Phytodiversity in relation to scale

Variables determining species richness vary with scale; the larger the scale, the greater the role that they play, and the more complex are the processes involved in determining species richness. A more or less hierarchical structure of patterns and processes predict species richness. At the global scale large gradient complexes, at the landscape scale the number of habitats, and at the plot scale the variability of soil factors, affect species diversity. Moreover, biotic patterns and related processes influence species diversity, often by changing environmental conditions, e.g. disturbance by grazing or competition by shrub encroachment. The spatial hierarchical structure is connected with the temporal scale and complexity of species area relations is enhanced by temporal dynamics. Thus for nature conservation aspects as well as for studying general biodiversity patterns and processes there is a necessity to consider different spatial and temporal scales.