Shifts in aquatic insect populations in a first-order southern Appalachian stream following a decade of old field succession.

Aquatic insect populations were sampled on two first-order southern Appalachian streams. Grady Branch, the control stream, drains an undisturbed hardwood watershed. Sawmill Branch has undergone natural succession since 1968, from artificially maintained grassland to hardwood coppice dominated by black locust. Aquatic insect densities on Sawmill Branch were about twice those on Grady Branch, a reversal of results obtained by a similar study in 1968. It is suggested that changes in watershed vegetation influence long-term changes in aquatic insect populations, including a shift toward an allochthonous energy base.