Population Structure of Mountain Plover as Determined Using Nuclear Microsatellites

Mountain Plover (Charadrius montanus) is a species of conservation concern that has experienced significant habitat loss and population decline. This, coupled with previous observations that the species exhibits strong fidelity to breeding grounds, suggests that breeding populations may be genetically differentiated and possibly suffer from reduced genetic variation associated with relatively small population sizes. A previous genetic study comparing mitochondrial DNA sequences of plovers in Montana and Colorado found high levels of genetic variability and very little genetic differentiation among breeding locales. Because mitochondrial DNA can track only female movements and is sampled from only one locus, we used 14 nuclear microsatellite loci to further examine population structure, thereby both documenting male movements and providing a more comprehensive view of genetic structure. We found no significant differences among breeding populations. The most likely number of unique genetic clusters was one, suggesting that all sampled breeding locations comprise a single relatively homogenous gene pool. Levels of genetic diversity were similar across all four populations, with the greatest diversity in the southern plains population. We speculate that the lack of detectable genetic differentiation among populations is due to sufficient gene flow among breeding populations that might ensue if at least some pair bonds are formed when birds form mixed flocks on wintering grounds. This study corroborates and expands upon the findings of a previous mitochondrial DNA study providing a more comprehensive view of Mountain Plover population structure.