Canadian Forest Service Publications
Modeling insect disturbance across forested landscapes: insights from the spruce budworm. 2015. Sturtevant, B.R.; Cooke, B.J.; Kneeshaw, D.D.; MacLean, D.A. Pages 93-134 (Chapter 5) in A.H. Perera, B.R. Sturtevant and L.J. Buse, editors. Simulation modeling of forest landscape disturbances. Springer International Publishing, Switzerland.
Issued by: Northern Forestry Centre
Catalog ID: 36486
CFS Availability: Not available through the CFS (click for more information).
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Irruptive forest insects have a rich history of empirical study and as subjects of modeling in both theoretical and applied ecology, yet compared with other disturbance agents landscape-scale insect disturbance modeling is rare. We examine the history of spruce budworm (Choristoneura fumiferana) disturbance modeling to provide insight into landscape-scale insect disturbance modeling more generally. First, we outline the evolution of competing approaches to budworm population modeling, illustrating the interplay of models and data, and highlighting the roles of reciprocal feedbacks among trophic levels (i.e., budworm, its forest host and its natural enemies) and broader-scale processes (i.e., dispersal, synchronization, climatic variation and change). We then overview studies relating budworm defoliation to its effects on forests, culminating in spruce budworm decision support tools designed for forest operations planning. Modeling applications using landscape disturbance and succession models are a more recent addition, focused on long-term responses of forested landscapes to a given budworm disturbance regime. Cross-scale interactions—recognized within the budworm–forest system for over three decades—demand sophisticated analyses and modeling that will ultimately lead to a more robust synthesis of budworm response to forest conditions, particularly under different climatic contexts. We describe the budworm case study to illustrate how insights from divergent perspectives can be complementary and ultimately lead to more complete understanding of the system. We propose that the most fruitful modern avenue of research in forest–insect–climate interactions is in testing inclusive hypotheses that allow for multiple processes acting simultaneously using integrative, multiscale landscape models that embrace the possible existence of a range of dynamic behaviors.
Plain Language Summary
Spruce budworm is arguably one of the best studied insects on the planet. We examine the history of spruce budworm disturbance modeling to provide insights into modeling methods that could be applied to other forest insects. First, we outline the evolution of competing approaches to budworm population modeling, illustrating the interplay of models confronted by data and highlighting key insights regarding the roles of reciprocal feedbacks between the budworm, its forest host, its natural enemies, and larger scaled processes (i.e., dispersal, synchronization, climatic variation, and change). We then review studies examining the impact of budworm defoliation on forests and we discussed spruce budworm decision support tools for forest managers. Our study illustrates how insights from divergent approaches to population modeling can be complementary and how debate about these approaches provides deeper insights that ultimately lead to a more complete understanding of the system. We suggest that the most fruitful modern avenue of research in forest-insect-climate interactions is in testing inclusive hypotheses that allow for the possibility that multiple processes are acting simultaneously, using integrative, multi-scale landscape models.