HR: 11:10h
AN: B31G-04    [PDF]
TI: Land Use and Stream Ecosystems in the Ozark Highlands, Missouri and Arkansas - Extracting a Weak Signal From Background Noise
AU: * Jacobson, R B
EM: robb_jacobson@usgs.gov
AF: U.S. Geological Survey - CERC, 4200 New Haven Road, Columbia, MO 65201 United States
AU: Rabeni, C F
EM: rabenic@missouri.edu
AF: Missouri Coop. Research Unit - U.S.G.S., 302 ABNR University of Missouri, Columbia, MO 65211 United States
AU: Petersen, J C
EM: petersen@usgs.gov
AF: U.S. Geological Survey - WRD, 401 Hardin Road, Little Rock, AR 72211 United States
AU: Magoulick, D D
EM: danmag@comp.uark.edu
AF: Arkansas Coop. Research Unit - U.S.G.S., SCEN 617 University of Arkansas, Fayetteville, AR 72701 United States
AU: Doisy, K E
EM: doisyk@missouri.edu
AF: Department of Fisheries and Wildlife Sciences, 302 ABNR University of Missouri, Columbia, MO 65211 United States
AU: Rettig, A V
EM: avrf3@mizzou.edu
AF: Department of Fisheries and Wildlife Sciences, 302 ABNR University of Missouri, Columbia, MO 65211 United States
AB: Land use history in the Ozark Highlands of Missouri and Arkansas included widespread timber harvest in the late 19th and early 20th centuries, followed by substantial depopulation that left a mosaic of land dominated by timber harvest, grazing, and other agricultural land uses. There is regional concern that present-day timber harvest and agricultural land-use practices may have detrimental effects on highly valued, biologically unique, and species-rich Ozarks streams. Our synthesis of five recent studies of landscape characteristics and stream ecosystems in the Ozarks documents scale-dependence and geographic complexities of links from land use to stream ecosystems. Over 100 study streams in the combined dataset range 6 - 4,300 km$^{2}$ in drainage area and drain rural land ranging 15-100% forested. Fish, aquatic insect, and periphyton communities can be reliably associated with some mesohabitat- and reach-scale measures of habitat and water quality. Biotic communities in some streams also appear linked to drainage-basin land use through controls on nutrient availability. However, physical habitat, thought to be an important factor affecting biotic community structure, is often only weakly linked to drainage-basin land use. We suggest that the weak relationships between drainage-basin land use, physical habitat, and biotic community structure in these streams is due to several interacting factors including: 1) stream morphology and physical habitat responses to land-use change are lagged in time, introducing considerable temporal noise in synoptic datasets; 2) lagged geomorphic responses accentuate and complicate the influence of drainage-basin area on habitat characteristics; 3) spatial variation of geology and physiography is large relative to the magnitude of land-use stress in this rural landscape, resulting in considerable spatial noise; 4) the karst landscape of much of the region tends to produce a bimodal sediment load and flashy hydrology; clay and silt are flushed from these streams whereas chert gravel moves slowly, resulting in land-use induced aggradation by coarse sediment rather than fine; 5) fish species distribution and abundance appear to be affected by drainage network structure as well as historical artifacts.
DE: 1615 Biogeochemical processes (4805)
DE: 1803 Anthropogenic effects
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting