A Test of Competition in Two Sympatric Populations of Desmognathine Salamanders

Abstract

The effect of competition on foraging success and density in two sympatric populations of salamanders (Desmognathus monticola and D. quadramaculatus) was examined by density and cover—object manipulation experiments from June 1980 to April 1982. A second—order mountain stream in southwestern North Carolina was divided into experimental and control sections, and four treatments were performed: (1) addition of D. monticola, (II) addition of D. quadramaculatus, (III) addition of cover objects (rocks), (IV) addition of rocks and D. monticola. Treatments III and IV were performed for D. monticola only. Salamanders were marked individually for mark—release—recapture data. After experiments were terminated, salamanders were collected from control and treatment plots. Total lipid contents were determined and were used as an indirect measure of foraging success. Additions of D. monticola increased the total number of conspecific salamanders on plots and decreased their lipid content; congeners were not affected by the additions. Additions of D. quadramaculatus did not affect the total lipid content or the density of conspecifics or congeners. Addition of rocks significantly increased the density of D. monticola but did not affect their lipid content. Addition of rocks and D. monticola increased conspecific density and total lipid content. Results of salamander additions indicated that intraspecific competition for limited cover objects and energy resources may be important for adults and juveniles of D. monticola but not for D. quadramaculatus; interspecific competition was not detected.