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These locations differ (30 X) in hydrologic parameters such as stream discharge and the extent of the hyporheic zone with a less dramatic difference in temperature. Standing stock of wood varies by 12 fold over the gradient. There is less variation in litter input or stading stock of benthic organic matter (< 2 X). Gross primary production and fish production varies 3-fold. Other ecological processes (invertebrate production, leaf decay rate, benthic respiration) over the gradient vary less than 1.5 X. Hence, the physical template appears more variable than the ecological response along this stream gradient. Biological communities change along the gradient. Biomass of benthic invertebrates generally declines downstream although there is little change in secondary production despite shifts in the relative importance of different functional groups. One of the unique aspects of this study is that we have measured both benthic invertebrates and fish biomass and production at the same sites. At some sites fish biomass exceeds invertebrates biomass -- an apparent paradox that is explained by measures of production that show invertebrate production to be greater than fish production. Taxomonic richness increases, although the greatest biodiversity occurs ever further downstream and outside the boundaries of Coweeta. Hence we are establishing stations further downstream, thereby expanding our stream studies to encompass the range of biodiversity in this region and to make them more relevant to issues of the ecological effects of changing land use in the Southern Appalachians.
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