Impact of human activities on plant species composition and vegetation coverage in the wetlands of Napahai, Shangri-La County, Yunnan Province, China

摘要

Plant species composition and vegetation coverage are critical indicators in vegetation disturbance and restoration, but their correlations are dynamic and complex under human disturbance. Inadequate attention has been paid to the correlations between species composition and vegetation coverage associated with vegetation disturbance on plateaus. We analyze the origin of species, chorological spectra, life-forms and dominant species in the Napahai wetland of Yunnan Province, China. The correlations between species composition and vegetation coverage associated with human disturbance were then investigated by hierarchical partitioning and regression analysis. A total of 71 plant species belonging to 47 genera and 24 families were identified. Our results revealed that the plant composition of the Napahai Plateau vegetation was relatively monotonous, with the three dominant chorological types consisting of 68.4-100.0% of all genera. The wetlands studied have suffered from significant changes in species composition caused by human disturbance, and several plant species might have disappeared following such disturbance. Species richness, the most significant explanatory variable, independently contributed to 25.9% of the variance in vegetation coverage. A model constructed using the three dominant factors explained 68% of the variance in vegetation coverage. Our results highlight the dramatic changes in characteristics of plant species composition after human disturbance, and the effects of human disturbance on vegetation coverage. Several suggestions were also proposed to increase vegetation coverage in degraded wetland plateau areas of Napahai.