Centroid Migration and Distribution of Dominant Species in Different Grassland Types Revealing Climate Change Responses on the Qinghai–Tibet Plateau

The Qinghai–Tibet Plateau (QTP) is highly sensitive to global climate change, and the stability of its grassland ecosystems is critical for regional ecological security and livestock development. Therefore, investigating future spatial distribution changes of dominant species on the QTP is of great importance for grassland management. In this study, an ensemble model was used to simulate and analyze the potential distribution and centroid migration directions of dominant species in alpine meadow, alpine grassland, desert grassland, and temperate grassland under current and future climate scenarios (SSP2-4.5 and SSP5-8.5). The results show that the ensemble model achieved excellent predictive accuracy for all species (AUC > 0.9, TSS > 0.7, Kappa > 0.6). Elevation is the key factor governing species distribution, while climate drivers differ significantly among species. The distribution of dominant species in alpine meadow and alpine grassland is primarily co-driven by the mean monthly temperature range (MTR), isothermality (ISO), and annual precipitation (AP); desert grassland dominants are mainly influenced by AP and the mean temperature of the driest quarter (MTDQ); and temperate grassland dominants are driven by the precipitation of the coldest quarter (PCQ) and AP. The suitable habitats of dominant species in the future will generally expand towards high-altitude, high-latitude regions in the north and northwest, with centroid migration directions varying markedly among species. Specifically, the centroids of desert grassland dominants and S. bungeana in temperate grassland will migrate northwest under SSP2-4.5 and SSP5-8.5, while N. splendens and S. krylovii in temperate grassland will migrate southwest. For alpine meadow and alpine grassland dominants, the centroids will generally move northwest under SSP2-4.5 but diverge under SSP5-8.5—E. nutans and S. purpurea in alpine grassland will continue to migrate northwest, whereas alpine meadow dominants and P. annua in alpine grassland will migrate east or northeast. This study provides a theoretical basis for grassland conservation, biodiversity conservation, and livestock production in response to climate change on the QTP.