Linking stream and landscape trajectories in the southern Appalachians
Abstract: 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 km2
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, N., A.B. Sutherland, R.J. Bixby, M.C. Scott, J.L. Meyer, G.S. Helfman, E.F. Benfield, C.M. Pringle, P.V. Bolstad, and D.N. Wear. 2008. Linking stream and landscape trajectories in the southern Appalachians. Environmental Monitoring and Management xx: xx-xx.
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