ABSTRACT

The general features of an ecosystem can be predicted from the underlying geology and exogenous abiotic driving forces, such as mean annual temperature, insolation, precipitation, and nutrient input. A more precise prediction of the ecosystem depends on knowing the natural variability of the driving forces, both temporally and spatially. These driving forces control processes of material accumulation and loss that result in the structural aspects of the ecosystem, for example, soil, vegetation, and landscape pattern. There are three general types of variability: gradual change, such as changes in climate and sea level; disturbances, such as hurricanes, freezes, and fires; and natural periodicities, such as the cycles of dry and wet seasons.