LAND-USE EFFECTS ON DECOMPOSITION: HOW IMPORTANT ARE SOIL FAUNA?

Authors: O Neill, Katherine; Godwin, Harry; Halvorson, Jonathan

Submitted to: Society of American Foresters
Publication Type: Abstract Only
Publication Acceptance Date: 6/22/2006
Publication Date: 10/25/2006
Citation: O Neill, K.P., Godwin, H.W., Halvorson, J.J. 2006. Land-use effects on decomposition: How important are soil fauna? In: Proceedings of the National Society of American Foresters meeting, October 25-29, 2006, Pittsburgh, Pennsylvania. 2006 CDROM.

Interpretive Summary:

Technical Abstract: Landscape fragmentation in West Virginia creates a mosaic of agricultural and forest transition zones in which microclimate, plant and animal species, and ecosystem processes may be expected to undergo significant changes across a relatively narrow spatial boundary. Developing sustainable soil management practices for these transitional lands requires the integration of nutrient dynamics from pasture and forest-dominated patches into a single agricultural system. However, relatively little is known about how differences in soil fauna in these two systems may influence the key ecosystem processes such as the cycling and availability of nutrients and the decomposition of organic materials. Integrated field and laboratory studies were 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; (2) microfauna and mesofauna; and (3) microfauna, mesofauna, and small macrofauna. Soil arthropods were extracted using a modified high gradient extraction system and classified to morphospecies. Over a 20-week incubation period, decomposition rates ranged between 0.018 and 0.032% litter mass loss day-1. Within each vegetation cover, decomposition showed a general, but not consistent, increase with increasing mesh size. Both abundance and species richness of microarthropods were greater in forested than in open grassland samples. Mass loss, faunal community structure, and diversity indices were combined to answer the following questions: (1) does forage mass loss differ as a function of vegetation cover?; (2) do these differences correspond to differences in soil faunal communities?; and (3) what are the implications for the management of pasture and silvopastoral systems?