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.

Rhizosphere-plant-microbe interactions and plant defense

The role of plant-associated microbes in regulating plant-herbivore interactions is an emerging research focus in plant science and community ecology. However, research in this area focused primarily on a few groups of plant-associated microbes such as mycorrhizae, plant-growth-promoting bacteria, and aerial obligate symbionts in grasses. The diverse endophytic fungi in roots receive far less attention and their importance in mediating plant defense, especially against root feeding insects, remains unclear. Our lab is investigating whether horizontally-transferred fungal endophytes can regulate plant defense against belowground herbivores. We are examining the effects of endophyte colonization on plant tissue chemistry as well as their influence on the production of volatile organic compounds in soils for plant indirect defense.

Belowground biological control

Nematode infection as seen under microscope.

Biological control is a promising tool for managing pests while preserving the environment and keeping workers and turfgrass users safe. However, many unknowns remain about biological control in soil, limiting our ability to effectively manage belowground pests. We evaluate the efficacy of insect pathogenic nematodes and fungi against soil pests such as white grubs in athletic fields and annual bluegrass weevil in golf course turf.  We also conduct basic research into how biological control organisms fit into the broader soil environment, and how soil management practices and interactions with the soil community affect their performance.

Postdoc position available in Bioacoustic Detection of Soil Animals

The Soil Arthropod Ecology Lab is searching for a postdoc to work on bioacoustic detection of soil animals!

Soil dwelling arthropods are diverse, and their populations are distributed heterogeneously.  Current methods for detecting and monitoring of soil arthropods are expensive and labor intensive for pest managers and scientists alike.  The primary objective of this position will be to develop methods for using bioacoustic techniques for detecting soil-dwelling invertebrates and for distinguishing acoustic signals generated by root-feeding pests, ecosystem engineers, and decomposers.   The project will entail working in the field and lab with bioacoustics equipment to characterize acoustic signals from field populations and to establish laboratory soil arenas with distinct arthropod composition to evaluate how acoustic signals change under changing soil animal structure.

The position will be housed in the Soil Arthropod Ecology Lab within the Department of Entomology, Cornell University, Cornell AgriTech, Geneva, NY 14456.  Anticipated start date for the position is Summer-Fall 2018.

Interested candidates are encouraged to contact Dr. Wickings directly at kgw37@cornell.edu.