Evaluating the Effects of Wetland Restoration at the Watershed Scale in Northwest Yunnan Plateau, China

Abstract

A long-term monitoring and restoration study was implemented from 2008 to 2014 at the watershed scale in the Napahai wetland, a typically degenerative closed and half-closed alpine wetland in the Northwest Yunnan Plateau, China. After restoration, the vegetation of the swamp, swamp meadow, and meadow in the transitional zone improved constantly, as well as the soil properties, such as water content, soil organic matter, and TN. The vegetation in the lakeside zone increased from 10 families, 11 genera, and 14 species before the restoration to 15 families, 21 genera, and 26 species after the restoration. The removal rate of total nitrogen, total phosphorus, and chemical oxygen demand in the wetland remained greater than 45, 80, and 55 %, respectively; and the transparency in the outlet of the lake increased 171.1 %. Due to the improvement of habitats, the species and number of wintering water birds increased considerably. According to a Canonical Correspondence Analysis (CCA), the soil water content, soil organic matter, total phosphorus and pH were the most important factors that influenced the distribution of vegetation in the transitional zone. Based on the correlation analysis, the bird was positively correlated with the wetland age and the water quality. The evaluation results indicate that the restoration was effective and could act as a guideline for the further ecological restoration of alpine wetlands in the future.