An Index of Spatial Organization in Ecological Systems: a Multiagent Model
Gund Institute for Ecological Economics University of Vermon
Computer Science Department and Gund Institute for Ecological Economics, University of Vermont
Chesapeake Biological Laboratory, University of Maryland System
Last modified: May 30, 2006
The Information theoretic measure of spatial organization, introduced earlier, is a correlation between spatial events that quantifies the degree of constraint inherent in the spatial organization of an ecological system. Using multiagent model experiments, it can be demonstrated that the spatial index captures principal patterns of spatial organization in the system. The spatial index is calculated in four different hypothetical ecological systems, which serve as simple examples of varying degrees of spatial organization: 1) individuals move about randomly; 2) the system exemplifies preferable or suitable states of a natural site that can satisfy an individualís demands (e.g., feeding, nesting, resting) is intended simply to change the suitability of a cell according to its previous state and number of inhabitants and then move accordingly; 3) aggregation (flocking/ grouping/ herding) - a natural mechanism important for the survival of individuals; and 4) flock/group of individuals follow a determined route by returning to the landmarks or local stopover patches at set time intervals. Simulation results illustrate first, that the spatial index defined earlier can be computed and second that it is both relevant and important to quantitative studies of ecosystems dynamics.