Patterns and Influencing Mechanism of Plant Species Richness of Carex-dominated Wetlands in China

Determining the pattern and mechanisms of species richness distribution at large spatial scales has been one of the core objectives in the field of ecology and biogeography. Although climate and soil effects on terrestrial ecosystems are well-documented, large-scale patterns in wetlands are poorly understood due to their unique hydrological processes and vegetation types. Here, we explored the pattern of plant species richness of Carex-dominated wetlands and its influencing mechanism in China based on a national field vegetation survey at 120 sites. Results showed that the community type and plant species richness of Carex-dominated wetlands differed significantly among different climate zones in China. The hierarchical partitioning analysis showed that community type and environmental context (spatial location, water regime, climate and soil conditions) together explained 41% of the variations in plant species richness, and community type had the greatest influence on species richness. Partial Least Squares Path Modeling result showed that plant species richness was directly affected by community type, climate factors, soil properties and water regime. Soil properties and water regime also indirectly affected plant species richness by directly affecting community type. These findings help us understand the pattern of plant diversity distribution in wetlands at large spatial scales and design effective conservation strategies for these valuable sedge meadow wetlands in a changing environment.