Assessing the vulnerability of species richness to anthropogenic climate change in a biodiversity hotspot

Aim To compare theoretical approaches towards estimating risks of plant species loss to anthropogenic climate change impacts in a biodiversity hotspot, and to develop a practical method to detect signs of climate change impacts on natural populations. Location The Fynbos biome of South Africa, within the Cape Floristic Kingdom. Methods Bioclimatic modelling was used to identify environmental limits for vegetation at both biome and species scale. For the biome as a whole, and for 330 species of the endemic family Proteaceae, tolerance limits were determined for five temperature and water availability‐related parameters assumed critical for plant survival. Climate scenarios for 2050 generated by the general circulation models HadCM2 and CSM were interpolated for the region. Geographic Information Systems‐based methods were used to map current and future modelled ranges of the biome and 330 selected species. In the biome‐based approach, predictions of biome areal loss were overlayed with species richness data for the family Proteaceae to estimate extinction risk. In the species‐based approach, predictions of range dislocation (no overlap between current range and future projected range) were used as an indicator of extinction risk. A method of identifying local populations imminently threatened by climate change‐induced mortality is also described. Results A loss of Fynbos biome area of between 51% and 65% is projected by 2050 (depending on the climate scenario used), and roughly 10% of the endemic Proteaceae have ranges restricted to the area lost. Species range projections suggest that a third could suffer complete range dislocation by 2050, and only 5% could retain more than two thirds of their range. Projected changes to individual species ranges could be sufficient to detect climate change impacts within ten years. Main conclusions The biome‐level approach appears to underestimate the risk of species diversity loss from climate change impacts in the Fynbos Biome because many narrow range endemics suffer range dislocation throughout the biome, and not only in areas identified as biome contractions. We suggest that targeted vulnerable species could be monitored both for early warning signs of climate change and as empirical tests of predictions.     

Climate change vulnerability for species—Assessing the assessments

Climate change vulnerability assessments are commonly used to identify species at risk from global climate change, but the wide range of methodologies available makes it difficult for end users, such as conservation practitioners or policymakers, to decide which method to use as a basis for decision‐making. In this study, we evaluate whether different assessments consistently assign species to the same risk categories and whether any of the existing methodologies perform well at identifying climate‐threatened species. We compare the outputs of 12 climate change vulnerability assessment methodologies, using both real and simulated species, and validate the methods using historic data for British birds and butterflies (i.e. using historical data to assign risks and more recent data for validation). Our results show that the different vulnerability assessment methods are not consistent with one another; different risk categories are assigned for both the real and simulated sets of species. Validation of the different vulnerability assessments suggests that methods incorporating historic trend data into the assessment perform best at predicting distribution trends in subsequent time periods. This study demonstrates that climate change vulnerability assessments should not be used interchangeably due to the poor overall agreement between methods when considering the same species. The results of our validation provide more support for the use of trend‐based rather than purely trait‐based approaches, although further validation will be required as data become available.     

Using fuzzy logic to determine the vulnerability of marine species to climate change

Marine species are being impacted by climate change and ocean acidification, although their level of vulnerability varies due to differences in species' sensitivity, adaptive capacity and exposure to climate hazards. Due to limited data on the biological and ecological attributes of many marine species, as well as inherent uncertainties in the assessment process, climate change vulnerability assessments in the marine environment frequently focus on a limited number of taxa or geographic ranges. As climate change is already impacting marine biodiversity and fisheries, there is an urgent need to expand vulnerability assessment to cover a large number of species and areas. Here, we develop a modelling approach to synthesize data on species‐specific estimates of exposure, and ecological and biological traits to undertake an assessment of vulnerability (sensitivity and adaptive capacity) and risk of impacts (combining exposure to hazards and vulnerability) of climate change (including ocean acidification) for global marine fishes and invertebrates. We use a fuzzy logic approach to accommodate the variability in data availability and uncertainties associated with inferring vulnerability levels from climate projections and species' traits. Applying the approach to estimate the relative vulnerability and risk of impacts of climate change in 1074 exploited marine species globally, we estimated their index of vulnerability and risk of impacts to be on average 52 ± 19 SD and 66 ± 11 SD, scaling from 1 to 100, with 100 being the most vulnerable and highest risk, respectively, under the ‘business‐as‐usual' greenhouse gas emission scenario (Representative Concentration Pathway 8.5). We identified 157 species to be highly vulnerable while 294 species are identified as being at high risk of impacts. Species that are most vulnerable tend to be large‐bodied endemic species. This study suggests that the fuzzy logic framework can help estimate climate vulnerabilities and risks of exploited marine species using publicly and readily available information.     

Assessing household livelihood vulnerability to climate change: The case of Northwest Vietnam

This study applied livelihood vulnerability index (LVI) and livelihood effect index (LEI) to assess vulnerability from climate variability and change of three agricultural and natural resources dependent commune in northwest Vietnam, a country that is expected to bear some of the most severe impacts of climate change. Based on a survey of 335 farm household data, complemented with secondary data on climate factors, a composite index was calculated and differential vulnerabilities were compared. The results of the analysis suggest that one of the communities, “Pa Vay Su,” was more vulnerable than the others, particularly in relation to housing, knowledge and skills, socio-demographics, health and water security, social networks, and livelihood strategy. “Hien Luong” commune, on the other hand, was more vulnerable in relation to other LVI indicators with the exception of food security, climate variability, and natural disasters. “Moc Chau” community was more vulnerable in relation to water security, social demographic than Hien Luong commune. Overall, the article shows that three different vulnerability assessment indices can be broadly applied in comparable setting in other areas of country and they could usefully establish the basis for a nationally applicable index to identify and prioritize adaptation and mitigation needs.     

Variable choice affects estimations of vulnerability to climate change

For practical reasons, assessments of species' vulnerability to rising temperatures are often limited to measuring responses to a single ecological response variable, but this could result in an underestimation of vulnerability. Using the Cape Rockjumper Chaetops frenatus (‘Rockjumper’) we examined the thermal risk to nestling Rockjumpers for sublethal (i.e. reduced nestling mass gain) and lethal (i.e. increased nest predation) consequences of sustained hot weather under both current and predicted future climatic conditions (RCP 8.5). We used a direct approach to examine these risks, first as independent ecological responses and then as combined risk driven by both response variables (mass gain and predation risk). This study revealed that the inclusion of multiple climate-related responses affected the predicted vulnerability to climate change. Further, our analyses showed that increased vulnerability to climate change will vary within the Rockjumper's habitat. Our results demonstrate that the variability in predicted thermal risk depends on which response variable was used, with implications for how and where conservation practitioners direct their already limited resources.     

Climate‐niche factor analysis: a spatial approach to quantifying species vulnerability to climate change

Climate change vulnerability assessments are an important tool for understanding the threat that climate change poses to species and populations, but do not generally yield insight into the spatial variation in vulnerability throughout a species’ habitat. We demonstrate how to adapt the method of ecological‐niche factor analysis (ENFA) to objectively quantify aspects of species sensitivity to climate change. We then expand ENFA to quantify aspects of exposure and vulnerability to climate change as well, using future projections of global climate models. This approach provides spatially‐explicit insight into geographic patterns of vulnerability, relies only on readily‐available spatial data, is suitable for a wide range of species and habitats, and invites comparison between different species. We apply our methods to a case study of two species of montane mammals, the American pika Ochotona princeps and the yellow‐bellied marmot Marmota flaviventris.     

Probabilistic spatio‐temporal assessment of vegetation vulnerability to climate change in Swaziland

In a spatially explicit climate change impact assessment, a Bayesian network (BN) model was implemented to probabilistically simulate future response of the four major vegetation types in Swaziland. Two emission scenarios (A2 and B2) from an ensemble of three statistically downscaled coupled atmosphere‐ocean global circulation models (CSIRO‐Mk3, CCCma‐CGCM3 and UKMO‐HadCM3) were used to simulate possible changes in BN‐based environmental envelopes of major vegetation communities. Both physiographic and climatic data were used as predictors representing the 2020s, 2050s and the 2080s periods. A comparison of simulated vegetation distribution and the expert vegetation map under baseline conditions showed an overall correspondence of 97.7% and a Kappa coefficient of 0.966. Although the ensemble projections showed comparable trends during the 2020s, the results from the A2 storyline were more drastic indicating that grassland and the Lebombo bushveld will be impacted negatively as early as the 2020s with about 1 °C temperature increase. The bioclimatically suitable areas of all but one vegetation type decline drastically after about 2 °C warming, more so under the more severe A2 scenario and in particular during the 2080s. The sour bushveld is the only vegetation type that initially responds positively to warming by possibly encroaching to the highly vulnerable grassland areas. Vulnerability of vegetation is increased by the limited ability to migrate into suitable climates due to close affinity to certain geological formations and the fragmentation of the landscape by agriculture and other land uses. This is expected to have serious impacts on biodiversity in the country. Under warmer climates, the likely vegetation types to emerge are uncertain due to future novel combinations of climate and bedrock lithology. The strengths and limitations of the BN approach are also discussed.     

Disproportional risk for habitat loss of high‐altitude endemic species under climate change

The expected upward shift of trees due to climate warming is supposed to be a major threat to range‐restricted high‐altitude species by shrinking the area of their suitable habitats. Our projections show that areas of endemism of five taxonomic groups (vascular plants, snails, spiders, butterflies, and beetles) in the Austrian Alps will, on average, experience a 77% habitat loss even under the weakest climate change scenario (+1.8 °C by 2100). The amount of habitat loss is positively related with the pooled endemic species richness (species from all five taxonomic groups) and with the richness of endemic vascular plants, snails, and beetles. Owing to limited postglacial migration, hotspots of high‐altitude endemics are situated in rather low peripheral mountain chains of the Alps, which have not been glaciated during the Pleistocene. There, tree line expansion disproportionally reduces habitats of high‐altitude species. Such legacies of climate history, which may aggravate extinction risks under future climate change have to be expected for many temperate mountain ranges.     

中国水稻生产对历史气候变化的敏感性和脆弱性

有效的适应措施需要了解两类基础信息,一是农业生产所面临的各种气候变异风险,二是作物产量对潜在气候变异风险的反应及其机制.评价作物生产对历史气候变化的敏感性和脆弱性,可以在时间上和空间上揭示气候变化的趋势及作物产量对其的反应,从而为适应行动的全面开展提供基础信息.通过分析1981-2007年水稻生育期3个气候因子(平均温度、日较差、辐射)的变化对水稻产量的影响,评估我国水稻生产对这3个气候因子变化的敏感性和脆弱性及其区域分布状况.结果表明,1981-2007年间我国大部分水稻产区生育期内3个气候因子均发生了明显变化,存在着气候变异风险,其中以最高温的变化最普遍和明显,导致水稻生产中高温热害风险增加.部分区域水稻产量变化与单一气象因子的变化存在着显著的线性相关,这些地区气候因子的变化可以一定程度地解释水稻产量变化趋势,其中产量变化对辐射变化最敏感.当水稻生育期内平均温度上升1℃、日较差升高1℃、辐射下降10％时,我国部分地区水稻产量随之发生了相应的变化,其中辐射降低导致我国水稻生产的脆弱面积最大,其次为日较差.受3种气象因子变化趋势的综合影响,约有30％的水稻产区对1981-2007年的气候变化趋势敏感,少部分地区表现为脆弱,但水稻主产区受到的影响不大,且在东北地区还集中表现出产量增加的趋势,为我国水稻发展提供了契机.     

Multiple axes of ecological vulnerability to climate change

Observed ecological responses to climate change are highly individualistic across species and locations, and understanding the drivers of this variability is essential for management and conservation efforts. While it is clear that differences in exposure, sensitivity, and adaptive capacity all contribute to heterogeneity in climate change vulnerability, predicting these features at macroecological scales remains a critical challenge. We explore multiple drivers of heterogeneous vulnerability across the distributions of 96 vegetation types of the ecologically diverse western US, using data on observed climate trends from 1948 to 2014 to highlight emerging patterns of change. We ask three novel questions about factors potentially shaping vulnerability across the region: (a) How does sensitivity to different climate variables vary geographically and across vegetation classes? (b) How do multivariate climate exposure patterns interact with these sensitivities to shape vulnerability patterns? (c) How different are these vulnerability patterns according to three widely implemented vulnerability paradigms—niche novelty (decline in modeled suitability), temporal novelty (standardized anomaly), and spatial novelty (inbound climate velocity)—each of which uses a distinct frame of reference to quantify climate departure? We propose that considering these three novelty paradigms in combination could help improve our understanding and prediction of heterogeneous climate change responses, and we discuss the distinct climate adaptation strategies connected with different combinations of high and low novelty across the three metrics. Our results reveal a diverse mosaic of climate change vulnerability signatures across the region's plant communities. Each of the above factors contributes strongly to this heterogeneity: climate variable sensitivity exhibits clear patterns across vegetation types, multivariate climate change data reveal highly diverse exposure signatures across locations, and the three novelty paradigms diverge widely in their climate change vulnerability predictions. Together, these results shed light on potential drivers of individualistic climate change responses and may help to inform effective management strategies.     

Regional and global climate risks for reef corals: Incorporating species-specific vulnerability and exposure to climate hazards

Climate change is driving rapid and widespread erosion of the environmental conditions that formerly supported species persistence. Existing projections of climate change typically focus on forecasts of acute environmental anomalies and global extinction risks. The current projections also frequently consider all species within a broad taxonomic group together without differentiating species-specific patterns. Consequently, we still know little about the explicit dimensions of climate risk (i.e., species-specific vulnerability, exposure and hazard) that are vital for predicting future biodiversity responses (e.g., adaptation, migration) and developing management and conservation strategies. Here, we use reef corals as model organisms (n = 741 species) to project the extent of regional and global climate risks of marine organisms into the future. We characterise species-specific vulnerability based on the global geographic range and historical environmental conditions (1900–1994) of each coral species within their ranges, and quantify the projected exposure to climate hazard beyond the historical conditions as climate risk. We show that many coral species will experience a complete loss of pre-modern climate analogs at the regional scale and across their entire distributional ranges, and such exposure to hazardous conditions are predicted to pose substantial regional and global climate risks to reef corals. Although high-latitude regions may provide climate refugia for some tropical corals until the mid-21st century, they will not become a universal haven for all corals. Notably, high-latitude specialists and species with small geographic ranges remain particularly vulnerable as they tend to possess limited capacities to avoid climate risks (e.g., via adaptive and migratory responses). Predicted climate risks are amplified substantially under the SSP5-8.5 compared with the SSP1-2.6 scenario, highlighting the need for stringent emission controls. Our projections of both regional and global climate risks offer unique opportunities to facilitate climate action at spatial scales relevant to conservation and management.     

气候变化背景下野生动物脆弱性评估方法研究进展

脆弱性评估是研究气候变化影响野生动物的重要内容,识别野生动物脆弱性,是适应和减缓气候变化影响的关键和基础。开展气候变化背景下野生动物的脆弱性评估工作,目的是为了确定易受气候变化影响的物种和明确导致物种脆弱性的因素,其评估结果有助于人类认识气候变化对野生动物的影响,为野生动物适应气候变化保护对策的制定提供科学依据。对野生动物而言(物种),脆弱性是物种受气候变化影响的程度,包括暴露度、敏感性和适应能力三大要素。其中,暴露度是由气候变化引起的外在因素,如温度、降雨量、极值天气等;敏感性是受物种自身因素影响,如种间关系、耐受性等;适应能力是物种通过自身调整来减小气候变化带来的影响,如迁移或扩散到适宜生境的能力、塑性反应和进化反应等。对近期有关气候变化背景下野生动物脆弱性评估方法予以综述,比较每种评估方法所选取指标的差异,总结在脆弱性评估中遇到的不确定性指标的处理方法,以及脆弱性评估结果在野生动物适应气候变化对策中的应用。通过总结野生动物脆弱性评估方法,以期为气候变化背景下评估我国野生动物资源的脆弱性提供参考方法。     

Rates of projected climate change dramatically exceed past rates of climatic niche evolution among vertebrate species

A key question in predicting responses to anthropogenic climate change is: how quickly can species adapt to different climatic conditions? Here, we take a phylogenetic approach to this question. We use 17 time‐calibrated phylogenies representing the major tetrapod clades (amphibians, birds, crocodilians, mammals, squamates, turtles) and climatic data from distributions of > 500 extant species. We estimate rates of change based on differences in climatic variables between sister species and estimated times of their splitting. We compare these rates to predicted rates of climate change from 2000 to 2100. Our results are striking: matching projected changes for 2100 would require rates of niche evolution that are > 10 000 times faster than rates typically observed among species, for most variables and clades. Despite many caveats, our results suggest that adaptation to projected changes in the next 100 years would require rates that are largely unprecedented based on observed rates among vertebrate species.     

气候变化影响下海岸带脆弱性评估研究进展

近百年来,全球气候系统正经历着以全球变暖为主要特征的显著变化。研究海岸带系统对气候变化的响应机制,评估气候变化对海岸带社会、经济和生态的潜在影响,提出切实可行的应对策略,是保障海岸带系统安全的重要前提。回顾了IPCC的四次评估报告,分析了全球气候变化对海岸带的影响。总结了海岸带脆弱性评估框架以及脆弱性评价指标体系,综述了国内外气候变化影响下海岸带脆弱性评估研究的进展。在综述国内外该领域研究进展的基础上,展望了气候变化影响下海岸带脆弱性评估研究。全球气候变化及其对海岸带的影响还有大量的科学技术问题需要进一步探讨,同时也需要对各种适应气候变化措施的可行性和有效性进行研究和验证。     

自然生态系统响应气候变化的脆弱性评价研究进展

以气候变暖为标志的全球气候变化已引起各国政府、国际组织和科学工作者的高度重视.气候变化给人类及自然生态系统带来的风险和危害日趋增大.生态系统脆弱性分析和评价是适应和减缓气候变化的关键和基础,已成为近年来气候变化领域和生态学领域的研究热点.目前国内外学者正在不同领域、不同空间尺度上开展响应气候变化的脆弱性评价,其中以自然生态系统为评价对象的脆弱性研究也有了长足的发展.本文通过对脆弱性的概念、气候变化脆弱性评价研究现状、自然生态系统响应气候变化的脆弱性定量评价方法的综述,探讨了该研究领域存在的问题和未来的发展前景.     

Patch dynamics in grazed subtropical native pastures in south‐east Queensland

Abstract Patch formation is common in grazed grasslands but the mechanisms involved in the formation and maintenance of patches are not clear. To increase our knowledge on this subject we examined possible reasons for patch formation and the influence of management on changes between patch states in three experiments in native pasture communities in the Crows Nest district, south‐east Queensland. In these communities, small‐scale patches (tall grassland (dominated by large and medium tussock grasses), short swards (dominated by short tussock grasses and sedges), and lawns (dominated by stoloniferous and/or rhizomatous grasses)) are readily apparent. We hypothesized that the formation of short sward and lawn patches in areas of tall grassland was due to combinations of grazing and soil fertility effects. This was tested in Experiment 1 by applying a factorial combination of defoliation, nutrient application and transplants of short tussock and stoloniferous species to a uniform area of tall grassland. Total species density declined during the experiment, was lower with high nutrient applications, but was not affected by defoliation. There were significant changes in abundance of species that provided support for our hypotheses. With light defoliation and low nutrients, the tall grassland remained dominated by large tussock grasses and contained considerable amounts of forbs. With heavy defoliation, the pastures were dominated by medium tussock grasses and there were significant decreases in forbs and increases in sedges (mainly with low nutrients) and stoloniferous grasses (mainly with high nutrients). Total germinable seed densities and those of most species groups were significantly lower in the heavy defoliation than the light defoliation plots. Total soil seed numbers were not affected by nutrient application but there were fewer seeds of the erect forbs and more sedge seeds in plots with high nutrients. The use of resting from grazing and fire to manage transitions between patches was tested. In Experiment 2 , changes in species density and abundance were measured for 5 years in the three patch types with and without grazing. Experiment 3 examined the effects of fire, grazing and resting on short sward patches over 4 years. In Experiment 2 , total species density was lower in lawn than short sward or tall grassland patches, and there were more species of erect forbs than other plant groups in all patch types. The lawn patches were originally dominated by Cynodon spp. This dominance continued with grazing but in ungrazed patches the abundance of Cynodon spp. declined and that of forbs increased. In the short sward patches, dominance of short tussock grasses continued with grazing but in ungrazed plots their abundance declined while that of large tussock grasses increased. The tall grassland patches remained dominated by large and medium tussock species. In Experiment 3 , fire had no effect on species abundance. On the grazed plots the short tussock grasses remained dominant but where the plots were rested from grazing the small tussock grasses declined and the large tussock grasses increased in abundance. The slow and relatively small changes in these experiments over 4 or 5 years showed how stable the composition of these pastures is, and that rapid changes between patch types are unlikely.     

The response of benthic macroinvertebrate communities to climate change: evidence from subtropical mountain streams in Central China

Ecological effects of climate change on terrestrial and marine ecosystems are increasingly apparent but evidence from freshwater is scarce, particularly in Asia. Using data from two subtropical Central China streams, we predicted the changes of some benthic macroinvertebrate communities under various climatic scenarios. Our results show that the average annual air temperature, in the study watershed, increased significantly (P < 0.05) by 0.6 °C over the last 30 years (1978–2007), whereas the average annual water flow declined by 30.9 m³ s^–1. Based on the winter sampling of benthic macroinvertebrates at four stream locations over last six years, we observed that macroinvertebrate abundance and Margalef diversity dropped with increasing water temperatures or decreasing smoothed sea surface temperatures (SSST). The winter macroinvertebrate abundance and biodiversity declined by 11.1% and 6.8% for every 1 °C water temperature rise. In contrast, increases in future SSST by one unit would increase winter macroinvertebrate abundance and biodiversity by 38.2% and 16.0%, respectively. Although many dominant taxa were predicted to persist when water temperatures increase by 1 °C, several scarce taxa, e.g., Orthocladius clarkei and Hippeutis umbilicalis, could be at a level of potential local extinction. Our identification of these links, between climate change and stream macroinvertebrate communities, has wide implications for the conservation of mountain stream ecosystems in the upper Yangtze River under scenarios of climate change. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)