Precipitation of the warmest quarter and temperature of the warmest month are key to understanding the effect of climate change on plant species diversity in Southern African savannah

In this study, we test for the key bioclimatic variables that significantly explain the current distribution of plant species richness in a southern African ecosystem as a preamble to predicting plant species richness under a changed climate. We used 54,000 records of georeferenced plant species data to calculate species richness and spatially interpolated climate data to derive nineteen bioclimatic variables. Next, we determined the key bioclimatic variables explaining variation in species richness across Zimbabwe using regression analysis. Our results show that two bioclimatic variables, that is, precipitation of the warmest quarter (R² = 0.92, P < 0.001) and temperature of the warmest month (R² = 0.67, P < 0.001) significantly explain variation in plant species richness. In addition, results of bioclimatic modelling using future climate change projections show a reduction in the current bio‐climatically suitable area that supports high plant species richness. However, in high‐altitude areas, plant richness is less sensitive to climate change while low‐altitude areas show high sensitivity. Our results have important implications to biodiversity conservation in areas sensitive to climate change; for example, high‐altitude areas are likely to continue being biodiversity hotspots, as such future conservation efforts should be concentrated in these areas.     

Spatial variation of climatic and non-climatic controls on species distribution: the range limit of Tsuga heterophylla

Aim To assess which climatic variables control the distribution of western hemlock (Tsuga heterophylla), how climatic controls vary over latitude and between disjunct coastal and interior sub‐distributions, and whether non‐climatic factors, such as dispersal limitation and interspecific competition, affect range limits in areas of low climatic control. Location North‐western North America. Methods We compared four bioclimatic variables [actual evapotranspiration (AET), water deficit (DEF), mean temperature of the coldest month (MTCO), and growing degree‐days (GDD5)] with the distribution of T. heterophylla at a 2‐km grid cell resolution. The distribution is based on a zonal ecosystem classification where T. heterophylla is the dominant late‐successional species. For each bioclimatic variable and at each degree of latitude, we calculated the threshold that best defines the T. heterophylla distribution and assessed the extent to which T. heterophylla was segregated to one end of the bioclimatic gradient. We also fitted two forms of multivariate bioclimatic models to predict the T. heterophylla distribution: a simple threshold model and a complex Gaussian mixture model. Each model was trained separately on the coastal and interior distributions, and predicted areas outside of the T. heterophylla distribution (overprediction) were evaluated with respect to known outlier populations. Results Actual evapotranspiration was the most accurate predictor across the T. heterophylla distribution; other variables were important only in certain areas. There was strong latitudinal variation in the thresholds of all variables except AET, and the interior distribution had wider bioclimatic thresholds than the coastal distribution. The coastal distribution was predicted accurately by both bioclimatic models; areas of overprediction rarely occurred > 10 km from the observed distribution and generally matched small outlier populations. In contrast, the interior distribution was poorly predicted by both models; areas of overprediction occurred up to 140 km from the observed distribution and did not match outlier populations. The greatest overprediction occurred in Idaho and Montana in areas supporting species that typically co‐exist with T. heterophylla. Main conclusions The high predictive capacity of AET is consistent with this species’ physiological requirements for a mild and humid climate. Spatial variation of MTCO, GDD5 and DEF thresholds probably reflects both the correlation of these variables with AET and ecotypic variation. The level of overprediction in portions of the interior suggests that T. heterophylla has not completely expanded into its potential habitat. Tsuga heterophylla became common in the interior 2000–3500 years ago, compared with > 9000 years ago in the coastal region. The limited time for dispersal, coupled with frequent fires at the margins of the distribution and competition with disturbance‐adapted species, may have retarded range expansion in the interior. This study demonstrates that bioclimatic modelling can help identify various climatic and non‐climatic controls on species distributions.     

Phylogeography of a migratory songbird across its Canadian breeding range: Implications for conservation units

The objectives of this study were to describe and evaluate potential drivers of genetic structure in Canadian breeding populations of the Ovenbird, Seiurus aurocapilla. We performed genetic analyses on feather samples of individuals from six study sites using nuclear microsatellites. We also assessed species identity and population genetic structure of quill mites (Acariformes, Syringophilidae). For male Ovenbirds breeding in three study sites, we collected light‐level geolocator data to document migratory paths and identify the wintering grounds. We also generated paleohindcast projections from bioclimatic models of Ovenbird distribution to identify potential refugia during the last glacial maximum (LGM, 21,000 years before present) as a factor explaining population genetic structure. Birds breeding in the Cypress Hills (Alberta/Saskatchewan) may be considered a distinct genetic unit, but there was no evidence for genetic differentiation among any other populations. We found relatively strong migratory connectivity in both western and eastern populations, but some evidence of mixing among populations on the wintering grounds. There was also little genetic variation among syringophilid mites from the different Ovenbird populations. These results are consistent with paleohindcast distribution predictions derived from two different global climate models indicating a continuous single LGM refugium, with the possibility of two refugia. Our results suggest that Ovenbird populations breeding in boreal and hemiboreal regions are panmictic, whereas the population breeding in Cypress Hills should be considered a distinct management unit.     

Evidence of niche shift and global invasion potential of the Tawny Crazy ant,Nylanderia fulva

Analysis of an invasive species' niche shift between native and introduced ranges, along with potential distribution maps, can provide valuable information about its invasive potential. The tawny crazy ant, Nylanderia fulva, is a rapidly emerging and economically important invasive species in the southern United States. It is originally from east‐central South America and has also invaded Colombia and the Caribbean Islands. Our objectives were to generate a global potential distribution map for N. fulva, identify important climatic drivers associated with its current distribution, and test whether N. fulva's realized climatic niche has shifted across its invasive range. We used MaxEnt niche model to map the potential distribution of N. fulva using its native and invaded range occurrences and climatic variables. We used principal component analysis methods for investigating potential shifts in the realized climatic niche of N. fulva during invasion. We found strong evidence for a shift in the realized climatic niche of N. fulva across its invasive range. Our models predicted potentially suitable habitat for N. fulva in the United States and other parts of the world. Our analyses suggest that the majority of observed occurrences of N. fulva in the United States represent stabilizing populations. Mean diurnal range in temperature, degree days at ≥10°C, and precipitation of driest quarter were the most important variables associated with N. fulva distribution. The climatic niche expansion demonstrated in our study may suggest significant plasticity in the ability of N. fulva to survive in areas with diverse temperature ranges shown by its tolerance for environmental conditions in the southern United States, Caribbean Islands, and Colombia. The risk maps produced in this study can be useful in preventing N. fulva's future spread, and in managing and monitoring currently infested areas.     

Mutualism influences species distribution predictions for a bromeliad‐breeding anuran under climate change

Ecological niche models, or species distribution models, have been widely used to identify potentially suitable areas for species in future climate change scenarios. However, there are inherent errors to these models due to their inability to evaluate species occurrence influenced by non‐climatic factors. With the intuit to improve the modelling predictions for a bromeliad‐breeding treefrog (Phyllodytes melanomystax, Hylidae), we investigate how the climatic suitability of bromeliads influences the distribution model for the treefrog in the context of baseline and 2050 climate change scenarios. We used point occurrence data on the frog and the bromeliad (Vriesea procera, Bromeliaceae) to generate their predicted distributions based on baseline and 2050 climates. Using a consensus of five algorithms, we compared the accuracy of the models and the geographic predictions for the frog generated from two modelling procedures: (i) a climate‐only model for P. melanomystax and V. procera; and (ii) a climate‐biotic model for P. melanomystax, in which the climatic suitability of the bromeliad was jointly considered with the climatic variables. Both modelling approaches generated strong and similar predictive power for P. melanomystax, yet climate‐biotic modelling generated more concise predictions, particularly for the year 2050. Specifically, because the predicted area of the bromeliad overlaps with the predictions for the treefrog in the baseline climate, both modelling approaches produce reasonable similar predicted areas for the anuran. Alternatively, due to the predicted loss of northern climatically suitable areas for the bromeliad by 2050, only the climate‐biotic models provide evidence that northern populations of P. melanomystax will likely be negatively affected by 2050.     

气候变暖背景下春兰和蕙兰的适生区分布预测

为了阐明气候变暖背景下春兰(Cymbidium goeringii)和蕙兰(C. faberi)在我国的适生区分布变化情况,根据157条分布记录和19个生物气候变量,应用最大熵物种分布模型,对2070年4种温室气体排放情景下春兰和蕙兰在我国的适生区分布进行预测,并筛选影响其地理分布的主要气候因子。结果表明:(1)2070年春兰和蕙兰分布点的年均温(bio1)、最冷月最低温度(bio6)和最冷季平均温度(bio11)等均升高,气候有变暖趋势;(2)受试者工作特征曲线下面积(AUC)值在0.9—1.0之间,模型预测结果可信度较高;(3)影响春兰、蕙兰当前和2070年地理分布的限制性气候因子主要有最冷月最低温度(bio6)、最冷季平均温度(bio11)、年均降水量(bio12)和最干月份降水量(bio14);(4)气候变暖将会对春兰和蕙兰的适宜生境范围和面积产生影响。预测2070年春兰的适宜生境面积将会有所减小,而蕙兰的适宜生境面积将会增加,且整体有向北迁移的趋势。研究结果为野生春兰和蕙兰的生态风险评价和引种提供了重要依据。     

Epiphyte sensitivity to a cross-scale interaction between habitat quality and macroclimate: an opportunity for range-edge conservation

Bioclimatic envelope models are frequently used to project the species response to climate change scenarios. Development and improvement of bioclimatic models has focussed on data properties and statistical tools, while significant criticism continues to challenge the ecological framework of model assumptions. We hypothesised that a potential for model improvement emerges from linkage across scales, between macroclimate and variation in local habitat quality: i.e. a species’ habitat specificity may shift along macroclimatic gradients. We first sampled two test-case epiphytic lichen species across a steep climatic gradient, and second developed standard bioclimatic models accompanied by a threshold likelihood value for discriminating presences and absences. We used the difference between predicted model values and the threshold as a response variable (D _thr): we show that values for D _thr are explained by an interaction between the climatic setting and habitat quality. A potential error in bioclimatic models is then quantified as the region of false absences or presences, which would be incurred as a consequence of sensitivity to variable habitat. This signature habitat effect occurs at a species’ range-edge, and, as a corollary, provides quantification in support of conservation: i.e. information is provided on how a habitat may be managed in marginal climatic regions (leading or trailing range-edge boundaries) in order to promote species protection.     

Climatic patterns in the establishment of wintering areas by North American migratory birds

Long‐distance migration in birds is relatively well studied in nature; however, one aspect of this phenomenon that remains poorly understood is the pattern of distribution presented by species during arrival to and establishment of wintering areas. Some studies suggest that the selection of areas in winter is somehow determined by climate, given its influence on both the distribution of bird species and their resources. We analyzed whether different migrant passerine species of North America present climatic preferences during arrival to and departure from their wintering areas. We used ecological niche modeling to generate monthly potential climatic distributions for 13 migratory bird species during the winter season by combining the locations recorded per month with four environmental layers. We calculated monthly coefficients of climate variation and then compared two GLM (generalized linear models), evaluated with the AIC (Akaike information criterion), to describe how these coefficients varied over the course of the season, as a measure of the patterns of establishment in the wintering areas. For 11 species, the sites show nonlinear patterns of variation in climatic preferences, with low coefficients of variation at the beginning and end of the season and higher values found in the intermediate months. The remaining two species analyzed showed a different climatic pattern of selective establishment of wintering areas, probably due to taxonomic discrepancy, which would affect their modeled winter distribution. Patterns of establishment of wintering areas in the species showed a climatic preference at the macroscale, suggesting that individuals of several species actively select wintering areas that meet specific climatic conditions. This probably gives them an advantage over the winter and during the return to breeding areas. As these areas become full of migrants, alternative suboptimal sites are occupied. Nonrandom winter area selection may also have consequences for the conservation of migratory bird species, particularly under a scenario of climate change.     

气候变化情景下裸冠菊在中国的潜在适生区分布预测

外来入侵植物裸冠菊(Gymnocoronis spilanthoides)具有较强的入侵适应性能快速繁殖扩散,会对本土物种的生长繁殖及本地生态安全、景观格局等产生不良影响。基于265个有效分布点和7个环境变量,调整优化预测模型的调控倍频和特征组合参数,应用MaxEnt、ArcGIS、R软件预测当前和未来(2050s, 2070s)不同气候情景(SSP126, SSP245,SSP370, SSP585)下裸冠菊在中国的潜在地理分布,定量分析其适生区的空间变化及质心移动轨迹,最后采用受试者工作特征(ROC)曲线下面积(AUC)和测试遗漏率评估模型的精确性。未来气候模式选择中国国家气候中心开发的CMIP6中BCC-CSM2-MR。结果表明：(1)模型预测结果极准确,各组模型的AUC值均高于0.97;(2)最干季降水量(bio17)、最冷季度平均温(bio11)、温度季节性变化(bio4)和最暖季度平均降雨量(bio18)是影响裸冠菊地理分布的主导气候因子;(3)当前气候条件下,裸冠菊的总适生区面积达到191.18×10⁴km²,约占国土总面积的1...     

Impact of climate change on the distribution of populations of an endemic Mexican columnar cactus in the Tehuacán-Cuicatlán Valley,Mexico

In this paper, we present a bioclimatic approach to (1) differentiate populations of the endemic Mexican columnar cactus Neobuxbaumia tetetzo within the Tehuacán-Cuicatlán Valley and (2) evaluate, under two possible future scenarios (years 2050 and 2080), the effects of climate change on the total species distribution in this area, as well as on groups of populations defined by their bioclimatic models. Four population groups were identified, and principal component analysis showed that the variables that explained more than 40% of the climatic variation were precipitation of the wettest quarter and temperature seasonality. Bioclimatic models under the different scenarios indicated that when the overall species distribution was analyzed, this area will probably have contracted by 19.5% by the year 2050 and 47.05% by the year 2080, whereas the separate analysis of population groups projected area contractions of 18.4% by the year 2050 and 51.95% by the year 2080. These results demonstrate the importance of exploring new approaches for evaluating and predicting current and future distribution of plant species.     

引种捕食螨胡瓜新小绥螨在中国的适生区分布预测

胡瓜新小绥螨(Neoseiulus cucumeris)是一种商业化的广食性生防天敌,可以防治多种农业害螨和害虫,具有重要的经济和生态价值。但是作为一种外来引种的捕食螨,它在我国的适生区域分布以及气候变化对其分布的影响尚不明确。根据胡瓜新小绥螨的现有分布点和19个生物气候因子,利用刀切法评估关键气候因素的重要性,并采用Maxent生态位模型分别预测了目前和未来气候条件下它在中国分布情况,分析了其在中国的潜在适生区域的变化。结果表明模型预测得到的受试者工作特征曲线ROC曲线下的面积AUC(Area under curve)值为0.87,表明模型的准确度好。最冷季节的降水量(Bio_19)、等温性(Bio_3)和气温季节性(Bio_4)是影响胡瓜新小绥螨适生性的最重要的环境因子, 对模型的贡献率分别为36.2%、25% 和18.1%。目前胡瓜新小绥螨的适生区面积约占我国陆地面积的60%,在未来气候条件下,其适生区域有进一步扩大的趋势,在2050年其中高度适生区域扩张至63%。不同时期胡瓜新小绥螨的分布中心比较稳定,均分布于四川省内,但有向东北迁移的趋势。本研究明确了胡瓜新小绥螨在中国适宜的释放区域及可能定殖的区域,为该引种天敌的合理利用提供了理论依据。     

Modelling species distributions to predict areas at risk of invasion by the exotic aquatic New Zealand mudsnail Potamopyrgus antipodarum (Gray 1843)

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Climate determinants of breeding and wintering ranges of lesser kestrels in Italy and predicted impacts of climate change

Climate warming would theoretically create conditions for the breeding range expansion of pseudo‐steppe Mediterranean and long‐distance migrant species and provide the possibility for these to overwinter in the same breeding areas. However, contemporary changes in rainfall regimes might have negative effects on the climate suitability and in turn, shrink species potential range. The lesser kestrel Falco naumanni is highly sensitive to rainfall oscillations and has recently extended its Italian breeding range towards northern latitudes and increasing its wintering records. We modelled the effects of temperature and rainfall on current and future climate suitability for lesser kestrels in both the breeding and wintering periods by using MaxEnt. Models were based on the distribution of 298 colonies and 40 wintering records. Future climate suitability was assessed under eight different scenarios. Spring rainfall amount resulted as the main determinant of breeding climate suitability, so its predicted reduction will determine a shrinkage in suitable areas (–42.10% in 2050; –32.07% in 2070). Specifically, the 66.05% of Italian colonies will be outside the climatically suitable area by 2050. However wide areas, suitable under current climate conditions, are still not occupied by lesser kestrel and allow the potential expansion of its Italian breeding range in the short term. Temperature seasonality mainly determined the species’ winter climate suitability, which is overall predicted to boost in the next decades (+145.03% in 2050; and +123.91% in 2070). All but one future scenarios predicted a northward shift of about 40 km for both breeding and wintering climate suitability. Despite its recent expansion, we have found that climate change will pose conservation concerns for the Italian breeding population of lesser kestrels. Indeed, changes in non‐climate factors will also outline the future suitability of the Italian range for lesser kestrels in both seasons with effects that might both strengthen or mitigate climate effects.     

Large‐scale geographic variation in iridescent structural ornaments of a long‐distance migratory bird

Iridescent colours produced during moult likely play an important role in pair formation in birds. We sought to quantify geographic variation in such colouration in a duck species, Eurasian teal Anas crecca, in winter (when mating occurs) to evaluate whether this variation reflects birds’ breeding origins or differential individual migration strategies in both males and females. We combined information on feather production region and individual attributes (body size, sex and age) of Eurasian teal from 82 wintering sites in France. Feather production region (moult site or natal origin) was inferred using feather deuterium values (δD_f). We performed spectral measurements to evaluate speculum colour and brightness contrasts for 1052 teal collected over four years. Colouration differed strongly among wintering regions, with birds wintering in eastern France exhibiting higher colour contrast than those wintering in the west. Body size and colouration were positively related. There were no differences in cohort‐specific δD_f values between separate wintering regions in France, indicating that within a winter quarter teal originated from areas across the entire breeding range. Overall, patterns of spatial variation in feather colouration were related most closely to body size which was consistent with predictions of a differential migration hypothesis, with larger and more colour‐contrasting birds wintering closer to their breeding grounds. Because moult speed is also known to affect colour production, early breeders or individuals that skipped reproduction may have invested more or earlier in their feather quality to gain potential advantages in monopolizing future mates.     

Bioclimatic constraints to Andean cat distribution: a modelling application for rare species

Aim To identify the bioclimatic niche of the endangered Andean cat (Leopardus jacobita), one of the rarest and least known felids in the world, by developing a species distribution model. Location South America, High Andes and Patagonian steppe. Peru, Bolivia, Chile, Argentina. Methods We used 108 Andean cat records to build the models, and 27 to test them, applying the Maxent algorithm to sets of uncorrelated bioclimatic variables from global databases, including elevation. We based our biogeographical interpretations on the examination of the predicted geographic range, the modelled response curves and latitudinal variations in climatic variables associated with the locality data. Results Simple bioclimatic models for Andean cats were highly predictive with only 3–4 explanatory variables. The climatic niche of the species was defined by extreme diurnal variations in temperature, cold minimum and moderate maximum temperatures, and aridity, characteristic not only of the Andean highlands but also of the Patagonian steppe. Argentina had the highest representation of suitable climates, and Chile the lowest. The most favourable conditions were centrally located and spanned across international boundaries. Discontinuities in suitable climatic conditions coincided with three biogeographical barriers associated with climatic or topographic transitions. Main conclusions Simple bioclimatic models can produce useful predictions of suitable climatic conditions for rare species, including major biogeographical constraints. In our study case, these constraints are also known to affect the distribution of other Andean species and the genetic structure of Andean cat populations. We recommend surveys of areas with suitable climates and no Andean cat records, including the corridor connecting two core populations. The inclusion of landscape variables at finer scales, crucially the distribution of Andean cat prey, would contribute to refine our predictions for conservation applications.     

不同气候变化情境下中国木灵藓属和蓑藓属植物的潜在分布格局

蓑藓属(Macromitrium)和木灵藓属(Orthotrichum)是木灵藓科(Orthotrichaceae)的两个最大的属,前者呈现泛热带分布式样,后者呈偏温带性分布式样。应用当前和基于RCP4.5(Medium-Low Representative Concentration Pathways)二氧化碳排放情景下2050和2070的11个生物气候变量,以及木灵藓属(Orthotrichum)66个、蓑藓属(Macromitrium)131个国内分布记录,应用最大熵模型(Max Ent),预测了气候变暖背景下这两属植物在我国38个自然保护区潜在分布范围的变化。11个生物气候变量包括昼夜温差月均值、年温度变化范围、温度季节变化、最热月份最高温、最干季度平均温度和最冷季度平均温度、最湿月份雨量、最干月份雨量、雨量变化方差和最暖季度平均雨量。选择了10%的遗漏错误对应的累积值作为分布预测阈值,为了更好地展示气候变化下这两个属的潜在分布区变化,选择了我国境内的38个自然保护区并计算了不同气候条件下两种藓类植物属在这些自然保护区的综合气候适应指数。38个自然保护区包括福建武夷山、甘肃祁连山、广东南岭、广西花坪、广西十万大山、贵州梵净山、贵州雷公山、海南尖峰岭、河北五台山、河南鸡公山、河南小秦岭、湖北神农架、湖北星斗山、吉林长白山、江西庐山、辽宁白石砬子、辽宁医巫闾山、内蒙古大黑山、宁夏贺兰山、青海三江源、山东云台山、山西历山、山西芦芽山、陕西佛坪、陕西太白山、四川贡嘎山、四川卧龙、云南哀牢山、云南大围山、云南纳板河、浙江凤阳山、浙江古田山、浙江九龙山、浙江普陀山、浙江清凉峰、浙江天目山、浙江乌岩岭和重庆大巴山。结果表明,随着气候变暖,蓑藓属和木灵藓属在我国的适生面积都将减少,蓑藓属植物在我国的潜在分布区面积从当前的31.5%下降到12.23%,木灵藓属的从当前的65.81%下降到44.94%,气候变化对蓑藓属植物分布的影响要大于木灵藓属。对于蓑藓属植物,当前气候条件下的38个自然保护区中,除了宁夏贺兰山和甘肃祁连山外,其他的36个保护区都有适合于蓑藓属植物分布的气候条件。到了2070,河南鸡公山、山东云台山、浙江普陀山、浙江九龙山、浙江古田山、内蒙古大黑山、山西芦芽山、江西庐山、辽宁医巫闾山、广西花坪、辽宁白石砬子、河北五台山、山西历山、河南小秦岭、陕西佛坪、吉林长白山、贵州梵净山、贵州雷公山和福建武夷山这19个自然保护区不再或几乎不再适合于蓑藓属的分布。对于木灵藓属植物,在当前的气候条件下,38个自然保护区中,除了海南尖峰岭保护区,其余的37个保护区均处于木灵藓属植物潜在分布范围之内。与当前气候条件相比,2070年38个保护区的气候条件均变得不利于木灵藓属分布,其中广西花坪、江西庐山、云南纳板河、广西十万大山、河南鸡公山、山东云台山、浙江普陀山、浙江天目山、浙江古田山、浙江九龙山、福建武夷山、贵州梵净山、辽宁医巫闾山、河南小秦岭和陕西佛坪等15个保护区已不在木灵藓属的潜在分布范围。     

Maxent modeling for predicting the spatial distribution of three raptors in the Sanjiangyuan National Park,China

Upland buzzard (Buteo hemilasius), Saker falcon (Falco cherrug), and Himalayan vulture (Gyps himalayensis) are three common large raptors in the Sanjiangyuan National Park (SNP), China's first national park. Among them, Upland buzzard and Saker falcon play a significant role in controlling plateau rodent populations and reducing the transmission of pathogens carried by rodents. The Himalayan vulture can provide services for the redistribution and recycling of nutrients in the ecosystem, and play an irreplaceable role in the celestial burial culture of Tibetans in China. Exploring their habitat suitability is important for the protection of the three raptors. Our research was based on the current distribution of Upland buzzard, Saker falcon, and Himalayan vulture that we had extensively surveyed in the Sanjiangyuan National Park from 2016 to 2017. Combined with the correlation analysis of environmental variables, we utilized maximum entropy model (MaxEnt) to evaluate and compare the habitat suitability of the three species in the Sanjiangyuan National Park. Elevation, climate, and human disturbance factors, which had direct or indirect effects on species survival and reproduction, were all included in the model. Among them, elevation was the most important environmental variables affecting the suitability of habitats of three species. Temperature‐related factor was another important predictor. The high (>60%) suitable habitat areas for Upland buzzard, Saker falcon, and Himalayan vulture were 73,017.63, 40,732.78, and 61,654.33 km², respectively, accounted for 59.32%, 33.09%, and 50.08% of the Sanjiangyuan National Park and their total suitable area (i.e., the sum area of high and moderate habitats) reached 96.07%, 60.59%, and 93.70%, respectively. Besides, the three species have overlapping areas for the suitable habitats, which means that overlapping areas should be highly valued and protected. Therefore, understanding the distribution of suitable habitats of the three raptors can provide useful information and reasonable reference for us to put forward suggestions for their protection and regional management.     

The impact of climate change on the distribution of two threatened Dipterocarp trees

Two ecologically and economically important, and threatened Dipterocarp trees Sal (Shorea robusta) and Garjan (Dipterocarpus turbinatus) form mono‐specific canopies in dry deciduous, moist deciduous, evergreen, and semievergreen forests across South Asia and continental parts of Southeast Asia. They provide valuable timber and play an important role in the economy of many Asian countries. However, both Dipterocarp trees are threatened by continuing forest clearing, habitat alteration, and global climate change. While climatic regimes in the Asian tropics are changing, research on climate change‐driven shifts in the distribution of tropical Asian trees is limited. We applied a bioclimatic modeling approach to these two Dipterocarp trees Sal and Garjan. We used presence‐only records for the tree species, five bioclimatic variables, and selected two climatic scenarios (RCP4.5: an optimistic scenario and RCP8.5: a pessimistic scenario) and three global climate models (GCMs) to encompass the full range of variation in the models. We modeled climate space suitability for both species, projected to 2070, using a climate envelope modeling tool “MaxEnt” (the maximum entropy algorithm). Annual precipitation was the key bioclimatic variable in all GCMs for explaining the current and future distributions of Sal and Garjan (Sal: 49.97 ± 1.33; Garjan: 37.63 ± 1.19). Our models predict that suitable climate space for Sal will decline by 24% and 34% (the mean of the three GCMs) by 2070 under RCP4.5 and RCP8.5, respectively. In contrast, the consequences of imminent climate change appear less severe for Garjan, with a decline of 17% and 27% under RCP4.5 and RCP8.5, respectively. The findings of this study can be used to set conservation guidelines for Sal and Garjan by identifying vulnerable habitats in the region. In addition, the natural habitats of Sal and Garjan can be categorized as low to high risk under changing climates where artificial regeneration should be undertaken for forest restoration.     

Reinforcing and expanding the predictions of the disturbance vicariance hypothesis in Amazonian harlequin frogs: a molecular phylogenetic and climate envelope modelling approach

The disturbance vicariance hypothesis (DV) has been proposed to explain speciation in Amazonia, especially its edge regions, e.g. in eastern Guiana Shield harlequin frogs (Atelopus) which are suggested to have derived from a cool-adapted Andean ancestor. In concordance with DV predictions we studied that (i) these amphibians display a natural distribution gap in central Amazonia; (ii) east of this gap they constitute a monophyletic lineage which is nested within a pre-Andean/western clade; (iii) climate envelopes of Atelopus west and east of the distribution gap show some macroclimatic divergence due to a regional climate envelope shift; (iv) geographic distributions of climate envelopes of western and eastern Atelopus range into central Amazonia but with limited spatial overlap. We tested if presence and apparent absence data points of Atelopus were homogenously distributed with Ripley’s K function. A molecular phylogeny (mitochondrial 16S rRNA gene) was reconstructed using Maximum Likelihood and Bayesian Inference to study if Guianan Atelopus constitute a clade nested within a larger genus phylogeny. We focused on climate envelope divergence and geographic distribution by computing climatic envelope models with MaxEnt based on macroscale bioclimatic parameters and testing them by using Schoener’s index and modified Hellinger distance. We corroborated existing DV predictions and, for the first time, formulated new DV predictions aiming on species’ climate envelope change. Our results suggest that cool-adapted Andean Atelopus ancestors had dispersed into the Amazon basin and further onto the eastern Guiana Shield where, under warm conditions, they were forced to change climate envelopes.