Energy flow through macroinvertebrates in a polluted plains stream

Abstract

AbstractThe trophic basis of production and energy flow through macroinvertebrate communities was determined at 3 sites differentially impaired by urbanization and agricultural activities on the plains section of the Cache la Poudre River, Colorado, USA. Site 1 received minimal impact from human activities and had the lowest annual secondary production (26.0 g ash-free dry mass [AFDM] m−2 y−1). Site 2 was enriched by treated wastewater and had the highest production (61.7 g AFDM m−2 y−1). Site 3 was impacted by urbanization and agriculture and showed intermediate secondary production (50.9 g AFDM m−2 y−1). Non-tanypodine Chironomidae accounted for 33, 87, and 50% of invertebrate production at sites 1, 2, and 3, respectively. Amorphous detritus was the most important energy base at all sites. Except for predators, all invertebrate taxa consumed a higher amount of amorphous detritus than any other food type (64–78% of total diet). Diatoms were the 2nd most common food type (8–23%). Non-tanypodine Chironomid...