Microbial Ecology A Molecular Comparison of Plumage and Soil Bacteria Across

We used molecular methods to determine the microbial community of soil and avian plumage across biogeo-graphic, ecological, and taxonomic scales. A total of 17 soil and 116 feather samples were collected from five avian species across multiple habitat types within one Neotrop-ical and one temperate locality. Hypotheses regarding patterns of microbial composition relative to acquisition and dispersal of plumage bacteria in the ecosystem were tested by comparing microbial communities within and between soil and plumage. Samples from the plumage of American Redstarts (Setophaga ruticilla) were collected across both habitat types and geographic scales for intra-specific comparisons. The microbial diversity in avian plumage was moderately diverse and was dominated by Pseudomonas species. Despite a highly significant indi-vidual bird effect on microbial composition of the plum-age, we detected significant biogeographic and type of habitat effects. Pseudomonas species were more abundant on the temperate site when all avian species were included in the analysis, and Bacillus subtilis and Xanthomonas groups were more abundant on the Neotropical site for redstarts alone. However, 16S rDNA sequence libraries were not significantly different between Jamaican and Maryland redstarts. Biogeographic and habitat effects were significant and more pronounced for soil samples indicating lower dispersal of soil microbiota. We detected a significant difference between soil and plumage micro-bial communities suggesting that soil plays a small role in plumage bacterial acquisition. Our results suggest bacte-rial communities on the plumage of birds are dynamic and may change at different stages in a bird_s annual cycle