Historical changes in the distribution of the Sichuan golden snub-nosed monkey (Rhinopithecus roxellana) in Sichuan Province, China.

The Sichuan golden snub-nosed monkey (Rhinopithecus roxellana) is a rare and endangered primate species endemic to China. Conducting research on the population distribution changes of the Sichuan golden snub-nosed monkey holds paramount importance for its conservation. Our study represented a comprehensive investigation into the population distribution of the Sichuan snub-nosed monkey by integrating data acquired from field surveys, protected areas, and historical records and using Geographic Information Systems (GIS) to explore changes in distribution across various time periods, including the historical (the Mid-to-Late Pleistocene), recent (1980-2000), and current (2001-2023). The research findings demonstrate a significant shift in the distribution range of the Sichuan golden snub-nosed monkey compared to historical time frames. Notably, between 1980 and 2000, there was a sharp decline in distribution area. Analyses revealed that the southernmost distribution county for the Sichuan golden snub-nosed monkey in Sichuan Province has shifted northward from Huili to Kangding. Furthermore, distribution changes in Sichuan Province are not solely characterized by a reduction in habitat area but also by a decrease in vertical distribution zones. Regions in the northeastern part of Sichuan with elevations below 1000 m, such as Guang'an City, Bazhong City, Dazhou City, and Nanchong City, no longer support the presence of the Sichuan golden snub-nosed monkey. At present, the distribution range is confined to elevations between 1000 and 4000 m in the two major mountain ranges of Qionglai and Minshan. A holistic approach is required to safeguard this species. The establishment of movement corridors can play a critical role in enhancing the overall connectivity of current distribution areas. Additionally, we propose implementing a hierarchical approach to protect current habitats. Spatially differentiated conservation measures should be implemented to prioritize the protection of key habitats while simultaneously monitoring anthropogenic activities in non-key habitats to prevent further fragmentation and isolation of the monkey's distribution areas.

Climate change and anthropogenic activities shrink the range and dispersal of an endangered primate in Sichuan Province, China.

The golden snub-nosed monkey (Rhinopithecus roxellana) is a rare and endemic species in China. The population of golden snub-nosed monkeys in Sichuan Province has an isolated genetic status, large population size, and low genetic diversity, making it highly vulnerable to environmental changes. Our study aimed to evaluate the potential impact of climate and land-use changes on the distribution and dispersal paths of the species in Sichuan Province. We used three general circulation models (GCMs), three greenhouse gas emission scenarios, and three land-use change scenarios suitable for China to predict the potential distributions of the golden snub-nosed monkey in the current and 2070s using the MaxEnt model. The dispersal paths were identified by the circuit theory. Our results suggested that the habitats of the golden snub-nosed monkey were reduced under all three GCM scenarios. The suitable habitats for the golden snub-nosed monkey would be reduced by 82.67%, 82.47%, and 75.17% under the RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively, compared to the currently suitable habitat area. Additionally, we found that the density of future dispersal paths of golden snub-nosed monkeys would decrease, and the dispersal resistance would increase. Therefore, relevant wildlife protection agencies should prioritize the climatically suitable distributions and key dispersal paths of golden snub-nosed monkeys to improve their conservation. We identified key areas for habitat preservation and increased habitat connectivity under climate change, which could serve as a reference for future adaptation strategies.

Ecological response of an umbrella species to changing climate and land use: Habitat conservation for Asiatic black bear in the Sichuan-Chongqing Region, Southwestern China.

Climate and land use changes are increasingly recognized as major threats to global biodiversity, with significant impacts on wildlife populations and ecosystems worldwide. The study of how climate and land use changes impact wildlife is of paramount importance for advancing our understanding of ecological processes in the face of global environmental change, informing conservation planning and management, and identifying the mechanisms and thresholds that underlie species' responses to shifting climatic conditions. The Asiatic black bear (Ursus thibetanus) is a prominent umbrella species in a biodiversity hotspot in Southwestern China, and its conservation is vital for safeguarding sympatric species. However, the extent to which this species' habitat may respond to global climate and land use changes is poorly understood, underscoring the need for further investigation. Our goal was to anticipate the potential impacts of upcoming climate and land use changes on the distribution and dispersal patterns of the Asiatic black bear in the Sichuan-Chongqing Region. We used MaxEnt modeling to evaluate habitat vulnerability using three General Circulation Models (GCMs) and three scenarios of climate and land use changes. Subsequently, we used Circuit Theory to identify prospective dispersal paths. Our results revealed that the current area of suitable habitat for the Asiatic black bear was 225,609.59 km2 (comprising 39.69% of the total study area), but was expected to decrease by -53.1%, -49.48%, and -28.55% under RCP2.6, RCP4.5, and RCP8.5 projection scenarios, respectively. Across all three GCMs, the distribution areas and dispersal paths of the Asiatic black bear were projected to shift to higher altitudes and constrict by the 2070s. Furthermore, the results indicated that the density of dispersal paths would decrease, while the resistance to dispersal would increase across the study area. In order to protect the Asiatic black bear, it is essential to prioritize the protection of climate refugia and dispersal paths. Our findings provide a sound scientific foundation for the allocation of such protected areas in the Sichuan-Chongqing Region that are both effective and adaptive in the face of ongoing global climate and land use changes.

Mitigation Strategies for Human-Tibetan Brown Bear (Ursus arctos pruinosus) Conflicts in the Hinterland of the Qinghai-Tibetan Plateau.

Personal injury and property damage caused by wildlife can worsen the relationship between humans and wildlife. In recent years, conflicts between herders and Tibetan brown bears (Ursus arctos pruinosus) (human-bear conflicts; HBCs) on the Qinghai-Tibetan Plateau have increased dramatically, severely affecting community motivation for the conservation of brown bears and other species. Understanding the types, effectiveness, and flaws of current HBC mitigation measures is critical to develop effective strategies to alleviate HBC. From 2017 to 2019, we conducted a systematic field survey regarding HBCs on the Qinghai-Tibetan Plateau. In addition, we invited bear specialists and multiple interest groups to hold an HBC seminar and proposed some potential mitigation strategies. We surveyed 312 families via semi-structured interviews and documented 16 types of HBC mitigation measures. A total of 96% of respondents were using more than two mitigation measures simultaneously. The effectiveness evaluation of HBC mitigation measures showed that: (1) removing food from winter homes while herders were at their summer pastures and asking people to keep watch of winter homes were effective at protecting food and houses; (2) traditional grazing methods (human guarding of livestock all day) and solar soundboxes (attached to livestock) were effective at protecting free-range livestock; (3) solar street lights had a deterrent effect on brown bears and were effective in protecting livestock, houses, and people; and (4) due to the unstable power supply of photovoltaic cells and improper installation of ground wires, electric fences were not ideal in practice. Evaluation of the potential mitigation measures at the seminar showed that upgrading electric fence technology, expanding electric fence pilot areas, installing diversionary feeders, and introducing bear spray were the most optimal solutions. This study provides a scientific basis for creating human-bear coexistence plans on the Qinghai-Tibet Plateau.

Identifying the ecological security patterns of the Three Gorges Reservoir Region, China.

Identifying and improving the existing ecological security patterns (ESPs) are of great importance to promoting ecological security and achieving sustainable development goals. The Three Gorges Reservoir Region (TGRR) is an area with a sensitive, fragile, and complex ecological environment in the Upper Reaches of the Yangtze River. The construction of ESPs for the TGRR is significant for maintaining regional ecosystem stability and promoting peaceful coexistence between humans and nature. The main objective of the study is to identify the ecological nodes, ecological corridors, and ecological sources that play essential roles in the ecosystem. Based on land use data and human interference factors, we have evaluated the current habitat quality using the InVEST model and identified vital ecological sources for the TGRR. The negative exponential transformation function was used to convert habitat suitability into a landscape resistance layer. Circuit theory modeling was utilized to identify ecological corridors, and the final ESPs of the TGRR were then constructed. Results showed that (a) the spatial distribution of habitat varied significantly in the TGRR. The optimal habitats were concentrated in the northeast, east, and southwest, accounting for 45.98% of the total suitable habitats; (b) habitat quality varied through space, with habitat quality being higher in the northeast and lower in the western regions. (c) Ecological sources were distributed primarily in the forests with high vegetation coverage in the east. The total area of ecological sources was about 15,412 km2, approximately accounting for 34% of the study area; (d) the ESPs were dominated by ecological sources composed of forests, which were radially connected by ecological corridors. In total, these included 14 significant ecological sources, 25 clusters of ecological corridors, and 23 ecological nodes. The results are of great significance to promote the ecological security of the TGRR and could provide theoretical support for biodiversity conservation and territorial space planning for the Three Gorges Region.

The overlap of suitable tea plant habitat with Asian elephant (Elephus maximus) distribution in southwestern China and its potential impact on species conservation and local economy.

The expansion of land being used for cash crop cultivation has threatened wildlife in recent decades. Tea has become the dominant cash crop in southwestern China. Unfortunately, tea plantations may threaten Asian elephant (Elephus maximus) populations via habitat loss and fragmentation. Identifying areas of suitable habitat for tea plant cultivation, and where this habitat overlaps with Asian elephant distribution, is vital for planning land use, managing nature reserves, shaping policy, and maintaining local economies. Here, we assess the potential impact of tea plantations on Asian elephants in southwestern Yunnan province, China. We used MaxEnt modeling with bioclimatic and environmental variables to identify suitable habitat for tea plant cultivation under the current climate scenario, and then overlapped this habitat with 9 known Asian elephant distribution areas (G1-G9) to determine "threatened areas." Our results showed that (1) annual precipitation (48.1% contribution), temperature constancy (29 % contribution), and slope (8.7 % contribution) were key in determining suitable habitat for tea plants; (2) the cumulative area of suitable habitat for tea plants was 13,784.88 km2, mainly distributed in Menghai (3934.53 km2), Lancang (3198.67 km2), and Jinghong (2657.74 km2); (3) the distribution area of elephants was 943.75 km2, and these areas overlapped with suitable tea plant habitat primarily located in G4 (379.40 km2), G3 (251.18), and G7 (168.03 km2); and (4) threatened areas in G1 and G7 were predominately located along the periphery of current nature reserves. Win-win solutions that work for elephant conservation and economic development include rescoping nature reserve boundaries, strengthening management on the periphery of nature reserves, establishing ecological corridors and new nature reserves within regions where elephants are currently distributed, planting alternative cash crops, and financial subsidies to farmers. This study improves understanding of human-elephant coexistence, and will assist in guiding land use policy for the future conservation outcomes seeking to promote responsible and profitable cash crop farming and elephant conservation.

Identifying the patterns of changes in α- and ß-diversity across Dacrydium pectinatum communities in Hainan Island, China.

Exploring vegetation distribution spatial patterns facilitates understanding how biodiversity addresses the potential threat of future climate variability, especially for highly diverse and threatened tropical plant communities, but few empirical studies have been performed. Dacrydium pectinatum is a constructive and endangered species in the tropical mountain forests of Hainan Island, China. In this study, sixty-eight 30 m × 30 m permanent plots of D. pectinatum were investigated, and species-based and phylogenetic-based methods were used to analyze the α- and ß-diversity pattern variation and its key drivers. Our study showed that species and phylogenetic α-diversity patterns are different on a local scale. However, on a regional scale, the variations in the two α-diversity patterns tend to converge, and they decrease with increasing elevation. The phylogenetic structure changes from overdispersion to convergence with increasing elevation. Soil (SOM, TP, AP), topography (EL, SL), and stand (CD) factors and α-diversity showed close correlations. Species and phylogenetic ß-diversity have significant positive correlations with changing environmental distance and geographical distance; however, as a representative form of habitat heterogeneity, elevation distance has a greater impact on ß-diversity changes than geographical distance. In conclusion, the α- and ß-diversity patterns of the D. pectinatum community are mainly related to habitat filtering, especially in high-elevation areas, and the colonization history of various regions also affects the formation of diversity patterns. Species-based and phylogenetic-based methods robustly demonstrated the key role of the habitat filtering hypothesis in community assembly. We believe that more plant diversity patterns need to be explored to understand the biodiversity formation mechanisms in tropical forests. We also recommend strengthening the construction and management of nature reserves to help address the biodiversity loss crisis in endangered tropical plant communities.

Implementing a comprehensive approach to study the causes of human-bear (Ursus arctos pruinosus) conflicts in the Sanjiangyuan region, China.

Personal injury and property loss caused by wildlife often deteriorates the relationship between humans and animals, prompting retaliatory killings that threaten species survival. Conflicts between humans and Tibetan brown bears (Ursus arctos pruinosus) (Human-Bear Conflicts, HBC) in the Sanjiangyuan region have recently dramatically increased, seriously affecting community enthusiasm for brown bears and the conservation of other species. In order to understand the driving mechanisms of HBC, we proposed six potential drivers leading to increased occurrences of HBC. We conducted field research in Zhiduo County of the Sanjiangyuan region from 2017 to 2019 to test hypotheses through semi-constructed interviews, marmot (Marmota himalayana) density surveys and brown bear diet analysis based on metagenomic sequencing. Analysis of herder perceptions revealed that the driving factors of HBC were related to changes in their settlement practice and living habits, changes in foraging behavior of brown bears and recovery of the brown bear population. Since the establishment of winter homes, brown bears have gradually learned to utilize the food in unattended homes. Although 91.4% (n = 285) of the respondents no longer store food in unattended homes, brown bears were reported to still frequently approach winter homes for food due to improper disposal of dead livestock and household garbage. The frequency and abundance of marmots were found to be high in brown bear diet, indicating that marmots were the bears' primary food. However, marmot density had no significant effect on brown bears utilizing human food (P = 0.329), and HBC appears to not be caused by natural food shortages. Distance to rocky outcrops (P = 0.022) and winter homes (P = 0.040) were the key factors linked to brown bears pursuing human food. The number of brown bears has increased over the past decade, and HBC is likely linked to its population recovery. Our findings will provide scientific basis for formulating effective mitigation measures and protection countermeasures for brown bears.

Identifying climate refugia and its potential impact on Tibetan brown bear (Ursus arctos pruinosus) in Sanjiangyuan National Park, China.

Climate change has direct impacts on wildlife and future biodiversity protection efforts. Vulnerability assessment and habitat connectivity analyses are necessary for drafting effective conservation strategies for threatened species such as the Tibetan brown bear (Ursus arctos pruinosus). We used the maximum entropy (MaxEnt) model to assess the current (1950-2000) and future (2041-2060) habitat suitability by combining bioclimatic and environmental variables, and identified potential climate refugia for Tibetan brown bears in Sanjiangyuan National Park, China. Next, we selected Circuit model to simulate potential migration paths based on current and future climatically suitable habitat. Results indicate a total area of potential suitable habitat under the current climate scenario of approximately 31,649.46 km2, of which 28,778.29 km2 would be unsuitable by the 2050s. Potentially suitable habitat under the future climate scenario was projected to cover an area of 23,738.6 km2. Climate refugia occupied 2,871.17 km2, primarily in the midwestern and northeastern regions of Yangtze River Zone, as well as the northern region of Yellow River Zone. The altitude of climate refugia ranged from 4,307 to 5,524 m, with 52.93% lying at altitudes between 4,300 and 4,600 m. Refugia were mainly distributed on bare rock, alpine steppe, and alpine meadow. Corridors linking areas of potentially suitable brown bear habitat and a substantial portion of paths with low-resistance value were distributed in climate refugia. We recommend various actions to ameliorate the impact of climate change on brown bears, such as protecting climatically suitable habitat, establishing habitat corridors, restructuring conservation areas, and strengthening monitoring efforts.

Identifying the risk regions of house break-ins caused by Tibetan brown bears (Ursus arctos pruinosus) in the Sanjiangyuan region, China.

Damage to homesteads by brown bears (Ursus arctos) has become commonplace in Asia, Europe, and the Americas. Science-based solutions for preventing damages can contribute to the establishment of mechanisms that promote human-bear coexistence. We examined the spatial distribution patterns of house break-ins by Tibetan brown bears (U. a. pruinosus) in Zhiduo County of the Sanjiangyuan region in China. Occurrence points of bear damage were collected from field surveys completed from 2017 to 2019. The maximum entropy (MaxEnt) model was then used to assess house break-in risk. Circuit theory modeling was used to simulate risk diffusion paths based on the risk map generated from our MaxEnt model. The results showed that (a) the total risk area of house break-ins caused by brown bears was 11,577.91 km2, accounting for 29.85% of Zhiduo County, with most of the risk areas were distributed in Sanjiangyuan National Park, accounting for 58.31% of the total risk area; (b) regions of alpine meadow located in Sanjiangyuan National Park with a high human population density were associated with higher risk; (c) risk diffusion paths extended southeast to northwest, connecting the inside of Sanjiangyuan National Park to its outside border; and (d) eastern Suojia, southern Zhahe, eastern Duocai, and southern Jiajiboluo had more risk diffusion paths than other areas examined, indicating higher risk for brown bear break-ins in these areas. Risk diffusion paths will need strong conservation management to facilitate migration and gene flow of brown bears and to alleviate bear damage, and implementation of compensation schemes may be necessary in risk areas to offset financial burdens. Our analytical methods can be applied to conflict reduction efforts and wildlife conservation planning across the Qinghai-Tibet Plateau.

Quantum Monte Carlo calculated potential energy curve for the helium dimer.

We report on the results of both the diffusion quantum Monte Carlo (DMC) and reptation quantum Monte Carlo (RMC) methods on the potential energy curve of the helium dimer. We show that it is possible to obtain a highly accurate description of the helium dimer. An improved stochastic reconfiguration technique is employed to optimize the many-body wave function, which is the starting point for highly accurate simulations based on the DMC and RMC methods. We find that the results of these methods are in excellent agreement with the best theoretical results at short range, especially the recently developed RMC method, yield particularly accurate results with reduced statistical error, which gives very excellent agreement across the whole potential curve. For the equilibrium internuclear distance of 5.6 bohrs, the calculated total energy with RMC method is -5.807 483 599+/-0.000 000 016 hartree and the corresponding well depth is -11.003+/-0.005 K.