Soil microbial communities represent complex biological systems responsible for many ecosystem functions. Differences in these systems are attributable to a variety of factors, including soil series, plant communities, and anthropogenic land use. We assessed the microbial diversity at 30 sites covering two ecoregions, three land usages, and seven soil series at Black Bayou Lake National Wildlife Refuge, an over 21 km² site located north of Monroe, Louisiana. Based on an average of over 47,000 amplified sequence variants per site, we found no significant difference in alpha diversity measures across groups but did find significant differences in beta diversity between ecoregions and the sites and soil series located within them. Bacteria associated with agricultural practices were significantly more abundant at the Ouachita River Backswamp sites, reflecting the historical land use of these areas. We found no significant differences between a managed prairie fragment and the Backswamp sites, suggesting that the microbial communities have not changed over twenty years post-restoration. Our data provide meaningful baseline measure of bacterial community diversity and abundance for the refuge, and highlight the necessity to manage these valuable soil resources in conjunction with the plant and animal communities.

Soil was collected at 30 sites at Black Bayou Lake NWR near Monroe, Louisiana. DNA extraction was carried out using the PowerSoil DNA isolation kit (Mo Bio Laboratories) according to manufacturer’s directions. DNA samples were sent to MrDNALab (Shallowater, Texas) where the 16S rDNA gene variable region V4 was PCR amplified using the 515/806 primer pair (Caporaso et al. 2011). Sequencing was performed on an Ion Torrent PGM (Thermo Fisher), and data were de-noised and depleted of barcodes, sequences less than 150 bp, and homopolymer runs over 6 bp using a proprietary pipeline.

FASTA file of ASVs with the site number in each sequence header. Sequences have not been dereplicated nor filtered.