Consequences of the Encroachment of Juniperus Virginiana in a Tallgrass Prairie: Soil Physical and Biological Alterations

Abstract

The invasion of J. virginiana into grasslands has multi-scale effects including loss of biodiversity, loss of habitat for wildlife species, and alterations in community-level and biogeochemical functions. Most previous studies focus on aboveground changes, therefore, in this study I assess belowground changes in soil characteristics including soil microbial communities, nutrient availability, moisture, and aggregate stability following establishment of J. virginiana into tallgrass prairie. To assess the influence of tree density, I included forested areas with moderate levels of encroachment, as well as sites that are highly encroached, and compare these sites to an adjacent non-encroached native prairie. To assess the impact of J. virginiana at the individual tree level, a single J. virginiana tree, paired with an uncut control, was cut and removed from each site. Findings and Conclusions: My results show significant differences in microbial communities, nutrient availability, moisture, and aggregate stability in forested sites compared to the native prairie sites. The removal of an individual J. virginiana tree did not significantly affect soil characteristics, compared to a corresponding uncut control tree. Possible explanations for this lack of response could be due to the relatively short (6 month) duration of this study or that there is a continued influence from surroundingJ.virginiana trees. Understanding how microbial communities and these plant-fungal associations are influenced by J. virginiana invasions may be a critical aspect of the ecology and management of this invading species, as well as the conservation and restoration of native ecosystems.