Local texture convergence within three communities in Fiordland, New Zealand

The texture of a plant community, i.e. the range of values in functional characters across the species present, integrates the ecological and evolutionary processes that have led to that communityÕs present species composition. The idealistic prediction of ecological theory is that selection for co-adaptation and competitive sorting will lead to convergence in texture between different patches of vegetation with the same environment. This concept has previously been applied at the continental scale; here it is applied for the first time at a within community scale. Three communities were sampled, all in Fiordland, New Zealand: a predominantly native heathland, a floodplain grassland largely dominated by exotic species but with a considerable native component, and a native sub-alpine grassland with shrubs. The same five functional characters were measured in each community: height, leaf area, specific leaf area, leaf thickness and support fraction. In all three communities, to varying degrees, there was evidence of texture divergence in height, either in the mean or in the distribution. Tall species tended to associate with other tall species, and short species with other short ones. In the sub-alpine grassland, significant texture convergence occurred in leaf area, i.e. each patch tended to comprise a mixture of some small-leaved species and some large-leaved species. It is suggested that convergence may have occurred only in the sub-alpine grassland because of the greater maturity of the vegetation in evolutionary and ecological terms.