Effects of Urbanization on the Salamander Desmognathus Fuscus Fuscus

Abstract

Five spring—fed streams near Atlanta, Georgia, comprise an urbanization gradient ranging from severely distributed to undistributed conditions. Population densities of the dusky salamander, Desmognathus fuscus fuscus, were estimated within these streams and were inversely proportional to the degree of urbanization. Differences in the chemical parameters among the stations, while reflecting habitat disruption, were not considered limiting factors on salamander densities. Analysis of invertebrate prey availability indicated no significant difference among the stations. Salamander populations were significantly affected by scouring caused by increased runoff and soil erosion in disturbed areas. Differences in salamander densities were also attributed to relative stability of the bank soils and availability and dispersal of protective cover. More cohesive substrates and increased availability of ground cover at the less distributed areas offered greater stability against erosion and better habitats for salamander burrowing. Urbanization thus creates physical instability within stream habitats. Such instability results in a disruption of trophic structure by a reduction or loss of this major stream predator.