Factors influencing above-ground and soil seed bank vegetation diversity at different scales in a quasi-Mediterranean ecosystem

Questions: Are factors influencing plant diversity in a fire-prone Mediterranean ecosystem of southeast Australia scale-dependent? Location: Heathy woodland, Otways region, Victoria, southeast Australia Methods: We measured patterns of above-ground and soil seed bank vegetation diversity and associated them with climatic, biotic, edaphic, topographic, spatial and disturbance factors at multiple scales (macro to micro) using linear mixed effect and generalized dissimilarity modelling. Results: At the macro-scale, we found species richness above-ground best described by climatic factors and in the soil seed bank by disturbance factors. At the micro-scale we found species richness best described above-ground and in the soil seed bank by disturbance factors, in particular time-since-last-fire. We found variance in macro-scale β-diversity (species turnover) best explained above-ground by climatic and disturbance factors and in the soil seed bank by climatic and biotic factors. Conclusions: Regional climatic gradients interact with edaphic factors and fire disturbance history at small spatial scales to influence species richness and turnover in the studied ecosystem. Current fire management regimes need to incorporate key climatic–disturbance–diversity interactions to maintain floristic diversity in the studied system.