Range-wide Connectivity of Greater Sage-Grouse Populations: Delineating Spatial Structure from Genetic Information
Dates
Publication Date
2013
Citation
2013, Range-wide Connectivity of Greater Sage-Grouse Populations: Delineating Spatial Structure from Genetic Information: .
Summary
Habitat and population fragmentation were considered as one of the top factors contributing to the recent U.S. Fish and Wildlife Service decision that listing greater sage-grouse was warranted but currently precluded. This study provides an approach that combines genetic markers and landscape analyses to delineate populations, estimate fragmentation and connectivity in sage-grouse populations, and potentially identify underlying causes that limit connectivity and isolate populations. State and federal agencies are focusing current management actions for greater sage-grouse in core areas containing the highest densities of breeding birds. The core area approach permits limited resources to be applied in regions that will have the greatest [...]
Summary
Habitat and population fragmentation were considered as one of the top factors contributing to the recent U.S. Fish and Wildlife Service decision that listing greater sage-grouse was warranted but currently precluded. This study provides an approach that combines genetic markers and landscape analyses to delineate populations, estimate fragmentation and connectivity in sage-grouse populations, and potentially identify underlying causes that limit connectivity and isolate populations. State and federal agencies are focusing current management actions for greater sage-grouse in core areas containing the highest densities of breeding birds. The core area approach permits limited resources to be applied in regions that will have the greatest potential to benefit the largest proportion of sage-grouse. As a trade-off, energy and other development then can proceed on public lands in areas outside of the core distributions, thus impacting only a small percentage of the sage-grouse in that area. This relatively simple concept of designating areas for sage-grouse conservation but permitting development in surrounding regions has the unwanted potential to fragment sagebrush habitat and increase isolation of individual sage-grouse populations. Information on gene flow and rates of genetic exchange derived from this study will be used to test the efficacy of this conservation model. The range-wide distribution of greater sage-grouse may consist primarily of a few large core populations surrounded by numerous small populations. The viability of many of these small populations may be sustained by dispersing individuals from neighboring populations. Development that causes habitat loss or creates barriers to dispersal between core areas has the potential to restrict movements important to maintain genetic diversity, augment small populations, or recolonize extirpated populations. Thus, an analysis of movement among sage-grouse populations is needed to assess levels of connectivity among core areas, and to identify and delineate features that may act as barriers to movement. Although other methods have been used regionally (radio-tracking, banding) to assess sage-grouse movement, the most efficient and informative approach uses molecular genetic techniques. Genetic methods are less costly, allow for investigations over broader spatial extents, and measure the actual breeding consequences of animal movement. In addition to defining populations and measuring connectivity, genetic approaches also address many other relevant questions including the conservation of genetic diversity, the impacts of inbreeding, and the association among landscape and geographic characteristics, habitats, and genetics.
