Riparian Timber Harvest Intensity Affects Diets Of Appalachian Brook Trout

Stream-dwelling Brook Trout Salvelinus fontinalis rely heavily on terrestrial invertebrates, especially when aquatic prey is limited. We examined the effects of an experimental harvest of riparian timber on the diet and condition of Brook Trout in late summer. We evaluated the effects of two riparian harvest intensities (50% and 90% of the basal area harvest) in each of two streams on the diet, consumption, abundance, and condition of Brook Trout in summer. The diets and consumption patterns of Brook Trout were affected by the percentage of riparian timber harvest. Timber harvest increased the use of aquatic invertebrates-primarily via increased consumption of crayfish. In the 90% treatments, the use of terrestrial invertebrates by Brook Trout declined primarily due to the decreased use of Lepidoptera. Overall, consumption levels in the 50% treatments were nearly double those in the reference or 90% treatments. A common forestry best management practice is to limit riparian harvest to 50% of the basal area. Provided water quality and quantity are not affected, our study suggests that a 50% timber harvest limitation in the riparian area may provide at least a temporary boost in consumption due to an increase in the use of aquatic insects.