Effects of grazing on the ecosystems multifunctionality of montane meadow-grassland, the northern slope of Tianshan Mountains, China

Abstract

Ecosystem multifunctionality (EMF) plays an irreplaceable role in maintaining ecological balance and ensuring human survival and development. However, few studies have focused on the effects of different grazing intensities on EMF, and little is known about the changes in the function of multiple ecosystems at different grazing intensities. The paper uses research methods such as plant community survey and high-throughput sequencing technology to study the grassland EMF on the northern slope of Tianshan Mountains in China. We use the mean value method to calculate the EMF and explore the effects of no grazing (CK), light grazing (LG) and heavy grazing (HG) on grassland EMF. Results showed that HG significantly improved moisture regulation (MR) function (p < 0.05), and decreased soil fertility (SF) (p > 0.05), soil carbon storage (SCS) (p > 0.05), nutrient conversion and cycling (NC) (p > 0.05), grassland productivity (GP) function (p < 0.05) and EMF (p < 0.05). The EMF index of the grassland ecosystem under grazing conditions ranges from 0.3328–0.6018. GP, SCS and NC functions have the highest contribution to EMF under CK, LG and HG conditions, respectively. Under grazing conditions, EMF showed a cooperative relationship with SF, SCS and GP, and the correlation coefficient (r) value was between 0.62–0.76 (P < 0.05). At the same time, EMF and grassland water MR showed a trade-offs relationship (r = 0.68, P < 0.05). The results of structural equation models showed that grazing have a significant effect on EMF directly, and indirectly through soil fungal diversity. Therefore, reasonable reduction of grazing intensity is the most effective management approach to maintain ecosystem function. At the same time, grazing plays a key role in maintaining EMF by regulating both above- and below-ground ecosystem functions, primarily through soil fungal diversity. This study sheds light on the EMF response to grazing intensity in montane grasslands, and provides a theoretical basis for restoring degraded grasslands and sustainable ecosystem development.