Deciphering Soil Microbial Dynamics in Pennsylvania Grasslands with Goldenrods (Solidago sp)

Grasslands are important centers of biodiversity, however these ecosystems have been in decline. Although many methods for grassland restoration have been developed, the abundant microbial communities in these regions are understudied and could be used to assist in these efforts. In this study, we aimed to understand how microbial communities varied by soil type, grassland site, and environmental conditions. Samples were taken from rhizosphere soil, proximal soil (close to the plant roots) and from bulk cores at Ricketts Glen State Park and Nescopeck State Park in Northeastern Pennsylvania during June and August of 2021 and 2022. Rhizosphere soil samples were taken from the common grassland plant, Solidago rugosa . 16S rRNA gene sequencing revealed that pH as well as soil type (bulk, proximal, or rhizosphere) significantly influenced the microbial community composition and taxonomic composition of each soil. Each soil type had its own distinct microbial communities, and proximal soil was identified as a transition zone between rhizosphere and bulk microbial communities. We also observed that the rhizosphere communities are dependent upon geography, as these communities were significantly different between grasslands even though the plant species remained the same. Our results highlight the complex nature of soil microbial communities and how many factors, including pH, soil type, and geography, are able to layer together and impact microbial community composition. Results showcase potential avenues for conservation and rehabilitation of diminished grassland regions through modification and regulation of specific soil microbial communities.