气候变化下露蕊乌头分布格局变化及其保护现状OACHSSCD

Gymnaconitum gymnandrum,an alpine herb endemic to the Qinghai-Tibet Plateau,is an important medicinal resource.Climate change exerts profound effects on species distributions at broad spatial scales.Understanding the responses of G.gymnandrum to climate change,reconstructing its historical distribution,identifying the key environmental drivers of its range,and assessing its conservation status provide a scientific foundation for the effective management and protection of this species.In this study,we optimized the MaxEnt model using the"ENMeval"package and integrated nine algorithms from the"biomod2"package.High-performing models were combined to generate an ensemble model.Using 12 environmental variables,we reconstructed the species' distribution across 18 time periods since the Mid-Holocene and identified the major environmental factors shaping its range.Compared with single-model predictions,the Biomod2 ensemble improved the AUC(Area under curve)by 10.23％and the TSS(True skill statistic)by 24.92％,substantially enhancing the accuracy and robustness of habitat suitability projections.bio12(Annual precipitation)was the dominant factor influencing distribution,with optimal growth occurring between 900-1300 mm and suitability declining at higher levels.Suitable habitats are concentrated on the Qinghai-Tibet Plateau and adjacent regions,particularly the Qilian and Hengduan Mountains.The total suitable area and high-suitability area were estimated at 199.78×104 km2 and 69.54X 104 km2,respectively.During the Mid-Holocene,the total suitable area reached a maximum of 283.12×104 km2,although the high-suitability area remained limited(3.31×104 km2).Relative to the Mid-Holocene,high-suitability habitats expanded 21 times,while medium-and low-suitability habitats contracted by 0.73 and 0.39 times,respectively,resulting in an overall loss of 83.33×104 km2 of suitable habitat.Future projections indicate severe habitat fragmentation,with total suitable area showing an initial increase before declining,while high-suitability habitats are projected to continuously shrink to as little as 41.49×104 km2.Centroid analysis revealed that during the Mid-Holocene,the distribution center was located in Wanzhou District,Chongqing(108.52°E,30.53° N),whereas at present it is centered in Zhongning County,Ningxia Hui Autonomous Region(105.74°E,36.93°N).This shift represents a westward displacement of approximately 100 km and a southward shift of 10 km,coupled with a general trend toward higher elevations in the northwest.In terms of conservation,the species achieved a FCSin(Final combined scores in situ)score of 30.45,ranking as"medium priority".With an AOO(Area of occupancy)below 2000 km2,it is assessed as Vulnerable based on combined threat indices.These findings provide a scientific basis for biodiversity conservation and sustainable management of G.gymnandrum under ongoing and future climate change.