HOW DO SOIL FAUNAL DIVERSITY AND DECOMPOSITION CHANGE AT GRASSLAND-FOREST MARGINS?: EFFECTS OF VEGETATION COVER, MANAGEMENT, AND SEASONALITY

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

Submitted to: Ecological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2006
Publication Date: 8/1/2006
Citation: O Neill, K.P., Godwin, H.W., Halvorson, J.J. 2006. How do soil faunal diversity and decomposition change at grassland-forest margins?: Effects of vegetation cover, management, and seasonality. Proceedings of the Ecological Society of America 91st Annual Meeting, Memphis, TN, August 6-11, 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 undergo significant changes across relatively narrow spatial boundaries. Developing sustainable soil management practices for these transitional lands requires the integration of nutrient dynamics from grass and forest-dominated patches into a single agricultural system. However, relatively little is known about how differences in soil fauna may influence key ecosystem processes. Two related studies were used to assess differences in soil microfaunal communities and mass loss of forage litter along a gradient from open grassland to closed canopy mixed hardwood forest in southern West Virginia. The first study assessed monthly changes in microfaunal communities over a one-year sampling period. The second evaluated differences in faunal communities and mass loss of litter using litterbags of four mesh sizes to selectively allow entry of different-sized microfauna. 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. However, these differences did not translate into significantly higher rates of litter mass loss. Increased management intensity in the grasslands (managed haymeadow vs. unmanaged meadow) corresponded to a significant decline in the abundance of collembola species relative to other faunal groups but did not significantly increase rates of mass loss. Mass loss, faunal community structure, and diversity indices were combined to answer the following questions: (1) do soil microfaunal communities differ as a function of vegetation cover, management, and seasonality? (2) do these differences correspond to differences in decomposition (mass loss)?; and (3) what are the implications for the management of pasture systems in transitional landscapes?