The Feedback Loop Between Aboveground Herbivores and Soil Microbes via Deposition Processes

Abstract

Many studies on herbivores are solely concerned with the damage that they cause to plants. However, the impacts of aboveground herbivores go further, as their additions to the soil affect the soil microbes and subsequently nutrient cycling that feeds back into aboveground production. This chapter focuses on the feedback loop beginning with inputs via invertebrate herbivores and leading to alteration of carbon (C) and nitrogen (N) cycling via soil microbes to change nutrient availability for the surrounding vegetation. This loop eventually leads back to affect the invertebrate herbivores through changes in vegetation. Inputs from invertebrate herbivores can result physically from the invertebrates (e.g., frass, honeydew, carcasses) or from their consumption of vegetation (e.g., impacts on quality of throughfall, litterfall). The consumption activity can also alter the timing, quantity, and quality of organic inputs to the soil, all of which will affect the soil microbial communities in different ways depending on their lability. That lability also drives changes in C and N cycling, altering the available nutrients within the soil. The goal of this chapter is to discuss the feedback loop described above and develop a greater understanding of how aboveground herbivores interact with the belowground microbial community.