Prediction Of Potential Habitable Zones Of Tibetan Juniperus In The Contese Of Limate Change

The genus Juniperus,commonly known as junipers,is an important component of high-altitude vegetation in Tibet.It plays a significant ecological role in afforestation,greening of high-altitude vegetation,and vegetation restoration in difficult areas of Tibet.The Qinghai-Tibet Plateau is considered the"driver"of climate change in China,and Tibet,as the core region of the plateau,is the most sensitive area to global warming.However,there has been little systematic research on whether the distribution of Juniperus plants in Tibet has changed with climate change.Maximum Entropy model(Max Ent)is a widely used method for predicting species distribution with high accuracy using limited sample data.It has been applied in research on invasive species warning,suitable areas for economic plants and vegetation restoration species,potential distribution of species under climate change,and prediction of the distribution of endangered species.In this study,we used the Max Ent model to link the distribution data of Juniperus plants in Tibet with corresponding environmental variables.By analyzing the contribution ratio,permutation importance value,and jackknife test,we identified the dominant environmental variables influencing the distribution of Juniperus plants.Based on this,we explored the potential distribution areas and future trends of Juniperus plants in Tibet.This study provides important reference information for the protection and utilization of Juniperus plants in Tibet,as well as the afforestation efforts in difficult areas of Tibet.The results showed that...1.The analysis based on contribution rate,importance value replacement,and Jackknife found that the cumulative contribution rate of the dominant environmental factors for the five species of Juniperus is above 70.0%.In the current period,the dominant environmental factors affecting the distribution of J.squamata are temperature seasonal variation(bio4),annual average precipitation(bio12),average diurnal temperature difference(bio2),and lowest temperature season precipitation(bio19),with a cumulative contribution rateof 78.1%;the dominant environmental factors affecting the distribution of J.recurva are the lowest average temperature in the coldest month(bio6),annual temperature difference(bio7),temperature seasonal variation(bio4),and average diurnal temperature difference(bio2),with a cumulative contribution rate of 71.4%;the dominant environmental factors affecting the distribution of J.tibetica are temperature seasonal variation(bio4),precipitation in the hottest season(bio18),annual temperature difference(bio7),and basic saturation(t＿bs),with a cumulative contribution rate of 0.6%;the dominant environmental factors affecting the distribution of J.pingii are temperature seasonal variation(bio4),average temperature in the coldest season(bio11),annual temperature difference(bio7),and annual precipitation(bio12),with a cumulative contribution rate of77.5%;and the dominant environmental factors affecting the distribution of J.indica are temperature seasonal variation(bio4),annual precipitation(bio12),altitude(alt),and precipitation seasonal variation(bio15),with a cumulative contribution rate of 71.4%.2.In the current period,the potential suitable habitat for J.squamata is primarily distributed in the southern,southeastern,and eastern regions of Tibet.It extends continuously from the southern slopes of the Gangdise Mountains in the west to the Hengduan Mountains in the east.The total suitable habitat area is4.10×10~5 km~2,with a middle-high suitable habitat area of 2.03×10~5 km~2.The potential suitable habitat for J.recurva is mainly found in the southern and southeastern regions of Tibet.J.recurva exhibits fragmented distribution in Tibet,with two main distribution areas.One area is situated between the northern slopes of the southern Himalayas and the southern slopes of the Gangdise Mountains.Another area is located between the Himalayan range and the Hengduan Mountains.The total suitable habitat area is 2.19×10~5 km~2,with a middle-high suitable habitat area of 1.00×10~5 km~2.The potential suitable habitat for J.tibetica is primarily distributed in the southern and southeastern regions of Tibet.There is also a small amount of distribution in the central-western region.It extends continuously in a belt shape from the Yarlung Tsangpo River and its tributaries(such as the Lhasa River and the Nyang River)in the west to the Sanjiang River basin in the east.The total suitable habitat area is 2.51×10~5 km~2,with a middle-high suitable habitat area of 1.20×10~5 km~2.The potential suitable habitat for J.pingii is mainly distributed in the southern,southeastern,and eastern regions of Tibet.It is found from the Xiangquan River basin in the west to the Sanjiang River basin in the east,with point-like distribution in the western Xiangquan River and Majiacangbu River basins.The total suitable habitat area is 3.44×10~5 km~2,with a middle-high suitable habitat area of 2.39×10~5 km~2.The potential suitable habitat for J.indica is primarily distributed in the southern and eastern regions of Tibet.It is distributed on the northern slopes of the Himalayas in southern Tibet,the Nianqing Tanggula Mountains in the southeastern region,and the eastern Hengduan Mountains.It also has point-like distribution in the Xiangquan River basin in the west.The total suitable habitat area is 2.14×10~5km~2,with a middle-high suitable habitat area of 7.41×10~4 km~2.3.In the 2050s and 2090s,under the SSP245 and SSP370 climate scenarios,the total suitable area of the five Juniperus species in Tibet shows a decreasing trend compared to the current situation.The medium-high suitability areas for J.squamata in high mountains all decrease.For J.recurva,the high suitability area increases in the 2090s under the SSP245 climate scenario,while decreases for the other scenarios,and the medium suitability area increases in the 2050s under the SSP370 climate scenario,while decreases for the other scenarios.The medium-high suitability areas for J.tibetica all decrease.For J.pingii,the high suitability area increases in the 2090s under the SSP370 climate scenario,while decreases for the other scenarios,and the medium suitability area decreases for all scenarios.The suitable habitat area for J.indica,also known as the Himalayan juniper,increases under the SSP245 climate scenario,decreases in the 2050s under the SSP370 climate scenario,and increases again in the 2090s under the SSP370 climate scenario.However,the moderately suitable habitat area decreases in all scenarios.4.This study reveals that the dominant environmental factors influencing the distribution of Juniperus species are climate factors,followed by elevation.It maps the current and future potential suitable areas for Juniperus species in Tibet at different time periods.This finding helps to avoid using risky areas for vegetation restoration with this genus and provides references for scientifically and effectively carrying out the delineation of protected areas for Juniperus species in Tibet and implementing afforestation projects in difficult areas of Tibet using J.squamata.