Abstract

A population of crayfish comprising six age classes gave almost 13 kg of production in an experimental section of a small woodland stream. Two-thirds of this production originated in the three juvenile age classes. One-third was produced in shallow habitats and two thirds was produced in larger pools. Exoskeleton synthesis amounted to some 22% of the total production (dry wt). Food basis for production involved a major shift from aquatic insect prey in juveniles to plant material, mainly tree leaves, in adult crayfish. The diet of adults in particular was supplemented through active cannibalism at ecdysis. The annual food budget was compared with the annual input of particulate organic matter to the stream ecosystem, of which 93% was allochthonous origin. Less than 2% of the latter passed through the crayfish population. The productivity of the four major animal populations in the stream community is thought to approximate 9-10 g (dry wt) /m / yr, and most of this is primary consumer energy that is blocked from upward flow due to low exploitation by fish predators. Snail and crayfish populations in the stream appear to function as semi-closed, recycling energy pathways. Their most important community function may be biological conditioning of the detrital reserve.

Supplemental Documents

• There are no supplementary documents for this article

Cited By

Citations: