SOIL FAUNA AND DECOMPOSITION ALONG A PASTURE-FOREST GRADIENT IN THE CENTRAL APPALACHIANS

Authors: O Neill, Katherine; Halvorson, Jonathan

Submitted to: Society of American Foresters
Publication Type: Abstract Only
Publication Acceptance Date: 4/18/2005
Publication Date: 10/19/2005
Citation: O Neill, K.P., Halvorson, J.J. 2005. Soil Fauna and Decomposition along a Pasture-Forest Gradient in the Central Appalachians. In: Society of American Foresters 2005 National Meeting, Austin, Texas. CDROM.

Interpretive Summary:

Technical Abstract: Silvopastoral management strategies offer the potential to expand spatial and temporal boundaries of forage production while diversifying small farm income and promoting ecosystem integrity. Previous research has demonstrated that decomposer food webs in forests and pastures are fundamentally different, with wooded systems typically dominated by fungi and managed grassland systems mediated by more rapidly cycling bacteria. Developing effective silvopastoral management practices requires the integration of these two different food web structures, along with their associated nutrient dynamics, into a single agricultural system. However, relatively little is known about how differences in soil micro- and mesofauna in these two systems may influence the cycling and availability of nutrients and the formation of soil organic matter. A set of integrated field and laboratory studies was used to assess differences in soil biological communities and decomposition along a gradient from open grassland to forest in southern West Virginia. Litterbags were constructed with four mesh sizes to selectively allow entry of: (1) microfauna only (< 105 um ); (2) microfauna and mesofauna (1 mm mesh); (3) microfauna, mesofauna, and small macrofauna (3 mm mesh); and, (4) microfauna, mesofauna, and small macrofauna (5 mm mesh). Soil arthropods were extracted using a modified high gradient extraction system and classified to morphospecies. Amount of litter lost and faunal assemblages were observed both as a function of canopy vegetation and length of incubation. Decomposition rates, faunal community structure, and diversity indices were combined with object-oriented models to answer the following questions: (1) does mass loss differ as a function of land cover; (2) do these differences correspond to differences in soil faunal communities; and, (3) what are the implications for silvopastoral management.