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Relating Post-Treatment Vegetation Responses to Habitat Requirements of Gunnison Sage-grouse

Relating Post-Treatment Vegetation Responses to Habitat Requirements of Gunnison Sage-grouse. Dr. Joe Brummer Colorado State University Department of Soil and Crop Sciences and John Scott Natural Resources Conservation Service. Methodology. Location: Gunnison Basin

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Relating Post-Treatment Vegetation Responses to Habitat Requirements of Gunnison Sage-grouse

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  1. Relating Post-Treatment Vegetation Responses to Habitat Requirements of Gunnison Sage-grouse Dr. Joe Brummer Colorado State University Department of Soil and Crop Sciences and John Scott Natural Resources Conservation Service

  2. Methodology • Location: Gunnison Basin • Sagebrush areas that had been recently and historically treated were sampled during the 2006 growing season • Sagebrush treatments investigated • Spike herbicide • 10 xeric sites • 4 to 12 years old • 2,4-D herbicide • 10 mesic sites • 1 to 15 years old • 7 xeric sites • 3 to 22 years old • Brushmowing • 8 xeric sites • 3 to 9 years old • Fire (prescribed and wild) • 16 mesic sites • 4 to 22 years old • 12 controlled burns, 4 wildfires

  3. Methodology • Sampling protocol • 30 meter line transects • 5 or 10 transects per area (depending on size of treated area) • 10 Daubenmire quadrats (0.1 m2) per transect for herbaceous cover • Variables measured • Canopy cover of sagebrush and other shrubs by line intercept • Height of sagebrush • Canopy cover and height of grasses and forbs • Tried to follow sampling guidelines as outlined in the Rangewide Conservation Plan • Status of vegetation related to breeding habitat guidelines • Control areas • When feasible, an equal number of samples was taken in an adjoining untreated area

  4. Spike 20P Herbicide • Chemical name: Tebuthiuron • Granular herbicide • Systemic • Must move into soil where it is taken up by roots and translocated to aerial portions of the plant • Effective control of many brush species • Has been used to thin big sagebrush when applied at low rates (0.1 to 0.5 lbs a.i./ac) • Higher rates must be used on soils with higher OM • Poor results in mountain big sagebrush in Gunnison area

  5. Spike 20P Herbicide • 8 sites were treated at the 0.2 lb/ac rate • Allowed regression over time • 4 sites treated in 1994 at different application rates • Control • 0.2 lbs a.i./ac • 0.3 lbs a.i./ac • 0.4 lbs a.i./ac • 0.5 lbs a.i./ac • Allowed comparison among rates

  6. Spike 20P Herbicide 1994 1996

  7. 2,4-D Herbicide • Foliar contact herbicide • Introduced in the 1940s • Most effective when there is adequate soil moisture and plants are actively growing at time of application (~2+ inches of new leader growth) • Effective control of many brush and broadleaf species • For big sagebrush control, generally applied at 2 lbs a.e./acre • More consistent control on mesic sites • Results often sporadic on the more xeric sites

  8. Minimum suggested cover for sagebrush (15%)

  9. 2,4-D Herbicide 2003 1994

  10. Brushmowing • One of several potential mechanical methods of manipulating sagebrush • Expensive, especially given current fuel and labor costs • Confined to areas with few or no large rocks and fairly gentle topography • Advantages • Can target areas of various sizes and shapes • Lays down litter • Helps reduce runoff and increase infiltration of precipitation • Mulch aids in establishment of grass and forb seedlings • Height of mowing can be manipulated which leads to varying degrees of sagebrush control • Disadvantage • Tends to be short-lived treatment

  11. Minimum suggested cover for grasses (10%)

  12. Minimum suggested cover for forbs (5%)

  13. Brushmowing • Treated in 2001 • Note grass response • Transition from untreated to treated

  14. Fire (Prescribed and Wild) • Natural occurrence in sagebrush ecosystems • Main factor that historically set succession back • Size and shape of treatment more difficult to control • Suppression of sagebrush tends to be more long lasting compared to other treatments • Easier to implement on more mesic sites because of presence of fine fuels to carry fire

  15. Fire (Prescribed and Wild) 1984 1988 1998 – Note forb response Note lack of sagebrush recovery

  16. Summary • Sagebrush recovery • Xeric sites (time to reach 15% cover) • Spike – 19 yrs • 2,4-D - no relationship • Brushmowing – 12 yrs • Mesic sites (time to reach 10% cover) • 2,4-D – 8 yrs • Fire – 36 yrs • Grass response • No or weak relationship to age of treatment • Generally, significant difference between treated and untreated • Majority of sites met minimum suggested cover • Regardless of age of treatment • Forb response • No consistent relationship • Spike and fire – decreased with age of treatment • 2,4-D – increased with age of treatment • Brushmowing – no relationship • Majority of sites did not meet minimum suggested cover

  17. Gunnison Tornado??

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