Effects of Red-cockaded Woodpecker Bottleneck and Current Management on Genetic Diversity

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The red-cockaded woodpecker is a federally listed species that declined in the southeastern United States from approximately 1.6 million cooperative breeding groups historically to less than 3,500 groups by 1978 due to loss and degradation of habitat and fire suppression.

A genetic study conducted in the early 1990’s confirmed this population bottleneck resulted in loss of genetic diversity. This species has been intensively managed since the late 1970’s and novel molecular techniques have enabled historical analysis of older museum samples. USGS scientists and others examined temporal change in genetic diversity and structure, or pattern, using microsatellite and mitochondrial DNA to assess genetic variability before and after the population bottleneck. Recently collected samples and those from the early 1990’s indicate reduced genetic diversity and increased structure due to population isolation, relative to museum samples from the early-mid 20th century. However, diversity and structure do not appear to have changed since the early 90’s indicating that management strategies, such as artificial cavity creation to promote nesting and translocation, have been successful in optimizing genetic resilience by maintaining diversity in addition to increasing population numbers.

 

Miller, M.P., Vilstrup, J.T., Mullins, T.D., McDearmon, W., Walters, J., Haig, S.M., 2019, Changes in genetic diversity and differentiation in red-cockaded woodpeckers (Dryobates borealis) over the past century: Ecology and Evolution, p. online, https://doi.org/10.1002/ece3.5135