Use of an Object-Based Model to Represent Complex Features of Ecosystems

Abstract

In this article, an ecosystem model that has been developed as anengineering tool is briefly described. Sample results from two simulationsare then presented, and the model is examined with regards to itsusefulness and applicability vis � vis the representation of complexfeatures of ecosystems. The model is in many ways unique: First,its scope (i.e., the number of different types of ecosystem componentsthat are included) is much broader than that of most other ecosystemmodels, and key processes are represented at relatively high spatialand temporal resolutions (10 metres and 10 minutes, respectively).Second, it is entirely object-based: every abiotic and biotic componentin the system is represented as a distinct entity. Thus, each organism,or small group of organisms, is treated as an individual object thatlives in a spatially explicit environment composed of cells arrangedin a 2-D lattice. Third, the model is completely configurable, sothat a wide range of ecosystem configurations and their correspondinginitial conditions can be specified for simulation. Thus, both thebiological composition (i.e., number and type of species, initialpopulation sizes, etc.) and the environment (i.e., terrain and atmosphere)of an ecosystem can be specified. When implemented in simulation,configurations based on simple food webs exhibit sustained materialcycling, non-random spatial variation and distribution of organismsover the terrain, and persistent, multi-trophic level populationdynamics. It is argued that these phenomena are emergent, and areindicative of spatial and temporal self-organisation in the modelledecosystems.