Black fly (Diptera: Simuliidae) response to phosphorus enrichment of an arctic tundra storm

The Kuparuk river, located on the North Slope of the Alaskan Brooks Range, was fertilized with phosphate every summer between 1983-1989 as part of a multi-investigator ecosystem level experiment. In this study the density, growth and production response of the dominant black fly, Prosimulium martini, to whole river fertilization in 1984 was reported. Increased larval growth and abundance of black fly was related to the increased algal and microbial activity, which in turn were a direct result of the increased nutrient supply. The indirect effects of phosphate addition to the river on Prosimulium included higher growth but decreased abundance in the fertilized section of the river leading to a net decrease in secondary production from 2.62 g per m2.year to 0.77 g per m2.year. Prosimulium emergence rates were apparently unaffected. Competitive displacement by the caddisfly, Brachycentrus americanus, which increased in abundance was used to explain the decrease in abundance of black fly. There are 46 references.