Hydroperiod of Wetlands and Reproduction in Wood Frogs (Rana Sylvatica) and Spotted Salamanders (Ambystoma Maculatum)

Kolozsvary, Mary Beth

A common objective of many aquatic amphibian studies involves documenting the presence or species richness of larval amphibians at breeding pools. Although several techniques are f f commonly employed for sampling larval amphibians, a side-by-side comparison of their efficiency at documenting species presence or in capturing individuals is not often assessed. I used 4 larval sampling techniques (dip nets, pipe samplers, funnel traps, and bottle traps) to sample amphibian larvae in 30 wetlands in July and August 1999. For the 4 focal species (i.e., spotted salamanders, [Ambystoma maculatum], eastern newts [Notophthalmus viridescens], green frogs [Rana clamitans), and bull frogs [Rana catesbeiana]), funnel traps had the highest probability of detection for a given level of effort (i.e., number of stations). For spotted salamanders and bull frogs, dip nets were the least effective; for eastern newts, bottle traps performed the poorest; and for green frogs, pipe samplers and bottle traps had the lowest probability of detection for a given level of effort. Green frog larvae had the highest probability of detection and spotted salamanders had the lowest for all 4 techniques. The mean number of person hours per station was lowest for dip nets and was similar for pipe samplers, funnel traps, and bottle traps. In terms of numbers of individuals captured, funnel traps generally captured the most spotted salamanders and bull frogs. For eastern newts, pipe samplers captured the most individuals whereas for green frogs, pipe samplers and funnel traps typically captured the most individuals. Dip nets and bottle traps typically yielded the lowest numbers of individuals across species.