Narrow-range Species Research Articles

Global evaluation of current and future threats to drylands and their vertebrate biodiversity.

Drylands are often overlooked in broad conservation frameworks and development priorities and face increasing threats from human activities. Here we evaluated the formal degree of protection of global drylands, their land vertebrate biodiversity and current threats, and projected human-induced land-use changes to drylands under different future climate change and socioeconomic scenarios. Overall, drylands have lower protected-area coverage (12%) compared to non-drylands (21%). Consequently, most dryland vertebrates including many endemic and narrow-ranging species are inadequately protected (0-2% range coverage). Dryland vertebrates are threatened by varied anthropogenic factors-including agricultural and infrastructure development (that is, artificial structures, surfaces, roads and industrial sites). Alarmingly, by 2100 drylands are projected to experience some degree of land conversion in 95-100% of their current natural habitat due to urban, agricultural and alternative energy expansion. This loss of undisturbed dryland regions is expected across different socioeconomic pathways, even under optimistic scenarios characterized by progressive climate policies and moderate socioeconomic trends.

Reproductive biology of Santolina ligustica Arrigoni, a rare narrow-ranged species: implications for conservation

Abstract Santolina ligustica is a rare narrow-ranged species endemic to Liguria (Italy) for which a likely trend of decline has been recorded. For this reason, it would be important to assess the reproductive biology of this endemic species. In this study, we investigated the plant–pollinator interactions, the reproductive mode of the plant, and we evaluated both reproductive efficiency and seeds’ germination performances. Santolina ligustica is an obligate cross-pollinating species with a generalist pollination system. The most frequent insects are Coleoptera belonging to the genus Oedemera. Seed set is low, but the seeds germinate under a wide range of temperatures. Taken together, our results indicate that S. ligustica is an insect pollinated and self-incompatible plant, in which low visitation rate, secondary pollen presentation and/or lack of compatible mate may cause a low seed set per capitulum. Nevertheless, the high number of capitula per plant and the high percentage of germination may assure high number of seedlings. Thus, the survival of S. ligustica is probably threatened by other factors such as fragmented distribution and habitat reduction because of land-use change. Under this scenario, we proved that species’ decline is not directly related to reproductive failure and different studies are desirable to provide suggestions for the species conservation.

Global richness patterns of alpine genus Gentiana depend on multiple factors.

Environmental factors impact species richness differently across taxonomic groups, and understanding the geographic patterns and drivers influencing alpine plant richness remains limited. This study compiled global distribution data of 404 species of Gentiana, an alpine genus, and analyzed the relative effects of different environmental factors and several previously proposed models on the variation of Gentiana richness. By evaluating the effects of range size and regions on the relationships between Gentiana richness and environmental factors, we found that all tested environmental factors had weak effects on richness variation for all species and wide-ranging species, while habitat heterogeneity was the best predictor for narrow-ranging species. Habitat heterogeneity was the main driver of richness variation in Europe and Asia, but not in North America. The multiple regression model that included variables for energy, water, seasonality, habitat heterogeneity and past climate change had the highest explanatory power, but it still explained less than 50% of the variation in species richness for all Gentiana species at both global and regional scale, except for Europe. The limited explanatory power of environmental factors in explaining species richness patterns for all species, along with the variations observed among regions, suggest that other factors, such as evolutionary processes and biogeographic history may have also influenced the geographic patterns of Gentiana species richness. In conclusion, our results indicate a limited influence of climate factors on alpine species richness, while habitat heterogeneity, along with its impacts on speciation and dispersal, likely play significant roles in shaping the richness of alpine Gentiana species.

Associations between Epiphytic Orchids and Their Hosts and Future Perspectives of These in the Context of Global Warming

Epiphytic species are ecologically important and a significant component of biodiversity. To ensure their efficient conservation, we need to understand their ecology and host plant associations. It is also important to investigate how the predicted temperature change will affect their future distribution. Here, we use data collected in Nepal to investigate how epiphytic orchids are associated with host species, their distribution patterns, and how they may be threatened by the predicted increase in temperature towards the end of the 21st century. We used the phi coefficient (Φ) of association to calculate the associations of epiphytic orchid species with plants and rarefaction to describe the diversity of orchids associated with a particular host species. We used interpolation to estimate the distribution of epiphytic orchids and their host species along altitudinal gradients. The phi (Φ) coefficient of association revealed that 30 species of host plants showed more association with different orchid species than expected. The number of epiphytic orchids increased with the number of host individuals. We predict that an increase in temperature by ~3 °C, which is a more moderate value of temperature increase by the end of the 21st century, will affect at least 52 narrow-ranged species of orchids and 58 narrow-ranged species of host plants. Therefore, we should make efforts to prevent many plant species from becoming extinct, as an increase in temperature is likely to affect their existence.

More losses than gains? Distribution models predict species-specific shifts in climatic suitability for European beech forest herbs under climate change

IntroductionHerbaceous plant species constitute an essential element of the flora of European beech (Fagus sylvatica) forests. There is increasing evidence that rapidly changing climate is likely to modify the spatial distribution of plant species. However, we lack understanding of the impact that climate change might have on beech forest herbs across the European continent. We investigated the possible effects of predicted increasing rates of global warming and altered precipitation regimes on 71 forest herbs closely associated with beech forests, but with varying biogeographic and climatic niche attributes.MethodsBy using a total of 394,502 occurrence records and an ensemble of species distribution models (SDMs), we quantified the potential current distribution and future (2061-2080) range shifts in climatic suitability (expressed as occurrence probability, OP) according to two climate change scenarios (moderate SSP2-4.5 and severe SSP5-8.5).ResultsOverall, precipitation of the warmest quarter and temperature seasonality were the most influential predictors in shaping current distribution patterns. For SSP5-8.5 scenario, all studied species experienced significant reductions (52.9% on average) in the total size of highly suitable areas (OP >0.75). However, the magnitude and directions of changes in the climatic suitability were highly species-specific; few species might even increase OP in the future, particularly in case of SSP2-4.5 scenario. The SDMs revealed the most substantial decline of climatic suitability at the trailing edges in southern Europe. We found that climatic suitability is predicted to show unidirectional northward shift and to move toward higher elevations. The gain/loss ratio was generally higher for narrow-ranged species compared to widespread taxa.DiscussionOur findings are contextualized with regards to potential confounding factors (dispersal limitation, microclimatic buffering) that may mitigate or accelerate climate change impacts. Given the low long-distance migration ability, many beech forest herbs are unlikely to track the velocity with which macroclimatic isotherms are moving toward higher latitudes, making this species group particularly vulnerable to climate change.

Environmental determinants of aquatic plant diversity differ between growth forms and range sizes

Aquatic plants are fundamental for aquatic ecosystems. Understanding variations in geographic patterns of aquatic plant diversity across growth forms is important for conservation and restoration of aquatic ecosystems. Environmental drivers, including climate, climate heterogeneity, water chemistry, habitat availability and geodiversity, could influence aquatic plant diversity and species composition across communities, yet their relative impacts remain controversial. Here, we examined geographic patterns and drivers of species richness of Chinese aquatic plants with different growth forms. We compiled distributions of 656 aquatic plant species in China at 50 × 50 km2 resolutions, and estimated richness patterns for species with different growth forms (i.e., helophyte, emergent, floating-leaved, free-drifting and submerged) and range sizes. Hierarchical partitioning analysis was employed to evaluate the independent effects of different environmental drivers on species richness. The Sørensen dissimilarity index and Multiple Matrix Regression with Randomization were used to compare the relative effects of environment and dispersal limitation on species dissimilarity between grid cells. Overall species richness was highest in northeastern and southern China, although species richness patterns varied across growth forms. Among environmental drivers examined, climate was the key determinant of the species richness of helophyte, emergent, floating-leaved and free-drifting plants, while habitat availability and water chemistry best explained the richness of submerged species. The richness of narrow-ranged species was dominated by climate, while the strongest determinant of wide-ranged species richness varied across growth forms. Our study mapped the species richness patterns of aquatic plants in China and indicated that the relationship between aquatic plant richness and environment significantly differed between growth forms and between wide-ranged and narrow-ranged species. These findings indicate the necessity of distinguishing growth forms in studies related to aquatic plants, and suggest that future climate change might threaten the distribution of narrow-ranged aquatic plants.

Ancient allopatry and ecological divergence act together to promote plant diversity in mountainous regions: evidence from comparative phylogeography of two genera in the Sino-Himalayan region

BackgroundHow geographical isolation and ecological divergence act together to promote plant diversity in mountainous regions remains largely unknown. In this study, we chose two genera comprising a small number of species distributed in the Sino-Himalayan region, Megacodon (Gentianaceae) and Beesia (Ranunculaceae), which both exhibit a fragmented distribution pattern and are found across a wide range of elevations. By summarizing their common patterns of speciation and/or divergence processes, we aim to understand how environmental changes accelerated lineage diversification in the Sino-Himalayan region through ancient allopatry and ecological divergence.ResultsUsing ddRAD-seq, chloroplast genome sequences, and specific molecular markers, we studied the phylogenetic relationships, population structure, and historical biogeography of Beesia and Megacodon. Both genera began to diverge from the late Miocene onwards, with ancient allopatry at lower elevations formed narrow-range species or relict populations. Mantel tests between genetic distance and climatic, elevational, or geographic distance revealed an isolation-by-distance pattern in Beesia and Megacodon stylophorus. Megacodon showed two clades occupying entirely different altitudinal ranges, whereas Beesia calthifolia exhibited a genetic divergence pattern along an elevation gradient. Furthermore, we conducted morphological measurements on Beesia calthifolia and found that different elevational groups had distinct leaf shapes.ConclusionsThe regional disjunctions of plant groups in the Sino-Himalayan region are drastic and closely related to several biogeographic boundaries. As a consequence of major geological and climate change, ecological divergence when different elevations are colonized often happens simultaneously within plant groups. Although habitat fragmentation and parapatric ecological divergence each spur speciation to different extents, a combined effect of these two factors is a common phenomenon in the Sino-Himalayan region.

Contrasting range changes of terrestrial orchids under future climate change in China

Climate change has impacted the distribution and abundance of numerous plant and animal species during the last century. Orchidaceae is one of the largest yet most threatened families of flowering plants. However, how the geographical distribution of orchids will respond to climate change is largely unknown. Habenaria and Calanthe are among the largest terrestrial orchid genera in China and around the world. In this paper, we modeled the potential distribution of eight Habenaria species and ten Calanthe species in China under the near-current period (1970–2000) and the future period (2081–2100) to test the following two hypotheses: 1) narrow-ranged species are more vulnerable to climate change than wide-ranged species; 2) niche overlap between species is positively correlated with their phylogenetic relatedness. Our results showed that most Habenaria species will expand their ranges, although the climatic space at the southern edge will be lost for most Habenaria species. In contrast, most Calanthe species will shrink their ranges dramatically. Contrasting range changes between Habenaria and Calanthe species may be explained by their differences in climate-adaptive traits such as underground storage organs and evergreen/deciduous habits. Habenaria species are predicted to generally shift northwards and to higher elevations in the future, while Calanthe species are predicted to shift westwards and to higher elevations. The mean niche overlap among Calanthe species was higher than that of Habenaria species. No significant relationship between niche overlap and phylogenetic distance was detected for both Habenaria and Calanthe species. Species range changes in the future was also not correlated with their near current range sizes for both Habenaria and Calanthe. The results of this study suggest that the current conservation status of both Habenaria and Calanthe species should be adjusted. Our study highlights the importance of considering climate-adaptive traits in understanding the responses of orchid taxa to future climate change.

Drought, fire, and rainforest endemics: A case study of two threatened frogs impacted by Australia's "Black Summer".

Deepening droughts and unprecedented wildfires are at the leading edge of climate change. Such events pose an emerging threat to species maladapted to these perturbations, with the potential for steeper declines than may be inferred from the gradual erosion of their climatic niche. This study focused on two species of amphibians-Philoria kundagungan and Philoria richmondensis (Limnodynastidae)-from the Gondwanan rainforests of eastern Australia that were extensively affected by the "Black Summer" megafires of 2019/2020 and the severe drought associated with them. We sought to assess the impact of these perturbations by quantifying the extent of habitat affected by fire, assessing patterns of occurrence and abundance of calling males post-fire, and comparing post-fire occurrence and abundance with that observed pre-fire. Some 30% of potentially suitable habitat for P. kundagungan was fire affected, and 12% for P. richmondensis. Field surveys revealed persistence in some burnt rainforest; however, both species were detected at a higher proportion of unburnt sites. There was a clear negative effect of fire on the probability of site occupancy, abundance and the probability of persistence for P. kundagungan. For P. richmondensis, effects of fire were less evident due to the limited penetration of fire into core habitat; however, occupancy rates and abundance of calling males were depressed during the severe drought that prevailed just prior to the fires, with the reappearance of calling males linked to the degree of rehydration of breeding habitat post-fire. Our results highlight the possibility that severe negative impacts of climate change for montane rainforest endemics may be felt much sooner than commonly anticipated under a scenario of gradual (decadal-scale) changes in mean climatic conditions. Instead, the increased rate of severe stochastic events places these narrow range species at a heightened risk of extinction in the near-term.

Distribution and conservation of near threatened plants in China

Plants classified as Near Threatened (NT) are at high risk of becoming threatened because of anthropogenic interference and climate change. Especially in conservation efforts, such species have however long been overlooked. Here, we obtained 98,419 precise occurrence points for 2442 NT plants in China, and used species richness, species complementarity, and weighted endemism that consider all, endemic and narrow-ranged species in order to identify the diversity hotspots of NT plants. Then we evaluated the conservation effectiveness of current nature reserves for them. Our results indicate that the diversity hotspots of NT plants were mainly confined to southwestern and southern China, and only 35.87% of hotspots and 71.5% of species were protected by nature reserves. Numerous hotspots in southwestern China (e.g., Sichuan, Yunnan, Guangxi, and Hainan) were identified as conservation gaps. Given that NT plants include large proportions of endemic and narrow-ranged species, they represent an important value in conservation priority. So, more conservation efforts in the future should be tilted towards NT plants. Additionally, when comparing with the recently updated NT list, there are already 87 species raised to threatened categories, while 328 species were lowered to least concern, 56 species were now categorized as data deficient, and 119 species considered as uncertain due to changes of scientific names. It is essential to carry out a continuous assessment of species' threatened categories to realize targeting conservation.

New insights into the geographic patterns of functional role and taxonomic richness of ants from Mexico

One approach to prioritise conservation efforts is to identify hotspots that are either species-rich or that harbour a high proportion of narrow-ranged species with varying functional roles. Given this, we have developed full ant species distribution models as tools for identifying biodiversity and hotspot areas in Mexico. We predicted ant species richness and potential areas of endemism using the more complete data available from across America (i.e., including both North America and South America) and habitat/ecological specificity (functional diversity) in a species distribution model (SDM). In Mexico, the ecoregions more relevant for ant species richness and endemism are Mesoamerica, Petenes, Sierra Madre Oriental, Trans-Mexican Volcanic, and the Sierra Madre Occidental. While for hypogeic and arboreal ants the hotspots were localized in the tropic biomes, for epigeic and subterranean ants, hotpots were most prevalent in the tropics and desert. Moreover, the geographical patterns suggest that some hotspots for ants converge with those hotspots proposed for other invertebrates and vertebrates.Implications for insect conservationOur study highlights the importance of hotspots areas for biodiversity conservation, and provides data and maps for ant conservation programs.

Comparative genomics of widespread and narrow-range white-bellied rats in the Niviventer niviventer species complex sheds light on invasive rodent success.

Widespread species that inhabit diverse environments possess large population sizes and exhibit a high capacity for environmental adaptation, thus enabling range expansion. In contrast, narrow-range species are confined to restricted geographical areas and are ecologically adapted to narrow environmental conditions, thus limiting their ability to expand into novel environments. However, the genomic mechanisms underlying the differentiation between closely related species with varying distribution ranges remain poorly understood. The Niviventer niviventer species complex (NNSC), consisting of highly abundant wild rats in Southeast Asia and China, offers an excellent opportunity to investigate these questions due to the presence of both widespread and narrow-range species that are phylogenetically closely related. In the present study, we combined ecological niche modeling with phylogenetic analysis, which suggested that sister species cannot be both widespread and dominant within the same geographical region. Moreover, by assessing heterozygosity, linkage disequilibrium decay, and Tajima's D analysis, we found that widespread species exhibited higher genetic diversity than narrow-range species. In addition, by exploring the "genomic islands of speciation", we identified 13 genes in highly divergent regions that were shared by the two widespread species, distinguishing them from their narrow-range counterparts. Functional annotation analysis indicated that these genes are involved in nervous system development and regulation. The adaptive evolution of these genes likely played an important role in the speciation of these widespread species.

Urbanization affects spatial variation and species similarity of bird diversity distribution

Although cities are human-dominated systems, they provide habitat for many other species. Because of the lack of long-term observation data, it is challenging to assess the impacts of rapid urbanization on biodiversity in Global South countries. Using multisource data, we provided the first analysis of the impacts of urbanization on bird distribution at the continental scale and found that the distributional hot spots of threatened birds overlapped greatly with urbanized areas, with only 3.90% of the threatened birds' preferred land cover type in urban built-up areas. Bird ranges are being reshaped differently because of their different adaptations to urbanization. While green infrastructure can improve local bird diversity, the homogeneous urban environment also leads to species compositions being more similar across regions. More attention should be paid to narrow-range species for the formulation of biodiversity conservation strategies, and conservation actions should be further coordinated among cities from a global perspective.

Conservation status of threatened land plants in China and priority sites for better conservation targets: distribution patterns and conservation gap analysis

There are about 10% of the world’s land plants in China, of which 11% are threatened species. Here, we used China as a proxy to identify hotspots of threatened species, evaluate the effectiveness of current conservation networks and assess the correlations between distribution patterns of different groups. We built the most complete database of 3,881 species of threatened land plants in China (TLPCs) to date, based on 43,710 occurrence records at county level. A total of 467 counties identified as hotspot by species richness, complementarity, and weighted algorithms, mostly confined to the mountainous areas in southern China, which account for 15.58% of land area, however, hold 95.34% of the total TLPCs. The correlation analysis revealed weak to moderate relationship between the distribution patterns of three groups (bryophytes, ferns, and gymnosperms) and angiosperms of TLPCs. We found 86.34%, 84.05% and 95.77% of TLPCs protected by NNRs, PNRs and NRs [nature reserves, including both national NRs (NNRs) and provincial NRs (PNRs)], respectively. Besides, there were 41.11% and 18.84% of hotspots identified as conservation gaps of NNRs and NRs, respectively. In conclusion, the NNRs do not play a more dominant role in conserving TLPCs diversity in comparison to PNRs. We proposed that conservation planning need to be established in the periphery of Yunnan-Guizhou Plateau due to a large number of hotspots and conservation gaps located in this area. Since a large proportion of unprotected TLPCs are critically endangered and narrow-ranged species, it is urgent to set priorities for their conservation in the nearest future.

The uplift of the Hengduan Mountains contributed to the speciation of three Rhododendron species

Plant speciation in mountain systems is crucial for shaping plant biodiversity, particularly for those endemic species with small populations. The mountain-geobiodiversity hypothesis (MGH) is among the possible mechanisms underlying mountain biodiversity. To test the MGH, we selected three Rhododendron species occupying the Hengduan Mountains (HDM) as focal species and then genotyped 12 populations using Restriction-site Associated DNA sequencing (RAD-seq) to reveal their speciation and divergence history. We found that there was high interspecific differentiation, low gene flow, and a high genetic drift among three Rhododendron species, suggesting that founder effects might play a key role in their differentiation. Historical gene flow occurred from R. brachypodum to R. calophytum var. pauciflorum. The effective population size of three Rhododendron species declined about 1 Kya ago. Rhododendron brachypodum experienced a bottleneck event during the Last Glacial Maximum (15–20 Kya). Three Rhododendron species diverged between 15.5 Mya and 3.13 Mya, which might be associated with the uplift of the HDM. These findings suggest that the speciation of three Rhododendron may be partly attributable to geological processes and climate fluctuations, strongly supporting the MGH. Additionally, our results provide new insights into the speciation patterns of endemic species and the protection of narrow-ranged species in mountain systems.

Recruitment Traits Could Influence Species' Geographical Range: A Case Study in the Genus Saxifraga L.

The reasons why some species occur widespread, while related species have restricted geographical ranges have been attributed to habitat specialization or ecological niche breadth. For species in the genus Saxifraga, habitat specialization alone cannot explain the distributional differences observed. We hypothesize that recruitment traits (i.e., germination, emergence, and survival) may account for differences in geographical ranges and that early life stages correlate to survival. We studied recruitment responses in 13 widespread and 12 narrow-ranged Saxifraga species in the laboratory and common garden experiments using seeds collected from 79 populations in the European Alps. We found that in the laboratory cold temperature led to higher germination percentages compared with warm temperature for both distribution groups. This represents an exception to the general assumption that alpine species require warm cues for germination. In warm laboratory temperatures, widespread species germinated better than narrow-ranged species, indicating a greater tolerance of warm temperatures for the former. Subsequent to germination, recruitment traits between the two distribution groups were lower or null in the common garden, suggesting that the impact of recruitment on species’ geographical ranges occurs at the earliest life stage. Mean time to emergence of narrow-ranged species showed lower variability than that of widespread species. Consistently, intraspecific variation of mean annual temperatures between seed collection sites was lower for narrow-ranged species, indicating a close relationship between home sites and emergence time. Emergence percentage was a strong predictor of survival only for widespread species, underlining that seed and seedling functional traits differ between distribution groups, which require further research. Our results support the view that early life stages are critical to population dynamics and thus can influence species’ geographical ranges. The wider responses to climatic conditions in widespread species may have facilitated their spread across the Alps. Our results also suggest that all Saxifraga species face a considerable threat from climate warming due to their overall cold-adapted recruitment niche.

Variation in diet of frugivorous bats in fragments of Brazil’s Atlantic Forest associated with vegetation density

AbstractSpecies distribution and persistence have long been known to vary with landscape structure; however, continued human activities in altered landscapes raise many questions as to how habitat fragmentation impacts the biology of persistent animal populations. Using carbon and nitrogen stable isotope analysis, we examined interspecific variation in the diet of frugivorous bats among remnant habitat patches of Brazil’s Atlantic Forest. We hypothesized that the diet of individuals captured in habitat patches would be different than those captured in contiguous habitats. We predicted that bats would alter their realized dietary niche breadth, taking food items (i.e., fruits or insects) according to landscape structure. However, more mobile species should be less impacted by small-scale landscape changes. We predicted that (1) a wide-ranging species (Artibeus lituratus), which move through open areas, will be less affected by small-scale landscape attributes, patch size, composition, and isolation; while (2) two narrow-ranging species (Carollia perspicillata and Sturnira lilium) will have more variation between populations in niche breadth and isotopic ratio ranges dependant on the local environment. Using Akaike’s Information Criterion (AIC) to rank a priori selected candidate models to explain variation, we found that fragment composition, largely involving vegetation density rather than spatial aspects of landscape structure (i.e., patch area, isolation) best explained diet variation in frugivorous bats. Additionally, there was evidence that wide-ranging A. lituratus were less impacted by differences in the landscape than narrow-ranging species. This supports the prediction that bats resident to fragments have altered feeding behavior, in response to environmental perturbation.

Chloroplast and Nuclear Genetic Diversity Explain the Limited Distribution of Endangered and Endemic Thuja sutchuenensis in China.

Narrow-ranged species face challenges from natural disasters and human activities, and to address why species distributes only in a limited region is of great significance. Here we investigated the genetic diversity, gene flow, and genetic differentiation in six wild and three cultivated populations of Thuja sutchuenensis, a species that survive only in the Daba mountain chain, using chloroplast simple sequence repeats (cpSSR) and nuclear restriction site-associated DNA sequencing (nRAD-seq). Wild T. sutchuenensis populations were from a common ancestral population at 203 ka, indicating they reached the Daba mountain chain before the start of population contraction at the Last Interglacial (LIG, ∼120–140 ka). T. sutchuenensis populations showed relatively high chloroplast but low nuclear genetic diversity. The genetic differentiation of nRAD-seq in any pairwise comparisons were low, while the cpSSR genetic differentiation values varied with pairwise comparisons of populations. High gene flow and low genetic differentiation resulted in a weak isolation-by-distance effect. The genetic diversity and differentiation of T. sutchuenensis explained its survival in the Daba mountain chain, while its narrow ecological niche from the relatively isolated and unique environment in the “refugia” limited its distribution.

Are narrow-ranging species doomed to extinction? Projected dramatic decline in future climate suitability of two highly threatened species

Narrow-ranging species are usually omitted from Species distribution models (SDMs) due to statistical constraints, while they are predicted to be particularly vulnerable to climate change. The recently available high-resolution environmental predictors, along with recently developed methods enable to increase the eligibility of narrow-ranging species for SDMs, provided their distribution is well known. We fill a gap of knowledge on the effect of predicted climate change on narrow-ranging species. We modelled the distribution of the golden mantella frog Mantella aurantiaca and the Manapany day gecko Phelsuma inexpectata, for which the distribution of their occurrence records is well documented. Our modelling scheme included a range of processes susceptible to address statistical issues related to narrow-ranging species. We predict an alarming decline in climate suitability in the whole current distribution area of both species by 2070, potentially leading to a complete extinction in most scenarios. We identified the areas with the best climate suitability in the future, but these remain largely suboptimal regarding species climatic niche. The high level of habitat fragmentation suggests that both species likely need to be at least partly translocated. Climate change may not only drive range contractions or distribution shifts in narrow-ranging species, but may lead to the complete extirpation of suitable environments across their entire region. This study suggests that the level of threats of narrow-ranging species already identified as threatened may be underestimated, especially in heterogeneous tropical areas. We stress the need to develop sampling campaigns and implement proactive actions for narrow-ranging species in the tropics.

Global determinants and conservation of evolutionary and geographic rarity in land vertebrates.

Deciphering global trends in phylogenetic endemism is crucial for understanding broad-scale evolutionary patterns and the conservation of key elements of biodiversity. However, knowledge to date on global phylogenetic endemism and its determinants has been lacking. Here, we conduct the first global analysis of phylogenetic endemism patterns of land vertebrates (>30,000 species), their environmental correlates, and threats. We found that low temperature seasonality and high topographic heterogeneity were the main global determinants of phylogenetic endemism. While phylogenetic endemism hotspots cover 22% of Earth, these regions currently have a high human footprint, low natural land cover, minimal protection, and will be greatly affected by climate change. Evolutionarily unique, narrow-range species are crucial for sustaining biodiversity in the face of environmental change. Our global study advances the current understanding of this imperilled yet previously overlooked facet of biodiversity.