Sage Grouse in Mono County, CA

Student: Joel Tebbenkamp
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 The Bi-State population of greater sage-grouse (Centrocercus urophasianus) is a Distinct Population Segment and candidate for listing under ESA.  The status of the Bi-State population is based largely on unique genetics and long-term geographic isolation from other greater sage-grouse populations.  The Bi-State population includes multiple localized populations, with some that appear demographically isolated, exhibiting lower vital rates and population trends.  Most notably, one of the populations exhibited low reproductive success due to nonviable eggs, which we hypothesized may be due to isolation and low genetic diversity.  To help facilitate a more comprehensive understanding of the dynamics within the Bi-State population our objectives were to identify genetically distinct populations, assess genetic diversity, and identify first-generation dispersers using molecular techniques.  Through capture and noninvasive genetic sample collection during 2007 - 2011 we sampled 331 sage-grouse throughout Mono County, California, characterizing each individual at 17 nuclear microsatellite loci.  Pairwise F_ST between localized populations ranged from 0.065 - 0.246.  Combining the results of the pairwise F_ST estimates and 2 Bayesian clustering analyses we identified 5 genetic populations.  Genetic diversity indices (He = 0.58 - 0.60, AR = 2.86 - 3.19) were not significantly different between populations, suggesting low genetic diversity was not likely causing egg non-viability.  We identified 9 first-generation dispersers, which combined with the relatively homogenous genetic diversity indices illustrates the population’s natural ability to avoid genetic isolation under the current landscape conditions.