Wildlife, Fish, and Conservation Biology

I. Research question(s) and testable hypothesis The serial discontinuity concept (Stanford and Ward 2001) puts dams into the context of the river continuum concept (Vannote et al. 1980), which attempts to explain changes in rivers as they move from their headwaters to the their ends. In the middle Green River, Flaming Gorge Dam creates a discontinuity, most notably by modifying the flow regime, reducing water temperatures, and eliminating sediment. These physical changes result in a cascade of ecological effects, including increased invertebrate abundance (Vinson 2001), that combine to create ideal habitat for a variety of salmonids (Börk 2006), but make much of the habitat unsuitable for eight native fish species once found in the middle Green River, including the speckled dace, roundtail chub, bluehead sucker, flannelmouth sucker, razorback sucker, bonytail chub, humpback chub, and Colorado pikeminnow (Wintzer 2006). According to the serial discontinuity concept, these habitat impacts should be moderated with increasing distance downstream from the dam (Stanford and Ward 2001). Vinson (2001) presented data that supported these predictions on the Green River, showing that conditions farther from the dam became closer to pre-dam conditions. The influx of warm, sediment-lade