5 Fungal Responses to Disturbance: Agriculture and Forestry

1 Terrestrial Ecology Group. Environmental Reseach Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA 2 Center for Forest Mycology, USA Forest Service, Forest Products Laboratory*, Box 1377, Luquillo. Puerto Rico 00773-1377, USA * The Forest Products Laboratory is maintained in coop eration with the University of Wisconsin. This paper was written and and prepared in part by a US Government employee on official time. and is therefore in the public domain and not subject to copyright. concerned with the composition and richness of fungal species. Furthermore, Zak indicated that this approach contributes little to our understanding of the role of fungi in nutrient cycling and accumulation of organic matter. More recent studies using trophic structure and food-web approaches to understanding the effects of tillage and crop rotation on fungi and associated soil biota appear to be more informative (e.g., Beare et al. 1992; Wardle 1995); for example, by integrating fungal responses with tillage practices, particularly informative linkages of fungi to processes associated with the dynamics of soil organic matter (SOM) have been identified (e.g., Beare et al. 1992; Hendrix et al. 1986). Also, investigations have corroborated the importance of fungi in the hierarchical model of soil structure (Tisdall and Oades 1982; Oades 1984) by demonstrating the structural role of hyphae and the annealing properties of the polysaccharides that they exude to form and maintain a stable aggregate structure (e.g., Gupta and Germida 1988; Chenu 1989; Miller and Jastrow 1990 Cambardella and Elliott 1994). Although there are many studies concerned with management practices in agriculture and forestry, a neglected area of research is the integration of fungal responses with these practices. especially as the responses relate to nutrient cycling and organic matter accumulation. One reason for this neglect is that plant and fungal responses and disturbance responses associated with land management practices are often studied at different spatial and temporal scales. Nevertheless, from a conceptual viewpoint, fungi do contribute to system processes and functions at various hierarchical organizational levels, indicating linkages and feedbacks between fungi and system responses (O’Neill et al. 1991; Miller and Jastrow 1994; Beare et al. 1995). The difficulty lies in our ability to focus questions and to measure responses or processes that function as control points.