Skip to main content
Dryad logo

Persistent panmixia despite extreme habitat loss and population decline in the threatened tricolored blackbird (Agelaius tricolor)

Citation

Barr, Kelly (2020), Persistent panmixia despite extreme habitat loss and population decline in the threatened tricolored blackbird (Agelaius tricolor), Dryad, Dataset, https://doi.org/10.5068/D1DM4H

Abstract

Habitat loss and alteration have driven many species into decline, often to the point of requiring protection and intervention to avert extinction. Genomic data provide the opportunity to inform conservation and recovery efforts with details about vital evolutionary processes with a resolution far beyond that of traditional genetic approaches. The tricolored blackbird (Agelaius tricolor) has suffered severe losses during the previous century largely due to anthropogenic impacts on their habitat. Using a dataset composed of a whole genome paired with reduced representation libraries (RAD-Seq) from samples collected across the species’ range, we find evidence for panmixia using multiple methods, including PCA (no geographic clustering), admixture analyses (ADMIXTURE and TESS conclude K = 1), and comparisons of genetic differentiation (average FST = 0.029). Demographic modeling approaches recovered an ancient decline that had a strong impact on genetic diversity but did not detect any effect from the known recent decline. We also did not detect any evidence for selection, and hence adaptive variation, at any site. These results indicate that species continues to have high vagility across its range despite population decline and habitat loss and should be managed as a single unit.