Single and interactive effects of low pH and leech predators on frog embryos and adults

used an experimental and field approach to assess single and interactive effects of leech predators and pH on frog embryos and adults. Experiments on embryos indicated that leeches (Macrobdella decora) and low pH affected hatching success, hatch timing and hatch length of wood frog (Rana sylvatica) and green frog (R. clamitans) embryos. However, effects of the leech on hatch length and timing did not occur in low pH. The loss of a presumably adaptive trait at low pH could have important fitness consequences for hatchlings.;I conducted a field study testing for negative associations or interactive effects between M. decora abundance or pond pH and abundance of adult bullfrogs (R. catesbeiana), green frogs and leopard frogs (R. pipiens). Only green frog abundance was negatively associated with M. decora. There were no relationships between frog abundance and pH or pH-M. decora interactions. This is due to the non-acidity of study ponds (pH...