Interseasonal movements of greater sage‐grouse, migratory behavior, and an assessment of the core regions concept in Wyoming

Abstract

Animals can require different habitat types throughout their annual cycles. When considering habitat prioritization, we need to explicitly consider habitat requirements throughout the annual cycle, particularly for species of conservation concern. Understanding annual habitat requirements begins with quantifying how far individuals move across landscapes between key life stages to access required habitats. We quantified individual interseasonal movements for greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) using radio-telemetry spanning the majority of the species distribution in Wyoming. Sage-grouse are currently a candidate for listing under the United States Endangered Species Act and Wyoming is predicted to remain a stronghold for the species. Sage-grouse use distinct seasonal habitats throughout their annual cycle for breeding, brood rearing, and wintering. Average movement distances in Wyoming from nest sites to summer-late brood-rearing locations were 8.1 km (SE ¼ 0.3 km; n ¼ 828 individuals) and the average subsequent distances moved from summer sites to winter locations were 17.3 km (SE ¼ 0.5 km; n ¼ 607 individuals). Average nest-to-winter movements were 14.4 km (SE ¼ 0.6 km; n ¼ 434 individuals). We documented remarkable variation in the extent of movement distances both within and among sites across Wyoming, with some individuals remaining year-round in the same vicinity and others moving over 50 km between life stages. Our results suggest defining any of our populations as migratory or non-migratory is innappropriate as individual strategies vary widely. We compared movement distances of birds marked using Global Positioning System (GPS) and very high frequency (VHF) radio marking techniques and found no evidence that the heavier GPS radios limited movement. Furthermore, we examined the capacity of the sage-grouse core regions concept to capture seasonal locations. As expected, we found the core regions approach, which was developed based on lek data, was generally better at capturing the nesting locations than summer or winter locations. However, across

Low neutral genetic diversity in isolated Greater Sage-Grouse (Centrocercus urophasianus) populations in northwest Wyoming

“…Teton, Wyoming, Wind River, and Gros Ventre ranges; Figures 1 and 2) that most likely limit Greater Sage-Grouse dispersal (Hupp and Braun 1991, Musil et al 1993, Reese and Connelly 1997, Garton et al 2011). Due to these high elevation and large forested tract barriers, the most likely dispersal route from Jackson Hole goes to the east and south toward the Pinedale population ( Figure 2); however, the Euclidian distance between the 2 populations exceeded the interseasonal movement and dispersal of Greater SageGrouse reported in Wyoming (Holloran and Anderson 2004, Bedrosian et al 2010, Fedy et al 2012) further supporting the differentiation we found with population genetics.…”

“…This study identified the Greater Sage-Grouse populations in Jackson Hole and Gros Ventre as genetically isolated with reduced neutral genetic diversity compared to nearby populations in Wyoming and southeast Montana. We were unable to obtain tissue samples from Greater Sage-Grouse populations in Idaho; however, the distance between populations in Jackson Hole and eastern Idaho are beyond the dispersal distance documented for Greater Sage-Grouse based on radiotelemetry (Fedy et al 2012), and the Teton Range eastern slope rises sharply from its base to~2 km above Jackson Hole (Figure 1). Future studies should include eastern Idaho to investigate whether connectivity exists between the 2 areas.…”

Quantifying functional connectivity: The role of breeding habitat, abundance, and landscape features on range‐wide gene flow in sage‐grouse

“…The algorithm iteratively joined each sampling location based on distance using the Lance–Williams dissimilarity formula (Legendre & Legendre, 2012). Subsequently, we used a cut distance to differentiate clusters separated by a distance >25 km, which represented the maximum average summer to winter movement distance for any population in Wyoming (Fedy et al., 2012). We used a minimum sample size of eight individuals per genetic cluster for all subsequent analyses.…”

“…One way of modeling the biological importance of multiple landscape features is through the use of habitat indices. Habitat indices are typically derived from occurrence or radiotelemetry data and are used to predict the probability of occupancy across a landscape based on the suitability of habitat (Fedy et al., 2012; Phillips, Anderson, & Schapire, 2006) or the probability of selection for habitat types (Gubili et al., 2017; Shafer et al., 2012). Using habitat indices in landscape genetic models can assist with establishing a direct link between model results and management actions, and can alleviate some of the issues related to testing a multitude of landscape variables (i.e., type I error).…”

Can Reliable Sage-Grouse Lek Counts Be Obtained Using Aerial Infrared Technology?

“…Sage-grouse fidelity to leks and the conspicuous behavior of males make it possible to estimate population trends. In an attempt to compare trends among populations, recent lek monitoring protocols have been published (Connelly et al 2003;Connelly and Schroeder 2007;Fedy et al 2012). During a lek count, attending males are directly counted from a distance to prevent disturbance of breeding behavior but still maintain high visibility and count accuracy (Patterson 1952;Jenni and Hartzler 1978;Connelly et al 2003).…”