TOPOGRAPHIC DIFFERENCE PLAYS A LIMITED ROLE ON SPECIES DISTRIBUTION IN A SUB-TROPICAL FOREST IN SOUTH CHINA

Habitat association test has been regarded as an effective way to evaluate the relative role of niche differentiation in a community Topographical attributes are often selected as surrogates of niche processes. However, the inference for relative role of niche differentiation is likely problematic if the spatial dependence of plant community on underlying spatially-structured topographic variables is not accounted for. In this study, we used the torus shift and principal component analysis (PCA) to resolve this problem, and tested the habitat associations by adjusted-SD test in a sub-tropical evergreen broad-leaved forest in south China. The result revealed that minority of 100 common species were specialist, among which 8 species associated with first two PC axes (accounted for 98% of total eigenvalue and contributed mainly by mean elevation and aspect) and 22 species associated with last two PC axes (contributed by slope and convexity). In conclusion, we found the niche processes represented by topographical attributes play a limited role in the Dinghushan sub-tropical evergreen broad-leaved forest plot. Further study should include more habitat variables to examine the habitat associations.