Retention of neutral genetic diversity and connectivity within the metapopulation of Florida Scrub-Jay at Kennedy Space Center

Abstract

Habitat specialists, impacted by anthropogenic land modification, are often of great conservation concern. Florida Scrub-Jays ( Aphelocoma coerulescens ) are threatened, scrub-endemic birds primarily found in small, isolated patches where they have a high probability of extirpation. One of the last large tracts of scrub habitat is found at Kennedy Space Center on the Atlantic coast of Florida, where almost 300 breeding pairs of scrub-jays occur. The majority of breeders are found among four subpopulations separated by suboptimal habitat matrix that could become barriers to movement. Neutral genetic diversity and connectivity among patches were investigated using 15 microsatellite loci. Globally and within study sites, heterozygosity (He 0.69–0.74) was comparable to values from similar studies using the same microsatellite loci in Florida Scrub-Jays. In addition, birds with territories in lower quality habitats had genetic diversity comparable to those in higher quality habitats. Three genetic clusters were identified; however, one of the clusters included individuals that were closely related but had dispersed to neighboring territories. Genetic relatedness was correlated with geographic distance, but not with habitat resistance, or with the size of the gap between suitable habitats. These results suggest that geographic distance, rather than the presence of suboptimal habitats or the size of habitat gaps, could limit dispersal among subpopulations at Kennedy Space Center. Territories found in higher quality habitats contained individuals with a higher probability of being first-generation migrants, possibly showing a preference for movement into high-quality areas. Continuing management for high quality scrub habitats is needed to maintain current levels of genetic diversity and connectivity among subpopulations at Kennedy Space Center.

Keywords

• aphelocoma coerulescens
• fragmentation
• gene flow
• habitat management
• microsatellite