The Oak Openings Preserve Frog Survey

The Oak Openings Preserve Frog Survey is the longest running anuran survey in the state of Ohio, and has been in operation since 1994. The survey raises awareness of local frog species through volunteerism, and considers frogs as indicator species to help to monitor the long-term ecological health of the Oak Openings Region.

Analysis of data from this long term survey can increase knowledge of yearly fluctuations in calling events for individual frog species, seasonal breeding patterns, relationships between frog advertisements and weather conditions, and relationships between indicator species and habitat restoration. Anurans are indicators of overall ecological health and sensitive to changes in land use.

Fragmentation or changes in vegetation in regard to the forest and meadow habitats that they use after breeding, as well as in vernal pools and ditches in which they use during breeding, will affect their success. Dependent on clean water and healthy environmental conditions at all stages of their life cycle, frog presence and absence helps determine the overall ecological health of an ecosystem. Also important, the timing of spring frog calling counts can reveal differences in the overall climactic conditions across a region over time.  Globally, frogs (amphibians) are of conservation concern. Worldwide, amphibian numbers are declining at 4-5% annually. Pollution, habitat loss, climate change, and diseases are suspected.

The survey operates annually three to seven nights per week from March 1 through May 31, along a set, 0.9-mile linear transect through various habitats in Oak Openings Preserve, encompassing one-tenth mile sections.  Beginning one-half hour after sunset, trained volunteers walk the survey path and record the number and species of anurans calling in the adjacent ditches within each section of the transect, as well as wind speed, cloud cover, precipitation, and air and water temperature. Volunteers use “tick marks” on the monitoring forms to represent the total amount of individuals calling per section. If there are too many animals to count (“full chorus”), then a “slash” is noted for that section.

The results are reported annually at the Oak Openings Research Forum. In past years, some results have been reported to FrogWatch USA, which is organized by the National Wildlife Federation; data has been presented twice at the Ohio Declining Amphibians Conference. Also, wood frog calling data from this site is noted in a recent, two volume Midwest herpetology textbook. Currently, this long-term data is being analyzed by The University of Toledo.