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Initial Baseline Assessment Results

Initial Baseline Assessment Results. Disturbance Thresholds Group September 3, 2013 Portland State University Theresa Burcsu tburcsu@pdx.edu. Values calculated using the 5 km radius area around leks . Percent Sagebrush by BLM District. Core Low. Core Low. Core Low.

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Initial Baseline Assessment Results

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  1. Initial Baseline Assessment Results Disturbance Thresholds Group September 3, 2013 Portland State University Theresa Burcsu tburcsu@pdx.edu

  2. Values calculated using the 5 km radius area around leks.

  3. Percent Sagebrush by BLM District

  4. Core Low Core Low Core Low Percent Sagebrush by ODFW Habitat Designation

  5. Percent Developed by BLM District

  6. Percent Developed by ODFW Habitat Designation

  7. Values calculated using Various spatial units

  8. County Proportions

  9. Key Landscape AttributesValues calculated for the whole landscape unit.

  10. At this spatial unit, things look pretty good.

  11. However, when you begin to partition the state, the picture changes substantially.

  12. ODFW BLM Counties Across different units, the picture is quite differentDashed lines separate spatial assessment units (e.g., core-low density from BLM districts)

  13. ODFW BLM Counties MZs Human and fire disturb habitat on the landscape. Assumptions:Human disturbances are permanent.Natural disturbances are temporary.

  14. ODFW BLM Counties MZs What is the recovery time of habitat following a fire disturbance?What is the effect on sage-grouse?It depends on factors such as the extent, severity, etc.

  15. Cautions • The Oregon population is declining; Average annual decline since 1980 is -4.0% per year. • Key threats in Oregon are difficult to control. Both are increasing. • The relationship between lek status and development shows a steep decline to three percent – Knick found that 99 percent of active leks had less than 3 percent development within 5 km. Three percent is not where populations start to decline. • Success rates for recovering/improving sagebrush habitat are low. • Sagebrush habitats take more than 20 to 30 years to mature; sage grouse use may take even longer to recover at a disturbed site. • Due to sage-grouse’s fidelity to sites, birds may continue to return to leks many years after habitat disturbances occur – giving a false impression of their ability to withstand disturbance.

  16. Trial Balloon Proposal • Conservative threshold with future increases tied to: • Stable or Increasing population numbers; and • Documented effectiveness of offset actions based on: - population response to restoration treatments; • effectiveness of threat reduction measures • Consider setting thresholds by type of development (e.g. agricultural conversion, roads versus transmission versus solar) • Consider applying a disturbance allowance to all Core Habitat or a percent of Core Habitat

  17. Base Facts • Current Core Policy on avoidance of core habitat affects 28% of the current range in Oregon; 72 percent of the range has option for offsetting impacts from unavoidable impacts. • 1 percent of a 4 miles buffered lek 80 acres of direct impact (habitat conversion).

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