Endemic Species Richness Research Articles

Bird Diversity Patterns in the Nuclear Central American Highlands: A Conservation Priority in the Northern Neotropics

The Nuclear Central American Highlands (NCAH) is a mountainous region located within a complex transition zone. Here, we analyzed the distribution patterns of 282 species of resident land birds of the NCAH. We gathered a database with records of presence of species, from which we generated realized ecological niche models using the Genetic Algorithm for Rule Set Production. These ecological niche models were used to obtain maps of each species’ potential distribution and generated species richness maps that were also compared to the map of protected areas. In addition, the maps were overlaid with a 0.25° diameter hexagonal grid to generate a presence–absence matrix to create regionalizations through (a) a Parsimony Analysis of Endemism and (b) a phenogram. Results show contrasting patterns of distribution between total species richness and endemic species richness. The regionalizations show groups influenced by slope and altitude. Species composition is mainly Mesoamerican and Neotropical species. Our results offer a new view of the regional understanding of bird diversity patterns and biogeographical processes that have shaped regional richness, like the effects of the Great American Biotic Interchange that are visible in the species composition of the NCAH. We believe that these maps of both species richness and regionalization can serve as useful tools for conservation biologists and authorities in implementing strategies for the protection of natural areas in the NCAH.

Plant species diversity in a Neotropical wetland: patterns of similarity, effects of distance, and altitude.

The Brazilian Pantanal is an extensive wetland with heterogeneous habitats, primarily due to the river-floodplain system and plants with differential adaptations and reproductive strategies. Factors such as altitude, distance among plant formations, and flood pulse must be considered to better understand its diversity. Aiming to assess the influence of biogeographic patterns in this system, we analyzed the floristic composition of six areas along the Paraguay River, including residual relieves, verifying the pattern of similarity, and effects of distance and altitude. We recorded 356 species in 87 families, mostly perennial (75%), and some annuals (15%) and pluriannuals (5%). Herbaceous plants were the most represented (48%), followed by arboreal (23%), shrubby (15%) and epiphytic (14%) habits, only 12% being endemic to Brazil. The studied areas showed low floristic similarity, but higher resemblance of species between neighboring areas, and no relation with altitude. The upper Paraguay River is diverse, with high spatial variability of species, predominantly perennial. The river-floodplain connectivity may be a determinant factor in species richness and occurrence of endemic species.

Spatial relationships between above-ground biomass and bird species biodiversity in Palawan, Philippines.

This study maps distribution and spatial congruence between Above-Ground Biomass (AGB) and species richness of IUCN listed conservation-dependent and endemic avian fauna in Palawan, Philippines. Grey Level Co-Occurrence Texture Matrices (GLCMs) extracted from Landsat and ALOS-PALSAR were used in conjunction with local field data to model and map local-scale field AGB using the Random Forest algorithm (r = 0.92 and RMSE = 31.33 Mg·ha-1). A support vector regression (SVR) model was used to identify the factors influencing variation in avian species richness at a 1km scale. AGB is one of the most important determinants of avian species richness for the study area. Topographic factors and anthropogenic factors such as distance from the roads were also found to strongly influence avian species richness. Hotspots of high AGB and high species richness concentration were mapped using hotspot analysis and the overlaps between areas of high AGB and avian species richness was calculated. Results show that the overlaps between areas of high AGB with high IUCN red listed avian species richness and endemic avian species richness were fairly limited at 13% and 8% at the 1-km scale. The overlap between 1) low AGB and low IUCN richness, and 2) low AGB and low endemic avian species richness was higher at 36% and 12% respectively. The enhanced capacity to spatially map the correlation between AGB and avian species richness distribution will further assist the conservation and protection of forest areas and threatened avian species.

A synthesis on cave-dwelling spiders in Europe

We provide the first overview on spiders living in subterranean habitats in Europe, including the first European subterranean spider checklist. In Europe, there are 486 spider species known to dwell in caves and other subterranean habitats, distributed across 22 families. Despite a few species being able to colonize caves across the whole continent, approximately 90% of the species show a restricted distribution, occurring exclusively in one or two countries. From a biogeographic perspective, southern Europe emerges as the main hot spot of subterranean spider diversity, showing the highest richness of endemic species. Compared to other temperate regions of the world, some families appear to be well represented and other poorly represented (or lacking) in European subterranean habitats. Overall, it appears that the taxonomical knowledge on subterranean spiders in Europe is sufficient, but not evenly distributed. As this checklist represents a useful baseline for advances in this field, we point out specific areas of interest for future research.

Model uncertainties do not affect observed patterns of species richness in the Amazon.

BackgroundClimate change is arguably a major threat to biodiversity conservation and there are several methods to assess its impacts on species potential distribution. Yet the extent to which different approaches on species distribution modeling affect species richness patterns at biogeographical scale is however unaddressed in literature. In this paper, we verified if the expected responses to climate change in biogeographical scale—patterns of species richness and species vulnerability to climate change—are affected by the inputs used to model and project species distribution.MethodsWe modeled the distribution of 288 vertebrate species (amphibians, birds and mammals), all endemic to the Amazon basin, using different combinations of the following inputs known to affect the outcome of species distribution models (SDMs): 1) biological data type, 2) modeling methods, 3) greenhouse gas emission scenarios and 4) climate forecasts. We calculated uncertainty with a hierarchical ANOVA in which those different inputs were considered factors.ResultsThe greatest source of variation was the modeling method. Model performance interacted with data type and modeling method. Absolute values of variation on suitable climate area were not equal among predictions, but some biological patterns were still consistent. All models predicted losses on the area that is climatically suitable for species, especially for amphibians and primates. All models also indicated a current East-western gradient on endemic species richness, from the Andes foot downstream the Amazon river. Again, all models predicted future movements of species upwards the Andes mountains and overall species richness losses.ConclusionsFrom a methodological perspective, our work highlights that SDMs are a useful tool for assessing impacts of climate change on biodiversity. Uncertainty exists but biological patterns are still evident at large spatial scales. As modeling methods are the greatest source of variation, choosing the appropriate statistics according to the study objective is also essential for estimating the impacts of climate change on species distribution. Yet from a conservation perspective, we show that Amazon endemic fauna is potentially vulnerable to climate change, due to expected reductions on suitable climate area. Climate-driven faunal movements are predicted towards the Andes mountains, which might work as climate refugia for migrating species.

Global Hotspots of Conflict Risk between Food Security and Biodiversity Conservation

The global challenges of food security and biodiversity are rarely addressed together, though recently there has been an increasing awareness that the two issues are closely related. The majority of land available for agriculture is already used for food production, but despite the productivity gains, one in nine people worldwide are classified as food insecure. There is an increasing risk that addressing food insecurity through methods such as agricultural expansion or intensification could lead to biodiversity loss through destruction of habitats important for conservation. This analysis uses various indicators of biodiversity at a global scale, including biodiversity hotspots, total species richness, and threatened and endemic species richness. Areas where high biodiversity coexists with high food insecurity or a high risk of agricultural expansion, were examined and found to mainly occur in the tropics, with Madagascar standing out in particular. The areas identified are especially at risk of biodiversity loss, and so are global priorities for further research and for policy development to address food insecurity and biodiversity loss together.

Evaluating Hypotheses of Plant Species Invasions on Mediterranean Islands: Inverse Patterns between Alien and Endemic Species

Invasive alien species cause major changes to ecosystem functioning and patterns of biodiversity, and the main factors involved in invasion success remain contested. Using the Mediterranean island of Crete as a case study, we present a framework for analyzing spatial data of alien species distributions, based on environmental predictors, aiming to gain an understanding of their spatial patterns and spread. Mediterranean islands are under strong ecological pressure from invading species due to their restricted size and increased human impact. Four hypotheses of invasibility, the ‘propagule pressure hypothesis’ (H1), ‘biotic resistance hypothesis vs. acceptance hypothesis’ (H2), ‘disturbance-mediated hypothesis’ (H3), and ‘environmental heterogeneity hypothesis’ (H4) were tested. Using data from alien, native, and endemic vascular plant species, the propagule pressure, biotic resistance versus acceptance, disturbance-mediated, and environmental heterogeneity hypotheses were tested with Generalized Additive Modelling (GAM) of 39 models. Based on model selection, the optimal model includes the positive covariates of native species richness, the negative covariates of endemic species richness, and land area. Variance partitioning between the four hypotheses indicated that the biotic resistance versus acceptance hypothesis explained the vast majority of the total variance. These results show that areas of high species richness have greater invasibility and support the acceptance hypothesis and “rich-get-richer” distribution of alien species. The negative correlation between alien and endemic species appears to be predominantly driven by altitude, with fewer alien and more endemic species at greater altitudes, and habitat richness. The negative relationship between alien and endemic species richness provides potential for understanding patterns of endemic and alien species on islands, contributing to more effective conservation strategies.

Spatial Downscaling of Alien Species Presences Using Machine Learning

Large scale, high-resolution data on alien species distributions are essential for spatially explicit assessments of their environmental and socio-economic impacts, and management interventions for mitigation. However, these data are often unavailable. This paper presents a method that relies on Random Forest (RF) models to distribute alien species presence counts at a finer resolution grid, thus achieving spatial downscaling. A sufficiently large number of RF models are trained using random subsets of the dataset as predictors, in a bootstrapping approach to account for the uncertainty introduced by the subset selection. The method is tested with an approximately 8×8 km2 grid containing floral alien species presence and several indices of climatic, habitat, land use covariates for the Mediterranean island of Crete, Greece. Alien species presence is aggregated at 16×16 km2 and used as a predictor of presence at the original resolution, thus simulating spatial downscaling. Potential explanatory variables included habitat types, land cover richness, endemic species richness, soil type, temperature, precipitation, and freshwater availability. Uncertainty assessment of the spatial downscaling of alien species’ occurrences was also performed and true/false presences and absences were quantified. The approach is promising for downscaling alien species datasets of larger spatial scale but coarse resolution, where the underlying environmental information is available at a finer resolution than the alien species data. Furthermore, the RF architecture allows for tuning towards operationally optimal sensitivity and specificity, thus providing a decision support tool for designing a resource efficient alien species census.

Floristic and ecological attributes of a Seasonal Semideciduous Atlantic Forest in a key area for conservation of the Zona da Mata region of Minas Gerais State, Brazil

ABSTRACT We evaluated the floristic and ecological attributes of a seasonal semideciduous forest remnant (SSF) (500-1,050 m) located in a key area for biodiversity conservation. The importance of the fragment to the ecosystem conservation was revealed by its species richness (253), diversity (Shannon index = 4.6; Simpson's complementary index = 0.98) and evenness (Pielou index = 0.83), which are considered high values for a SSF. Zoochory occurred in 77% of the species, indicating the existence of important biotic interactions that ensure the occurrence of gene flow. We recorded 14 endangered species, among which two are rare (Trigynaea oblongifolia and Trattinnickia ferruginea) and two are indicators of mature forests (Trattinnickia ferruginea and Virola bicuhyba). We confirmed the importance of key areas for biodiversity conservation and of the Atlantic SSF located at the 0-1,000 m altitudinal range. These areas deserve attention from conservationists due to the high species richness and high number of endemic and endangered species.

Patterns of the Diversity of Characteristic Species Across Vegetation Ecosystems of Ethiopia

Understanding plant species distribution across ecosystems is fundamental for designing conservation mechanisms at different ecological scales. Here, the aim of this study is to examine the pattern of plant species richness, unique/restricted, endemic and threatened species across eleven vegetation ecosystems of Ethiopia. The species data were compiled from the atlas of the potential vegetation of Ethiopia that describes the plant species by ecosystems and elevational gradients. Moreover, the data on threatened species was collated from the Red List Endemic Trees and Shrubs of Ethiopia and Eritrea. The comparative patterns of these different characteristic species were analyzed using descriptive statistics. Moreover, the relationship between the ecosystem characteristic species richness vs. species unique to each ecosystems; ecosystem characteristic species richness vs. species common to ecosystems; ecosystem characteristic species richness vs. species unique to each ecosystems and species unique to each ecosystems vs. endemic species richness across ecosystems was tested with Pearson’s correlation using R statistical program. The results showed that the Acacia-Commiphora woodland bushland ecosystem is comprised of the higher number of species (i.e., 37% of the total ecosystem characteristic species), while in contrast, the Afroalpine belt and Wooded grassland of the western Gambela region ecosystems had lower species richness (i.e., 1.4–1.5%) when compared with the other ecosystems. Dry evergreen Afromontane forest and grassland complex ecosystem is composed of the higher number of species that are common to the majority of other ecosystems, but Desert and semi-desert scrubland does not have any species which are common to other ecosystems. The number of ecosystem characteristic species, endemic and threatened species are higher in Acacia-Commiphora woodland bushland ecosystems and the majority are found in Euphorbiaceae and Fabaceae families. Moreover, the ecosystem characteristic species richness in general and of endemic in particular took hump-shaped pattern where the number of species was higher at “mid altitude”. These different patterns may indicate that conserving the whole system only at mega scale may not necessarily mean that the rare/unique, endemic and threatened species are conserved. Therefore, the overall results emphasize the importance of understanding the ecological processes in each ecosystem and the corresponding species specific properties to plan and design conservation system following either ecosystem approach or multiple spatial scales.

Spatial patterns of the Iberian and Balearic endemic vascular flora

The Iberian flora has a high degree of originality (1328 endemic species, 24% of endemism), comparable to other regions in the Mediterranean Basin. The richness of Iberian endemic species is unevenly distributed; the greatest diversity is found in the main mountain ranges although the southwestern Atlantic coast and specially the Balearic Islands are rich in range-restricted endemic species. The largest number of endemic genera is found in the northwestern mountains, which might have acted as a refugium area. The Baetic System, which includes nearly half (46%) of the total Iberian endemic species, is by far the richest region of the territory. Its endemic flora is characterized by the great richness of narrow endemics and the high species turnover rate. The k-means partitioning analysis enables us to identify 11 units, generally well defined by the natural geographic features. The clusters including the northwestern mountains, the Cantabrian Mountains, the southwestern coast and especially the Balearic Islands, the Pyrenees and the Baetic System are compact and consist of a high proportion of diagnostic species, and can therefore be considered areas of endemism on a large scale. The regionalization reflects a primary longitudinal division of Iberia between a basic eastern and an acidic western region, but also partly reveals a climatic division between Eurosiberian and Mediterranean regions. Southeastern Iberia seems to be an important center of differentiation for several typically Mediterranean genera (e.g. Centaurea, Linaria, Armeria, Teucrium and Thymus), but other large genera are also highly diversified.

The general dynamic model of island biogeography revisited at the level of major flowering plant families

AbstractAimThe general dynamic model (GDM) proposed by Whittaker et al. () has become a widely accepted theoretical framework in island biogeography. In this study, we explore whether GDM predictions hold when overall plant diversity is deconstructed into major plant families.Location101 islands from 14 oceanic archipelagos world‐wide.MethodsOccurrence data for all species of nine large, cosmopolitan flowering plant families were used to test predictions derived from the GDM. We analysed the effects of island area and age on species richness as well as number and percentage of single‐island endemic species per family using mixed‐effect models.ResultsTotal species and endemic richness as well as the percentage of endemic species showed the predicted hump‐shaped relationship with island age. The overall pattern was mainly driven by few species‐rich plant families. Varying patterns were found for individual families, some of them opposing the general trend. In most cases, native and endemic species richness peaked much earlier in the island life cycle than suggested by the GDM. The contribution of area to the explained variation of all dependent variables was much higher than that of island age.Main conclusionsThe results suggest that biodiversity‐age relationships reported for large taxonomic groups like plants are driven by only a few species‐rich clades. The way these families influence the overall patterns of species richness and endemism is related to family‐specific properties, such as evolutionary history or dispersal strategies. Deviances from the GDM predictions can hence largely be explained by family characteristics and considering taxon‐specific traits may help to further improve the explanatory power of the GDM. Families not following the expectations, like Orchidaceae, may be particularly valuable candidates to unveil so far neglected drivers of island biogeographical patterns.

Description of a new species of Thevenetimyia (Diptera: Bombyliidae)from Madagascar, with a revised checklist of Madagascan bee fly fauna.

Madagascar is an island known for its richness of endemic species, including flies. Only eight genera of bee flies (Bombyliidae), including 17 described species (the majority of which are in the subfamily Anthracinae), are known from Madagascar. Here we describe a new species of Bombyliidae from Madagascar, Thevenetimyia spinosavus Maass & Bertone sp. nov. This fly represents the first record of the genus Thevenetimyia from Madagascar and the second species recorded in the Afrotropical Region. A revised checklist of Bombyliidae in Madagascar is provided, along with an appendix of associated literature. The known bee fly species likely represent only a fraction of the true diversity on the island, which has been relatively well sampled through extensive Malaise trapping of flies in Madagascar over the past decade.

Testing the Efficacy of Global Biodiversity Hotspots for Insect Conservation: The Case of South African Katydids

The use of endemism and vascular plants only for biodiversity hotspot delineation has long been contested. Few studies have focused on the efficacy of global biodiversity hotspots for the conservation of insects, an important, abundant, and often ignored component of biodiversity. We aimed to test five alternative diversity measures for hotspot delineation and examine the efficacy of biodiversity hotspots for conserving a non-typical target organism, South African katydids. Using a 1° fishnet grid, we delineated katydid hotspots in two ways: (1) count-based: grid cells in the top 10% of total, endemic, threatened and/or sensitive species richness; vs. (2) score-based: grid cells with a mean value in the top 10% on a scoring system which scored each species on the basis of its IUCN Red List threat status, distribution, mobility and trophic level. We then compared katydid hotspots with each other and with recognized biodiversity hotspots. Grid cells within biodiversity hotspots had significantly higher count-based and score-based diversity than non-hotspot grid cells. There was a significant association between the three types of hotspots. Of the count-based measures, endemic species richness was the best surrogate for the others. However, the score-based measure out-performed all count-based diversity measures. Species richness was the least successful surrogate of all. The strong performance of the score-based method for hotspot prediction emphasizes the importance of including species’ natural history information for conservation decision-making, and is easily adaptable to other organisms. Furthermore, these results add empirical support for the efficacy of biodiversity hotspots in conserving non-target organisms.

Climatic and topographical correlates of plant palaeo- and neoendemism in a Mediterranean biodiversity hotspot.

Understanding the evolutionary and ecological forces contributing to the emergence of biodiversity hotspots is of outstanding importance to elucidate how they may withstand current climate changes. Here we explored patterns of phylogenetic and non-phylogenetic plant endemism in a Mediterranean biodiversity hotspot. We hypothesized that areas with wet and equable climatic conditions would be prone to long-term persistence of endemic lineages (palaeoendemism), whilst areas of recent local speciation (neoendemism) would be more related to harsher environmental conditions and to high topographical relief promoting speciation. We focused on the Baetic-Rifan biodiversity hotspot (southern Iberian Peninsula and northern Morocco) in combination with molecular phylogenetic information and relative phylogenetic endemism (RPE), a recent phylogenetic measure of endemism, allowing us to discern centres of palaeo- from those of neoendemism. Using eco-geographical regions as study units, we explored correlations between both RPE and endemic species richness with precipitation- and temperature-related variables and with elevation range. Centres of neoendemism were concentrated towards the easternmost part of the hotspot, while centres of palaeoendemism were clustered in the vicinity of the Strait of Gibraltar. The RPE index, indicating more palaeoendemism, was positively correlated with total annual precipitation, while endemic species richness showed a poor correlation. In contrast, elevation range and mean annual temperature were poor predictors of RPE, despite elevation range showing a strong correlation with endemic species richness. The Baetic-Rifan biodiversity hotspot shows clearly differentiated centres of neo- and palaeoendemism. Topographical relief may have driven evolutionary diversification of newly evolved species, while water availability seems more critical for the long-term persistence of ancient lineages in refuge areas of smoother topography. Given climatic trends towards increasing aridification, conservation planners should pay particular attention to preserve areas retaining older phylogenetic lineages, as these areas act as 'natural museums' of biodiversity within the Baetic-Rifan biodiversity hotspot.

English

Tropical Afromontane forests are among the most species-rich ecosystems on earth and comprise exceptional species richness and high concentrations of endemic species. The natural forest of Agama, an Afromontane forest, was studied with the objectives of determining its species composition, diversity and community types. Systematic sampling design was used to collect vegetation data. Soil samples were taken from each releve at a depth of 0 to 30 cm and soil pH, sand, clay and silt were analyzed. The plant communities’ classification was performed using the hierarchical cluster analysis. We evaluated species richness, eveness (Pielou J’ index) and diversity (Shanon-Wiener index). Sorensens’s similarity ratio was used to compare Agama forest with other similar forest in Ethiopia. A total of 162 plant species, 130 genera and 70 families were recorded from which Acanthaceae and Rubiaceae were the richest families. Furthermore nine endemic plant species were identified. In this study, four plant community types were identified and described. Post-hoc comparison of means among the community types showed that altitude was differed significantly between community types, indicating altitude is the most important factor in determining community type. Phytogeographical comparison of Agama Forest with other vegetation using Sorensens’s similarity ratio revealed the highest similarity with Masha and Godre forest. In conclusion Agama forest presents high richness, diversity and endemism, with different plant communities according to altitude. Thus conservation of plant biodiversity is highly recommended. Key words: Diversity, altitude, phytogeography, richness, endemism.

Diversity hotspots and conservation gaps for the Chinese endemic seed flora

The flora in China is highly endemic. Decisions about conservation and management of biodiversity based on hotspots and conservation gaps of endemic seed plant species diversity in China are essential. In this paper, based on a species distribution data set with 12,824 Chinese endemic plants, we measured Chinese endemic seed plant diversity using five indices: endemic species richness (ER), weighted endemism (WE), phylogenetic diversity (PD), phylogenetic endemism (PE), and biogeographically weighted evolutionary distinctiveness (BED). Five percent of China's total land area with the highest biodiversity was used to identify hotspots for each index. In total, 19 hotspots covering 7.96% of China's total land area were identified. Most hotspots are located in mountainous areas, mainly in the Qinling Mountains and further south or in the Hengduan Mountains and to the east in China. Nine hotspots are identified with all five indices. These hotspots include the Hengduan Mountains, the Xishuangbanna Region, the Qinling Mountains, southwest Chongqing, and five mountainous areas (located in east Chongqing and west Hubei; in east Yunnan and west Guangxi; in north Guangxi, southeast Guizhou and southwest Hunan; in north Guangdong and south Hunan; and in southeast Tibet, respectively). Furthermore, we detected conservation gaps for hotspots of Chinese endemic seed flora by overlaying national nature reserves with the identified hotspots, and we designated priority conservation gaps for hotspots by overlaying global biodiversity hotspots with conservation gaps for hotspots. Most hotspots for Chinese endemic seed plant species are badly protected. Only 26.48% of the hotspot areas of Chinese endemic seed plant species were covered by nature reserves. We suggest that it is essential to pay more attention to herbaceous plants in biodiversity conservation, and to promote a network function of nature reserves within these hotspots in China.

Global analyses underrate part of the story: finding applicable results for the conservation planning of small Sardinian islets’ flora

Although many studies have addressed island biogeography, the biodiversity of very small islets has mostly been ignored due to the lack of high-resolution data. We analysed the vascular plant taxa distribution pattern of 81 satellite islets scattered around Sardinia, the second largest island in the Mediterranean Basin. Power models were used to determine the influence of environmental and anthropogenic factors on both endemic and non-endemic species richness. Analyses of the distribution pattern highlighted the high endemism rate in these islets. In addition, reliable results for conservation, such as correlations with land use diversity, climate and human presence, were found only when categorising the islets by their environmental characteristics instead of their geographical position. This study of a representative set of Mediterranean islets contributes to the knowledge base about the controversial role of very small islets in biological conservation. Large-scale analyses have often underrated their importance and we therefore suggest that local studies about their conservation planning are needed worldwide.

Trade-offs between savanna woody plant diversity and carbon storage in the Brazilian Cerrado.

Incentivizing carbon storage can be a win-win pathway to conserving biodiversity and mitigating climate change. In savannas, however, the situation is more complex. Promoting carbon storage through woody encroachment may reduce plant diversity of savanna endemics, even as the diversity of encroaching forest species increases. This trade-off has important implications for the management of biodiversity and carbon in savanna habitats, but has rarely been evaluated empirically. We quantified the nature of carbon-diversity relationships in the Brazilian Cerrado by analyzing how woody plant species richness changed with carbon storage in 206 sites across the 2.2million km(2) region at two spatial scales. We show that total woody plant species diversity increases with carbon storage, as expected, but that the richness of endemic savanna woody plant species declines with carbon storage both at the local scale, as woody biomass accumulates within plots, and at the landscape scale, as forest replaces savanna. The sharpest trade-offs between carbon storage and savanna diversity occurred at the early stages of carbon accumulation at the local scale but the final stages of forest encroachment at the landscape scale. Furthermore, the loss of savanna species quickens in the final stages of forest encroachment, and beyond a point, savanna species losses outpace forest species gains with increasing carbon accumulation. Our results suggest that although woody encroachment in savanna ecosystems may provide substantial carbon benefits, it comes at the rapidly accruing cost of woody plant species adapted to the open savanna environment. Moreover, the dependence of carbon-diversity trade-offs on the amount of savanna area remaining requires land managers to carefully consider local conditions. Widespread woody encroachment in both Australian and African savannas and grasslands may present similar threats to biodiversity.

Explaining patterns of avian diversity and endemicity: climate and biomes of southern Africa over the last 140,000 years

AbstractAimTest hypotheses that present biodiversity and endemic species richness are related to climatic stability and/or biome persistence.LocationAfrica south of 15° S.MethodsSeventy eight HadCM3 general circulation model palaeoclimate experiments spanning the last 140,000 years, plus a pre‐industrial experiment, were used to calculate measures of climatic variability for 0.5° grid cells. Models were fitted relating distributions of the nine biomes of South Africa, Lesotho and Swaziland to present climate. These models were used to simulate potential past biome distribution and extent for the 78 palaeoclimate experiments, and three measures of biome persistence. Climatic response surfaces were fitted for 690 bird species regularly breeding in the region and used to simulate present species richness for cells of the 0.5° grid. Species richness was evaluated for residents, mobile species (nomadic or partially/altitudinally migrant within the region), and intra‐African migrants, and also separately for endemic/near‐endemic (hereafter ‘endemic’) species as a whole and those associated with each biome. Our hypotheses were tested by analysing correlations between species richness and climatic variability or biome persistence.ResultsThe magnitude of climatic variability showed clear spatial patterns. Marked changes in biome distributions and extents were projected, although limited areas of persistence were projected for some biomes. Overall species richness was not correlated with climatic variability, although richness of mobile species showed a weak negative correlation. Endemic species richness was significantly negatively correlated with climatic variability. Strongest correlations, however, were positive correlations between biome persistence and richness of endemics associated with individual biomes.Main conclusionsLow climatic variability, and especially a degree of stability enabling biome persistence, is strongly correlated with species richness of birds endemic to southern Africa. This probably principally reflects reduced extinction risk for these species where the biome to which they are adapted persisted.