The potential contribution of vegetation ecology to biodiversity research

The contribution of vegetation ecology to the study of biodiversity depends on better communication between the different research paradigms in ecolog y. Recent developments in vegetation theory and associated statistical mode lling techniques are reviewed for their relevance to biodiversity. Species composition and collective properties such as species richness vary as a co ntinuum in a multi-dimensional environmental space; a concept which needs t o be incorporated into biodiversity studies. Different kinds of environment al gradients can be recognised and species responses to them vary. Species response curves of eucalypts to an environmental gradient of mean annual te mperature have been shown to exhibit a particular pattern of skewed respons e curves. Generalised linear modelling (GLM) and generalised additive model ling (GAM) techniques are important tools for biodiversity studies. They ha ve successfully distinguished the contribution of environmental (climatic) and spatial (history and species dispersal ability) variables in determinin g forest tree composition in New Zealand. Species richness studies are examined at global, regional and local scales. At all scales, direct and resource environmental gradients need to be inco rporated into the analysis rather than indirect gradients e.g. latitude whi ch have no direct physiological influence on biota. Evidence indicates that species richness at the regional scale is sensitive to environment, confou nding current studies on local/regional species richness relationships. Pla nt community experiments require designs based on environmental gradients r ather than dependent biological properties such as productivity or species richness to avoid confounding the biotic components. Neglect of climatic an d other environmental gradients and the concentration on the collective pro perties of species assemblages has limited recent biodiversity studies. Con servation evaluation could benefit from greater use of the continuum concep ts and statistical modelling techniques of vegetation ecology. The future d evelopment of ecology will depend on testing the different assumptions of c ompeting research paradigms and a more inclusive synthesis of ecological th eory.