Ecosystem model specification within an agent based framework

Agent-based modelling and the management strategy evaluation approach are increasingly popular techniques used in natural resource management. Agent-based modelling is a technique that is used in a variety of fields (spanning the sciences, social services, humanities and economics) while management strategy evaluation (MSE) is a decision support framework that can be extended from its single sector roots into the exploration of more interdisciplinary questions and issues. Tying the two together, by building agent-based models for use in MSE studies has immense potential for increasing the breadth of natural resource management questions that can usefully be considered with any degree of success. The MSE framework is centred upon an operating model made up of biophysical and resource exploitation sub-models (that attempts to capture the dynamics of the entire system to be managed). Combined with this operating model are sub-models that simulate the management processes (including simulation of observations, assessments, decision making and implementation). Together, these models attempt to represent how the ecosystem is effected, monitored and managed. This simulation approach provides a means for pinpointing key research areas and (potentially more importantly) highlighting performance tradeoffs between alternative management strategies across a range of management objectives in the face of uncertainty (Sainsbury, 1988; Sainsbury, 1991; Sainsbury et al. 1997; Punt et al. 2001; Fulton et al. 2006b). The track record of management strategy evaluation (which models each part of the resource-management loop) in single sector management is now fairly extensive (Butterworth &amp; Punt, 1999; Sainsbury et al. 1997; Sainsbury et al. 2000; Punt et al. 2001); the record for agent-based resource modelling is not as long, but it is diverse. It is an exceptionally flexible modelling approach that is a useful tool for situations in which small scale or individual level variability may play a significant role in the outcome. This is the case in some natural resource questions and is increasingly the case as management issues have to span more questions (such as the fate of threatened, endangered or protected species). One disadvantage to the agent-based modelling technique is the computational overheads involved  this can make some large scale questions infeasible if pure decision based agents are used to represent all aspects of a system. New hybrid methods that tie classical dynamic (differential equation) models with decision based agents seem to be the best means of solving these dilemmas. NWS-InVitro is an example of just such a hybrid model. It simulates effects of human activity, such as fishing, tourism, and LNG or salt production on the regional ecosystem, and the response of the system to different management regimes. The model does not attempt to represent all ecosystem details, but focuses on the dominant system components, in this case the North West Shelf ecosystem of Australia. These include commercially valuable fish and crustaceans, sharks, turtles, benthic communities, seagrass and mangroves and with the major industries in the area  fisheries, shipping, oil and gas production, salt extraction, coastal development, port maintenance (such as dredging) and recreational activities, such as fishing. The remainder of this document details the formulation of NWS-InVitro.

Organization: Australian Ocean Data Network