Simulation as an approach to pastoral system analyses

This chapter addresses analyses of pastoral systems using coupled simulation models. Such models allow for control over all aspects of a streamlined representation of an area, such that a limited number of things may be changed and the effects of those changes quantified. The coupled models may address a wide range of questions about animal access, animal health, tradeoffs in support for wildlife and livestock, changes in climate, human energy acquisition, effects of cropping, livestock sales, and many other topics. A spatially explicit and process-based ecosystem computer model is typically joined to a rule-based model representing people and their livestock. The structure of the code allows for the representation of time passing and proper scheduling of events. Code may represent hypotheses to be tested or allow scenarios describing potential policy changes or alternative futures to be simulated. Following assessment of the applications to ensure they represent reality adequately, baseline simulations are done representing current conditions or some other helpful benchmark, and then a limited number of changes to the parameters informing the applications or to the code itself are made to represent scenarios, and another set of simulations made. Comparing the scenario results to those from the baseline quantifies magnitudes and directions of change we may expect. This chapter introduces several means of coupled systems modeling and includes three case studies that demonstrate the method and its utility.