Thoughts on the Generation and Importance of Spatial Heterogeneity in Ecosystems and Landscapes

Landscapes are spatially dynamic because materials and energy spread over them and change the distribution of ecosystem properties.This heterogeneity of the distribution of ecosystem properties can either be random or patterned. The landscape becomes patterned when the spread of materials and energy correlates an ecosystem property in one local neighborhood with that at another.When the spread of materials and energy does not correlate properties of different neighborhoods, then the landscape can still be heterogeneous but random.Various processes that result in spatial heterogeneity include physical disturbances (e.g., fire, erosion, etc.) that spread across neighborhoods and remove materials but whose spread is partly determined by previous disturbances; directional gradients in the flow of materials, energy, or information; and different diffusion rates of coupled ecosystem components combined with positive feedbacks, otherwise known as diffusive instability. Examples of these processes will be given from other papers in this conference and elsewhere.