Canadian Forest Service Publications
The balance of complexity in mechanistic modeling: Risk analysis in the mountain pine beetle. 2006. Nelson, W.A.; Potapov, A.; Lewis, M.A.; Hundsdörfer, A.E.; He, F. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Mountain Pine Beetle Initiative Working Paper 2006-03. 26 p.
Available from: Pacific Forestry Centre
Catalog ID: 26244
CFS Availability: PDF (download)
In most fields of applied ecology, there is a need to predict and manage the risk of pest outbreaks. One challenge to the development of mechanistic risk models is striking a balance between the tactical details of a system, and the strategic simplifications necessary to maintain generality and mathematical tractability. In this review we analyze the balance of complexity for risk models in the mountain pine beetle system. Mountain pine beetles are the single most destructive pine-forest pest in western North America. Much effort has gone into collecting empirical evidence and developing mechanistic outbreak models. Yet, current risk models only utilize tree-susceptibility indices that have proven ineffective at predicting the risk or extent of an infestation. We develop a conceptual framework of the beetle-host interaction that allows us to compare across both phenomenological and mechanistic models. From this framework, we demonstrate how current risk models emerged and why they predict ranked-risk as opposed to absolute-risk. Existing mechanistic models include a wide variety of possible interactions which has lead to disagreement about the ingredients essential for beetle outbreaks. By contrasting these models against the ecological framework, we extract systematic insight into the factors that determine risk, and suggest what dynamical processes must be modeled explicitly and what can be strategically abstracted.