Interspecific correlation between exotic and native plants under artificial wetland forests on the Dianchi lakeside, south-west China

Abstract

The core issue of community ecology and biodiversity is the coexistence of species in a real community, but few studies have considered species coexistence in artificial wetland forests. The present study focused on interspecific correlations of exotic and native species in 8-year-old artificial wetland forests. Four large plots (each 1500m2) were established to record the species and abundance of all plants; 160 quadrats (1×1m) were set to record the number, height and coverage of each plant species. In the large plots, 78 species (6 trees, 11 shrubs and 61 herbs) were recorded. The interspecific relationships of major species (frequency >3%) from quadrats were analysed using the Chi-Square test and Spearman rank correlation coefficient index. Of 253 species pairs, 49 and 45 were significant (P<0.05), with positive and negative correlations respectively, showing intense interspecific competition. Ward’s method of hierarchical clustering was used to divide the major species from quadrats into three and five ecological species groups at a rescaled distance cluster combine of 20 and 10 respectively. Dominant invasive species (Solidago canadensis, Ageratina adenophora and Bidens pilosa) formed monodominant patches; however, species of different sizes and ecological demands, whether exotic or native, could coexist. These findings imply that exotic species can coexist with native species and become a common species composition when they have existed for a sufficient period time in artificial wetland forests.