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Comparing Cost, Risk, and Benefit Trade-offs Under Uncertainty: Cheatgrass Case Study Lisa Wainger and Dennis King, University of Maryland Richard Mack,

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Presentation on theme: "Comparing Cost, Risk, and Benefit Trade-offs Under Uncertainty: Cheatgrass Case Study Lisa Wainger and Dennis King, University of Maryland Richard Mack,"— Presentation transcript:

1 Comparing Cost, Risk, and Benefit Trade-offs Under Uncertainty: Cheatgrass Case Study Lisa Wainger and Dennis King, University of Maryland Richard Mack, Washington State University Jim Opaluch, University of Rhode Island

2 Establish Management Priorities Evaluate Risks of No Treatment Option Estimate Costs and Risk- Adjusted Benefits of Site/Treatment Options Identify Options with highest Cost-Effectiveness Select Portfolio of Options to Manage Risk Test Assumptions Decision Framework

3 Decision analysis components to examine with case study Benefits of Treatment –How do measures of damage avoided vary with location and scale of analysis? Probability of Successful Restoration –How do site, location and characteristics of invasion influence whether ecosystem services will be restored? Costs of Treatment –How do costs vary by location and scale of treatment?

4 Columbia Basin Study Area

5 Bromus tectorum (cheatgrass) distribution through time 1930s - present

6 Federal Land Ownership Source data: USGS

7 Risks created by cheatgrass invasion Increasing scale

8 with project without project Measuring Benefits Benefits Time i = service, t = time period E D

9 Risk-Adjusted Benefits as a Function of Site and Landscape Conditions Service Capacity Service Scarcity Service Loss Risk Site Qualities Service Value Index Treatment effectiveness X Performance Risk E= [f(s r,l r ) * p] + [f(s d,l d ) * (1- p)] s = site qualities; l = location factors r = restored conditions; d = degraded conditions p = probability of restoring service

10 Does the Site Provide a Valued Service? Site has features necessary to produce service Site has capacity to produce service because “users” have access and complementary inputs are available Service value is enhanced because service is scarce and substitutes are unavailable or expensive The risk that the stream of services will end due to factors beyond the control of restoration is low.

11 Fire Risk Source data: USDA FS ICBEMP

12 Fire Risk with Population

13 Treatment Scenarios 1.Preventive reseeding following fire –Apply to uninvaded sites –Spread seeds aerially or use drill-seeding –Sometimes follow aerial seeding with chaining 2.Herbicide treatment of existing stands –Applied to heavily invaded sites –Multi-step process of burning, herbicide, seeding

14 Treatment Decision Tree Type of Seed B1 B3 Treat / No- treat Cheatgrass Dominant Natives Dominant Forage Species Dominant Cheatgrass Dominant Natives Dominant B1 B2 B1 B3 native forage No- treat treat (p = 0.90) (p = 0.10)

15 Restorability Model Probability of Success Site Variables Landscape Variables Stochastic Variables Cheatgrass regrowth New cheatgrass infestation Native / Forage regrowth

16 Comparing Restorability Contagion Index = 0.30Contagion Index = 0.85 sparse dense

17 Evaluating Costs Trying to supply treatment effort to multiple sites for minimum cost –How do costs vary over infested area? –How many sites to treat? –How much area to treat in each location? Is it worth treating?

18 Site Town Road Initial Cost jk = Fixed Cost k + Travel Cost j *time j + Search Cost j *area + Treatment Cost jk *area j = location k=treatment method SC = f(site factors); TC = g(site factors) Minimum-Cost Network Flow

19 Equipment Sources and Treatment Destinations

20 Cost Per Unit Distance low high

21 Cumulative Travel Cost Map

22 Evaluating Marginal Costs of Treatment Not Infested High Cost Avg. Cost Low cost Lowest cost Source cell MC = max {cell cost jk | m} Treated area m Cell Cost jk = Travel C j *time j + Search C j *area + Treat C jk *area j = location k=treatment method

23 Marginal Cost Surface (time-dependent costs)

24 Sparse Infestation Dense Infestation 8.8Total Cost Marginal Cost Total Treatment (m 2 )6, Marginal Treatment366.0 Comparing Costs and Kill Efficiency sparse dense

25 Intensity of Invasion Ecosystem Service Benefits Site A Risk of Treatment Failure Uncertainty of Returns from Treatment Reversibility of Decline p

26 Transferring Results to Risk Analysis for Recent Invasions How well do GIS databases perform for doing this type of modeling? What were the main factors contributing to cost of control and degree of impact? How does an evaluation of cost-effectiveness change with the scale of analysis? How do costs of control and level of impact change through time? How have transitions in land uses (e.g., recreation vs. rangeland) changed our perception of the impacts of cheatgrass? Given our current values, when, in the progression of the cheatgrass invasion, would treatment have been the most cost- effective?


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