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

摘要： 为探讨高寒沼泽湿地植被和土壤养分对野火的响应，本文选择高寒沼泽湿地野火影响区和非影响区(对照区)调查植被群落和土壤养分特征。结果发现：与对照区比，野火显著增加了禾本科和杂类草盖度(P<0.05)，豆科和苔藓盖度分别从6.17%和32.67%下降到0.17%和4.50%(P<0.05)。野火显著降低了土壤全氮和速效磷含量，但显著增加了速效氮含量(P<0.05)。结构方程模型分析发现，对照区苔藓盖度直接影响土壤全磷和速效磷含量，影响系数分别为0.990和0.913。野火影响区苔藓盖度与Shannon-Wiener指数存在正向直接影响(影响系数=0.604)。死苔藓生物量与Pielou指数和全磷含量之间为直接负向影响关系，影响系数为-0.652(P<0.01)和-0.503(P<0.05)。野火影响区和对照区的苔藓均是影响土壤养分和植物多样性的关键因子。故在分析野火的影响时，除重点关注禾本科、豆科以及氮磷等敏感指标变化特征外，也要重视苔藓的生态作用。

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