Impact of Climate Change on the Distribution of Three Rare Salamanders (Liua shihi, Pseudohynobius jinfo, and Tylototriton wenxianensis) in Chongqing, China, and Their Conservation Implications

The Wushan Salamander (Liua shihi), Jinfo Salamander (Pseudohynobius jinfo), and Wenxian Knobby Salamander (Tylototriton wenxianensis) are rare national Class II protected wild animals in China. We performed MaxEnt modeling to predict and analyze the potential distribution and trends of these species in Chongqing under current and future climate conditions. Species distribution data were primarily obtained from field surveys, supplemented by museum collections and the existing literature. These efforts yielded 636 records, including 43 for P. jinfo, 23 for T. wenxianensis, and 570 for L. shihi. Duplicate records within the same 100 m × 100 m grid cell were removed using ENMTools, resulting in 10, 12, and 58 valid distribution points for P. jinfo, T. wenxianensis, and L. shihi, respectively. The optimization of feature class parameters (FC) and the regularization multiplier (RM) were applied using R package "ENMeval 2.0" to establish the optimal model with MaxEnt. The refined models were applied to simulate the suitable distribution areas for the three species. The results indicate that the current suitable habitat area for L. shihi accounted for 9.72% of the whole region of the Chongqing municipality. It is projected that, by 2050, the proportion of suitable habitat will increase to 12.54% but will decrease to 11.98% by 2070 and further decline to 8.80% by 2090. The current suitable habitat area for P. jinfo accounted for 1.08% of the whole region of the Chongqing municipality, which is expected to decrease to 0.31%% by 2050, 0.20% by 2070, and 0.07% by 2090. The current suitable habitat area for T. wenxianensis accounted for 0.81% of the whole region of the Chongqing municipality, which is anticipated to decrease to 0.37% by 2050, 0.21% by 2070, and 0.06% by 2090. Human disturbance, climate variables, and habitat characteristics are the primary factors influencing the distribution of three salamander species in Chongqing. The proximity to roads significantly impacts L. shihi, while climate conditions mainly affect P. jinfo, and the distance to water sources is crucial for T. wenxianensis. The following suggestions were made based on key variables identified for each species: (1) For L. shihi, it is imperative to minimize human disturbances and preserve areas without roads and the existing vegetation within nature reserves to ensure their continued existence. (2) For P. jinfo, the conservation of high-altitude habitats is of utmost importance, along with the reduction in disturbances caused by roads to maintain the species' ecological niche. (3) For T. wenxianensis, the protection of aquatic habitats is crucial. Additionally, efforts to mitigate the impacts of road construction and enhance public awareness are essential for the preservation of this species and the connectivity of its habitats.

Distributional responses to climate change of two maple species in southern China

Climate change is a major factor affecting biodiversity and species distribution, particularly of montane species. Species may respond to climate change by shifting their range to higher elevations. The southeastern Qinghai-Tibetan Plateau (QTP) and the Hengduan Mountains are considered as global biodiversity hotspots. However, information on the response of maple species to climate change in these regions was limited. Therefore, we selected two maple species that occur there and assessed changes in their habitat suitability under past, present and future climate scenarios in Biomod2. The results showed that temperature seasonality (bio4) was the most critical factor influencing their potential distributions. The distribution of potentially suitable habitat for Acer caesium and Acer stachyophyllum was predicted to be larger during the LGM compared to the present. Under the current climate scenario, the largest areas of potentially suitable habitat for these species were mainly located in southeastern Tibet, the Hengduan Mountains in northwestern Yunnan and western Sichuan, the Qinling-Daba Mountains in southern Gansu and the Wumeng-Daliang Mountains in northeastern Yunnan, western Guizhou and southeastern Sichuan. Under future climate change scenarios, the predicted loss of suitable habitat areas for these two species ranged from 13.78% to 45.71% and the increase ranged from 18.88% to 57.98%, with an overall increasing trend. The suitable habitat areas were predicted to shift towards the eastern parts of the QTP under both the pessimistic and optimistic future climate change scenarios in the 2050s and the 2070s, which became evident as global warming intensified, particularly in the eastern QTP and the Hengduan Mountains. Our results highlight the possibility that the diverse topography along altitudinal gradients in the QTP and the Hengduan Mountains may potentially mitigate the range contraction of mountain plants in response to climate warming. These findings provide a basis for planning conservation areas, planting and species conservation in the mountainous areas of southern China under the anticipated global warming.

Impacts of anthropogenic climate change on tropical montane forests: an appraisal of the evidence

In spite of their small global area and restricted distributions, tropical montane forests (TMFs) are biodiversity hotspots and important ecosystem services providers, but are also highly vulnerable to climate change. To protect and preserve these ecosystems better, it is crucial to inform the design and implementation of conservation policies with the best available scientific evidence, and to identify knowledge gaps and future research needs. We conducted a systematic review and an appraisal of evidence quality to assess the impacts of climate change on TMFs. We identified several skews and shortcomings. Experimental study designs with controls and long-term (≥10 years) data sets provide the most reliable evidence, but were rare and gave an incomplete understanding of climate change impacts on TMFs. Most studies were based on predictive modelling approaches, short-term (<10 years) and cross-sectional study designs. Although these methods provide moderate to circumstantial evidence, they can advance our understanding on climate change effects. Current evidence suggests that increasing temperatures and rising cloud levels have caused distributional shifts (mainly upslope) of montane biota, leading to alterations in biodiversity and ecological functions. Neotropical TMFs were the best studied, thus the knowledge derived there can serve as a proxy for climate change responses in under-studied regions elsewhere. Most studies focused on vascular plants, birds, amphibians and insects, with other taxonomic groups poorly represented. Most ecological studies were conducted at species or community levels, with a marked paucity of genetic studies, limiting understanding of the adaptive capacity of TMF biota. We thus highlight the long-term need to widen the methodological, thematic and geographical scope of studies on TMFs under climate change to address these uncertainties. In the short term, however, in-depth research in well-studied regions and advances in computer modelling approaches offer the most reliable sources of information for expeditious conservation action for these threatened forests.

Distribution pattern and change prediction of Phellodendron habitat in China under climate change

Phellodendron has always been of great significance in promoting human health and ecological restoration. However, human activities and climate change have severely affected habitat, population dynamics and sustainable use of Phellodendron. Little is known about the geographical distribution pattern and their responses to climate change of Phellodendron. In order to reveal the impact of climate change on Phellodendron, we conducted a study based on natural distribution data of two species (297 occurrence points), 20 environmental factors, and an optimized MaxEnt model. Our results identified the main environmental factors influencing Phellodendron, predicted their potential geographical distribution, and assessed migration trends under climate change in China. Our analysis showed that Ph. amurense and Ph. chinense have potential suitable habitats of 62.89 × 104 and 70.71 × 104 km2, respectively. Temperature and precipitation were found to play an essential role in shaping the present geographical distribution of Phellodendron populations. Based on two future climate scenarios, we forecasted that the potential suitable habitat of Ph. amurense would decrease by 12.52% (SSP245) and increase by 25.28% (SSP585), while Ph. chinense would decline by 19.61% (SSP245) and 15.78% (SSP585) in the late-21st century. The potential suitable habitats of Ph. amurense and Ph. chinense would shift to northward and westward, respectively. Hydrothermal change was found to be the primary driver of the suitable habitat of Phellodendron populations in the future. We recommend establishing nature reserves for existing Phellodendron populations, especially Ph. chinense. Our study provided a practical framework for the impact of climate change on the suitable habitat of Phellodendron species and guided regional cultivation, long-term conservation, and sustainable use.

Projecting future aboveground carbon sequestration rate of alpine forest on the eastern Tibetan Plateau in response to climate change

The aboveground carbon sequestration rate (ACSR) of forests serves as an indicator of their carbon sequestration capacity over time, providing insights into the potential carbon sequestration capacity of forest ecosystems. To explore the long-term Spatiotemporal variation of ACSR in the transitional ecotone of the eastern Tibetan Plateau under climate change scenarios, we utilized a forest landscape model that was parameterized with forest inventory data from the eastern Tibetan Plateau to simulate this ecological function changes. The study found that climate warming had significant effect on forests ACSR in different types of forests. ACSR was significantly reduced (p<0.05) in cold temperate coniferous and temperate coniferous forests, whereas it was significantly increased in deciduous broad-leaved forests. However, the impact of climate warming on evergreen broad-leaved forests was found to be negligible. At the species level, climate warming has mostly suppressed the ACSR of coniferous trees, except for Chinese hemlock. The main dominant species, spruce and fir, have been particularly affected. Conversely, the ACSR of most broad-leaved trees has increased due to climate warming. In addition, at the landscape scale, the ACSR within this region is expected to experience a steady decline after 2031s-2036s. Despite the effects of climate warming, this trend is projected to persist. In conclusion, the forests ACSR in this region will be significantly affected by future climate warming. Our research indicates that climate warming will have a noticeable suppressive effect on conifers. It is imperative that this factor be taken into account when devising forest management plans for the future in this region.

Riparian areas as a conservation priority under climate change

Identifying climatic refugia is important for long-term conservation planning under climate change. Riparian areas have the potential to provide climatic refugia for wildlife, but literature remains limited, especially for plants. This study was conducted with the purpose of identifying climatic refugia of plant biodiversity in the portion of the Mekong River Basin located in Xishuangbanna, China. We first predicted the current and future (2050s and 2070s) potential distribution of 50 threatened woody species in Xishuangbanna by using an ensemble of small models, then stacked the predictions for individual species to derive spatial biodiversity patterns within each 10 × 10 km grid cell. We then identified the top 17 % of the areas for spatial biodiversity patterns as biodiversity hotspots, with climatic refugia defined as areas that remained as biodiversity hotspots over time. Stepwise regression and linear correlation were applied to analyze the environmental correlations with spatial biodiversity patterns and the relationships between climatic refugia and river distribution, respectively. Our results showed potential upward and northward shifts in threatened woody species, with range contractions and expansions predicted. The spatial biodiversity patterns shift from southeast to northwest, and were influenced by temperature, precipitation, and elevation heterogeneity. Climatic refugia under climate change were related closely to river distribution in Xishuangbanna, with riparian areas identified that could provide climatic refugia. These refugial zones are recommended as priority conservation areas for mitigating the impacts of climate change on biodiversity. Our study confirmed that riparian areas could act as climatic refugia for plants and emphasizes the conservation prioritization of riparian areas within river basins for protecting biodiversity under climate change.

Precipitation and potential evapotranspiration determine the distribution patterns of threatened plant species in Sichuan Province, China

A fundamental goal of ecologists is to determine the large-scale gradients in species richness. The threatened plants are the priority of such studies because of their narrow distribution and confinement to a specific habitat. Studying the distribution patterns of threatened plants is crucial for identifying global conservation prioritization. In this study, the richness pattern of threatened plant species along spatial and elevation gradients in Sichuan Province of China was investigated, considering climatic, habitat-heterogeneity (HHET), geometric constraint and human-induced factors. The species richness pattern was analyzed, and the predictor variables, including mean annual temperature (MAT), mean annual precipitation (MAP), potential evapotranspiration (PET), HHET, and disturbance (DIST), to species richness were linked using the geographical distribution data of threatened species compiled at a spatial resolution of 20 km × 20 km. Generalized linear models and structural equation modelling were used to determine the individual and combined effects of each variable on species richness patterns. Results showed a total of 137 threatened plant species were distributed between 200 and 4800 m.a.s.l. The central region of the province harbors the highest species diversity. MAP and PET profoundly explained the richness pattern. Moreover, the significant role of DIST in the richness patterns of threatened plants was elucidated. These findings could help determine the richness pattern of threatened plant species in other mountainous regions of the world, with consideration of the impact of climate change.

Climate Change and Dispersal Ability Jointly Affects the Future Distribution of Crocodile Lizards

Crocodile lizards (Shinisaurus crocodilurus) are an endangered, 'living fossil' reptile from a monophyletic family and therefore, a high priority for conservation. We constructed climatic models to evaluate the potential impact of climate change on the distribution of crocodile lizards for the period 2000 to 2100 and determined the key environmental factors that affect the dispersal of this endangered species. For the construction of climatic models, we used 985 presence-only data points and 6 predictor variables which showed excellent performance (AUC = 0.974). The three top-ranked factors predicting crocodile lizard distribution were precipitation of the wettest month (bio13, 37.1%), precipitation of the coldest quarter (bio19, 17.9%), and temperature seasonality (bio4, 14.3%). Crocodile lizards were, just as they are now, widely distributed in the north of Guangdong Province in China and Quảng Ninh Province in Vietnam at the last glacial maximum (LGM). Since the LGM, there has been an increase in suitable habitats, particularly in east-central Guangxi Province, China. Under future global warming scenarios, the potential habitat for crocodile lizards is expected to decrease significantly in the next 100 years. Under the most optimistic scenario, only 7.35% to 6.54% of suitable habitat will remain, and under the worst climatic scenario, only 8.34% to 0.86% of suitable habitat will remain. Models for no dispersal and limited dispersal showed that all crocodile lizards would lose habitat as temperatures increase. Our work contributes to an increased understanding of the current and future spatial distribution of the species, supporting practical management and conservation plans.

Combining the Effects of Global Warming, Land Use Change and Dispersal Limitations to Predict the Future Distributions of East Asian Cerris Oaks (Quercus Section Cerris, Fagaceae) in China

Species shift their ranges in response to climate change (CC). However, they may not be able to track optimal conditions as soon as possible, due to limited dispersal ability or habitat fragmentation, caused by land use and land cover change (LULC). This study aimed to explore the combined impacts of CC, LULC and dispersal limitations on the future range dynamics of Quercus acutissima Carruth., Q. variabilis Blume and Q. chenii Nakai, three dominant Cerris oak tree species in warm-temperate and subtropical deciduous forests of China. We used the Maximum Entropy (Maxent) algorithm to predict the suitable habitats for the years 2050 and 2070, under three representative concentration pathways (RCPs). Habitat fragmentation patterns were examined to assess the influence of LULC. Two migration scenarios (full- and partial-migration) were compared to evaluate the effect of dispersal limitations. We found that annual precipitation (AP), minimum temperature in the coldest month (MTCM) and temperature seasonality (TS) play a key role in determining the present distributions of Q. chenii, while AP, MTCM and annual mean temperature (AMT) contribute the most to the distribution models of Q. variabilis and Q. acutissima. For all the three species, LULC will increase the level of habitat fragmentation and lead to the loss of core areas, while limited dispersal ability will restrict the accessibility of future potentially suitable habitats. Under the scenarios of CC and LULC, the suitable areas of Q. chenii will decrease sharply, while those of Q. variabilis in South China will become unsuitable. Our findings highlight the importance of considering dispersal ability, as well as land use and land cover change, for modeling species’ range shifts in the face of global warming. Our study also provides vital information for guiding the management of East Asian Cerris oaks in China; Q. chenii should be listed as a species requiring priority protection, and the threatened habitats of Q. variabilis should be protected to buffer the impacts of CC and LULC.

The potential habitat of desert locusts is contracting: predictions under climate change scenarios

Desert locusts are notorious for their widespread distribution and strong destructive power. Their influence extends from the vast arid and semiarid regions of western Africa to northwestern India. Large-scale locust outbreaks can have devastating consequences for food security, and their social impact may be long-lasting. Climate change has increased the uncertainty of desert locust outbreaks, and predicting suitable habitats for this species under climate change scenarios will help humans deal with the potential threat of locust outbreaks. By comprehensively considering climate, soil, and terrain variables, the maximum entropy (MaxEnt) model was used to predict the potential habitats of solitary desert locusts in the 2050s and 2070s under the four shared socioeconomic pathways (SSP126, SSP245, SSP370, and SSP585) in the CMIP6 model. The modeling results show that the average area under the curve (AUC) and true skill statistic (TSS) reached 0.908 ± 0.002 and 0.701, respectively, indicating that the MaxEnt model performed extremely well and provided outstanding prediction results. The prediction results indicate that climate change will have an impact on the distribution of the potential habitat of solitary desert locusts. With the increase in radiative forcing overtime, the suitable areas for desert locusts will continue to contract, especially in the 2070s under the SSP585 scenario, and the moderately and highly suitable areas will decrease by 0.88 × 10⁶ km² and 1.55 × 10⁶ km², respectively. Although the potentially suitable area for desert locusts is contracting, the future threat posed by the desert locust to agricultural production and food security cannot be underestimated, given the combination of maintained breeding areas, frequent extreme weather events, pressure from population growth, and volatile sociopolitical environments. In conclusion, methods such as monitoring and early warning, financial support, regional cooperation, and scientific prevention and control of desert locust plagues should be further implemented.

Spatial dynamics of Chinese Muntjac related to past and future climate fluctuations

Climate fluctuations in the past and in the future are likely to result in population expansions, shifts, or the contraction of the ecological niche of many species, and potentially leading to the changes in their geographical distributions. Prediction of suitable habitats has been developed as a useful tool for the assessment of habitat suitability and resource conservation to protect wildlife. Here, we model the ancestral demographic history of the extant modern Chinese Muntjac Muntiacus reevesi populations using approximate Bayesian computation (ABC) and used the maximum entropy model to simulate the past and predict the future spatial dynamics of the species under climate oscillations. Our results indicated that the suitable habitats for the M. reevesi shifted to the Southeast and contracted during the Last Glacial Maximum, whereas they covered a broader and more northern position in the Middle Holocene. The ABC analyses revealed that the modern M. reevesi populations diverged in the Middle Holocene coinciding with the significant contraction of the highly suitable habitat areas. Furthermore, our predictions suggest that the potentially suitable environment distribution for the species will expand under all future climate scenarios. These results indicated that the M. reevesi diverged in the recent time after the glacial period and simultaneously as its habitat’s expanded in the Middle Holocene. Furthermore, the past and future climate fluctuation triggered the change of Chinese muntjac spatial distribution, which has great influence on the Chinese muntjac’s population demographic history.

Contrasting Gymnosperm Diversity Across an Elevation Gradient in the Ecoregion of China: The Role of Temperature and Productivity

The species richness–climate relationship is a significant concept in determining the richness patterns and predicting the cause of its distribution. The distribution range of species and climatic variables along elevation have been used in evaluating the elevational diversity gradients (EDG). However, the species richness of gymnosperms along elevation and its driving factors in large geographic areas are still unknown. Here, we aimed at evaluating the EDG of gymnosperms in the ecoregions of China. We divided the geographical region of China into 34 ecoregions and determine the richness pattern of gymnosperm taxa along elevation gradients. We demonstrated the richness patterns of the 237-gymnosperm (219 threatened, 112 endemic, 189 trees, and 48 shrubs) taxa, roughly distributed between 0 and 5,300 m (above sea level) in China. As possible determinants of richness patterns, annual mean temperature (TEMP), annual precipitation (PPT), potential evapotranspiration (PET), net primary productivity (SNPP), aridity index (AI), temperature seasonality (TS), and precipitation seasonality (PS) are the major predictor variables driving the EDG in plants. We used the species interpolation method to determine the species richness at each elevation band. To evaluate the richness pattern of gymnosperms in an ecoregion, generalized additive modeling and structural equation modeling were performed. The ecoregions in the southern part of China are rich in gymnosperm species, where three distinct richness patterns—(i) hump-shaped, (ii) monotonic increase, and (iii) monotonic decline—were noticed in China. All climatic variables have a significant effect on the richness pattern of gymnosperms; however, TEMP, SNPP, TS, and PS explained the highest deviance in diversity-rich ecoregions of China. Our results suggests that the highest number of gymnosperms species was found in the southwestern and Taiwan regions of China distributed at the 1,600- and 2,800-m elevation bands. These regions could be under severe stress in the near future due to expected changes in precipitation pattern and increase of temperature due to climate change. Thus, our study provided evidence of the species–climate relationship that can support the understanding of future conservation planning of gymnosperms.

Predicting the Potential Geographic Distribution and Habitat Suitability of Two Economic Forest Trees on the Loess Plateau, China

The Loess Plateau is one of the most fragile ecosystems in the world. In order to increase the biodiversity in the area, develop sustainable agriculture and increase the income of the local people, we simulated the potential geographic distribution of two economic forest trees (Malus pumila Mill and Prunus armeniaca L.) in the present and future under two climate scenarios, using the maximum entropy model. In this study, the importance and contributions of environmental variables, areas of suitable habitats, changes in habitat suitability, the direction and distance of habitat range shifts, the change ratios for habitat area and land use proportions, were measured. According to our results, bioclimatic variables, topographic variables and soil variables play a significant role in defining the distribution of M. pumila and P. armeniaca. The min temperature of coldest month (bio6) was the most important environmental variable for the distribution of the two economic forest trees. The second most important factors for M. pumila and P. armeniaca were, respectively, the elevation and precipitation of the driest quarter (bio17). At the time of the study, the area of above moderately suitable habitats (AMSH) was 8.7967 × 104 km2 and 11.4631 × 104 km2 for M. pumila and P. armeniaca. The effect of Shared Socioeconomic Pathway (SSP) 5-85 was more dramatic than that of SSP1-26. Between now and the 2090s (SSP 5-85), the AMSH area of M. pumila is expected to decrease to 7.5957 × 104 km2, while that of P. armeniaca will increase to 34.6465 × 104 km2. The suitability of M. pumila decreased dramatically in the south and southeast regions of the Loess Plateau, increased in the middle and west and resulted in a shift in distance in the range of 78.61~190.63 km to the northwest, while P. armeniaca shifted to the northwest by 64.77~139.85 km. This study provides information for future policymaking regarding economic forest trees in the Loess Plateau.

Endemic Juniperus Montane Species Facing Extinction Risk under Climate Change in Southwest China: Integrative Approach for Conservation Assessment and Prioritization

Simple Summary

Climate change is one of the most significant drivers of habitat loss and species extinction, particularly montane endemic species such as Juniper trees, which are restricted to unique habitats. Therefore, assessing the impact of climate change on the extinction risk of species is a promising tool or guide for species conservation planning. The loss in species habitat due to global warming indicates the level of extinction or endangerment. Predictions of suitable habitats are outputs from assessment analysis. This will help conservationists discover new populations of endemic species and help raise the awareness of local people to save and rescue these endangered species.

Abstract

Climate change is an important driver of biodiversity loss and extinction of endemic montane species. In China, three endemic Juniperus spp. (Juniperuspingii var. pingii, J.tibetica, and J.komarovii) are threatened and subjected to the risk of extinction. This study aimed to predict the potential distribution of these three Juniperus species under climate change and dispersal scenarios, to identify critical drivers explaining their potential distributions, to assess the extinction risk by estimating the loss percentage in their area of occupancy (AOO), and to identify priority areas for their conservation in China. We used ensemble modeling to evaluate the impact of climate change and project AOO. Our results revealed that the projected AOOs followed a similar trend in the three Juniperus species, which predicted an entire loss of their suitable habitats under both climate and dispersal scenarios. Temperature annual range and isothermality were the most critical key variables explaining the potential distribution of these three Juniperus species; they contribute by 16–56.1% and 20.4–38.3%, respectively. Accounting for the use of different thresholds provides a balanced approach for species distribution models’ applications in conservation assessment when the goal is to assess potential climatic suitability in new geographical areas. Therefore, south Sichuan and north Yunnan could be considered important priority conservation areas for in situ conservation and search for unknown populations of these three Juniperus species.

The fate of Meconopsis species in the Tibeto-Himalayan region under future climate change

High-mountain areas such as the Tibeto-Himalayan region (THR) host cold-adapted biota expected to be sensitive to anthropogenic climate change. Meconopsis is a representative endangered genus confined to alpine meadow or subnival habitats in the THR. We used climate-niche factor analysis to study the vulnerability of ten Meconopsis species to climate change, comparing current climate (representative of 1960-1990) to future climate scenarios (2070: average 2061-2080). For these ten Meconopsis species, we then identified potential future climate refugia and determined optimal routes for each species to disperse to the proposed refugia. Our results indicate that for the ten Meconopsis species, the regions with low vulnerability to climate change in the THR are the central Qinghai-Tibet Plateau, the Hengduan Mountains (HDM), the eastern Himalayas, and the West Qinling Mountain (WQL), and can be considered potential future climate refugia. Under future climate change, we found for the ten Meconopsis species potential dispersal routes to three of the four identified refugia: the HDM, the eastern Himalayas, and the WQL. Our results suggest that past refugia on the THR will also be the future climate refugia for the ten Meconopsis species, and these species may potentially persist in multiple future climate refugia, likely reducing risks from climate change. Furthermore, climate change may affect the threat ranking of Red Listed Species for Meconopsis species, as Least Concern species were estimated to become more vulnerable to climate change than the only Near Threatened species.

Energy-water and seasonal variations in climate underlie the spatial distribution patterns of gymnosperm species richness in China

Studying the pattern of species richness is crucial in understanding the diversity and distribution of organisms in the earth. Climate and human influences are the major driving factors that directly influence the large-scale distributions of plant species, including gymnosperms. Understanding how gymnosperms respond to climate, topography, and human-induced changes is useful in predicting the impacts of global change. Here, we attempt to evaluate how climatic and human-induced processes could affect the spatial richness patterns of gymnosperms in China. Initially, we divided a map of the country into grid cells of 50 × 50 km2 spatial resolution and plotted the geographical coordinate distribution occurrence of 236 native gymnosperm taxa. The gymnosperm taxa were separated into three response variables: (a) all species, (b) endemic species, and (c) nonendemic species, based on their distribution. The species richness patterns of these response variables to four predictor sets were also evaluated: (a) energy-water, (b) climatic seasonality, (c) habitat heterogeneity, and (d) human influences. We performed generalized linear models (GLMs) and variation partitioning analyses to determine the effect of predictors on spatial richness patterns. The results showed that the distribution pattern of species richness was highest in the southwestern mountainous area and Taiwan in China. We found a significant relationship between the predictor variable set and species richness pattern. Further, our findings provide evidence that climatic seasonality is the most important factor in explaining distinct fractions of variations in the species richness patterns of all studied response variables. Moreover, it was found that energy-water was the best predictor set to determine the richness pattern of all species and endemic species, while habitat heterogeneity has a better influence on nonendemic species. Therefore, we conclude that with the current climate fluctuations as a result of climate change and increasing human activities, gymnosperms might face a high risk of extinction.

Distribution Pattern of Endangered Plant Semiliquidambar cathayensis (Hamamelidaceae) in Response to Climate Change after the Last Interglacial Period

Semiliquidambar cathayensis is a special and endangered plant in China, used for traditional Chinese medicine and in landscape applications. Predicting the impact of climate change on the distribution of S. cathayensis is crucial for its protection and the sustainable use of resources. We used the maximum entropy (MaxEnt) model optimized by the ENMeval data packet to analyze the potential geographic distribution changes of S. cathayensis in 12 provinces of Southern China for the different periods since the last interglacial period (LIG, 120–140 ka). Considering the potential geographic distribution changes in the province, and based on the two climate scenarios of Representative Concentration Pathways (RCP) 2.6 and RCP 8.5, the distribution range of S. cathayensis was analyzed and we predicted the range for the 2050s (average for 2041–2060) and 2070s (average for 2061–2080). The area under AUC (Area under the receiver operating characteristic (ROC) curve) is 0.9388 under these parameters, which indicates that the model is very accurate. We speculate that the glacial period refugia were the Nanling and Wuyi Mountains for S. cathayensis, and central and Western Fujian and Taiwan are likely to be the future climate refugia. In the mid-Holocene (MH, 6 ka), the growth habitat was 32.41% larger than the modern habitat; in the 2050s and 2070s (except RCP2.6–2070s), the growth habitat will shrink to varying degrees, so efforts to support its in situ and ex situ conservation are urgently needed. The jackknife test showed that the main factors affecting the geographical distribution of S. cathayensis were annual precipitation, precipitation of the wettest month, and precipitation of the driest month. The annual precipitation may be the key factor restricting the northward distribution of S. cathayensis. In general, the centroid of the distribution of S. cathayensis will move northward. The centroid of the adaptive habitats will move northward with the highest degree of climate abnormality. We think that Hainan Island is the most likely origin of S. cathayensis. These findings provide a theoretical basis for the establishment of genetic resources protection measures, the construction of core germplasm resources, and the study of the formation and evolution of Hamamelidaceae.