Joint effects of environmental filtering and dispersal limitation on the species assemblage of the Tibetan Plateau

Aim Mountains harbour a rich and non-random cluster of species, yet knowledge of the species' biological attributes that support their coexistence in the montane community is limited. Here, we investigated the association of species occurrence on the Tibetan Plateau with their morphological, ecological or evolutionary constraints. Location Tibetan Plateau (TP). Taxon Mammals and birds. Methods We tested whether species occurrence on the TP correlates with morphological, ecological or evolutionary constraints using the spatial distribution, phylogeny, dispersal ability and thermal niche property data for 1353 terrestrial vertebrates (383 mammals and 970 birds). We used standard (non-phylogenetic) and phylogenetic logistic regressions to elucidate the relative contributions of these attributes of species to explaining their occurrence on the TP. We assessed the geographical patterns of the community structures on the TP and fitted linear mixed models to explore the underlying eco-evolutionary forces. Results The TP species exhibited a higher cold tolerance, wider thermal niche breadth and higher rate of niche evolution than non-TP species. We supported the assumption that the TP species were not a random subset from the species pool, but were structured jointly by environmental filtering and dispersal limitation. While dispersal and ecological processes underlying species assemblages varied spatially and among taxa, we found that species in stressful environments were limited by environmental filtering, whereas dispersal limitation was more pronounced under favourable climatic conditions. Main conclusions Our study finds that environmental filtering and dispersal limitation jointly shape the species assemblage on the TP. These findings provide significant insights into community assembly processes on the TP and other montane ecosystems on Earth, especially those that are sensitive to global warming.

Automated summary

In this study, the association between species occurrence on the Tibetan Plateau and their morphological, ecological, or evolutionary constraints was investigated. The study revealed that species on the Tibetan Plateau exhibited higher cold tolerance and a faster rate of niche evolution compared to non-Plateau species. The species assemblage on the Tibetan Plateau was shaped by both environmental filtering and dispersal limitation. These findings provide significant insights into the community assembly processes in high-altitude ecosystems and their sensitivity to global warming.