高寒湿地退化对植物群落特征与土壤特性的影响

以黄河首曲湿地为研究对象，基于野外采样数据和不同退化程度（无明显退化ND；轻度退化LD；中度退化MD；重度退化HD），分析植物群落、土壤特性及其关系。结果表明，随湿地退化程度增加，禾本科重要值呈减少趋势而毒杂草重要值呈增加趋势，且植物高度、盖度及地上生物量显著降低；重度退化程度下Patrick物种丰富度指数最低，表明植物群落结构由复杂趋向简单。土壤有机碳、全氮随退化程度增加均显著降低，碳氮比与pH值则呈相反变化，表明高寒湿地退化不利于养分的积累，且土壤逐渐呈碱性。pH、有机碳及全氮为高寒湿地响应退化的理化因子；湿地不同退化程度影响植物群落的土壤因子略有不同，且尤以电导率最为明显，这与土壤养分状况相关。湿地退化过程中植物群落的生长、结构发生改变，植物与土壤理化性质相互作用进而影响湿地生态功能。因此，探究植物群落与土壤理化特征可为修复退化湿地提供依据。

Effects of alpine wetland degradation on plant community characteristics and soil properties

Wetland is a unique ecosystem formed by the interaction of land and water, but due to the impact of climate change and human activities in recent years, it has shown a certain degree of degradation. Wetland have become one of the most threatened ecosystems. Therefore, this paper chooses the wetland of the first meander of the Yellow River was selected as the research object. Based on field sampling data and different degradation degrees of the wetland (Non Degradation, ND; Light Degradation, LD; Moderate Degradation, MD; Heavy Degradation, HD) to analyze the characteristics of plant community and soil and their relationships. The results showed that the importance value of Gramineae decreased with the increase of wetland degradation. The important values of noxious weeds showed an increasing trend. Plant height, coverage and aboveground biomass decreased significantly with the increasing of degradation degree. The Patrick species richness index was the lowest under severe degradation, indicating that the plant community structure changed from complex to simple. Soil organic carbon and total nitrogen decreased significantly with the increase of wetland degradation, while the ratio of carbon to nitrogen and pH value showed the opposite trend. The result indicated that the increase of alpine wetland degradation was not conducive to the accumulation of soil nutrient content, and the soil gradually became alkaline. This study found that soil pH, soil organic carbon and total nitrogen were physicochemical factors in response to alpine wetland degradation. Soil factors affecting plant community characteristics were slightly different in different wetland degradation degrees, among which soil electrical conductivity had the most obvious effect on plant community characteristics, which was related to soil nutrient content at that time. In the degradation process of wetland, the growth and structural characteristics of plant community have changed obviously. And the physical and chemical properties of soil and their interaction with plant community have changed, affecting the ecological function of wetland. Therefore, the study of plant community and soil physical and chemical characteristics can provide a basis for restoring the degraded wetlands.