Managing multiple vital rates to maximize greater sage
Grouse population growth
Rebecca L. Taylor,* Wildlife Biology Program, College of Forestry and Conservation, University
of Montana, 32 Campus Drive, Missoula, Montana 59812.
Brett L. Walker, Colorado Division of Wildlife, 711 Independent Avenue, Grand Junction, Colorado
81505
David E. Naugle, Wildlife Biology Program, College of Forestry and Conservation, University of
Montana, 32 Campus Drive, Missoula, Montana 59812
L. Scott Mills, Wildlife Biology Program, College of Forestry and Conservation, University of
Montana, 32 Campus Drive, Missoula, Montana 59812
Despite decades of greater sage grouse (Centrocercus urophasianus) field research, the
resulting range-wide demographic data has yet to be synthesized into sensitivity analyses to
guide management actions. We summarized range-wide demographic rates from 71 studies
from 1938-2008 to better understand greater sage-grouse population dynamics. We used
data from 38 of these studies with suitable data to parameterize a two-stage, female-based
population matrix model. We conducted analytical sensitivity, elasticity, and variance-
stabilized sensitivity analyses to identify the contribution of each vital rate to population
growth rate (λ) and life-stage simulation analysis (LSA) to determine the proportion of
variation in λ accounted for by each vital rate. Greater sage grouse showed marked annual
and geographic variation in multiple vital rates. Sensitivity analyses suggest that, in contrast
to most other North American galliforms, female survival is as important for population
growth as chick survival and more important than nest success. In lieu of quantitative data
on factors driving local populations, we recommend that management efforts for sage grouse
focus on increasing juvenile, yearling, and adult female survival by restoring intact sagebrush
landscapes, reducing persistent sources of mortality, and eliminating anthropogenic habitat
features that subsidize predators. Our analysis also supports efforts to increase chick survival
and nest success by managing shrub, forb, and grass cover and height to meet published
brood-rearing and nesting habitat guidelines, but not at the expense of reducing shrub cover
and height below that required for survival in fall and winter.