The Role of Terrestrial Invertebrates in Allopatric Brook Trout Headwater Streams in the Central Appalachian Mountains

Abstract

ABSTRACT We investigated the importance of terrestrial organisms to brook trout (Salvelinus fontinalis) diet in six headwater streams in the Greenbriar River Watershed, West Virginia. The mean number of prey items and mean biomass per brook trout stomach decreased between July and September 2002. While the percent total number of terrestrial inputs (TI) was similar between July and September (45% to 46%), the percent total biomass of TI increased from almost 45% in July to nearly 75% in September. Dipteran larvae were highest in percent relative importance for both periods (35.6% and 45.5%), and lepidopteran larvae showed a large increase between July and September (7.7% to 29.6%). The large biomass of terrestrial organisms in headwater streams shows the importance of allocthonous inputs to instream food cycles.