Diversity Patterns of Wetland Angiosperms in the Qinghai-Tibet Plateau, China

The Qinghai-Tibet Plateau, has a special geological history, diverse habitats, a complex climate, and a large number of wetlands, which harbor a huge of wetland plants. In this study, we sorted out the monographs, literatures and online databases, as well as our own collection from field surveys, and comprehensively combed the checklist and county-level diversity of wetland angiosperms and endangered species in the Qinghai-Tibet Plateau for the first time. The distribution pattern of species richness was analyzed through three groups of environmental variables: energy, water, and habitat. The wetland angiosperms have high richness, with a total of 2329 species, belonging to 91 families and 438 genera, mainly hygrophytes (94.98%). The spatial distribution is uneven, and gradually decreases from the southeast to the northwest of the plateau. Species richness decreased with elevation and latitude and increased with longitude. Annual precipitation (AP) and annual mean temperature (AMT) are the most important variables affecting species diversity. Habitat environmental variables had less influence on species richness distribution and wetland area was not associated with richness distribution. The setting of endangered wetland angiosperm reserves needs to focus on the Hengduan Mountains and southeastern Tibet. Our study provided basic data for the research and protection of wetland plant diversity in the Qinghai-Tibet Plateau.