The Genetic Variation of Peregrine Falcons (Falco peregrinus) in the Chesapeake Bay




Ravinskas, Jennifer

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For the last century, the local population of Chesapeake Bay Peregrine falcons (Falco peregrinus) has been fluctuating in its abundance, making genetic diversity difficult to assess (Johnson et al., 2010). Recently, the well-being of falcon populations in Coastal Virginia has improved, and their population numbers have been stabilizing. The extent of the Peregrine falcon genetic variation in the Chesapeake Bay population of falcons is unknown, yet the possibility of a genetic bottleneck does exist. To assess levels of allelic heterozygosity in this population, genetic analyses were performed on blood and feather samples taken from breeding pairs in the Bay during 2007 and 2013. DNA was extracted from these samples then fingerprinted at microsatellite loci with Peregrine falcon specific labeled primers (Nesje 2000b). Fingerprint results were analyzed using the GenAlEx 6.5 software, then observed alleles (AO), expected heterozygosity (HE), observed heterozygosity (HO), and fixation index (FST) were assessed. At each locus studied, there were similarities in HO between contemporary populations of falcons in the Chesapeake Bay and other global reintroduction programs in southern Scandinavia and southern Norway. At locus NVH fp54, observed heterozygosity in the Chesapeake Bay population was dramatically lower than that in the European populations. In the Chesapeake Bay population, FST values were close to zero at each locus, suggesting complete panmixis of this population. The cluster analyses performed with the STRUCTURE 2.3.4 software confirmed that the contemporary populations of Peregrine falcons in the Chesapeake Bay are genotypically one genetic cluster. Comparisons were made between the historic population of Peregrine falcons endemic to the east coast (the Appalachian mountains) and the contemporary population of birds reintroduced to and currently living in the Chesapeake Bay. These comparisons showed no significant difference when levels of observed heterozygosity, expected heterozygosity, and number of alleles were assessed. This suggests that the reintroduced population of peregrines is no more able to cope with anthropogenic or environmental disturbances than their historic counterparts. Known susceptibility of Peregrine falcons to environmental contamination as well as relatively low heterozygosity levels in the contemporary Chesapeake Bay population of Peregrine falcons suggest that continued monitoring and further conservation efforts of this population are warranted.



Chesapeake Bay, Peregrine falcon, Variations, Genetics