Interactive response and spatial heterogeneity of alpine grassland biodiversity to soil, topography, climate, and human factors on the Qinghai‐Tibet Plateau

Abstract

The alpine grassland ecosystem is a critical part of the Qinghai‐Tibet Plateau (QTP), mainly including alpine meadows and alpine steppes. However, the influence factors of alpine grassland biodiversity are not clear for different alpine grassland types. In this study, pathway analysis was applied to explore the influences of soil, topography, climate, and human factors on alpine grassland biodiversity. Then, by using the geographically weighted regression (GWR) model, the spatial sensitivity response of alpine grassland biodiversity to soil, topography, climate, and human activities was revealed in different grassland types. The results were as follows: (1) The data and pathway analysis passed the validity and reliability analysis, indicating that the model fit of alpine grassland biodiversity was good for different grassland types. (2) For alpine meadows, the total effect coefficients of altitude, slope, and topographic wetness index (TWI) on normalized difference vegetation index (NDVI) (net primary productivity [NPP]) were 0.50, 0.21, and −0.48 (0.59, 0.17, and −0.41), respectively, suggesting that altitude had the strongest and positive effect on alpine meadow diversity. In addition, among human activity and climate variables, human activity intensity and precipitation exhibited significant effects on NDVI (NPP), with total effect coefficients of −0.17 and 0.61 (−0.19 and 0.63). The influence of soil, topography, climate, and human variables on alpine steppe diversity showed similarities with alpine meadow diversity. (3) Alpine grassland biodiversity was directly and indirectly influenced by multiple driving factors for different grassland types. The total coefficients of soil, topography, climate, and human factors on NDVI (NPP) were 0.41, 0.38, −0.21, and 0.71 (0.32, 0.50, −0.21, and 0.91), respectively, which indicated that alpine meadow diversity was mainly regulated by climate on the QTP, consistent with alpine steppe diversity. (4) For different grassland types, the spatial effects of various driving factors on alpine grassland biodiversity all showed significant spatial heterogeneity at the grid scale. Based on the knowledge about the driving mechanism and spatial response of alpine grassland biodiversity to its driving factors in different grassland types of the QTP, we aim to provide guidance for alpine grassland biodiversity conservation and rational ecosystem management.