Gunnison sage-grouse lek site suitability modeling

Open-File Report 2014-1010

Prepared in cooperation with the National Audubon Society, the Bureau of Land Management, the National Park Service, the U.S. Department of Agriculture Forest Service, Colorado Parks and Wildlife, and the Habitat Partnership Program
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In order to better understand and protect species with minimal or decreasing populations, it is imperative to determine their actual existing population size. The focal species for this project is the Gunnison sage-grouse (GUSG), which became a proposed endangered species under the Endangered Species Act, thus confirming the need for better population estimates. Lek site counting during mating season has historically been the primary method for estimating population size since the grouse are very difficult to count at other times of the year. The objective of this project was to use historical data and available technology to identify additional potential lekking sites. This was done by determining areas throughout the study area that have the same landscape characteristics as those where known lekking activities occur. More accurate population counts could be the outcome of locating more lek sites.

One of the remaining seven GUSG populations, the Crawford population (estimated at 128 individuals) exists in an area that includes the Gunnison Gorge National Conservation Area and the northern portion of the Black Canyon of the Gunnison National Park (our study area). While the Crawford population is small, it is still considered a self-sustaining population; the persistence and growth of this population directly contribute to genetic diversity conservation of this declining species. To date, only observational and anecdotal information about the Crawford population’s range, movements, and seasonal habitat use exist.

From 1978 to the present, GUSG population monitoring has been accomplished through annual lek counts conducted each spring during GUSG mating season. Although this method has provided information on GUSG population trends, it is somewhat limited because counts are based only on known lekking sites and historically minimal efforts have been made to identify additional lek sites. To meet the objective of locating more potential lekking sites, we used a suite of spatial data, geographic information system tools, and maximum entropy species distribution tools. Based on expert knowledge and landscape variables, the modeling process evolved into a hybrid approach for delineating areas that would have a significant probability for supporting GUSG lekking activities. Based on model results, a sampling protocol was developed for model verification. The results of this project provide wildlife managers with a more sophisticated methodology to evaluate GUSG habitat for potential lekking sites.

Study Area

Additional publication details

Publication type:
Publication Subtype:
USGS Numbered Series
Gunnison sage-grouse lek site suitability modeling
Series title:
Open-File Report
Series number:
Year Published:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Fort Collins Science Center
iv, 18 p.
United States
Delta County;Gunnison County;Montrose County
Other Geospatial:
Black Canyon Of Gunnison National Park;Gunnison Gorge National Conservation Area
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