Evaluating Costs & Benefits of Alternative Management Strategies in Montana

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TELSA (Tool for Exploratory Landscape Scenario Analysis) is a toolbox of models and programs. Together, the tools help users: prepare spatial and other model input data, define various management and natural disturbance scenarios, simulate these scenarios, and analyze compare and display simulation results. TELSA computer models and programs were used to simulate the spread of leafy spurge and spotted knapweed, and the effects of management actions on weed infestations on the Rocky Mountain Front. Several management strategies were compared under a variety of budget constraints to evaluate the long-term benefits of different approaches, and determine costs and benefits of various strategies. The computer simulations ranged from no management (zero budget) to unlimited management (unlimited budget), with four additional intermediate budget levels. Management scenarios included: improving control success rates, treating new infestations when they first appear, prioritizing large infestations instead of small infestations, and conversely -- treating only a portion of the landscape each year, and delaying the onset of management.

Results of the 40-year computer simulations showed the following management implications for the RMF:

  • Prevention is important to reduce spread rates. 
  • Prioritizing treatment of small patches (early detection-rapid response) is more effective than focusing on large patches. 
  • Efforts to increase treatment success (applicator education, GPS use, etc.) should be a priority. 
  • Effective management has net positive economic outcome, even when only accounting for grazing revenue. 
  • Biocontrol is important for treating unmanageable infestations and reducing overall costs. 
  • Detecting new infestations early and tracking existing weed locations, including previously treated patches, is important for consistent and effective control efforts. 
  • Regularly managing only a portion of weed infestations or waiting to manage until patches become a noticeable problem is costly in the long-run and results in significantly higher levels of future invasion, which will be more difficult to manage. 
  • At a broad scale, relatively un-invaded areas should be prioritized over heavily invaded areas. 

Summarized from the 2011 “Evaluating the costs and benefits of alternative weed management strategies for three Montana landscapes” by Leonardo Frid1, David Hanna2, Nathan Korb2, Brad Bauer2, Katy Bryan1, Brian Martin2, and Brett Holzer3. 1ESSA Technologies Ltd., 2The Nature Conservancy in Montana, 3Private.

Originally appeared in the 2012 Fall Issue of TechLine Invasive Plant News