Species range shifts in response to climate change and human pressure for the world's largest amphibian

Future climate change increase species vulnerability and present new opportunities for biodiversity conservation in China

Climate change is exerting severe pressure on terrestrial biodiversity. It is essential to clarify how vulnerabilities to climate change differ among taxonomic groups to mitigate biodiversity loss. Conservation planning should aim to minimize additional threats while maximizing the opportunities that climate change offers. In this study, we used species distribution models to simulate the current and future (2050s) suitable distributions of Chinese mammals, reptiles, amphibians, birds, and plants. We analyzed the climate change vulnerability across these taxonomic groups and identified conservation priorities based on the vulnerable and opportunity areas that will result from climate change. By the 2050s, the losses of current habitat suitable for amphibians, mammals, reptiles, birds, and plants will reach 26.8 %, 16.8 %, 13.8 %, 11.9 %, and 10.0 %, respectively, indicating high vulnerability to climate change. The relative loss of suitable habitat is influenced by the threat status of species. Spatially, the areas of China with the highest vulnerability to climate change are mainly distributed in the north, northwest, and Qinghai-Tibet regions, whereas high-opportunity areas are mainly in the south. Areas with high opportunity and vulnerability will together account for 11.8 % of land area in China and represent conservation priorities for reducing species extinction. However, provinces with large priority areas will have lower human development and human footprint indexes, which will challenge the successful implementation of conservation efforts. Our results highlight the different responses of different Chinese taxonomic groups to climate change and will guide the selection of crucial areas for reducing species extinction risk.

Rethinking Conservation and Restoration Strategies of Endangered and Key Medicinal Clavicarpa Plants in Yunnan-Kweichow Plateau's Karst Areas Under Climate Change

The Clavicarpa species, valued for their pharmaceutical, ornamental, and economic importance, exhibit notable rarity and endemism in the Karst areas of the Yunnan-Kweichow Plateau in China. These species face significant threats from habitat loss and fragmentation, leading to a decline in biodiversity. To mitigate these threats, the Maxent algorithm was employed to analyze current and future distribution patterns, with a particular focus on the influence of climate variables in predicting potential distribution shifts and assessing extinction risks under the optimistic SSP1-2.6 and the pessimistic SSP5-8.5 socioeconomic scenarios. The EC-Earth3-Veg, MRI-ESM2-0, and MPI-ESM1-2-HR models were utilized for conservation status assessment and project future distributions for four time periods: the present, 2030s, 2050s, and 2070s. The minimum temperature during the coldest month (Bio 6) was identified as the most critical environmental factor, influencing both habitat contraction and expansion. Our modeling indicates that regions such as South, Central, and East China, particularly areas east of the Aihui-Tengchong line and south of the Yangtze River, exhibit the highest suitability for Clavicarpa species within the geographical coordinates of 18° N-45° N and 97° E-120° E. Conversely, climate change projections suggest a habitat expansion for Impatiens claviger, Impatiens tubulosa, Impatiens pritzelii, and Impatiens apalophylla, while Impatiens guizhouensis and Impatiens wilsonii face increased extinction risks. Specifically, I. claviger, I. tubulosa, and I. apalophylla are expected to shift northward, necessitating potential relocation to southern regions, while I. guizhouensis and I. wilsonii are projected to experience habitat losses of over 23.94% and 9.13%, respectively. Our research provides a robust scientific foundation for the conservation and sustainable utilization of these important pharmaceutical species and offers a framework for effective biodiversity management. We recommend using protected areas as a basis for the future conservation, breeding, cultivation, and utilization of Clavicarpa species.

Identifying priority conservation areas for threatened amphibian habitats in the Yangtze river Delta region to maintain regional biodiversity

The complex life cycle traits of amphibians make them especially sensitive to environmental change, and their ongoing conservation requires the maintenance of suitable habitat that accounts for such life cycle characteristics which may impacted by local environmental dynamics arising from climate change and human disturbance. Many existing studies on amphibian habitats disregard this important issue, leading to uncertainty in managing critical habitats. The application of appropriate conservation practices is therefore constrained by the fact that the major factors influencing amphibian habitats, and their spatio-temporal dynamics at different life stages, are poorly understood. In responding to this notable shortcoming, we applied a Bayesian Belief Network model and geographical detector method to identify spatial and seasonal changes in threatened amphibian habitats of the Yangtze River Delta region (YRDR). Our results reveal the relative importance of different environmental factors contributing to spatio-temporal change of threatened amphibian habitats in YRDR. The results highlight the spatially heterogenous nature of amphibian habitats and the impacts of urbanization, as evidenced by quantitative metrics of percentage area of built-up land and distance to built-up land. Habitat conservation priority analyses also indicate the importance of prioritizing habitat restoration efforts in severely degraded areas. Analysis of seasonality indicates that amphibians face particularly severe challenges during their autumn hibernation period (Slope=-0.002). In revealing seasonal variations in the level of threat to amphibians at different life stages across different habitats, this study fills an important knowledge gap and therefore supports regional amphibian habitat conservation and restoration efforts. The results of the study further imply that current conservation strategies need to comprehensively account for seasonal changes, life-cycle stages, and spatial heterogeneity.

Influence of wildfire ash concentration on development, survival, and skin and gut microbiota of Rana dybowskii

Climate changes can increase wildfires and thereby endanger the habitats and survival of amphibians, but relevant research is limited. The gut and skin microbiota plays a critical role in amphibian protection. Wildfire ash may negatively impact amphibians, causing inflammation and microbiota disruption, but the impact on microbial communities is still uncertain. In this study, the impact of wildfire ash on the cutaneous and gut microbiota of Rana dybowskii was investigated over a 28-day period using five groups with aqueous extracts of ash. Polycyclic aromatic hydrocarbons in the ash were analyzed. Body mass, development, survival rates, and microbiota diversity were tested. Significant differences in body mass, development rates, and survival rates among the treatment groups were observed. The survival and development rates at lower concentrations of ash (T0 and T0_75) were more similar to those under control conditions. Analyses of alpha and beta diversity revealed significant changes in microbiota composition across ash concentrations, with specific phyla and genera affected. Linear discriminant analysis effect analysis identified distinct microbiota associated with each treatment group, demonstrating the specific influence of ash concentrations on the microbiota composition of tadpoles. BugBase analysis revealed significant differences in the same phenotypes in gut microbiota, but not in nine skin microbiota phenotypes across groups. This research underscores the sensitivity of amphibian microbiota to environmental changes and provides insights into the ecological consequences of wildfires on aquatic ecosystems.

Detecting Range Shrinking From Historical Amphibian Species Occurrences Under Influence of Human Impacts: A Case Study Using the Chinese Giant Salamander, Andrias davidianus

Amphibian declines, driven by climate change (e.g., shifting temperatures, altered precipitation) and human activities like deforestation, agriculture, and urbanization, may lead to local extinctions. Quantifying the relative impact of climate change versus human influence remains challenging. This study uses species distribution models (SDMs) and nearly 1000 years of historical distribution data from ancient texts and local archives to reconstruct the past distribution range of the Chinese giant salamander (Andrias davidianus) and to assess the spatiotemporal shifts in its range over time. The results reveal that over the past millennium, the potential distribution range of the Chinese giant salamander consistently contracted, decreasing by 10% from the Ming Dynasty (1368-1644) to the Qing Dynasty (1644-1912) and a further 30% from the Qing Dynasty to the modern era. Losses are concentrated in eastern plains with abundant water bodies, resulting in available habitat reduction to 27% of the Qing Dynasty's area. Climate factors have been key in shaping the salamander's distribution, but our findings reveal that population density has consistently impacted its range throughout history, highlighting the lasting influence of human activity. Climate models project a about 10% decrease in suitable habitat by around 2090, with northward shifts in suitable habitat. Given the urgent threat of habitat loss and environmental degradation, immediate and effective actions are crucial to prevent the local extinction of the Chinese giant salamander, including habitat protection, environmental restoration, and strict regulations against hunting and habitat destruction. This study, analyzing the Chinese giant salamander's suitable habitat historically, identifies human activities as a pivotal force in early amphibian species decline in China, contributing valuable perspectives to future amphibian conservation and management.

Incorporating Implicit Information to Disentangle the Impacts of Hydropower Dams and Climate Change on Basin-Scale Fish Habitat Distribution

The loss of freshwater fish habitats, exacerbated by climate change and dam constructions, poses a critical environmental concern. The upper Yangtze River basin, noted for its abundant fish fauna and concentrated dam development, serves as a crucial locale for investigating the impacts of climate shifts and dam construction. This study aims to disentangle the impacts of hydroelectric dams and climate change on fish habitat distribution by analyzing species presence data across different periods. Species distribution models were constructed using Maxent for Coreius guichenoti (a warm-water endangered fish) and Schizopygopsis malacanthus (a cold-water endangered fish). The model accuracy was assessed using the area under the curve of the receiver operating characteristic. Habitat distribution modeling and prediction for the pre-dam period (1970-2000) and post-dam period (2001-2020), as well as future climate change under two shared socioeconomic pathways scenarios, were conducted. The impacts of climate change and dam construction on the habitat suitability of two fish species were quantified. The results revealed dam construction predominantly diminished habitat suitability and range, with high-suitability habitats in the post-dam period decreasing by 56.3% (720.18 km) and 67.0% (1665.52 km) for the two fishes, respectively. Climate change would enhance the habitat suitability of Coreius guichenoti, while it would decrease the habitat suitability of Schizopygopsis malacanthus. The impact of dam construction is greater that of climate change for them. This study underscores the profound impacts of dam construction on fish habitats, particularly for cold-water species, and highlights the critical need for habitat restoration in sustainable hydropower development. Our method of disentangling these factors also provides a new approach to evaluating environmental impacts in large river basins.

Prediction of Potential Suitable Distribution Areas for an Endangered Salamander in China

Climate change has been considered to pose critical threats for wildlife. During the past decade, species distribution models were widely used to assess the effects of climate change on the distribution of species' suitable habitats. Among all the vertebrates, amphibians are most vulnerable to climate change. This is especially true for salamanders, which possess some specific traits such as cutaneous respiration and low vagility. The Wushan salamander (Liua shihi) is a threatened and protected salamander in China, with its wild population decreasing continuously. The main objective of this study was to predict the distribution of suitable habitat for L. shihi using the ENMeval parameter-optimized MaxEnt model under current and future climate conditions. Our results showed that precipitation, cloud density, vegetation type, and ultraviolet radiation were the main environmental factors affecting the distribution of L. shihi. Currently, the suitable habitats for L. shihi are mainly concentrated in the Daba Mountains, including northeastern Chongqing and western Hubei Provinces. Under the future climate conditions, the area of suitable habitats increased, which mainly occurred in central Guizhou Province. This study provided important information for the conservation of L. shihi. Future studies can incorporate more species distribution models to better understand the effects of climate change on the distribution of L. shihi.

Species distribution modeling combined with environmental DNA analysis to explore distribution of invasive alien mosquitofish (Gambusia affinis) in China

China has become one of the most serious countries suffering from biological invasions in the world. In the context of global climate change, invasive alien species (IAS) are likely to invade a wider area, posing greater ecological and economic threats in China. Western mosquitofish (Gambusia affinis), which is known as one of the 100 most invasive alien species, has distributed widely in southern China and is gradually spreading to the north, causing serious ecological damage and economic losses. However, its distribution in China is still unclear. Hence, there is an urgent need for a more convenient way to detect and monitor the distribution of G. affinis to put forward specific management. Therefore, we detected the distribution of G. affinis in China under current and future climate change by combing Maxent modeling prediction and eDNA verification, which is a more time-saving and reliable method to estimate the distribution of species. The Maxent modeling showed that G. affinis has a broad habitat suitability in China (especially in southern China) and would continue to spread in the future with ongoing climate change. However, eDNA monitoring showed that occurrences can already be detected in regions that Maxent still categorized as unsuitable. Besides temperature, precipitation and human influence were the most important environmental factors affecting the distribution of G. affinis in China. In addition, by environmental DNA analysis, we verified the presence of G. affinis predicted by Maxent in the Qinling Mountains where the presence of G. affinis had not been previously recorded.

Evaluating effects of climate change on the spatial distribution of an atypical cavefish Onychostoma macrolepis

Comprehending endangered species' spatial distribution in response to global climate change (GCC) is of great importance for formulating adaptive management, conservation, and restoration plans. However, it is regrettable that previous studies mainly focused on geoclimatic species, while neglected climate-sensitive subterranean taxa to a large extent, which clearly hampered the discovery of universal principles. In view of this, taking the endemic troglophile riverine fish Onychostoma macrolepis (Bleeker, 1871) as an example, we constructed a MaxEnt (maximum-entropy) model to predict how the spatial distribution of this endangered fish would respond to future climate changes (three Global Climate Models × two Shared Socio-economic Pathways × three future time nodes) based on painstakingly collected species occurrence data and a set of bioclimatic variables, including WorldClim and ENVIREM. Model results showed that variables related to temperature rather than precipitation were more important in determining the geographic distribution of this rare and endemic fish. In addition, the suitable areas and their distribution centroids of O. macrolepis would shrink (average: 20,901.75 km2) and move toward the northeast or northwest within the study area (i.e. China). Linking our results with this species' limited dispersion potential and unique habitat requirements (i.e. karst landform is essential), we thus recommended in situ conservation to protect this relict.

Predicting the impact of climate change on the distribution of two relict Liriodendron species by coupling the MaxEnt model and actual physiological indicators in relation to stress tolerance

Climate change has a crucial impact on the distributions of plants, especially relict species. Hence, predicting the potential impact of climate change on the distributions of relict plants is critical for their future conservation. Liriodendron plants are relict trees, and only two natural species have survived: L. chinense and L. tulipifera. However, the extent of the impact of future climate change on the distributions of these two Liriodendron species remains unclear. Therefore, we predicted the suitable habitat distributions of two Liriodendron species under present and future climate scenarios using MaxEnt modeling. The results showed that the area of suitable habitats for two Liriodendron species would significantly decrease. However, the two relict species presented different habitat shift patterns, with a local contraction of suitable habitat for L. chinense and a northward shift in suitable habitat for L. tulipifera, indicating that changes in environmental factors will affect the distributions of these species. Among the environmental factors assessed, May precipitation induced the largest impact on the L. chinense distribution, while L. tulipifera was significantly affected by precipitation in the driest quarter. Furthermore, to explore the relationship between habitat suitability and Liriodendron stress tolerance, we analyzed six physiological indicators of stress tolerance by sampling twelve provenances of L. chinense and five provenances of L. tulipifera. The composite index of six physiological indicators was significantly negatively correlated with the habitat suitability of the species. The stress tolerance of Liriodendron plants in highly suitable areas was lower than that in areas with moderate or low suitability. Overall, these findings improve our understanding of the ecological impacts of climate change, informing future conservation efforts for Liriodendron species.

Dispersal abilities favor commensalism in animal-plant interactions under climate change

Scientists still poorly understand how biotic interactions and dispersal limitation jointly interact and affect the ability of species to track suitable habitats under climate change. Here, we examine how animal-plant interactions and dispersal limitations might affect the responses of Brazil nut-dependent frogs facing projected climate change. Using ecological niche modelling and dispersal simulations, we forecast the future distributions of the Brazil nut tree and three commensalist frog species over time (2030, 2050, 2070, and 2090) in the regional rivalry (SSP370) scenario that includes great challenges to mitigation and adaptation. With the exception of one species, projections point to a decrease in suitable habitats of up to 40.6%. For frog species with potential reductions of co-occurrence areas, this is expected to reduce up to 23.8% of suitable areas for binomial animal-plant relationships. Even so, biotic interactions should not be lost over time. Species will depend on their own dispersal abilities to reach analogous climates in the future for maintaining ecological and evolutionary processes associated with commensal taxa. However, ecological and evolutionary processes associated with commensal taxa should be maintained in accordance with their own dispersal ability. When dispersal limitation is included in the models, the suitable range of all three frog species is reduced considerably by the end of the century. This highlights the importance of dispersal limitation inclusion for forecasting future distribution ranges when biotic interactions matter.

Temporal Dynamics of the Goose Habitat in the Middle and Lower Reaches of the Yangtze River

The middle and lower reaches of the Yangtze River are the most important areas for geese to overwinter in the East Asian–Australasian Flyway, where about 180,000 geese fly to overwinter each year. Over the past 20 years, the region has experienced extensive and rapid land cover changes that may have exceeded the adaptability of geese, and have led to suitable goose habitat area loss, thereby, reducing the stability of the geese population. In order to identify the suitable goose habitat areas in this region, based on ensemble modeling and satellite tracking data, in this study, we simulated the spatial distribution changes in the suitable goose habitat areas over the past 20 years. The results showed that the suitable goose habitat areas had suffered varying degrees of loss, among which, the lesser white-fronted goose had the greatest suitable goose habitat area loss of over 50%. Moreover, we found that wetlands, lakes, and floodplains were the key components of suitable goose habitat areas, and the categories (land use) showed significant differences in different periods (p < 0.01). This may be one of the main reasons for the decrease in suitable goose habitat areas. The results of this study provide an important reference for the adaptive management and protection of geese in the middle and lower reaches of the Yangtze River.

Driven to the edge: Species distribution modeling of a Clawed Salamander (Hynobiidae: Onychodactylus koreanus) predicts range shifts and drastic decrease of suitable habitats in response to climate change

Climate change is one of the major threats to global amphibian diversity, and consequently, the species distribution is expected to shift considerably in the future. Therefore, predicting such shifts is important to guide conservation and management plans. Here, we used eight independent environmental variables and four representative concentration pathways (RCPs) to model the current and future habitat suitability of the Korean clawed salamander (Onychodactylus koreanus) and then defined the dispersal limits of the species using cost distance analysis. The current habitat suitability model generated using the maximum entropy algorithm was highly consistent with the known distribution of the species and had good predictive performance. Projections onto years 2050 and 2070 predicted a drastic decrease of habitat suitability across all RCPs, with up to 90.1% decrease of suitable area and 98.0% decrease of optimal area predicted from binary presence grids. The models also predicted a northeastward shift of habitat suitability toward high-elevation areas and a persistence of suitability along the central ridge of the Baekdudaegan Range. This area is likely to become a climatic refugium for the species in the future, and it should be considered as an area of conservation priority. Therefore, we urge further ecological studies and population monitoring to be conducted across the range of O. koreanus. The vulnerability to rapid climate change is also shared by other congeneric species, and assessing the impacts of climate change on these other species is needed to better conserve this unique lineage of salamanders.

Predicting range shifts of Davidia involucrata Ball. under future climate change

Understanding and predicting how species will respond to climate change is crucial for biodiversity conservation. Here, we assessed future climate change impacts on the distribution of a rare and endangered plant species, Davidia involucrate in China, using the most recent global circulation models developed in the sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC6). We assessed the potential range shifts in this species by using an ensemble of species distribution models (SDMs). The ensemble SDMs exhibited high predictive ability and suggested that the temperature annual range, annual mean temperature, and precipitation of the driest month are the most influential predictors in shaping distribution patterns of this species. The projections of the ensemble SDMs also suggested that D. involucrate is very vulnerable to future climate change, with at least one-third of its suitable range expected to be lost in all future climate change scenarios and will shift to the northward of high-latitude regions. Similarly, at least one-fifth of the overlap area of the current nature reserve networks and projected suitable habitat is also expected to be lost. These findings suggest that it is of great importance to ensure that adaptive conservation management strategies are in place to mitigate the impacts of climate change on D. involucrate.

Species on the move around the Australian coastline: A continental-scale review of climate-driven species redistribution in marine systems

Climate-driven changes in the distribution of species are a pervasive and accelerating impact of climate change, and despite increasing research effort in this rapidly emerging field, much remains unknown or poorly understood. We lack a holistic understanding of patterns and processes at local, regional and global scales, with detailed explorations of range shifts in the southern hemisphere particularly under-represented. Australian waters encompass the world's third largest marine jurisdiction, extending from tropical to sub-Antarctic climate zones, and have waters warming at rates twice the global average in the north and two to four times in the south. Here, we report the results of a multi-taxon continent-wide review describing observed and predicted species redistribution around the Australian coastline, and highlight critical gaps in knowledge impeding our understanding of, and response to, these considerable changes. Since range shifts were first reported in the region in 2003, 198 species from nine Phyla have been documented shifting their distribution, 87.3% of which are shifting poleward. However, there is little standardization of methods or metrics reported in observed or predicted shifts, and both are hindered by a lack of baseline data. Our results demonstrate the importance of historical data sets and underwater visual surveys, and also highlight that approximately one-fifth of studies incorporated citizen science. These findings emphasize the important role the public has had, and can continue to play, in understanding the impact of climate change. Most documented shifts are of coastal fish species in sub-tropical and temperate systems, while tropical systems in general were poorly explored. Moreover, most distributional changes are only described at the poleward boundary, with few studies considering changes at the warmer, equatorward range limit. Through identifying knowledge gaps and research limitations, this review highlights future opportunities for strategic research effort to improve the representation of Australian marine species and systems in climate-impact research.

Design of Protected Area by Tracking and Excluding the Effects of Climate and Landscape Change: A Case Study Using Neurergus derjugini

This study aimed to use the applications of Ensemble Species Distribution Modelling (eSDM), Geographical Information Systems (GISs), and Multi-Criteria Decision Analysis (MCDA) for the design of a protected area (PA) for the critically endangered yellow-spotted mountain newt, Neurergus derjugini, by tracking and excluding the effects of climate and landscape changes in western Iran and northeastern Iraq. Potential recent and future distributions (2050 and 2070) were reconstructed by eSDM using eight algorithms with MRI-CGCM3 and CCSM4 models. The GIS-based MCDA siting procedure was followed inside habitats with high eSDM suitability by eliminating the main roads, cities, high village density, dams, poor vegetation, low stream density, agricultural lands and high ridge density. Then, within the remaining relevant areas, 10 polygons were created as “nominations” for PAs (NPAs). Finally, for 10 different NPAs, the suitability score was ranked based on ratings and weights (analytical hierarchy process) of the number of newt localities, NPA connectivity, NPA shape, NPA habitat suitability in 2070, NPA size, genetic diversity, village density and distance to nearest PAs, cities, and main roads. This research could serve as a modern realistic approach for environmental management to plan conservation areas using a cost-effective and affordable technique.

Capturing response differences of species distribution to climate and human pressures by incorporating local adaptation: Implications for the conservation of a critically endangered species

Considering local adaptation has been increasingly involved in forecasting species distributions under climate change and the management of species conservation. Herein, we take the critically endangered Chinese giant salamander (Andrias davidianus) that has both a low dispersal ability and distinct population divergence in different regions as an example. Basin-scale models that represent different populations in the Huanghe River Basin (HRB), the Yangtze River Basin (YRB), and the Pearl River Basin (PRB) were established using ensemble species distribution models. The species ranges under the future human population density (HPD) and climate change were predicted, and the range loss was evaluated for local basins in 2050 and 2070. Our results showed that the predominant factors affecting species distributions differed among basins, and the responses of the species occurrence to HPD and climate factors were distinctly different from northern to southern basins. Future HPD changes would be the most influential factor that engenders negative impacts on the species distribution in all three basins, especially in the HRB. Climate change will likely be less prominent in decreasing the species range, excluding in the YRB and PRB under the highest-emissions scenario in 2050. Overall, the high-emissions scenario would more significantly aggravate the negative impacts produced by HPD change in both 2050 and 2070, with maximum losses of species ranges in the HRB, YRB, and PRB of 83.4%, 60.0%, and 53.5%, respectively, under the scenarios of the combined impacts of HPD and climate changes. We proposed adapted conservation policies to effectively protect the habitat of this critically endangered animal in different basins based on the outcomes. Our research addresses the importance of incorporating local adaptation into species distribution modeling to inform conservation and management decisions.