Biodiversity plays a crucial role in driving multiple ecosystem functions in temperate grasslands. However, our understanding of how biodiversity regulates the impacts of desertification processes on ecosystem multifunctionality (EMF) remains limited. In this study, we investigate plant diversity, soil microbial diversity (fungal, bacterial, archaeal, and arbuscular mycorrhizal fungal (AMF) diversity), soil properties (soil water content, pH, and soil clay content), and multiple ecosystem functions (soil N mineralization, soil phosphatase activity, AMF infection rate, microbial biomass, plant biomass, and soil C and nutrients (N, P, K, Ca, Fe, Na, Cu, Mg, and Mn)) at six different grassland desertification intensities. The random forest model was conducted to assess the importance of soil properties, plant diversity, and soil microbial diversity in driving EMF. Furthermore, a structural equation model (SEM) was employed to analyze the indirect and direct impacts of these predictors on EMF. Our study showed that plant, soil bacterial, fungal, and archaeal diversity gradually decreased with increasing desertification intensity. However, only AMF diversity was found to be less sensitive to desertification. Similarly, EMF also showed a significant decline with increasing desertification. Importantly, both plant and soil microbial diversity were positively associated with EMF during desertification processes. The random forest model and SEM revealed that both plant and soil microbial diversity were identified as important and direct predictors of EMF during desertification processes. This highlights the primary influence of above- and below-ground biodiversity in co-regulating the response of EMF to grassland desertification. These findings have important implications for planned ecosystem restoration and sustainable grassland management.

In arid and semi-arid regions, grassland vegetation is the most important element in maintaining the basic functions of ecosystems. Plateau in northwestern China is an important hotspot area for the research of grassland ecosystems in the global arid areas, and is facing the dual effects of high -intensity grazing activities and significant climate change. Study the trend of changes in vegetation under the double influence of grassland vegetation is of great significance to environmental management and biodiversity protection in the region. However, the current impact of climate change and human grazing activities on vegetation lacks substantial evidence, and its impact mechanism is currently unclear. We conducted vegetation surveys and analyzed the dual pressure of plant diversity index under the dual pressure of grazing intensity and climate factors to reveal the mechanism of interaction impact on the intensity impact. The results showed that the vegetation was more sensitive to the rainfall during the rainy season, and under the pressure of low grazing, the stability of vegetation should change the stability of precipitation in the rainy season. In addition, precipitation in the rainy season is a more important climatic factors affecting the diversity of vegetation in drought and semi -arid areas. In the warm and dry climate mode, vegetation is more sensitive to grazing interference and more vulnerable to vegetation; in the cold and humid climate mode, the stability (or elastic) of vegetation should be higher. The results of the research provide direct evidence for the interaction between grazing and climate on the interaction of vegetation diversity and stability, and provide a scientific basis for the grazing management and vegetation protection in the arid area.