Effects of habitat complexity and predator identity on predation of Rana clamitans larvae

Abstract

AbstractWe examined the microhabitat distribution of green frog larvae (Rana clamitans) and two common predacious insect genera at 27 wetlands in southern New Hampshire to determine if it was related to the presence of vegetation. Rana clamitans and hemipterans (Belostoma spp.) were rarely captured in non-vegetated microhabitats. Larval odonates (Aeshna spp.) were captured more frequently in vegetated microhabitats but the difference was not significant. In a laboratory experiment, we tested the effects of plant density on the survival of R. clamitans larvae exposed to either Belostoma flumineum or Aeshna mutata. When no cover was available, survival of R. clamitans tadpoles was very low when exposed to either predator. Belostoma flumineum was a less effective predator than A. mutata, and survival rates of tadpoles did not differ between high and low plant density when exposed to this predator. In contrast, survival of tadpoles was significantly higher in the high density vegetation treatment compared to the low density treatment when exposed to A. mutata. Although plant structure can reduce predation on R. clamitans larvae, the level of structure necessary to significantly mediate predation may depend largely on the foraging mode of the predator.