Breeding habitat of the northern leopard frog, Rana pipiens: An analysis of the effects of selected biotic and abiotic factors on leopard frog reproduction in northeastern Ohio.

摘要

Recent decades have seen documented declines and extinctions of numerous frog species worldwide. The northern leopard frog, Rana pipiens, is included among these declining species, with reports of dwindling numbers and localized extirpation existing for areas throughout the species range in the continental United States and Canada. One objective of this study was to determine the current status of the northern leopard frog in northeastern Ohio. The animals were predictably absent from urban areas, but were found to be relatively common and in some cases even abundant in most rural areas. Having determined that northeastern Ohio continues to support healthy populations of leopard frogs, my second objective was to describe the optimum habitat for the species. I was particularly interested in testing the hypothesis that succession is the biggest enemy of the leopard frog in northeastern Ohio; i.e. the species is a colonizing species and therefore disperses to less mature ecosystems when its original habitat undergoes succession.;Eighty-eight ponds in seven northeastern Ohio counties were studied over a five year period of time in order to determine which habitat characteristics were most important in determining breeding habitat suitability. Of the 14 characteristics considered, the 3 that proved most important in breeding pond selectivity were as follows: maximum depth not in excess of 2 m, presence of large areas of nonfloating-leaved emergent aquatic vegetation, and presence of early successional stage terrestrial habitat surrounding the ponds.;With regards to the effects of succession, leopard frogs were found to prefer breeding ponds surrounded by early successional terrestrial habitat. Comparison of degree of site disturbance based on vegetation studies did not show a preference for early successional aquatic habitat, or that leopard frogs abandon ponds as the ponds age. Leopard frogs were, however, quick to exploit newly created wetlands and the data suggest that very young ponds (less than five years of age) may be especially attractive to reproducing leopard frogs.