HR: 1330h
AN: B33E-11    [Abstracts]
TI: Modeling Hierarchical Relationships Between Terrestrial Disturbance and Responses of Headwater Streams in the Southern Appalachians
AU: * Sokol, E R
EM: sokole@vt.edu
AF: Virginia Polytechnic Institute and State University, Department of Biology, Blacksburg, VA 24061-0406
AU: Benfield, E F
EM: benfield@vt.edu
AF: Virginia Polytechnic Institute and State University, Department of Biology, Blacksburg, VA 24061-0406
AB: Strong relationships have been demonstrated between catchment-wide logging practices and benthic community structure in headwater streams. Disturbance-induced changes in both abiotic and biotic factors often correlate with short term shifts in community dominance from collector-filterers to scrapers. We suggest a hierarchical model may apply where catchment-scale terrestrial disturbance modifies a suite of in-stream environmental factors (endogenous variables) that influence benthic macroinvertebrate community structure (response variable) at a variety of scales (e.g., reach, bedform, or substrate). Structural Equation Modeling was used to delineate possible hierarchical models of the dominant relationships among in-stream factors in forested headwater streams. Models developed from regional data (logged and un-logged headwater catchments) resolve which terrestrial-aquatic linkages (e.g., sediment input, allochthonous input) remain important predictors across the disturbance intensity gradient. Models generated with data from forested catchments were compared to those from logged catchments to predict how some linkages may become irrelevant, while others are accentuated following a disturbance. This study will provide testable hypotheses for forthcoming experimental clear cuts in headwater catchments in the southern Appalachians.
DE: 9810 New fields (not classifiable under other headings)
DE: 9901 NABS Student Award - Basic Research
SC: Biogeosciences [B]
MN: 2005 Joint Assembly