Predicting The Potential Distributions Of Cushion Plant In The Three-river Headwaters Region Of Qinghai Province Under Future Climate Scenarios

The Three-Rivers Headwaters region of Qinghai Province,China,is an important ecological zone.Changes in climate are seriously affecting the growth and distribution of vegetation in this region.As a typical alpine plant in the headwaters of the Three-Rivers Headwaters region,cushion plants play an important role in regulating the composition and structure of community species,and play the role of ecosystem engineers.Therefore,their distribution dynamics are important indicators for the stability of alpine ecosystems.Based on distribution data of Arenaria kansuensis Maxim.,Saussurea subulate,Androsace tapete Maxim from the literature and climate environmental factors found in the World Clim,a jackknife test method and correlation analyses were applied to determine the dominant factors affecting distribution.The Max Ent model was calibrated with present climate conditions for the species.Suitable distribution area was projected in the mid-term(2041—2060)and long-term(2061—2080)under the four climate scenarios in Coupled Model Intercomparison Project Phase 6.Response to climate change was explored for spatial distribution and scientific reference was provided for future conservation decisions.The main conclusions are as follows:(1)The MaxEnt model showed that the AUC value of Arenaria kansuensis Maxim was 0.839.The potential suitable area of the Three-River Headwaters region is 357,500km~2,and conditions in the central region were more suitable for the species under present climate conditions.The dominant environmental factors and the optimal range are:Temperature Seasonality(standard deviation×100)(6.5～8℃),Annual Precipitation(500～750mm),Precipitation of Driest Month(80～98mm),and Precipitation of Coldest Quarter(>15mm).In the future,medium and far term,its suitable areas will expand by1.47%and 4.80%,respectively under the climate scenarios of SSP370(Regional Rivalry),while its area will decline under SSP126(Sustainability),SSP245(Middle of the Road),SSP585(Fossil-fueled Development)scenarios.Most areas will become unsuitable under the SSP245 climate scenario,its suitable areas will decline by 40.27%and 37.53%,particularly unsuitable in Zhiduo County,Tanggulashan County,Qumalai County,Xinghai County and Gonghe County.The center of the suitable area will move toward the southeast region and the migration range will be within 230 km.(2)The MaxEnt model showed that the AUC value of Saussurea subulate was 0.924.The potential suitable area of the Three-River Headwaters region is 201,100 km~2,and conditions in the west and east area and Nangqian County were more suitable for the species under present climate conditions.The dominant environmental factors and the optimum range are Isothermality(>0.36℃),Annual Precipitation(0～300mm),Precipitation of Wettest Month(<80mm)and Precipitation of Coldest Quarter(0～6mm).In the future mid-term,the area of suitable area will only expand by 6.68%under the SSP126 climate scenario compared with the current climate conditions.In the long-term,the area of suitable area only expanded by 12.39%in the SSP245 climate scenario compared with the current climate condition.In the SSP370 path,the area of suitable area decreased the most compared with the current climate conditions,lost 18.94%and 3.38%respectively.The loss area mainly distributed in Nangqian County,Guide County,Jianzha County,Tongren County and the southern part of Tanggula Mountain Township.The center of the suitable area will move toward the eastern region and the migration range will be within 140 km.(3)The MaxEnt model showed that the AUC value of Androsace tapete was 0.935.The potential suitable area of the Three-River Headwaters region is 354,200 km~2,conditions in the central and southeast region and the eastern of Tanggula Mountain Township were more suitable for the species under present climate conditions.The dominant environmental factors and the optimum range are:Annual Mean Temperature(-4～2℃),Temperature Seasonality(>8.5℃),Precipitation of Driest Month(>3mm),and Precipitation Seasonality(Coefficient of Variation)(<100mm).The area of suitable area expanded in the mid-term and long-term climate scenarios.The expansion of the high suitable area will mainly be distributed in Zhiduo County and Tanggula Mountain Township,and even no unsuitable area under the path of SSP370 and SSP585.The center of the suitable area will move toward the northwest region and the migration range will be within 260 km.