PARENT SESSION
Oral Session #2: Riparian Ecology.
Presiding: M. Dixon
Monday, August 5. 8:00 AM to 11:30 AM. Greenlee Meeting Room, TCC.
Effects of past and present land use practices on small streams at Fort Benning, .
Maloney, Kelly*,1, Feminella, Jack1, Mulholland, Patrick2, Dale, Virginia2, Olsen, Lisa2, 1 Auburn University, Auburn, Alabama2 Environmental Sciences Division, Oak Ridge, Tennessee
ABSTRACT- Stream ecosystems are intimately tied to past and present watershed conditions, therefore quantifying stream disturbance requires an accurate classification of historical and current land use patterns. We present results from an ongoing U.S. DoD-funded landscape classification project (SEMP; SERDP Ecosystem Management Project) designed to develop ecological indicators of landscape change at Ft. Benning, GA. Landscape disturbance occurs from military training (infantry, heavy machinery) and forest management (thinning, controlled burning). Eight watersheds varying in disturbance are being studied. Remotely sensed imagery spanning four separate decades (1960-2000) is being used to derive historic and contemporary disturbance classifications. Three ARCVIEW extensions (ATtILA, BASINS, geoWEPP) are being used to develop disturbance metrics from LANDSAT imagery to derive disturbance classifications, which are being compared to ground-based estimates. Preliminary data from contemporary imagery indicate that the ATtILA extension revealed a higher percentage of bare ground on steep slopes (> 8%) in the 3 watersheds field-classified as high-disturbance (mean = 4.8% of watershed area) than for watersheds classified as low-disturbance sites (< 1%). The watershed with the highest stream-road crossings (4) also was correctly classified as a high-disturbance site. In-stream disturbance indicators (benthic macroinvertebrate and substrate composition) generally corresponded with remotely sensed classifications. Macroinvertebrate community similarity was higher between streams within a disturbance class (contemporary imagery) than between classes. Likewise, percent organic matter and silt/clay in the stream channel also corresponded to imagery-based disturbance classifications, being higher in low-disturbance watersheds than in high-disturbance sites.
KEY WORDS: Landuse , Landsat, GIS, macroinvertebrate