Larval Periods, Population Structure and the Effects of Stream Drift in Larvae of the Salamanders Desmognathus quadramaculatus and Leurognathus marmoratus in a Southern Appalachian Stream

Non-destructive sampling of salamander larvae at East Fork Overflow Creek and its tributaries in the Blue Ridge Mountains of North Carolina provided information on larval life histories of Desmognathus quadramaculatus and Leurognathus marmoratus. Snout-vent length data indicated that both D. quadramaculatus and L. marmoratus have larval periods of three years, which is considerably longer than estimates provided by previous investigators. Individual growth rates were higher and metamorphic sizes larger in D. quadramaculatus than in L. marmoratus. In both species, first-year larvae were under-represented in the samples from East Fork Overflow Creek. Sampling in tributaries yielded higher frequencies of young larvae of D. quadramaculatus. These data suggested that in the latter species, reproduction was concentrated in headwater tributaries and that the downstream larval populations were constituted in part from stream drift. Although drift may thus account for the population structure of D. quadramaculatus, it does not explain similar findings for L. marmoratus, inasmuch as the latter species was nearly absent from the tributaries.