|SREL Reprint #1966|
Impacts of hydroperiod on growth and survival of larval amphibians in temporary ponds of Central Pennsylvania, USA
Christopher L. Rowe - William A. Dunson
Abstract The effects of variable hydroperiod (three levels) and initial density of
amphibians (two levels) on survival, growth rate, and time to and mass at
metamorphosis were studied for wood frogs (Rana sylvatica), Jefferson
salamanders (Ambystoma jeffersonianum), and spotted salamanders (A.
maculatum). Experiments were carried out in 260-1 mesocosms set up outdoors
in a forest. These pond simulations were designed to mimic conditions that occur
in palustrine temporary wetlands in central Pennsylvania. No animals reached
metamorphosis in the short hydroperiod (56 days). However a greater proportion
(66%) of tadpoles of R. sylvatica survived to the end of the 56-day treatment
than the 84- or 158-day treatments (29 and 14%, respectively), from which all
survivors metamorphosed. In contrast, neither of the salamanders metamorphosed
by 84 days; survival to metamorphosis at 158 days was 15% for A.
jeffersonianum and 10% for A. maculatum. Average instantaneous growth rates
for A. jeffersonianum decreased with each increase in hydroperiod. Growth of
R. sylvatica was greater in the 56-day hydroperiod than in hydroperiods of 84 or
158 days. Initial amphibian density had no effect on growth or survival of any
species. It appears that salamander larvae were predatory on tadpoles, since
survival of R. sylvatica was negatively correlated with survival of A.
jeffersonianum in 84-day treatments and with growth of A. maculatum in
SREL Reprint #1966
Rowe, C.L. and W.A. Dunson. 1995. Impacts of hydroperiod on growth and survival of larval amphibians in temporary ponds of Central Pennsylvania, USA. Oecologia 102:397-403.