The edaphic control of plant diversity

BACKGROUND: The central thesis of plant ecology is that climate determines the distribution of global vegetation. Within a vegetation type, however, finer-scale environmental features such as the physical and chemical properties of soil (edaphic variation) control plant distributions and diversity patterns. AIMS: Here, we review the literature to provide a mechanistic framework for the edaphic control of plant diversity. First, we review three examples where soils have known, prevalent effects on plant diversity: during soil formation, on unusual soils, and in regions with high edaphic heterogeneity. Second, we synthesize how edaphic factors mediate the relative importance of the four key processes of community assembly (speciation, ecological drift, dispersal, and niche selection). Third, we review the potential effects of climate change in edaphically heterogeneous regions. Finally, we outline key knowledge gaps for understanding the edaphic control of plant diversity. In our revie...