A survey of soil bacterial diversity across a Northeast Louisiana federal wildlife refuge

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.