Frog Call Surveys Help Inform Health of Habitat
July 1, 2021
Does it seem to be getting louder in the backyard as you wind down for the night? Do you hear a chorus of frogs and toads (anurans) calling tirelessly in the darkness?
The beginning of the summer rainy season heralds the breeding season for most of Sanibel’s anuran species. During the dry season, they keep moist in some permanent water bodies, such as lakes and rivers, or seek out damp places to avoid desiccation (drying out)—burrows, fallen trees, bark piles, or by simply burying themselves. The onslaught of regular June and July rains in Southwest Florida invites frogs and toads to emerge and breed in both temporary and permanent water bodies.
To understand the local anuran species, and the health of their populations, SCCF participates in the national FrogWatch program through the Southwest Florida Amphibian Monitoring Network.
SCCF biologists visit 20 sites across the island every third Wednesday of the month June through September after dark to record the species heard, call intensity, temperature, humidity, wind speed, sky condition, traffic noise, and other environmental variables.
“Amphibians (frogs, toads, and salamanders) are an excellent indicator species for water quality and environmental problems,” explains SCCF Wildlife & Habitat Management Director Chris Lechowicz, pictured here on a frog call survey. “Because their skin is exceptionally absorbent, they take in water constantly, as well as toxins. A reduction or total loss of a frog species in a wetland can mean some type of environmental contamination, loss of water quality, or habitat change has occurred.”
While “some frog and toad species are more tolerant than others of contaminants, the loss of a highly sensitive frog species can mean the beginning of an issue in a wetland,” Lechowicz says.
How does SCCF conduct frog call surveys?
Male anurans attract breeding females by producing a species-specific call in areas suitable for egg deposition (wetlands). On a good night, you can hear hundreds of male frogs calling all at once. The nine species of frogs and toads on Sanibel have distinct mating calls, and SCCF volunteer frog monitors have been trained to identify the nuances in each species’ distinctive calls.
This information is added to the extensive Southwest Florida Amphibian Monitoring Network database, which is shared at the national level through FrogWatch and the North American Amphibian Monitoring Program to get a big-picture understanding of how amphibian populations are faring around the country.
If you have questions about frog or toad calls, please email email@example.com.