Landscape Influence on Gene Flow in Greater Sage-Grouse: Conservation Actions Through Cores and Corridors
Dates
Publication Date
2013
Citation
2013, Landscape Influence on Gene Flow in Greater Sage-Grouse: Conservation Actions Through Cores and Corridors: .
Summary
Habitat and population fragmentation were among the primary factors contributing to the recent U.S. Fish and Wildlife Service decision that listing greater sage-grouse (Centrocercus urophasianus, hereafter sage-grouse) was warranted but currently precluded by higher priority actions. Increasingly, current management is focused on core or priority areas containing the highest densities of breeding birds with little regard to understanding connectivity within and among areas. The most fundamental objective of species conservation is to first identify and subsequently maintain a set of viable and connected populations. Therefore, if management emphasis on core areas is to be successful for long-term conservation, it is important to know [...]
Summary
Habitat and population fragmentation were among the primary factors contributing to the recent U.S. Fish and Wildlife Service decision that listing greater sage-grouse (Centrocercus urophasianus, hereafter sage-grouse) was warranted but currently precluded by higher priority actions. Increasingly, current management is focused on core or priority areas containing the highest densities of breeding birds with little regard to understanding connectivity within and among areas. The most fundamental objective of species conservation is to first identify and subsequently maintain a set of viable and connected populations. Therefore, if management emphasis on core areas is to be successful for long-term conservation, it is important to know (1) the spatial delineation of breeding populations across the range-wide distribution of sage-grouse, (2) how primary populations located in high quality habitat are interconnected across regions of lower population densities and less suitable habitat, and (3) the spatial scale and relative importance of landscape features that influence gene flow.
The working model for spatial organization of the range-wide distribution of sage-grouse likely consists primarily of numerous small populations in the periphery surrounding large core populations. In this study, we used non-invasive genetic data obtained from feathers collected at leks (breeding locations) to test this model and to understand the processes that underlie the spatial pattern of populations. Genetic data provide unique information on individual movements or dispersals and subsequent mating, as expressed through gene flow. Barriers to dispersal can fragment large populations, restrict exchange among small populations, and limit the ability of populations to respond to environmental stressors or changes in sagebrush (Artemisia spp.) land cover. Therefore, understanding how individuals disperse within and among breeding populations is important for maintaining genetic diversity, to sustain populations that are experiencing declining trends, or to recolonize extirpated populations when suitable habitat remains.
We will first use information on genetic relatedness derived from individual-, lek-, and population-based analyses to better delineate the range-wide network of breeding populations. We will then combine genetic data with landscape models of cost-surfaces to identify characteristics of barriers, including geographic distance, topographic features, and anthropogenic land uses that influence dispersal and genetic exchange. These results are important for incorporating landscape and genetic connectivity into conservation planning to delineate core or priority populations, and to reduce population fragmentation, isolation, and subsequent risk of extirpation.
