关键词: 野火, 土壤养分, 植被特征, 苔藓, 结构方程模型, 高寒沼泽湿地

Abstract: In order to investigate the response of vegetation properties and soil nutrients to wildfires in an alpine swampy wetland,the vegetation community and soil nutrient characteristics were investigated in both wildfire-affected alpine swampy wetlands and intact (CK) areas. The results showed that wildfires significantly increased coverage of grass and weed (P<0.05) compared to that of the CK areas,but decreased the coverage of leguminous and moss from 6.17% and 32.67% to 0.17% and 4.50%,respectively (P<0.05). Wildfires significantly decreased the content of soil total nitrogen and available phosphorus,but significantly increased the content of available nitrogen (P<0.05). Analyzing by structural equation modeling (SEM) showed that in the CK area,moss coverage directly affected soil total phosphorus and available phosphorus with an influence coefficient of 0.990 and 0.913,respectively. The live moss coverage in the wildfire-affected area had a direct positive influence on Shannon-Wiener index (influence coefficient =0.604). There was a direct negative influence between the biomass of dead moss and Pielou index and total phosphorus content,with the impact coefficients of -0.652 (P<0.01) and -0.503 (P<0.05),respectively. In both the wildfire-impacted wetlands and CK,moss was a key factor affecting soil nutrients and vegetation diversity. Therefore,in the process of studying the impacts of wildfires on alpine wetlands,attention should be paid to the ecological functions of mosses in addition to the changes of sensitive indicators such as grasses,legumes,nitrogen and phosphorus.

Key words: Wild fire, Soil nutrients, Vegetation characteristics, Moss, SEM, Alpine swampy wetland