Abstract:In order to effectively prevent and control invasive alien species (IAS), the associations among community species composition, vegetation structure and environmental factors were analyzed based on nested plot survey of plantations in Luchuan County, Guangxi. Mantel test showed that species composition correlated stronger to vegetation structure (r=0.208, P=0.002) than to other environment factors (r=0.084, P=0.051). MRPP analysis revealed that vegetation structures of plots invaded by Spermacoce alata, or Praxelis clematidea and Ageratum conyzoides were significantly different from that uninvaded by them, but plots invaded by Mikaina micrantha had similar vegetation structure with that uninvaded. From t test, there was not significant correlation between presence-absence of 4 IASs and canopy covers (>3.0 m, P>0.073). When community vegetation density at 1.5 m above-ground increased, the invasion of S. alata, P. clematidea or A. conyzoides might reduce, except of M. micrantha. Vegetation structure as a filter may mainly act on plant seeding time, germination cycle or growth attributes, and invasions of those IASs propagating only by seeds may depend more on disturbances and bare soil; while M. micrantha which conferred with asexual and sexual reproductions and capable of climbing and creeping, may colonize relative randomly in communities of varied vegetation structures.
