A general theme that will emerge from the discussion is the intimate, even circular, relationship between fire and postfire ecosystem processes. Fire affects individual species through direct mortality and postfire changes in nutrient, food, and habitat availability. The diversity of species' responses to fire as well as the variety of fire intervals and fire intensities contribute to the overall biodiversity of the Sierra Nevada. The diversity of plants leads to the accumulation of different quantities and quality of fuel. Animals and fire change the quantity and the horizontal and vertical continuity of these fuels, which in turn generate variations in fire behavior.
Fire also interacts with other ecosystem processes to create heterogeneity across the landscape.
The heterogeneity in the amount, structure, and continuity of fuels across the landscape in turn generates variations in fire regimes. Such diversity, variation, and changes are important components of Sierra Nevada ecosystems.