University of Wisconsin - Madison Madison, WI, United States
Abstract: Maintaining soil health is essential to support a thriving ecosystem, and to this end, soil health scientists continuously develop indicators to assess environmental concerns. One such indicator is the diversity and abundance of microorganisms, given their key role in various soil processes. By quantifying the relative abundance of specific microbial taxa or genes, we can infer specific soil properties even if the underlying mechanisms are not yet understood. We can also assess microbial diversity and abundance response to environmental change and how their response relates to soil properties changes, making them a great tool for assessing soil health. Microbial communities can help us understand the effects of agricultural management on various soils and the potential recovery of soil function after long-term disturbance. The aim of our study was to assess how land-use legacies affect soil ecosystem dynamics across different soil environments using microbial communities as indicators. In specific, we assessed 1) how microbial composition, diversity, and abundance change as a result of pasture abandonment and forest regrowth on two soil orders and 2) if microbial communities and abundances can explain variations in soil properties such as soil carbon. We collected soil samples across a forest recovery chronosequence in Puerto Rico that were used to measure soil organic carbon and extract and amplify DNA targeting 16S and ITS2 genes to identify microbial diversity and specific taxa abundances. Our results showed that microbial communities differ among forest successional stages after pasture abandonment and between soil orders. Soil orders had a greater influence on bacterial communities, while forest successional stages had a greater influence on fungal communities. The relative abundance of different microbial taxa varied between pastures and forests, suggesting that vegetation type may have a stronger effect than successional stages. Some groups, such as saprotrophic and symbiotic fungi, showed a significant relationship with soil carbon in pasture systems. Our findings suggest that using microbial diversity and specific abundance taxa can be an effective tool to assess soil dynamics resulting from land use legacies in diverse soil environments. Overall, our study provides valuable insights into the relationship between microbial communities and soil health and the potential use of microbial diversity as a tool for soil health assessment.
