Tony Apa, Mindy Rice, Michael Phillips, and Amy Davis
Gunnison Basin and Montrose & San Miguel Counties
Data collection completed; analysis is ongoing
To compare the demography, habitat use and movement patterns of a large Gunnison sage-grouse population to smaller populations.
To use Gunnison sage-grouse movement patterns to develop movement and spatial models.
To analyze genetic diversity in Gunnison sage-grouse populations.
To use demographic data and model outputs to develop and evaluate consequences of alternative management plans.
To provide an update on the sustainability of Gunnison sage-grouse populations.
Seven Gunnison sage-grouse (GUSG) populations are distributed across southwestern Colorado and southeastern Utah. GUSG depend on sagebrush throughout most their life. The loss and fragmentation of sagebrush habitat may have important impacts on the long-term sustainability of GUSG populations. Our ability to conserve GUSG will depend on our ability to restore and protect a biologically relevant mosaic of habitats in a human-dominated landscape.
CPW has conducted research to evaluate seasonal use patterns of GUSG in the past but still lacked detailed information on demographics and dispersal patterns within and among populations. Therefore, CPW initiated this project to determine the impact of landscape features, such as habitat fragmentation, on the movement patterns and demography of GUSG.
Researchers focused the study on two different populations of GUSG: the Gunnison Basin population, which is the largest and most genetically diverse population, and one of the smaller populations that inhabits Montrose and San Miguel Counties (the San Miguel population). Using radiotelemetry, researchers tracked GUSG movements, estimated nest success and estimated survival rates of juvenile and adult GUSG. Researchers analyzed the data collected using Geographic Information System to develop movement and spatial models.
Nest success did not differ between the two populations or in relation to female age, and was not strongly related to vegetation measures at nest sites. Nest success was variable among years, and nests initiated early in a season had higher success than nests initiated later in the season.
There was no juvenile recruitment into the San Miguel population during the study. Annual juvenile recruitment was variable in the Gunnison Basin and declined over the course of the study.
Annual and seasonal survival of adult GUSG was variable and did not differ between the two populations or between yearlings and older adults.
During the study, the two populations were declining from recent high levels, with the San Miguel population experiencing greater declines than the Gunnison Basin population. Projections of population persistence indicated that the Gunnison Basin population is likely to persist over the long term.
Habitat selection and movement analyses are ongoing.
The results of this research will help wildlife managers evaluate the relative outcomes of alternative management actions.
Davis, A.J. 2012. Gunnison sage-grouse demography and conservation. Dissertation, Colorado State University.
Davis, A.J., M.B. Hooten, M.L. Phillips, and P.F. Doherty, Jr. In press. An Integrated Modeling Approach to Estimating Gunnison Sage-Grouse Population Dynamics: Combining Index and Demographic Data" Journal of Ecology and Evolution.
Davis, A.J., M.L. Phillips, and P.F. Doherty, Jr. In press. Survival of Gunnison Sage Grouse in Colorado, USA. Journal of Avian Biology.