Terrestrial Ecosystem Sciences
Decision analysis for controlling invasive plants at the landscape scale
Parks Canada, The Nature Conservancy of Montana
Noxious weeds are one of the biggest threats to biodiversity, particularly in grasslands and rangelands of western North America. At the landscape scale, there is a great deal of uncertainty about how fast these weeds are spreading, how frequently they are introduced to a landscape, and how effective available management tools are at controlling them.
In the face of this uncertainty, landscape managers must make decisions about how many resources to allocate to weed management and how to prioritize them. ESSA used a branch of game theory known as "decision analysis," in combination with landscape simulation modelling, to evaluate management strategies for invasive plants in Canada’s Grasslands National Park and in three Montana landscapes. Simulations were undertaken using the Vegetation Dynamics Development Tool (VDDT) and the Tool for Exploratory Scenario Analysis (TELSA).
Results from the simulations indicated that, for smaller landscapes or those with lower levels of infestation, strategies focused on detecting and eliminating small new infestations are more effective and robust to uncertainty than strategies that focus on controlling large known infestations, given current weed management budgets. For larger landscapes with a high degree of infestation, results indicated that larger budgets than are currently available are necessary to abate the spread of weeds; a strategy that focuses both on containing the edges of large infestations and detecting and eliminating new foci is ideal.
Reports
Martin, B., D. Hanna, N. Korb and L. Frid. 2007. Decision Analysis of Alternative Invasive Weed Management Strategies for Three Montana Landscapes. Prepared by The Nature Conservancy of Montana, Helena, MT and ESSA Technologies Ltd., Vancouver, BC. 34 pp.
[PDF - 873 kb]
Frid, L. 2006. Decision analysis to evaluate control strategies for crested wheatgrass in Grasslands National Park of Canada. Prepared by ESSA Technologies Ltd., Vancouver, BC for Parks Canada, Winnipeg, MB. 21 pp.
[PDF - 1.1 mb]