Ecosystem structure and function modeling

An important component of ecological assessments is the ability to predict and display changes in ecosystem structure and function over a variety of spatial and temporal scales. These changes can occur over short (less than 1 year) or long time frames (over 100 years). Models may emphasize structural responses (changes in species composition, growth forms, canopy height, amount of old growth, etc.) or functional responses (cycling of carbon, nutrients, and water). Both are needed to display changes in ecosystem components for use in robust ecological assessments. Structure and function models vary in the ecosystem components included, algorithms employed, level of detail, and spatial and temporal scales incorporated. They range from models that track individual organisms to models of broad-scale landscape changes. This chapter describes models appropriate for ecological assessments. The models selected for inclusion can be implemented in a spatial framework and for the most part have been run in more than one system.