Plant communities and soil variations along a successional gradient in an alpine wetland on the Qinghai-Tibetan Plateau

• The drying of wetland can lead to clear quality losses in vegetation.
• Soils have a great influence on the successional processes and conditions.
• Correlation was high in wet habitats and low in dry habitats.

Wetlands provide essential ecosystem services, such as improved water quality and climate regulation; however, these ecosystems are shrinking on the landscape because of land use practices and climate change. We aimed to characterise how vegetation and soil factors change in these systems in a globally important wetland area on the Qinghai-Tibetan Plateau. Vegetation and soil samples were collected from four successional stages (wetland, swamp meadow, transitional meadow and mature meadow), and CCA was used to evaluate relationship changes between plant communities and soil properties with degradation succession. We observed that species richness significantly increased with degradation, and the herbaceous and sedge plants yielded to forb species. Soil clay, organic matter and nutrient content significantly decreased along successional age, but soil sand, bulk density, pH and electric conductivity significantly increased. Additionally, our results obviously indicated that vegetation composition variation was driven by soil features, particularly soil clay, bulk density and nutrient content in the early successional stage and soil sand and available nitrogen in the later stage. These observations indicated that alpine wetland degradation results in the variation of plant communities, which present different floristic compositions and species abundances that are highly structured by soil properties.