The role of Chironomidae in energy flow of a lotic ecosystem

Abstract

Chironomid secondary production was estimated on a species-specific basis for 14 dominant taxa in a third-order woodland stream. Results from this study were used to provide an expalanation for the common observation that benthos secondary production in streams is insufficient to account for levels of fish production,i.e., the ALLEN paradox. Annual chironomid secondary production was 29.7 g dry mass m−2 and accounted for 80% of the total aquatic insect secondary production. A contribution by chironomids this high has not been reported previously from similar streams and indicates that chironomids are an energetically important group available for fish consumption. Most studies examining chironomid secondary production group all taxa at the family level and calculate secondary production for the entire family using the size-frequency method. This approach violates assumptions of the size-frequency method and will result in inaccurate and unpredictable estimates of chironomid secondary production. The species-specific approach to estimate chironomid production used in this study, combined with non-chironomid production, yielded a benthos annual production rate that exceeded consumption necessary to support fish production.