Spatial pattern of degraded alpine communities invaded by Stellera chamaejasme and environmental interpretation in the central Qilian Mountain
To determine the spatial pattern of Stellera chamaejasme invaded alpine communities and its relationship with environmental factors,a typical study area in Qilian County of Qinghai Province was selected,the classification of degraded alpine communities and the corresponding environmental re-sponse at the regional scale were analyzed with integrating two-way indicator species analysis (TWINS-PAN) classification,detrended correspondence analysis (DCA)/canonical correspondence analysis (CCA) and geographic information system (GIS) technology. The results showed that 18 families,30 genera,and 37 species was examined in the study area. The dominant species of communities in the region were Poa annua,S. chamaejasme,Kobresia pygmaea,Potentilla chinensis,Medicago ruthenica,and Gentiana straminea,and the companion species include Taraxacum mongolicum,Gueldenstaedtia diver-sifolia,Lancea tibetica,Anemone rivularis,and Thermopsis lanceolata. TWINSPAN classification di-vides alpine meadow communities into six groups:Poa annua+K. pygmaea+Thermopsis lanceolata+Potentilla bifurca community,S. chamaejasme+Poa annua+Potentilla chinensis+Thermopsis lanceola-ta community,S. chamaejasme+Poa annua+Gentiana straminea+M. ruthenica community,Poa an-nua+S. chamaejasme+Anemone rivularis+M. ruthenica community,Elymus nutans+M. ruthenica+Ta-raxacum mongolicum+Argentina anserina community,Potentilla fruticosa+Poa annua+Plantago asiat-ica+Argentina anserina community. Compared with native communities,the proportion of the forbs and poisonous plants in S. chamaejasme communities notably increased,and cyperaceous plants did not exhibit significant growth advantages. As invasion aggravated,the average coverage of S. chamaejasme invaded communities increased. Hierarchical CCA ordination of soil,topographic and climatic factors,and subsequent comprehensive ordination showed that key environmental factors affecting spatial distri-bution of S. chamaejasme communities in the study area were soil moisture content,followed by mean annual temperature and longitude,indicating that the distribution pattern of plant communities is con-trolled by a combination of moisture,heat and spatial factors in the degraded alpine meadow.
万方数据
维普
