Linking stream and landscape trajectories in the southern Appalachians.
A proactive sampling strategy was designed and implemented in 2000 to document changes in streams whose catchment land uses were predicted to change over the next two decades due to increased building density. Diatoms, macroinvertebrates, fishes, suspended sediment, dissolved solids, and bed composition were measured at two reference sites and six sites where a socioeconomic model suggested new building construction would influence stream ecosystems in the future; we label these "hazard sites." The six hazard sites were located in catchments with forested and agricultural land use histories. Diatoms were species-poor at reference sites, where riparian forest cover was significantly higher than all other sites. Cluster analysis, Wishart's distance function, non-metric multidimensional scaling, indicator species analysis, and t-tests show that macroinvertebrate assemblages, fish assemblages, in situ physical measures, and catchment land use and land cover were different between streams whose catchments were mostly forested, relative to those with agricultural land use histories and varying levels of current and predicted development. Comparing initial results with other regional studies, we predict homogenization of fauna with increased nutrient inputs and sediment associated with agricultural sites where more intense building activities are occurring. Based on statistical separability of sampled sites, catchment classes were identified and mapped throughout an 8,600 km(2) region in western North Carolina's Blue Ridge physiographic province. The classification is a generalized representation of two ongoing trajectories of land use change that we suggest will support streams with diverging biota and physical conditions over the next two decades.
Gardiner
Edward P
EP
American Museum of Natural History, New York, NY 10024, USA. ned@amnh.org
Sutherland
Andrew B
AB
Bixby
Rebecca J
RJ
Scott
Mark C
MC
Meyer
Judy L
JL
Helfman
Gene S
GS
Benfield
E Fred
EF
Pringle
Cathy M
CM
Bolstad
Paul V
PV
Wear
David N
DN
D000818:Animals; D044822:Biodiversity; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D009657:North Carolina; D045483:Rivers; D014197:Trees; D014481:United States