Elevation Changes Of Plant And Soil Biodiversity And Their Responses To Warming In Alpine Meadow Ecosystem In Tibet

The mountain biodiversity in the high altitude area of the Qinghai-Tibet Plateau is very sensitive to climate change.In the context of global warming,it is of great significance to study the effects of warming on the biodiversity of vegetation-soil system in the alpine meadow of Tibet.Based on the existing OTCs（open top chambers）warming experimental platform along the altitudinal gradient,this paper explores whether the distribution pattern of vegetation and soil biodiversity in alpine meadow ecosystem on the altitudinal gradient is consistent.What environmental factors regulate the distribution of vegetation and soil biodiversity?Will increasing temperature change the elevation pattern of vegetation and soil biodiversity in alpine meadow ecosystem?What are the similarities and differences between high altitude and low altitude in response to warming?The main findings of this paper are as follows:（1）The plant species diversity and soil bacterial diversity of the alpine meadow ecosystem showed a unimodal trend with the elevation gradient increasing（P<0.05）.The soil animal community Richness and Shannon-Weiner indexes,as well as the Simpson index and PD whole tree indexes of soil fungi were increased with increasing altitude（P<0.05）.Precipitation and temperature（air temperature and soil temperature）are the main drivers of elevation changes in plant and soil biodiversity.（2）Along the elevation gradient,soil moisture and water content decreased after warming,while soil NO₃^--N and NH₄⁺-N contents showed a significant increasing trend（P<0.05）.Increasing temperature decreased plant community coverage,diversity index and aboveground biomass,but significantly increased Simpson index（P<0.05）.There were no significant changes in soil animal and microbial diversity after increasing temperature（P>0.05）.（3）Under warming conditions,water conditions were the dominant factors limiting the community structure and species composition of plants and soil organisms in the alpine meadow.The elevation pattern peak of plant diversity shifted upward due to increasing temperature,and reached its peak value at the sample site with the highest annual precipitation of 5000 m.In addition,increasing temperature also decreased soil organic carbon,water-soluble organic carbon and total nitrogen at the elevation of 5000m.The results of this study can provide data reference for the impact of climate change on biodiversity of alpine meadow in Tibet under the background of climate warming,and provide data support for predicting the impact of climate change on biodiversity of vegetation-soil system in high-altitude mountain.