Effect of siltation on stream fish communities

Abstract

The effect of siltation on stream fish in northeast Missouri was evaluated using community structural measurements and a functional approach that emphasized feeding and reproductive guilds. As the percentage of fine substrate increased, the distinction among riffle, run, and pool communities decreased, primarily because the number of individuals of typical riffle species decreased. Within the riffle communities the abundance of fish of two feeding guilds — benthic insectivores and herbivores — was reduced as the percent of fine substrate increased. The abundance of fish in other feeding guilds was not affected. The only reproductive guild to be similarly affected was the simple and lithophilous, whose members require a clean gravel substrate for spawning. Species within each guild affected by siltation had significantly similar trends in abundance. The guild analysis indicated that species with similar ecological requirements had a common response to habitat degradation by siltation.