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 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

Sampling protocol 30 meter line transects 5 or 10 transects per area (depending on size of treated area) 10 Daubenmire quadrats (0.1 m 2 ) 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 Methodology

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 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 Spike 20P 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 2,4-D Herbicide

Minimum suggested cover for sagebrush (15%)

2,4-D Herbicide

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 Brushmowing

Minimum suggested cover for grasses (10%)

Minimum suggested cover for forbs (5%)

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

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 Fire (Prescribed and Wild)

– Note forb response 1984 Note lack of sagebrush recovery

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 Summary

Gunnison Tornado??