Flow management for hydropower extirpates aquatic insects, undermining river food webs

Two unique datasets were gathered to document whether flow management for hydropower affects the abundance and diversity of aquatic insect assemblages. The first dataset was collected in Grand Canyon from 2012-2014 by citizen scientists rafting the Colorado River. Simple light traps were set out each night in camp and used to capture the adult life stages of aquatic insects that emerged from the Colorado River. Three aquatic insect taxa were captured in sufficient abundance to analyze statistically including midges (order Diptera, family Chironomidae), micro-caddisflies (order Trichoptera, family Hydroptilidae), and blackflies (order Diptera, family Simuliidae, principally Simulium arcticum). These data were used to identify whether flow management for hydropower at Glen Canyon Dam was affecting the abundance or diversity of aquatic insects throughout the 400 kilometer long Grand Canyon reach of the Colorado River. The second dataset that was gathered represents estimates of aquatic insect diversity across 16 different dam regulated rivers of the western United States. These data were originally collected by various agencies including US Geological Survey personnel, other state and federal agencies, and consulting firms using standard invertebrate sampling methods.