Spatial Variation in Desert Spring Vegetation Biomass, Richness and Their Environmental Controls in the Arid Region of Central Asia

Abstract

A precise evaluation of spatial patterns in desert vegetation biomass, species richness and their environmental controls is essential for a deeper comprehension of the potential carbon preservation and sustainability of grassland ecosystems. There are widespread reports suggesting robust associations among biomass, species richness and mean annual precipitation (MAP) or temperature (MAT) at different scales. However, these reports were inconsistent, and knowledge on the desert grasslands of Central Asia remains limited. In this study, we showed that spatial patterns of biomass and species richness along the zonal climate of the northern Tianshan Mountains exhibited substantial regional differences and the relationship among biomass, richness and elevation exhibited a substantial exponential decline. We discovered that functional groups of biomass, total biomass and species richness in the desert exhibited exponential growth along the MAP gradient and a quadratic relationship with MAT. Furthermore, the biomass–species richness relationships were bell-shaped in the desert zone. Accordingly, the biomass and species richness had spatial differences. At a regional scale, the spatial variation in the desert biomass and species richness was primarily dependent on climate. Our results demonstrated the specificity between the desert vegetation and climate in arid regions of Central Asia and revealed the regularity between biomass and species richness in desert areas. The research results emphasized the impact of precipitation on desert vegetation in arid regions of Central Asia and the relationship between biomass and plant species richness, which is of great significance for understanding desert ecosystems and protecting the ecological environment.