Degradation of alpine meadows exacerbated plant community succession and soil nutrient loss on the Qinghai-Xizang Plateau, China 后印本

摘要: In recent decades, global climate change and overgrazing have led to severe degradation of alpine meadows. Understanding the changes in soil characteristics and vegetation communities in alpine meadows with different degrees of degradation is helpful to reveal the mechanism of degradation process and take the remediation measures effectively. This study analyzed the changes in vegetation types and soil characteristics and their interrelationships under three degradation degrees, i.e., non-degradation (ND), moderate degradation (MD), and severe degradation (SD) in the alpine meadows of northeastern Qinghai-Xizang Plateau, China through the long-term observation. Results showed that the aggressive degradation changed the plant species, with the vegetation altering from leguminous and gramineous to forbs and harmful grasses. The Pielou evenness and Simpson index increased by 24.58% and 7.01%, respectively, the Shannon-Wiener index decreased by 17.52%, and the species richness index remained constant. Soil conductivity, soil organic matter, total potassium, available potassium, and porosity declined. However, the number of vegetation species increased in MD. Compared with ND, the plant diversity in MD enhanced by 8.33%, 8.69%, and 7.41% at family, genus, and species levels, respectively. In conclusion, changes in soil properties due to degradation can significantly influence the condition of above-ground vegetation. Plant diversity increases, which improves the structure of belowground network. These findings may contribute to designing better protection measures of alpine meadows against global climate change and overgrazing.