Reproduction of Amphibians in Natural and Anthropogenic Temporary Pools in Managed Forests

Abstract

Abstract Vernal-pool breeding amphibians often oviposit in anthropogenic pools formed during industrial forest-management activities, as well as in natural ephemeral pools. We quantified wood frog (Rana sylvatica) and spotted salamander (Ambystoma maculatum) reproductive effort and metamorph emergence, pool hydroperiods and environmental features, and the density of natural and anthropo-genic pools across the landscape to compare the reproductive effort and success of amphibians breeding in natural and anthropogenic pools in managed forests in Maine. Numbers of egg masses in anthropogenic and natural pools did not differ for either wood frogs (median number masses/pool = 15 and 14, respectively) or spotted salamanders (13 and 13 masses/pool). Anthropogenic pools outnumbered natural pools on survey transects by a factor of 3.7. Pool area, depth, temperature, solar exposure, and coverage of closed-canopy forest within 100 m influenced amphibian reproductive effort in temporary pools. In a year with typical breeding-season rainfall (1997), anthropogenic pools dried sooner than natural pools (median drying dates: June 17 and July 30, respectively), and extensive larval mortality occurred upon pool drying. During an unusually wet breeding season (1996), the two pool types had similar hydroperiods (median drying dates: August 17 and 28). Metamorphs emerged from natural pools later and at larger size than metamorphs emerging from anthropogenic pools. Anthropogenic pools seem to function as ecological traps for breeding wood frogs in most years, and thus they should be avoided or designed with adequate size, depth, and shading to maintain an adequate hydroperiod. FOR. SCI. 48(2):397–406.