Seasonal Changes in Anuran Populations in a Northern Michigan Pond

Population estimates of metamorphosed frogs were calculated in the summer of 1975 in an enclosed pond-marsh habitat in northern Michigan. Eight species of amphibians were found in the study area of which five, H. crucifer, B. americanus, R. sylvatica, R. clamitans and R. septentrionalis contributed significantly to total biomass. Densities varied from 0.03/m2 for R. sylvatica to 0.39/m2 for R. clamitans. The highest densities were reached in August when newly metamorphosed frogs entered the population. R. clamitans accounted for about 85% of the biomass in July and August.