Functional diversity of native and invasive plant species in tropical rainforests

摘要

Tropical forests are usually considered to have high functional diversity. Functional diversity is often seen as a proxy for ecosystem function and can be used to explore ecosystem responses to environmental change such as that caused by invasive species. In theory, functionally-diverse communities should utilise resources more fully and therefore resist invasion more readily. However, if an invading species is of a functional group not well represented in a target community, it may have an increasedlikelihood of successful invasion. We compiled data on the functional traits of native and exotic species co-occurring in Mabi forest in North Queensland. We determined whether exotic species are functionally distinct from the native flora, and examinedthe relationship between exotic and native species functional diversity and invasion. We found that exotic species occupy distinct regeneration niches and while exotic species functional diversity increases with disturbance, native species functional diversity decreases. Our results suggest exotics in this system are less constrained in terms of regeneration in disturbed habitats than predominantly shade-tolerant native species, making them 'passengers' to disturbance rather than 'drivers' of communitychange.