PARENT SESSION
Poster Session # 18: Avian Ecology.

Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Sage grouse in space: What measure of spatial heterogeneity is most meaningful in assessing population dynamics?

LaMontagne, Jalene¹, Irvine, Robyn^*,2, ¹ University of Alberta, Edmonton, Alberta, Canada² University of Calgary, Calgary, Alberta, Canada

ABSTRACT- Sage grouse populations (Centrocercus urophasianus) in Utah are in decline. Sage grouse populations in Utah are estimated to occupy only 50% of the habitat they once did and their abundance is approximately half what it was in 1850. The strutting grounds (leks) for sage grouse are distributed throughout the state and these leks are situated at a wide range of vertical (approx. 1300 to 2800 meters above sea level) and horizontal (up to 1400 km apart) locations. Despite the increasing recognition of the role of habitat heterogeneity and environmental variability in driving population cycles, the role of altitude in conjunction with the role of the linear separation distance between populations has not been explored. Sage grouse in Utah are predicted to be listed as endangered within a year. It is therefore important to understand what drives the dynamics of the spatially separate populations scattered around the state to allow management plans to address the decline. We modeled the population dynamics of 150 sage grouse populations, restricting our analysis to populations with a minimum of 10 years of count data, and we assessed the spatial autocorrelation among leks using non-centered correlograms. Linear distances (latitude and longitude), vertical distances (altitude), and absolute distances (the hypotenuse distance of the altitude and latitude/longitude triangle) were assessed within the structure of the correlogram to infer spatial patterns of different types of population dynamics. We will present results for the effects of the different distance types on correlations in population fluctuations and the spatial patterning of population dynamics. We will also comment on the management implications associated with different spatial locations of populations.

Key words: Centrocercus urophasianus, population dynamics, spatial correlation, non-centered correlogram