This study is a continuation of long-term, whole-stream experiments begun in 1981 by Bruce Wallace, Judy Meyer, and Jack Webster. Since 1993 we have excluded all litter inputs to a 170-m stream at Coweeta Hydrologic Laboratory. In addition we removed all sticks and logs from the stream in 1996 and 1998. In 2000 we added plastic pipes to the stream to simulate the structural role of wood. Results have shown that the aquatic insects, salamanders, and other animals living in this stream are directly or indirectly dependent on the organic inputs from the forest. After several years of leaf exclusion, animals were almost completely absent from the stream. We’ve also shown that the absence of leaves and wood has significantly affected many ecosystem processes including dissolved organic carbon transport, sediment retention, dissolved nutrient retention, microbial processes, and metabolism. Our long-term study of Coweeta streams has made it possible to use experiments such as this to understand the critical terrestrial-aquatic linkages of southern Appalachian watersheds.
Leaf exclusion movie ( you will need Quicktime to view this VERY large [18MB] movie)
Leaf exclusion
canopy, Nov 1998
Leaf exclusion canopy, Nov 1998
Leaf exclusion canopy, Nov 2000
Under the stream canopy, Nov 2000
Publications from the Leaf Exclusion Study
Baer, S.G., E.R. Siler, S.L. Eggert, and J.B. Wallace. In press. Colonization and production of macroinvertebrates on artificial substrates: Upstream-downstream responses to a leaf litter exclusion manipulation. Freshwater Biology.
Hall, R.O. and J.L. Meyer. 1998. The trophic significance of bacteria in a detritus-based stream food web. Ecology 79: 1995-2012.
Hall, R.O., J.B. Wallace, and S.L. Eggert. 2000. Organic matter flow in stream food webs with reduced detrital resource base. Ecology. In press.
Huryn, A.D., and J.B. Wallace. 2000. Life history and production of stream insects. Annu. Rev. Entomol. 45:83-110.
Meyer, J.L., C. Hax, J.B. Wallace, S.L. Eggert, and J.R. Webster. Terrestrial litter inputs as determinants of food quality of organic matter in a forest stream. Verh. Internat. Verein. Limnol. 27: In press.
Meyer, J.L., J.B. Wallace and S.L. Eggert. 1998. Leaf litter as a source of dissolved organic carbon in streams. Ecosystems 1:240-249.
Tank, J.L. and J.R. Webster. 1998. Interaction of substrate availability and nutrient distribution on wood biofilm development in streams. Ecology 79:2168-2179.
Tank, J.L., J.R. Webster, and E.F. Benfield. 1998. Effect of leaf litter exclusion on microbial enzyme activity associated with wood biofilms in streams. J. N. Am. Benthol. Soc. 17:95-103.
Wallace, J.B., S.L. Eggert, J.L. Meyer, and J.R. Webster. 1999. Effects of resource limitation on a detrital-based ecosystem. Ecological Monographs 69:409-442.
Wallace, J.B., S.L. Eggert, J.L. Meyer, and J.R. Webster. 1997. Multiple trophic levels of a forest stream linked to terrestrial litter inputs. Science 277:102-104.
Wallace, J.B., J.R. Webster, S.L. Eggert, and J.L. Meyer. Small woody debris dynamics in a headwater stream. Verh. Internat. Verein. Limnol. 27: In press.
Wallace, J.B., J.R. Webster, S.L. Eggert, J.L. Meyer, and E.R. Siler. 2000. Large woody debris in a headwater stream: long-term legacies of forest disturbance. Internat. Review of Hydrobiology.
Webster, J.R. , J.L. Tank, J.B. Wallace, J.L. Meyer, S.L. Eggert, T.P. Ehrman, B.R. Ward, B.L. Bennett, P.F. Wagner, and M.E. McTammany. Effects of litter exclusion and wood removal on phosphorus and nitrogen retention in a forest stream. Verh. Internat. Verein. Limnol. 27: In press.
Theses and Dissertations:
Adams. J. 1998. The role of leaf litter and small wood in the retention of fine particles during storms in an Appalachian stream. Master of Science, Virginia Polytechnic Institute and State University.
Baer, S.G. 1995. Colonization of benthic macroinvertebrates on artificial substrates in Appalacian headwater streams. M.S. Thesis, University of Georgia, Athens, GA 104 p.
Hall, R.O., Jr. 1996. Bacterivory and organic matter flow in stream food webs. Ph.D. Dissertation, University of Georgia, Athens, GA 184 p.
Tank, J.L. 1996. Microbial activity on wood in streams: exploring
abiotic and biotic factors affecting the structure and function of wood biofilms.
Ph.D. Dissertation, Virginia Polytechnic Institute and State University, Blacksburg,
VA 175 p.