Variation Of Plant Species Diversity And Productivity And Soil Organic Carbon On Cliamte And Soil Texture Gradients In The Northern Xilingol Region Of Inner Mongolia

The Inner Mongolian grassland is an important ecological security barrier,a base for regional pastoral economic development,and a treasure trove of biodiversity in northern China.However,the grassland degradation has become a seriously problem in recent years due to climate change and intensified human interference,which is demonstrated by productivity decline,biodiversity loss,soil carbon stock reduction,nutrient cycle imbalance of the grassland Understanding the impact of environmental change on grassland biodiversity,productivity,and soil carbon is the foundation for formulating grassland protection and sustainable management policies.Many studies have been done on plant diversity,productivity,and soil carbon in the temperate semi-arid grasslands,but the information is still imcomplete on the relationships among plant diversity,productivity,and soil carbon changes in climate and soil texture gradients.In the present study,we investigated the changes in grassland plant species diversity,community productivity of the temperate semi-arid grassland along a climate gradient in the north part of Xilingol region,Inner Mongolia,which spans the meadow steppe,typical steppe and desert steppe zones from east to west.Combined with the regional climate,soil texture and organic carbon content data,we used analysis of variance,regression analysis,correlation and partial correlation analysis,random forest analysis and other methods to explore the changes of species diversity,community productivity and soil organic carbon storage of the studied grassland or its different grassland subtypes in the region in relationswith climate and soil texture factors,as well as their relationships.The results will provide a theoretical basis for protecting grassland biodiversity,maintaining and improving grassland forage production and carbon sink storage.The main conclusions are as follows:1.The plant community productivity and soil organic carbon content of the steppe region,or its typical steppe or desert steppe zones,decreases significantly with the increase of climate dryness on the climate gradient.Whether the whole grassland region in the north part of Xilingol,or its meadow steppe,typical steppe or desert steppe zones,plant species diversity and community productivity is significantly correlated.2.Climate factors have the highest explanatory power for the variation in community productivity in the studied region,or in its typical steppe or desert steppe zones.However,species diversity has the highest degree of explanation for the variation in community productivity in the meadow steppe zone,where resources are relatively abundant.Climate factors also have the highest explanatory power on the changes in soil organic carbon content in the grassland region,or in its meadow steppe,typical steppe,or desert steppe zones.The soil texture has a high explanatory power for the variation in soil organic carbon content in the region ot its typical steppe zone,but not in the desert steppe zone.3.Plant species diversity has a significant positive effect on plant community productivity in the grassland region or its meadow steppe,typical steppe or desert steppe zone.Species diversity has a positive effect on soil organic carbon content in the typical steppe zone,while in meadow steppe and desert steppe zones,climate and species diversity synergistically improve soil organic carbon content.