Assembly of nonnative floras along elevational gradients explained by directional ecological filtering.

ABSTRACT: Nonnative species richness typically declines along environmental gradients such as elevation. It is usually assumed that this is because few invaders possess the necessary adaptations to succeed under extreme environmental conditions. Here, we show that nonnative plants reaching high elevations around the world are not highly specialized stress tolerators but species with broad climatic tolerances capable of growing across a wide elevational range. These results contrast with patterns for native species, and they can be explained by the unidirectional expansion of nonnative species from anthropogenic sources at low elevations and the progressive dropping out of species with narrow elevational amplitudes--a process that we call directional ecological filtering. Independent data confirm tha

SUBMITTER: Alexander JM 

PROVIDER: S-EPMC3021079 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature