Faunal impacts on soil organic matter dynamics

Soil organic matter (SOM) cycling has significant consequences for ecosystem processes and functioning. Studies of SOM have focused traditionally on soil microorganisms that regulate the fundamental biochemical processes of litter mineralization and organic matter formation. However, microbe-mediated processes rarely occur in isolation in natural systems without the involvement of soil fauna. Nevertheless, little attention has been paid to soil fauna –  e.g., the direct roles they play in SOM cycling, and indirect roles through changing microbial community composition, activity, and function to influence soil C and N dynamics. We combine traditional morphological characterization of soil invertebrates with microbial functional assays, and modern chemical techniques to identify relationships among soil fauna, microbe, plant residue inputs, and SOM. Our ultimate goal is to investigate whether/how soil fauna contribute to soil organic carbon storage, especially through their impacts on microbial communities. We believe this knowledge is important for sustaining ecosystem productivity and predicting the impacts of future disturbances on belowground processes.

Soil biological composition and function in managed systems

Soil biota play critical roles in decomposition, nutrient cycling and soil structure maintenance in both natural and managed ecosystems. Many management practices can alter soil biological communities and the links between management practices, diversity of soil organisms and ecosystem functions are not clear. We are studying soil arthropod and microbial communities in horticultural and agricultural systems to better understand the links between composition and function, to assess how different management practices impact soil biota and to improve management practices to optimize soil ecosystem services.