Dr. Jeffrey L. Beck

Ecosystem Science and Management

Greater Sage-Grouse Migration Ecology and Response to Bentonite Mining in the Bighorn Basin, Wyoming

Sage Grouse - photo by Gib Mathers

PHD Student: Aaron Pratt

For greater sage-grouse (Centrocercus urophasianus), one of the potential factors that may lead to habitat loss, degradation, and fragmentation, and concurrently to population declines, is mining.  Bentonite clay deposits in Wyoming make up 70% of the world’s supply, and mines in the Bighorn Basin produced over 50% of Wyoming’s total bentonite production in 2008.  Bentonite clay extraction is carried out by open-pit mining that leads to loss of sagebrush (Artemisia spp.) habitat.  In addition, mining support activities (e.g., exploration drilling, construction and maintenance of roads, haul trucking) increase disturbance and fragment habitat around mines.  Plans call for mining to increase in the future in sagebrush habitat that is occupied by sage-grouse in the Bighorn Basin.  These mining activities may prevent or limit the ability of the sagebrush landscape in the Bighorn Basin to provide the space and resources to meet the life history requirements of greater sage-grouse.  Therefore, there is a need to assess whether bentonite mining impacts the sage-grouse population in the Bighorn Basin.  We initiated our study in spring 2011 through capturing male and female grouse in 2 study areas (1 study area impacted by bentonite mining and 1 reference study area not impacted by bentonite mining) in the eastern portion of the Bighorn Basin for use in monitoring population demographics, movements, and macro- and micro-scale habitat selection patterns for both populations across 3 years (2011–2013).  Our study objectives include:

1. Describing the migration ecology of these sage-grouse populations through the use of solar-powered GPS transmitters attached to male and female grouse.  A pilot study conducted by American Colloid Company in summer 2010 indicated that some birds make substantial altitudinal migrations to access summer habitat along the base of the west slope of the Bighorn Mountains.  Better understanding the migratory status and migration ecology of these grouse populations will assist managers in ensuring that connectivity to seasonal habitats is maintained as mining operations expand.
2. Estimating demographic rates and habitat selection patterns for sage-grouse exposed to bentonite mining.  This information is important to provide to assist reclamation activities on mined lands after clay is extracted
3. Describing the nesting and brood-rearing microhabitat used by sage-grouse in our study areas, which will also guide the industry’s reclamation practices  
4. Evaluating whether sage-grouse are using reclaimed mine sites, which will be a good measurement of the suitability of reclamation efforts for sage-grouse 
5. Estimating male sage-grouse survival through mark-recapture analyses of males banded, marked, and recaptured on leks in subsequent years