Modeling ecological and economic benefits of post fire revegetation in the great basin
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Modeling Ecological and Economic Benefits of Post-Fire Revegetation in the Great Basin. Becky Niell. Brief Ecological History of Sagebrush-Steppe. Historically co-dominated by native bunchgrasses and sagebrush Cattle grazing (1850’s)  decline of native bunchgrasses & increase in sagebrush

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Modeling ecological and economic benefits of post fire revegetation in the great basin

Modeling Ecological and Economic Benefits of Post-Fire Revegetation in the Great Basin

Becky Niell


Brief ecological history of sagebrush steppe
Brief Ecological History of Sagebrush-Steppe Revegetation in the Great Basin

  • Historically co-dominated by native bunchgrasses and sagebrush

  • Cattle grazing (1850’s)  decline of native bunchgrasses & increase in sagebrush

  • Cheatgrass invasion (early 1900’s)  increased fire frequency & changed successional patterns


Ramifications of Ecological Change Revegetation in the Great Basin

  • invasion of nonnative plant

  • species

  • loss of native shrublands

  • increased fire frequency

  • loss of native biodiversity

  • reduced forage for livestock

  • increased management costs

  • decreased water quality

  • reduced recreation values


What to do…… Revegetation in the Great Basin

  • Aggressive management is needed ….

    • Revegetation

      • Crested wheatgrass

      • Native seed

Constrained by lack of information & high costs.


  • Need: Revegetation in the Great Basin

    • “predictive models to forecast the potential effects of various management actions on resources”

    • “economic models that can put restoration costs and benefits into a framework that will support choosing among restoration alternatives as well as explaining benefits to the public and other constituents (BLM 2000).”


State and transition model conceptual model
State-and-transition model Revegetation in the Great Basin(conceptual model)

Markov chain model(quantitative, dynamic model)

  • Predict long term vegetation change

  • Predict costs and benefits of revegetation strategies


2. Revegetation in the Great BasinNativePerennial Bunchgrass - Sagebrush

3. Sagebrush- Native Perennial Bunchgrass

4. DenseSagebrush- Sparse Bunchgrass Cheatgrass Understory

1. Native Perennial Bunchgrass Dominant

5. DenseSagebrush w/ Cheatgrass Understory

11. Sagebrush - Introduced Perennial Bunchgrass

6. Cheatgrass Dominant w/ Sagebrush

10. IntroducedPerennial Bunchgrass - Sagebrush

7. Cheatgrass w/ Sagebrush seedlings & rootsprouting shrubs

9. Introduced Perennial Bunchgrass Dominant

8. Cheatgrass Monoculture

Natural Succession

Fire Event

Fire Event with Revegetation

State Transition

Wyoming Big Sagebrush Vegetation in the Great Basin with grazing and cheatgrass present. (8-10 inch precipitation zone)


Average Transition Times Between Vegetation Types Revegetation in the Great Basin

Average Fire Frequencies


Markov chain model
Markov Chain Model Revegetation in the Great Basin


150 year simulation of cheatgrass monoculture

No reveg. Revegetation in the Great Basin

Reveg.

150 year simulation of Cheatgrass Monoculture:

t = 0

t = 20

t = 150

31 - 41%

35 - 51%

w/ revegetation

25%

40 - 69%

78 - 89%

no revegetation


Immediate action needed
Immediate Action Needed!! Revegetation in the Great Basin

Without revegetation:

40 – 69% of the landscape cheatgrass monoculture or worse in 20 years.

1/20 to 1/3 of landscape burning every year…

Costs….

Revegetation is not cheap: $25-100+ /acre

(1.7 million acres burned in 1999)


So… Revegetation in the Great Basin

What are economic and ecological trade-offs of different post-fire revegetation strategies?

  • Reducing cheatgrass monoculture

  • Maintaining native vegetation

  • Minimizing management costs


Area of Cheatgrass Monoculture Revegetation in the Great Basin(% of landscape)

50 YEAR RESULTS:

Goal 1. Reduce Area of Cheatgrass Monoculture:

  • No revegetation (71%)

  • Native seed (42%) *

  • CWG (42%) *

Area of Native Vegetation (% of landscape)

Goal 2. Increase Area of Native Vegetation:

  • No revegetation (10%)

  • Native seed (42%) *

  • CWG (10%)


Average Management Costs Revegetation in the Great Basin($ / 100 ac.)

Goal 3. Minimize

Management Costs:

  • No revegetation ($7.83/ac)

  • Native seed ($6.64/ac)

  • CWG ($6.00/ac) *

  • Management costs = fire suppression costs + reveg. costs

Revegetation can cost 1.9 times more per acre than fire suppression and still cost less than no revegetation in the long run!!


Conclusions
Conclusions: Revegetation in the Great Basin

  • 1) No revegetation  Ecological and economic disaster

  • 2) Post-fire revegetation was more effective than no revegetation for:

    • achieving ecosystem objectives

    • reducing costs

  • 3) The appropriate choice of seed mix depends on the prioritization of management objectives

    • native seed costs more than crested wheatgrass seed

    • native seed was equally or more effective for achieving each ecosystem goal

  • 4) Post-fire revegetation is not sufficient!


Questions?? Revegetation in the Great Basin


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