Microbial-mesofaunal interactions are known to play a significant role in the decomposition process and many researchers have examined interactions between microbes and common decomposer fauna (i.e. Acari and Collembola) under laboratory conditions. Biological succession in soil and litter has also been studied extensively in the field, however, few experiments have examined the concurrent succession of microbial and faunal communities. We propose that until this is done, our understanding of how microbial-faunal interactions influence decomposition will be incomplete.
The objective of this study was to compare patterns of microbial and mesofaunal succession during litter decomposition over the course of a growing season. Successional patterns were compared between corn and grass residue and among three levels of land management intensity. In particular we aimed to assess the affects of management intensity on the community structure and activity of microbes and mesofauna at various stages throughout the decomposition process. A litter bag experiment was conducted from June through October 2008 within the Conventional- (CT), No-Till (NT) and Old Field (OF) main plots at the Kellogg Biological Station, LTER. Litter bags, containing either corn or grass residue, were placed in direct contact with the soil surface in each of 12 plots. At weekly to monthly time intervals litterbags were collected and analyzed for mass loss, microbial community composition and activity (extracellular enzyme analysis), and mesofaunal abundance. Mass loss, mesofaunal abundance, bacterial to fungal ratio and hydrolytic enzyme activity were all greater in grass than in corn. In contrast, the activity of phenol oxidase was not influenced by litter type. While hydrolytic enzymes and fungal to bacterial ratios were both negatively affected by management intensity, mass loss and phenol oxidase activity were affected positively. Mesofaunal abundance did not respond linearly to management intensity and total abundance was highest in No-till systems. The abundance of oribatid mites and collembola correlated with the activity of chitinase and phenol oxidase respectively. This experiment demonstrates that a) the development of microbial and mesofaunal communities are strongly influenced by litter type and management intensity and b) that the abundance of various mesofaunal taxa may be influenced by the activity of specific extracellular enzymes.