Eyes on the Eel: Level 3

Level 3. Quantitative Transects with drift, emergence, and key invertebrate, amphibian, and fish counts

(graduate research level data—this section is still under considerable discussion, and methods will be tested and revised in pilot experiments in 2015).

We will survey about 8 locations through the South Fork and Mainstem Eel to test hypotheses about how temporal (annual/seasonal hydrologic regimes), and spatial controls (landscape context and river network position) will influence the distribution of trophic level biomass in summer food webs. We will compare biomass of primary producers, primary consumers, secondary consumers, and apex predators, as well as numerical abundance of key taxa, during the two likely bottlenecks of the summer low flow season: maximum temperatures expected in early-mid July, and minimum flow expected in early September. These surveys may help us formulate more mechanistic hypotheses about how history, connectivity and dispersal limitation, and spatial-temporal variation in environmental conditions (radiation (temperature and sunlight), flow regimes, or habitat structure (e.g. bed materials)) will affect distributions and abundances of key taxa and functional groups. Key taxa of interest to particular researchers include the macroalga Cladophora, its diatom epiphytes, cyanobacteria (esp. Anabaena, Phormidium), insect grazers Dicosmoecus, native frog tadpoles Rana boylii, introduced predators-pike minnow, black bass, green sunfish, and native salmonids-steelhead/rainbow trout, juvenile coho, and possibly chinook).

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