Distribution of Plant Functional Groups in the Natural Grasslands of Xizang, China

Grassland is a predominant vegetation type in Xizang and is characterized by complex composition and structure. Studies on species distribution in this region are limited. Integrating species presence data from field surveys and literature, with 19 environmental factors, including categories of climate, topography, vegetation and soil, we modeled the distribution of four plant functional groups (PFGs) using Maxent. Results showed that the simulated distribution ranges of the PFGs highly corresponded with the in-situ investigation results. Precipitation seasonality, precipitation of the driest month, annual mean temperature, and temperature of the coldest and warmest months played important roles in determining the distribution of the four PFGs. These climatic factors, which reflect the precipitation and temperature ranges of the study area and are key factors regulating ecosystem processes, significantly influenced the distribution ranges of the four PFGs. Furthermore, elevation, which directly affects temperature and limits the distribution of some temperature-sensitive species, was also important to the distribution of PFGs. This study will assist in clarifying resource distribution, and can provide a valuable theoretical basis for the ecological protection of grassland and sustainable development of the local economy in Xizang.