover outside of sandy soil regions. Working pine landscapes in the western Gulf Coastal Plain can support diverse herpetofaunal assemblages, including open-pine-associated species, when management practices maintain open-canopy conditions on sandy, upland soils. More broadly, our results provide insight into how forest management practices affect herpetofauna and may guide practices that can contribute to conservation value of working pine forests.     

Managing open habitats by wild ungulate browsing and grazing: A case‐study in North‐Eastern Germany

Question: Can wild ungulates efficiently maintain and restore open habitats? Location: Brandenburg, NE Germany. Methods: The effect of wild ungulate grazing and browsing was studied in three successional stages: (1) Corynephorus canescens‐dominated grassland; (2) ruderal tall forb vegetation dominated by Tanacetum vulgare; and (3) Pinus sylvestris‐pioneer forest. The study was conducted over 3 yr. In each successional stage, six paired 4 m²‐monitoring plots of permanently grazed versus ungrazed plots were arranged in three random blocks. Removal of grazing was introduced de novo for the study. In each plot, percentage cover of each plant and lichen species and total cover of woody plants was recorded. Results: Wild ungulates considerably affected successional pathways and species composition in open habitats but this influence became evident in alteration of abundances of only a few species. Grazing effects differed considerably between successional stages: species richness was higher in grazed versus ungrazed ruderal and pioneer forest plots, but not in the Corynephorus sites. Herbivory affected woody plant cover only in the Pioneer forest sites. Although the study period was too short to observe drastic changes in species richness and woody plant cover, notable changes in species composition were still detected in all successional stages. Conclusion: Wild ungulate browsing is a useful tool to inhibit encroachment of woody vegetation and to conserve a species‐rich, open landscape.     

Testate Amoeba (Arcellinida,Euglyphida) Ecology along a Poor‐Rich Gradient in Fens of Western Poland

We investigated the relationships between testate amoebae (Arcellinida, Euglyphida), vegetation and water chemistry along environmental gradients in minerotrophic peatlands (fens) in western Poland. We hypothesized that: a) hydrochemistry significantly influences structure of testate amoeba communities, and b) testate amoeba communities are more closely correlated with the hydrochemical variables (environment) than with the vegetation data. Testate amoeba communities and vegetation from 71 sample plots were investigated together with the hydro‐chemistry and hydrology based on 16 environmental variables and vegetation composition. Testate amoeba communities revealed a distinctive poor‐rich gradient in analysed fens. Mineral‐rich habitats, which were dominated by brown mosses, were preferred by a higher number of taxa than acidic habitats, which were dominated by Sphagnum. We recorded a total of 107 testate amoebae taxa. The average species richness of testate amoebae for brown mosses was higher (20) than for Sphagnum (13). We found that testate amoebae communities were similarly correlated with vascular plants, mosses and environmental parameters. Results of direct ordination demonstrate that hydrology, pH, Mg²⁺ and sodium remain the most important environmental control for the entire data set. CCA showed that in case of brown mosses hydrology, sodium and oxygen affect testate amoeba communities significantly whereas in Sphagnum only sodium emerge as most significant determining testate amoeba assemblages. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Biological diversity of a temporary pond herpetofauna in north Florida sandhills

From 1985 through 1990, the herpetofauna of a temporary pond in an uplands longleaf pine sandhills community in north-central Florida was monitored. A drift fence completely encircled the pond. Animals were captured in pitfall traps and marked as they entered and exited the pond basin. I captured 16 155 individuals of 42 species (16 amphibians, 26 reptiles). The species richness, diversity (using Margalef's Diversity Index) and dominance (using the Berger-Parker Index) varied among years. Between 62.5% and 87.5% of the amphibian species and 65% to 81% of the reptile species were captured in any one year. Daily amphibian capture was positively correlated with rainfall, whereas reptile capture was either not correlated or weakly negatively correlated with rainfall. Hydroperiod duration was not correlated with the numbers of either amphibians or reptiles captured. Neither the amphibian nor the reptile community showed any trends in diversity or dominance indices during the course of the study, although both communities were dominated by a few species. However, the species responsible for community dominance changed somewhat as the study progressed. Assessing the results of this study is hampered by the lack of comparable studies elsewhere, expected natural fluctuations of amphibian populations, and a prolonged drought, especially during the latter stages of the study. The herpetological community at Breezeway Pond does not appear to follow theoretical predictions of community response to stress. Temporary ponds are important centres of herpetofaunal biodiversity in uplands sandhills communities. Long-term studies are needed to monitor the composition, structure, and functional interactions of their resident species.     

Postwildfire seeding to restore native vegetation and limit exotic annuals: an evaluation in juniper‐dominated sagebrush steppe

Reestablishment of perennial vegetation is often needed after wildfires to limit exotic species and restore ecosystem services. However, there is a growing body of evidence that questions if seeding after wildfires increases perennial vegetation and reduces exotic plants. The concern that seeding may not meet restoration goals is even more prevalent when native perennial vegetation is seeded after fire. We evaluated vegetation cover and density responses to broadcast seeding native perennial grasses and mountain big sagebrush (Artemisia tridentata Nutt. spp. vaseyana [Rydb.] Beetle) after wildfires in the western United States in six juniper (Juniperus occidentalis ssp. occidentalis Hook)‐dominated mountain big sagebrush communities for 3 years postfire. Seeding native perennial species compared to not seeding increased perennial grass and sagebrush cover and density. Perennial grass cover was 4.3 times greater in seeded compared to nonseeded areas. Sagebrush cover averaged 24 and less than 0.1% in seeded and nonseeded areas at the conclusion of the study, respectively. Seeding perennial species reduced exotic annual grass and annual forb cover and density. Exotic annual grass cover was 8.6 times greater in nonseeded compared to seeded areas 3 years postfire. Exotic annual grass cover increased over time in nonseeded areas but decreased in seeded areas by the third‐year postfire. Seeded areas were perennial‐dominated and nonseeded areas were annual‐dominated at the end of the study. Establishing perennial vegetation may be critical after wildfires in juniper‐dominated sagebrush steppe to prevent the development of annual‐dominated communities. Postwildfire seeding increased perennial vegetation and reduced exotic plants and justifies its use.     

Long‐term changes in semi‐arid vegetation: Invasion of an exotic perennial grass has larger effects than rainfall variability

Abstract. Questions: This paper examines the long‐term change in the herbaceous layer of semi‐arid vegetation since grazing ceased. We asked whether (1) there were differences in the temporal trends of abundance among growth forms of plants; (2) season of rainfall affected the growth form response; (3) the presence of an invasive species influenced the abundance and species richness of native plants relative to non‐invaded plots, and (4) abundance of native plants and/or species richness was related to the time it took for an invasive species to invade a plot. Location: Alice Springs, Central Australia. Methods: Long‐term changes in the semi‐arid vegetation of Central Australia were measured over 28 years (1976–2004) to partition the effects of rainfall and an invasive perennial grass. The relative abundance (biomass) of all species was assessed 25 times in each of 24 plots (8 m × 1 m) across two sites that traversed floodplains and adjacent foot slopes. Photo‐points, starting in 1972, were also used to provide a broader overview of a landscape that had been intensively grazed by cattle and rabbits prior to the 1970s. Species’abundance data were amalgamated into growth forms to examine their relationship with environmental variation in space and time. Environmental variables included season and amount of rainfall, fire history, soil variability and the colonization of the plots by the exotic perennial grass Cenchrus ciliaris (Buffel grass). Results: Constrained ordination showed that season of rainfall and landscape variables relating to soil depth strongly influenced vegetation composition when Cenchrus was used as a covariate. When Cenchrus was included in constrained ordination, it was strongly related to the decline of all native growth forms over time. Univariate comparisons of non‐invaded vs impacted plots over time revealed unequivocal evidence that Cenchrus had caused the decline of all native growth form groups and species richness. They also revealed a contrasting response of native plants to season of rainfall, with a strong response of native grasses to summer rainfall and forbs to winter rainfall. In the presence of Cenchrus these responses were strongly attenuated. Discussion: Pronounced changes in the composition of vegetation were interpreted as a response to removal of grazing pressure, fluctuations in rainfall and, most importantly, invasion of an exotic grass. Declines in herbaceous species abundance and richness in the presence of Cenchrus appear to be directly related to competition for resources. Indirect effects may also be causing the declines of some woody species from changed fire regimes as a result of increased fuel loads. We predict that Cenchrus will begin to alter landscape level processes as a result of the direct and indirect effects of Cenchrus on the demography of native plants when there is a switch from resource limited (rainfall) establishment of native plants to seed limited recruitment.     

Biodiversity responses to land‐use and restoration in a global biodiversity hotspot: Ant communities in Brazilian Cerrado

Given that land‐use change is the main cause of global biodiversity decline, there is widespread interest in adopting land‐use practices that maintain high levels of biodiversity, and in restoring degraded land that previously had high biodiversity value. In this study, we use ant taxonomic and functional diversity to examine the effects of different land uses (agriculture, pastoralism, silviculture and conservation) and restoration practices on Cerrado (Brazilian savanna) biodiversity. We also examine the extent to which ant diversity and composition can be explained by vegetation attributes that apply across the full land management spectrum. We surveyed vegetation attributes and ant communities in five replicate plots of each of 13 land‐use and restoration treatments, including two types of native vegetation as reference sites: cerrado sensu stricto and cerradão. Several land‐use and restoration treatments had comparable plot richness to that of the native reference habitats. Ant species and functional composition varied systematically among land‐use treatments following a gradient from open habitats such as agricultural fields to forested sites. Tree basal area and grass cover were the strongest predictors of ant species richness. Losses in ant diversity were higher in land‐use systems that transform vegetation structure. Among productive systems, therefore, uncleared pastures and old pine plantations had similar species composition to that occurring in cerrado sensu stricto. Restoration techniques currently applied to sites that were previously Cerrado have focused on returning tree cover, and have failed to restore ant communities typical of savanna. To improve restoration outcomes for Cerrado biodiversity, greater attention needs to be paid to the re‐establishment and maintenance of the grass layer, which requires frequent fire. At the broader scale, conservation planning in agricultural landscapes, should recognize the value of land‐use mosaics and the risks of homogenization.     

Restoration of species‐rich flood‐plain meadows from abandoned arable fields in NE France

Abstract. Attempts to restore species‐rich flood‐plain meadows from abandoned arable fields in the valley of the river Meuse, NE France, were studied. The study area was sown with a commercial seed mixture, composed of Phleumpratense, Festuca pratensis, Lolium perenne and Trifolium repens. The above‐ground vegetation in the study area 1, 2 and 3 yr after restoration was compared to (1) the vegetation present during the previous 5‐yr fallow stage and (2) target flood‐plain meadows. Before restoration, the above‐ground fallow vegetation was dominated by ruderal and annual species, while only very few meadow species were present. Sowing led to tall, dense vegetation, mainly dominated by the sown species. Ruderal and annual species had decreased 3 yr after restoration, but target species were still poorly represented. Species richness was significantly lower in the sown site than in the semi‐natural target meadows and the vegetation had a different composition. Analysis of the soil seed bank of the restored meadow showed that only a few meadow species were present and that it was dominated by a few ruderal species. Three years after sowing, the vegetation of our experimental site is moving slowly towards the target communities but impoverished seed sources seem to limit the success of this restoration operation and will lead to under‐saturated communities.     

Amphibian and reptile communities of rainforest fragments: minimum patch size to support high richness and abundance

Information on animal communities inhabiting Neotropical fragmented landscapes is important for developing conservation strategies. The structure of amphibian and reptile communities in six tropical rainforest fragments (<20?ha) and two reference areas in continuous forest at Los Tuxtlas, Mexico was studied. A total of 3,481 individuals of 51 species of amphibians and reptiles were recorded across 12 bimonthly surveys during 2 years. Taxonomic composition was different between the smallest fragments and the reference areas. Six species were exclusive to large undisturbed forest and richness was significantly lower in the five smallest fragments (1.4–6.6?ha) compared with the largest patch, one or both of the reference areas. Amphibian abundance tended to be higher in large areas, while reptiles were more abundant in the five smallest fragments. Craugastor loki and Anolis uniformis were the dominant species in all sites, and particularly in the smaller fragments. Amphibian and reptile richness was positively related to larger patch sizes, deeper leaf litter, closed canopy cover, and higher relative humidity and negatively related to linear patch shape and high temperatures. Abundance of reptiles was positively associated to high temperatures, high density of woody debris, and closed canopy cover; it was negatively affected by linear patch shape, low humidity levels, and steeper slopes. While amphibian and reptile communities were strongly affected in vegetation fragments, these patches retained a considerable number of rainforest species. Fragments up to at least 17?ha have the potential for preserving communities with similar structure to those occurring in large tropical rainforests.     

Long‐term phosphite application maintains species assemblages,richness and structure of plant communities invaded by Phytophthora cinnamomi

The impact of the plant pathogen Phytophthora cinnamomi and the fungicide phosphite on species assemblages, richness, abundance and vegetation structure was quantified at three sites in Kwongkan communities in the Southwest Australian Floristic Region. Healthy and diseased vegetation treated with phosphite over 7–16 years was compared with non‐treated healthy and diseased vegetation. After site differences, disease had the greatest effect on species assemblages, species richness and richness within families. Disease significantly reduced cover in the upper and lower shrub layers and increased sedge and bare ground cover. Seventeen of 21 species assessed from the families Ericaceae, Fabaceae, Myrtaceae and Proteaceae were significantly less abundant in non‐treated diseased vegetation. In diseased habitats, phosphite treatment significantly reduced the loss of shrub cover and reduced bare ground and sedge cover. In multivariate analysis of species assemblages, phosphite‐treated diseased plots grouped more closely with healthy plots. Seven of 17 susceptible species were significantly more abundant in phosphite‐treated diseased plots compared with diseased non‐treated plots. The abundance of seven of 10 Phytophthora‐susceptible species was significantly higher along transects in phosphite‐treated vegetation. Comparison of the floristics of healthy non‐treated with healthy‐treated plots showed no significant differences in species assemblages. Of 21 species assessed, three increased in abundance and only one decreased significantly in phosphite‐treated healthy plots. In three Kwongkan communities of the SWAFR, P. cinnamomi had a profound impact on species assemblages, richness, abundance and vegetation structure. There was no evidence of adverse effects of phosphite treatment on phosphorus‐sensitive species, even after fire. Treatment with phosphite enhanced the survival of key susceptible species and mitigated disease‐mediated changes in vegetation structure. In the absence of alternative methods of control in native communities, phosphite will continue to play an important role in the protection of high priority species and communities at risk of extinction due to P. cinnamomi.     

Species richness,alien species and plant traits in Central Argentine mountain grasslands

Abstract. Pattern of native vegetation, distribution of alien species and variation of environmental parameters were studied in mountain grasslands in a lithologically homogeneous Córdoba mountain range in Central Argentina. CCA showed that altitude was the most important factor determining the compositional variation of the vegetation, with soil nutrient status and stoniness as additional factors. Short‐grass communities, associated with the driest habitats on plateaus, showed higher small‐scale native species richness than wet‐turf communities in valleys and tall‐grass communities on slopes. Species richness was negatively correlated with soil parameters that indicate nutrient status and water availability. Also, there was a negative correlation between soil Ca‐ and Mg‐ content and richness. High native species richness coincided with high alien species richness. When smaller units – community types – were considered, it became evident that within short‐grass vegetation, the three most species‐rich community types contained significant numbers of alien species, while the other two did not. Even within one community type, the same quadrats that contained the highest number of native species, were also characterized by the highest numbers of alien species. Evidently, the same mechanism was responsible for high richness of both native and alien species. Alien species were distinguished by a greater proportion of annuals and prostrate stoloniferous plants, by lower palatability and by smaller proportion of zoochory. DCA ordination of quadrats on the basis of plant traits as attributes resulted in a clear distinction of three main vegetation types. Short‐grass vegetation was distinguished by a predomination of late flowering species, tall‐grass vegetation by the presence of high herbaceous plants and bushes, and wet‐turf vegetation by the presence of plants with storage organs, the lack of hairy leaves, and by a high proportion of cryptophytes. Quadrats with and without alien species were distinguished as well, indicating that the occurrence of aliens may be dependent on plant traits in a particular patch of a community.     

Environmental determinants of amphibian and reptile species richness in China

Understanding the factors that regulate geographical variation in species richness has been one of the fundamental questions in ecology for decades, but our knowledge of the cause of geographical variation in species richness remains poor. This is particularly true for herpetofaunas (including amphibians and reptiles). Here, using correlation and regression analyses, we examine the relationship of herpetofaunal species richness in 245 localities across China with 30 environmental factors, which include nearly all major environmental factors that are considered to explain broad-scale species richness gradients in such theories as ambient energy, water–energy dynamics, productivity, habitat heterogeneity, and climatic stability. We found that the species richness of amphibians and reptiles is moderately to strongly correlated with most of the environmental variables examined, and that the best fit models, which include explanatory variables of temperature, precipitation, net primary productivity, minimum elevation, and range in elevation, explain ca 70% the variance in species richness for both amphibians and reptiles after accounting for sample area. Although water and temperature are important explanatory variables to both amphibians and reptiles, water variables explain more variance in amphibian species richness than in reptile species richness whereas temperature variables explain more variance in reptile species richness than in amphibian species richness, which is consistent with different physiological requirements of the two groups of organisms.     

Reptile, amphibian, and lemur diversity of the Malahelo Forest, a biogeographical transition zone in southeastern Madagascar

Ambatorongorongo Mountain lies at the historical intersection betweenhumid, spiny, and littoral forests in southeastern Madagascar. We report theresults of surveys of the herpetofauna and lemurs occurring in Malahelo Forest,a small (<25 ha) forest fragment lying on the western slope ofAmbatorongorongo Mountain. There are at least 41 reptile, 11 amphibian, and 7lemur species in this forest, including several that are endemic to southeasternMadagascar and are at severe risk of extinction. The species richness of theMalahelo fauna is comparable to that of even the largest forest reserves in theregion. We also evaluate the similarity of the Malahelo herpetofauna to that ofnearby humid, spiny, and littoral forests to assess the biogeographic affinitiesof its amphibians and reptile assemblages. Both groups contain speciescharacteristic of each of the three surrounding forest types, but thebiogeographic patterns appear to differ for amphibians and reptiles. Overall,the herpetofauna and lemurs of the Malahelo Forest indicate that it is a remnantof a biogeographic transition zone between the major forest types ofsoutheastern Madagascar. The combination of high species richness, regionalendemics, and unique herpetofaunal and lemur assemblages should make MalaheloForest a high conservation priority, and we give recommendations for protectingwhat remains of this important transitional forest.     

Eaten Out of House and Home: Impacts of Grazing on Ground-Dwelling Reptiles in Australian Grasslands and Grassy Woodlands

Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing.     

Shrub encroachment in the Alps gives rise to the convergence of sub‐alpine communities on a regional scale

Question: How does Alnus alnobetula colonization affect plant communities in sub‐alpine grasslands undergoing land abandonment on a regional scale? Location: Savoie, French Alps. Methods: Variations within and between communities were monitored in 243 plots within three types of stands representing an A. alnobetula colonization chronosequence from grassland to dense vegetation. They were tested for species richness, species strategies and species distribution through multivariate analysis. Regional variations were assessed at three sites along a rain shadow gradient. Results: We detected a convergence of the understorey communities along an A. alnobetula colonization gradient at all sites, associated with a reduction in species richness and the replacement of stress related strategists by competitor strategists. This convergence was unaffected by the rain shadow gradient although it was a key factor of plant distribution. Conclusions: The dense cover and the soil properties provided by A. alnobetula stands buffered the heterogeneity of sub‐alpine communities induced by a rain shadow gradient throughout the study region. It facilitated the development a homogeneous understorey community dominated by competitor related strategists while excluding grasslands stress adapted species through competition processes. The resulting community, although species‐poor, has an interesting conservation value. Accordingly, as a ‘native invader’, A. alnobetula does not display typical traits of biological invaders. Future experimental research on the interactions between A. alnobetula and components of the understorey would be particularly interesting in a severe environment that promotes facilitation among plants.