Species-rich Sites Research Articles

Composition and changes in the spontaneous flora of the Wadi El Rayan Ramsar site, Fayoum, Egypt, in the last 20 years

Abstract Wadi El Rayan is located in Egypt in the Sahara ecoregion the Palearctic ecozone (the world’s largest hot desert). The total area of Wadi El Rayan is 1759km2. The aim of this work was to study the ecosystems, compare species composition, species richness and species diversity of the study sites in the Wadi El Rayan protected area and the distributions of plants in the different landform. The field observations found that there is a low diversity and number of plant species around the lakes, in particular a decline in vegetation cover in accordance with a dramatic decrease in the water level in the lakes compared to earlier studies. The reduction of water levels due to decreased water supply is considered the main threat facing ecosystems and biodiversity in the lake area which requires a continuous survey of flora and measures to be implemented to conserve the natural vegetation in the area. Based on investigations of the spontaneous flora of Wadi El Rayan in 2018, 18 taxa of vascular plants were recorded. This inventory was compared with published records of investigations made in 1998, 2002 and 2014. A total of 18 vascular plant species belonging to 14 families were recorded in the wetland and desert ecosystems around the lakes of Wadi El Rayan. The vegetation mainly consists of sparsely distributed xerophytic and halophytic plants except in the wetland ecosystem around the lakes where it is characterized by some hydrophytic and halophytic plants. The family with the highest number of species was Poaceae followed by Zygophyllaceae. The results showed that a higher number of species was recorded from the Lower Lake (13 species) than the Upper Lake (10 species) and (5 species) for the connecting channel. The most frequently recorded species were Phragmites australis, Tamarix nilotica, Juncus rigidus and Alhagi graecorum: the first two species were the most successful species as they grow in a variety of ecosystems and habitats.

Zoonotic host diversity increases in human-dominated ecosystems.

Land use change-for example, the conversion of natural habitats to agricultural or urban ecosystems-is widely recognized to influence the risk and emergence of zoonotic disease in humans1,2. However, whether such changes in risk are underpinned by predictable ecological changes remains unclear. It has been suggested that habitat disturbance might cause predictable changes in the local diversity and taxonomic composition of potential reservoir hosts, owing to systematic, trait-mediated differences in species resilience to human pressures3,4. Here we analyse 6,801 ecological assemblages and 376 host species worldwide, controlling for research effort, and show that land use has global and systematic effects on local zoonotic host communities. Known wildlife hosts of human-shared pathogens and parasites overall comprise a greater proportion of local species richness (18-72% higher) and total abundance (21-144% higher) in sites under substantial human use (secondary, agricultural and urban ecosystems) compared with nearby undisturbed habitats. The magnitude of this effect varies taxonomically and is strongest for rodent, bat and passerine bird zoonotic host species, which may be one factor that underpins the global importance of these taxa as zoonotic reservoirs. We further show that mammal species that harbour more pathogens overall (either human-shared or non-human-shared) are more likely to occur in human-managed ecosystems, suggesting that these trends may be mediated by ecological or life-history traits that influence both host status and tolerance to human disturbance5,6. Our results suggest that global changes in the mode and the intensity of land use are creating expanding hazardous interfaces between people, livestock and wildlife reservoirs of zoonotic disease.

Potential anthropogenic influence on oribatid mite communities in ancient to modern settlements of the Russian Far East

ABSTRACT The southernmost Russian Far East represents a soil biodiversity hotspot in which settlements of ancient to modern ages form a mosaic within seminatural vegetation. We explored whether these settlements form potential “concentration points” of soil biodiversity by examining their oribatid mite (Acari: Oribatida) fauna. We sampled soils in nine settlements which were established during one of the three periods of territory colonization: “legendary”- before 1600, “imperial” – between the 1600s and 1917 and “soviet” – after 1917 and nine respective control sites with the seminatural vegetation located nearby. Forty-two species were identified from the collected material, of which 12 require further taxonomic examination. Species richness in control sites was higher (GLM, p < 0.05) than in the settlements – 8.9 ± 1.3 and 5.8 ± 1.0 (S.E.) per sample, respectively. The highest species richness among all settlements was in the “imperial” ones (8.7 ± 0.3) due to higher amount of cosmopolitan and oriental oribatids. We further speculate that elevated species richness in the settlements of the “imperial” period may be linked with the arrival of farmers from European Russia and Siberia in the nineteenth century. The younger “soviet” settlements had the boreal species Heminothrus humicola (Forsslund, 1955), indicating its invasion following the last wave of human migration.

Are cities hotspots for bees? Local and regional diversity patterns lead to different conclusions

With the decline of natural habitats, there is an ongoing debate about the importance of the urban environment for pollinating insects. Our research assessed patterns in wild bee species composition, as well as α-, β- and γ-diversity patterns and the nestedness structure in urban, suburban and rural areas. For three years bees were collected along 18 sampling transects in the Poznań area in western Poland. The average species diversity (α-diversity) and the average number of specimens per sample (local abundance) did not differ significantly between the three classes of urbanization. The rarefaction analysis, however, was partly contradictory to the results recorded on the local scale. The highest dissimilarity in the species composition among the samples was observed in the rural areas, while the lowest (more homogenous) was in the urban areas. The differences were significant. This resulted in the highest γ-diversity (cumulative number of species) in the rural areas and the lowest in the urban areas. Furthermore, the bee community in the habitats studied was significantly nested, indicating that species-poor sites (sites with high rank) constituted subsets of species-rich sites (sites with low rank) and that this pattern was not random. Samples collected in urban areas had a significantly higher nestedness rank compared to samples from the other two classes of urbanization, thus suggesting that the urban bee community is a subset of the rural bee community. This is an important conclusion, which emphasises that different components of species diversity need to be screened to identify the real biological impact of urbanisation on bee communities.

Patterns of change in α and β taxonomic and phylogenetic diversity in the secondary succession of semi-natural grasslands in the Northern Apennines.

We studied the secondary succession in semi-natural grasslands (dry grasslands and hay meadows) located in the eastern side of the Tuscan Apennines (Tuscany, Central Italy). We compared these habitats, investigating: (i) the changes in species richness, composition and phylogenetic diversity during the succession; (ii) whether the trends in species loss and species turnover in taxonomic diversity matched those in phylogenetic diversity. We performed a stratified random sampling, in a full factorial design between habitat type and succession stage (60 sampled plots, 10 × 2 types of habitat × 3 stages of succession). We constructed a phylogenetic tree of the plant communities and compared the differences in taxonomic/phylogenetic α- and β-diversity between these two habitats and during their succession. We identified indicator species for each succession stage and habitat. Looking at α-diversity, both habitats displayed a decrease in species richness, with a random process of species selection in the earlier succession stages from the species regional pool. Nevertheless, in the latter stage of dry grasslands we recorded a shift towards phylogenetic overdispersion at the higher-level groups in the phylogenetic tree. In both habitats, while the richness decreased with succession stage, most species were replaced during the succession. However, the hay meadows were characterized by a higher rate of new species’ ingression whereas the dry grasslands became dominated with Juniperus communis. Accordingly, the two habitats showed similar features in phylogenetic β-diversity. The main component was true phylogenetic turnover, due to replacement of unique lineages along the succession. Nevertheless, in dry grasslands this trend is slightly higher than expected considering the major importance of difference in species richness of dry grasslands sites and this is due to the presence of a phylogenetically very distant species (J. communis).

High spatial turnover in springtails of the Cape Floristic Region

AbstractAimThe extraordinary diversity of plants across the Cape Floristic Region is characterized by considerable species turnover among sites. Phytophagous insects show similarly high turnover, but their patterns are closely coupled to those of their hosts. If the mechanisms underlying high plant turnover are not unique to plants, similar patterns of turnover should also be seen in non‐herbivorous arthropod groups. We tested this hypothesis using new data for the Collembola fauna of the Fynbos biome.LocationThe south‐western Cape, South Africa.TaxonSpringtails (Hexapoda: Collembola).MethodsWe sampled springtails from six sites over two seasons. Species richness was compared with expected values from other studies worldwide given the environmental characteristics of the sites sampled. Nestedness and turnover components of beta diversity were calculated and compared against beta diversity patterns of springtails across Europe.ResultsA total of 114 morphospecies from 14 families was collected. Species richness of Fynbos sites ranged from 14 to 31 species, which was not significantly different to that previously reported for non‐Fynbos locations and generally within expectations given the temperature, rainfall and productive energy of each site. Beta diversity was high across all pairwise comparisons of Fynbos sites and dominated by species replacement rather than assemblage nestedness. Relative to the distance between sites, Fynbos assemblages, with a median inter‐site distance of 140 km, showed beta diversity substantially higher than in European assemblages, which had a median inter‐site distance of 1,270 km.Main conclusionsAlpha diversity of Fynbos Collembola assemblages is in keeping with species richness expectations. By contrast, beta diversity is high given the small distances among sites and is characterized predominantly by species turnover. These patterns of unremarkable alpha diversity, but high turnover among sites are comparable to many Fynbos plant groups. The mechanisms giving rise to high beta diversity of the plants may also have led to high diversity in other taxa.

Drivers of avian species richness and community structure in urban courtyard gardens

Abstract Increasing global urbanisation has steered research towards understanding biodiversity in urban areas. Old city spaces throughout Europe have a proliferation of urban court gardens, which can create a mosaic of habitat pockets in an urban area. This article examines the patterns and drivers of avian species richness and community structure in 20 gardens of the constituent colleges of the University of Oxford. We conducted morning surveys across 7 weeks in May and June 2017 and used an information-theoretic approach and model averaging to identify important habitat predictors of species richness. We also studied community structure with Sorensen indices and non-metric multi-dimensional analysis. A total of 43 avian species were observed across all sites. Our sites generally differed in their avian assemblages, with greater species turnover than nestedness between sites. Site area was the strongest predictor of site species richness and surrounding habitat composition was the dominant driver of community structure. Thus, the largest gardens were the most species rich, but species composition among gardens differed based on the habitats in which they were embedded. We support using island biogeography theory to understand the avian species assemblages of urban ecosystems and stress the suitability of our study sites for future urban ecosystem research and generating wildlife awareness.

Diversity and distribution of Orthoptera communities of two adjacent mountains in northern part of the Carpathians

During 2013&amp;ndash;2017, assemblages of bush-crickets and grasshoppers were surveyed in two neighbouring&amp;nbsp;flysch mountains &amp;ndash; &amp;#268;ergov Mts (48 sites) and Levo&amp;#269;sk&amp;eacute; vrchy Mts (62 sites) &amp;ndash; in northern part of&amp;nbsp;Western Carpathians. Species were sampled mostly at grasslands and forest edges along elevational&amp;nbsp;gradient between 370 and 1220 m a.s.l. Within the entire area (ca 930 km2) we documented 54 species,&amp;nbsp;representing 38% of Carpathian Orthoptera species richness. We found the same species number (45)&amp;nbsp;in both mountain ranges with nine unique species in each of them. No difference in mean species richness&amp;nbsp;per site was found between the mountain ranges (mean &amp;plusmn; SD = 12.5 &amp;plusmn; 3.9). Elevation explained&amp;nbsp;2.9% of variation in site species richness. Elevation and mountain range identity explained 7.3% of&amp;nbsp;assemblages composition. We found new latitudinal as well as longitudinal limits in the distribution&amp;nbsp;for several species. Occurrence and distributional patterns of some noteworthy species (Isophya&amp;nbsp;stysi, Pholidoptera transsylvanica, Poecilimon schmidtii, Polysarcus denticauda, Pseudopodisma nagyi,&amp;nbsp;Chorthippus tatrae), as well as habitat specialists (Chorthippus pullus, Tetrix tuerki) are discussed.

English

In tropics, species diversity in agricultural systems is often assessed without distinction between native and exotic species. However, the conservation value of an ecosystem depends on its richness in native species. This study was conducted to determine the conservation value of agricultural systems in Togo megahotspot, one of the species-rich sites in Upper Guinean. Specifically, the study compares fallow systems (FS), coffee systems (COFS), cocoa systems (COCS) to forest relics (FR) on the one hand, and on the other hand the agricultural systems (FS, COFS, COCS) between them base on natives tree species diversity and composition. Sites have been selected to represent different forest lands use types. Plots (n = 233) of different sizes (400, 500 and 625 m&sup2;) were used for data collection. In each plot, all living trees (DBH &ge; 10 cm) were counted. Rarefaction, generalized linear models (GLM) and ecological distance approach were used to standardized and compare the data. A total of 183 species were recorded, of which 42% were absent from the agricultural plots. Difference in diversity index were significant between the FR and agricultural systems (p&lt;0.001), but not between agricultural systems (p=0.23). Guineo-Congolian climax and endemic species were seriously under threat. The study poses a real problem of regeneration dynamic of these species in human-dominated landscapes that requires further specific work. &nbsp; Key words: Rainforests, agricultural practices, biodiversity conservation, Reducing Emissions from Deforestation and Forest Degradation (REDD+), Togo, Upper Guinean.

Risk assessment and conservation strategies for rare lichen species and communities threatened by sea-level rise in the Mid-Atlantic Coastal Plain

The Mid-Atlantic Coastal Plain (MACP) is an ecoregion with high biodiversity that is under imminent threat from sea level rise and habitat loss. Previous studies have shown i) the area to be high in lichen biodiversity, including endemic species, ii) the most lichen species-rich sites are the most imperiled by sea-level rise, and iii) common, widespread lichens have lost significant suitable habitat and are projected to lose more due to sea-level rise. Despite this, the spatial distributions of rare species and the compositional dynamics of lichen communities has not previously been examined. Here, we evaluate the community composition of 599 lichen species in 215 sites across the MACP. We tested whether community similarity is correlated with spatial proximity or environmental conditions. We found that sites with similar environmental characteristics had similar species composition, after controlling for geographic distance. Inland swamps had the highest per-site average number of unique species (1.3) and the two coastal ecosystems, maritime forests and pocosin (a unique form of peatland vegetation), each had an average of nearly one unique species per site. Across the entire MACP, 42% of species were found at five or fewer sites and these were mostly at sites under high risk of being affected by sea level rise. While habitats and species throughout the MACP have been projected to be negatively affected by sea level rise, our results suggest that rare lichens face particularly acute threats. Lack of suitable habitat inland at higher elevations may necessitate intensive mitigation, including facilitated transplants of both lichens and their host trees.

Managing sustainable agroecosystem: Study on diversity of parasitic Hymenoptera on riparian sites of oil palm and rubber plantation

Parasitic Hymenoptera is important natural enemies to control pest population but threatened by habitat transformation. It is important to know the sustainable management agroecosystem that may conserve beneficial insects. There is still minimum research about the effect of riparian buffers effect on Hymenoptera diversity. The objectives of this research were to study parasitic Hymenoptera species richness and abundance in oil palm and rubber plantation, investigate the effect of riparian sites on diversity and species composition across the different habitat. The research was conducted in Jambi Province, Sumatra, Indonesia which consists of two different agroecosystems, oil palm, and rubber plantation. Parasitic Hymenoptera was collected by direct sampling using insect nets and traps using a yellow pan and malaise traps. Parasitic Hymenoptera species richness was different among oil palm and rubber plantation. Oil palm had higher species richness than rubber plantation. Riparian buffers sites, either oil palm or rubber plantation, had higher numbers of parasitic Hymenoptera species richness and abundance than upland dry sites. These results are related to the high number of wild flowering plants species richness in riparian buffers sites. Community structure between riparian and dry agroecosystem was not different. The same agroecosystem provided the same feeding source and host for parasitoid. Therefore, managing sustainable agroecosystem should consider the presence of wild flowering plants that may preserve parasitic Hymenoptera diversity in providing natural enemy services in an agroecosystem.

Experimental evidence of the long‐term effects of reindeer on Arctic vegetation greenness and species richness at a larger landscape scale

Abstract Large herbivores influence plant community structure and ecosystem processes in many ecosystems. In large parts of the Arctic, reindeer (or caribou) are the only large herbivores present. Recent studies show that reindeer have the potential to mitigate recent warming‐induced shrub encroachment in the Arctic and the associated greening of high‐latitude ecosystems. This will potentially have large scale consequences for ecosystem productivity and carbon cycling. To date, information on variation in the interactions between reindeer and plants across Arctic landscapes has been scarce. We utilized a network of experimental sites across a latitudinal gradient in the Scandinavian mountains where reindeer have been excluded from 59 study plots for at least 15 years. We used this study system to test the effect of long‐term exclusion of reindeer on the abundance of major plant functional groups, the greenness indexes Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI), soil mineral nitrogen (N) and phosphorous (P), and species richness, and to determine whether the effect of reindeer exclusion is dependent on reindeer density, productivity, soil fertility or climate. We found that NDVI and LAI, lichen and deciduous shrub abundances were largely reduced while soil mineral N was enhanced by reindeer. The direction and amplitude of other plant functional group responses to reindeer exclusion differed between forest and tundra as well as shrub‐ and herbaceous‐dominated vegetation. Higher reindeer densities were related to decreased plant species richness in low‐productive sites and to increased species richness in productive sites. The relative reduction in LAI and associated absolute reductions of deciduous shrubs in response to reindeer were positively related to reindeer density, while the relative reduction in NDVI was not. Further, relative reductions in LAI and NDVI in response to reindeer were unrelated to climate and soil fertility. Synthesis. Our results provide long‐term experimental evidence highlighting the role of reindeer density in regulating plant species richness, global climate change induced greenness patterns and shrub encroachment at regional scales in the Arctic. These findings emphasize the need to consider reindeer in models predicting vegetation patterns and changes in high‐latitude ecosystems.

Ponderosa Pine Regeneration, Wildland Fuels Management, and Habitat Conservation: Identifying Trade-Offs Following Wildfire

Increasing wildfires in western North American conifer forests have led to debates surrounding the application of post-fire management practices. There is a lack of consensus on whether (and to what extent) post-fire management assists or hinders managers in achieving goals, particularly in under-studied regions like eastern ponderosa pine forests. This makes it difficult for forest managers to balance among competing interests. We contrast structural and community characteristics across unburned ponderosa pine forest, severely burned ponderosa pine forest, and severely burned ponderosa pine forest treated with post-fire management with respect to three management objectives: ponderosa pine regeneration, wildland fuels control, and habitat conservation. Ponderosa pine saplings were more abundant in treated burned sites than untreated burned sites, suggesting increases in tree regeneration following tree planting; however, natural regeneration was evident in both unburned and untreated burned sites. Wildland fuels management greatly reduced snags and coarse woody debris in treated burned sites. Understory cover measurements revealed bare ground and fine woody debris were more strongly associated with untreated burned sites, and greater levels of forbs and grass were more strongly associated with treated burned sites. Wildlife habitat was greatly reduced following post-fire treatments. There were no tree cavities in treated burned sites, whereas untreated burned sites had an average of 27 ± 7.68 cavities per hectare. Correspondingly, we found almost double the avian species richness in untreated burned sites compared to treated burned sites (22 species versus 12 species). Unburned forests and untreated burned areas had the same species richness, but hosted unique avian communities. Our results indicate conflicting outcomes with respect to management objectives, most evident in the clear costs to habitat conservation following post-fire management application.

Unmasking structural patterns in incidence matrices: an application to ecological data.

Null models have become a crucial tool for understanding structure within incidence matrices across multiple biological contexts. For example, they have been widely used for the study of ecological and biogeographic questions, testing hypotheses regarding patterns of community assembly, species co-occurrence and biodiversity. However, to our knowledge we remain without a general and flexible approach to study the mechanisms explaining such structures. Here, we provide a method for generating ‘correlation-informed’ null models, which combine the classic concept of null models and tools from community ecology, like joint statistical modelling. Generally, this model allows us to assess whether the information encoded within any given correlation matrix is predictive for explaining structural patterns observed within an incidence matrix. To demonstrate its utility, we apply our approach to two different case studies that represent examples of common scenarios encountered in community ecology. First, we use a phylogenetically informed null model to detect a strong evolutionary fingerprint within empirically observed food webs, reflecting key differences in the impact of shared evolutionary history when shaping the interactions of predators or prey. Second, we use multiple informed null models to identify which factors determine structural patterns of species assemblages, focusing in on the study of nestedness and the influence of site size, isolation, species range and species richness. In addition to offering a versatile way to study the mechanisms shaping the structure of any incidence matrix, including those describing ecological communities, our approach can also be adapted further to test even more sophisticated hypotheses.

Characterizing bumble bee (Bombus) communities in the United States and assessing a conservation monitoring method.

AimBumble bees (Hymenoptera: Apidae: Bombus) are economically and ecologically important pollinators in agroecosystems and wildland habitats. In the Nearctic region, there are approximately 41 species, of which the IUCN lists twelve species as vulnerable, endangered, or critically endangered. We conducted a standardized faunal survey to inform ongoing conservation efforts including petitions under review for the Endangered Species Act. Furthermore, we test the appropriateness of a methodology for accurately sampling bumble bee communities.LocationThe United States of America, including 31 sites in 15 states.MethodsWe surveyed 15 states in the summer of 2015 to assess community composition and relative species abundance at agricultural and seminatural sites throughout the United States. We collected approximately 100 bees, using aerial nets, from each of 31 sites and identified specimens to species, totaling 3,252 bees. We assessed our survey methodology to understand whether it accurately sampled the potential community of bumble bees at each site for utility in future monitoring efforts.ResultsAverage site species richness was 5.1 ± 2.05, and we detected 30 of the 41 species documented historically within the contiguous United States. Sampling a site beyond 100 bees rarely added additional species detections, whereas adding additional sampling sites within an ecoregion frequently increased the species richness for the ecoregion. Thirteen of the 30 species we detected each accounted for <1% of the total fauna, and two species accounted for 49.02% of all bees captured. Species richness and evenness increased with increasing latitude across communities.Main ConclusionsSpecies diversity and evenness in bumble bees increases in northern latitudes and increasing elevation in the United States; however, a few common species tend to dominate communities while many species occur only in low numbers. The results of this survey effort can inform current conservation evaluations and planning.

Long‐Term Change of Fish Communities in a Polluted Watershed: Does Cleaner Water “Act” on Fishes?

AbstractPollution is a threat to lotic fishes that enter streams via point source (PS) and nonpoint source (NPS) pathways. The Clean Water Act (CWA) of 1972 and the Surface Mining Control and Reclamation Act (SMCRA) of 1977 reduced PS pollution in the United States, but little information is available concerning the response of fish communities to this legislation. The objectives of this research were to quantify the responses of fishes to the CWA and SMCRA in the Cow Creek watershed of southeastern Kansas, a wadeable stream network that experienced large reductions in PS pollution. Responses were quantified by measuring changes in site occupancy, relative abundance, and species richness across 25 sites sampled in 1963 and again in 2017. Responses were compared among fishes that were intolerant, moderately intolerant, moderately tolerant, and tolerant of pollution using an analysis of deviance coupled with general linear hypothesis testing. We predicted that intolerant fishes would exhibit the most dramatic increases in distribution and abundance and that these changes would be most evident in streams that were directly receiving PS pollution in 1963. However, our predictions were not met, as species tolerant of pollution exhibited greater occupancy, relative abundance, and richness than did intolerant fishes, regardless of time period. Contemporary pH and substrate composition were also quantified and revealed that most streams had recovered from historical acid mine drainage but were dominated by fine substrates. We hypothesized that the limited responses exhibited by intolerant fishes were at least partially attributable to NPS pollution (i.e., sedimentation) resulting from agriculture, which was the dominant land use both historically and currently. We conclude that reductions in both NPS pollution coupled with historical reductions in PS pollution may be necessary to increase the prevalence of intolerant fishes. These management actions may have conservation implications as many intolerant fishes are also imperiled.

Benthic diatom metacommunity across small freshwater lakes: driving mechanisms, β-diversity and ecological uniqueness

In this study, driving forces and diversity patterns of a benthic diatom metacommunity across small freshwater lakes exhibiting environmental heterogeneity were investigated. Furthermore, local (LCBD) and species (SCBD) contributions to β-diversity and their driving parameters were assessed with abundance- and incidence-based analyses. Our results revealed that both spatial distance and environmental heterogeneity affected the community assembly, which corresponds most to the mass-effect (ME) concept. This theory was confirmed by high α-diversity of sampling sites; however, high overall β-diversity enhanced mainly by turnover contradicted the ME paradigm. LCBD indices were affected by environmental variables; furthermore, LCBD and LCBD in terms of species replacement showed a strong positive correlation. The ecologically most unique sites hosted relatively low species richness, and common species with intermediate-sized or broad niches contributed mostly to the regional β-diversity. However, abundance- and incidence-based calculations revealed different relationships of SCBD with the species’ total abundance and the number of occupied sites. Consequently, we favor the previous suggestions that comprehensive research focusing on conservation should incorporate the investigation of LCBD, SCBD, species-rich sites and also ecologically restricted species. Moreover, in assessing ecological uniqueness, both abundance and binary data sets should be considered since they might shed light on distinct patterns.

Metabolic adaptation of a Chlamydomonas acidophila strain isolated from acid mine drainage ponds with low eukaryotic diversity

The diversity and biological characteristics of eukaryotic communities within acid mine drainage (AMD) sites is less well studied than for prokaryotic communities. Furthermore, for many eukaryotic extremophiles the potential mechanisms of adaptation are unclear. This study describes an evaluation of eight highly acidic (pH 1.6–3.1) and one moderately acidic (pH 5.6) metal-rich acid mine drainage ponds at a disused copper mine. The severity of AMD pollution on eukaryote biodiversity was examined, and while the most species-rich site was less acidic, biodiversity did not only correlate with pH but also with the concentration of dissolved and particulate metals. Acid-tolerant microalgae were present in all ponds, including the species Chlamydomonas acidophila, abundance of which was high in one very metal-rich and highly acidic (pH 1.6) pond, which had a particularly high PO4-P concentration. The C. acidophila strain named PM01 had a broad-range pH tolerance and tolerance to high concentrations of Cd, Cu and Zn, with bioaccumulation of these metals within the cell. Comparison of metal tolerance between the isolated strain and other C. acidophila strains previously isolated from different acidic environments found that the new strain exhibited much higher Cu tolerance, suggesting adaptation by C. acidophila PM01 to excess Cu. An analysis of the metabolic profile of the strains in response to increasing concentrations of Cu suggests that this tolerance by PM01 is in part due to metabolic adaptation and changes in protein content and secondary structure.

Habitat‐contingent responses to disturbance: impacts of cattle grazing on ant communities vary with habitat complexity

Predicting community responses to disturbance is a major challenge for both ecology and ecosystem management. A particularly challenging issue is that the same type and intensity of disturbance can have different impacts in different habitats. We investigate how habitat contingency influences ant community responses to disturbance in arid Australia, testing the hypothesis that disturbance has a greater impact in more complex habitats. We also assess the effectiveness of a highly simplified ant assessment protocol that considers larger species only. We sampled ants at 46 sites from two habitats (Chandler, low chenopod shrubland; and mulga, low woodland) with contrasting complexity, using distance from water as a surrogate for variation in grazing intensity. We assessed variation in habitat structural variables (basal area of perennial grass, and cover of herbs, litter, and bare ground) and ant communities in relation to habitat and distance from water, first using data from the entire ant community and then for larger ants (>4mm body length) only. Site species richness was almost twice as high in mulga, the more structurally complex habitat, than in Chandler, and ant communities in mulga showed far more variation in relation to distance from water. Litter cover was the key environmental variable associated with the interaction between grazing and habitat: it increased with increasing distance from water in mulga and was virtually absent from Chandler. Analysis of only larger species revealed the same patterns of variation in ant abundance, species richness and composition in relation to habitat and grazing as shown by entire ant communities. Our findings support the hypothesis that disturbance impacts on faunal communities increase with increasing habitat complexity. An appreciation of such habitat contingency is important for a predictive understanding and therefore effective management of disturbances such as rangeland grazing. Our findings also show that simplified assessment can provide robust information on the responses of highly diverse ant communities to disturbance, which enhances their feasibility for use as bio-indicators in land management.

Habitat Structure, Quality and Landscape Predict Species Richness and Communities of Collembola in Dry Grasslands in Austria.

We assessed the relationships between site size, habitat quality, landscape factors (fragmentation, landscape diversity) and species richness in communities of Collembola in 50 small dry grassland habitat patches in an agricultural landscape of eastern Austria. Grasslands in that region were once widespread and extensive, but have become increasingly fragmented and isolated. We hypothesized that dry grassland springtails species richness is significantly correlated with site variables (soil properties, habitat quality) and that the size of grassland sites is positively correlated with species richness. We used pitfall traps in 50 dry grasslands in differently structured agricultural landscapes and tested total abundance and three species richness measures: (1) the number of dry grassland specialist species; (2) total number of dry grassland species and (3) overall species richness. In the multivariate correlation models, we found that all species richness measures were significantly related to the plant species richness, a shape parameter of the sites, soil properties such as humus, temperature, sand and gravel content and the landscape variable reflecting isolation (distance to the nearest large dry grassland area). This landscape variable indicates that neighbouring grasslands are influencing the species richness of the sites. This may be a result of passive wind dispersal across the landscape or historic connection of the small sites with much larger dry grasslands. The size of the site did not show any significant correlation with total, dry grassland specialist, dry grassland generalist or generalist species richness. The small size of Collembola might explain these findings, because they have high population densities even in small patches.