Dune soil communities primarily associated with climate factors, not exotic plant presence

Abstract

Soil communities are shaped by multiple biotic and environmental components. We assessed the role of multiple factors in shaping soil bacterial and nematode communities in an ongoing plant invasion in western Michigan sand dunes. We aimed to determine which factors were important for structuring soil communities. We surveyed seven sites containing the exotic plant, Leymus arenarius, in western Michigan, USA sand dunes. We sampled the plant community and collected soil cores to assess bacterial and nematode communities. We assessed bacterial functional diversity using Biolog Ecoplates. Nematode communities were assessed based on morphological identification. Temperature was a strong determinant of bacterial functional diversity and community composition. Precipitation and Ammophila density were also correlated with bacterial function composition. Nematode communities were shaped by a combination of temperature, precipitation, Ammophila density, and to a lesser degree soil organic matter and Leymus density. Soil bacteria and bacterivorous nematode assemblages were not significantly associated in their responses to the environment. Soil communities of bacteria and nematodes in this early successional dune system are affected strongly by changes in climatic factors, rather than exotic plant presence.