Citizen Science: Conservancy Continues CASP Summer Frog Call Surveys

by Tim Chisholm

Frogs and toads are essential components of the ecosystem that exploit the abundance of invertebrates in our environment while at the same time serving as sustenance for other animals. Scientists have discovered frog and toad populations have been undergoing population declines worldwide because of habitat loss, ultraviolet radiation, pollution, disease, and introduced (exotic) species. These changes are hard to detect, quantify, or diagnose without standardized, long-term monitoring systems in place.

The North American Amphibian Monitoring Program (NAAMP) is filling this need by creating and coordinating a continent wide monitoring program that relies on participation by individual states to monitor their frog and toad populations. Long-term tracking of frog and toad distributions and relative abundance over time will serve as an early warning system for any changes so that action can be taken if necessary.

In 2005, the Wildlife Diversity Program of the North Carolina Wildlife Resources Commission (NCWRC) initiated the Calling Amphibian Survey Program (CASP) in order to establish a frog and toad monitoring program and participate in NAAMP. NAAMP and its interactive website are administered by the Biological Resources Division of the United States Geological Survey (USGS). In 2006, NC had sixty-one original random routes generated through NAAMP. Due to perceived high demand of routes from observers and a need to cover more areas of the state not covered by previous routes, seventy-four additional random routes were created for NC. Along with four nonrandom routes, this brings the total number of routes in the state to 139.

The BHI Conservancy participates and volunteers in CASP 3 times a year in the spring and early summer in search of frogs and toads! We conduct these frog and toad call auditory surveys after sunset at 8 stops around Bald Head Island, including Bald Head Woods, Kent Mitchell Trail, and the Wildlife Overlook. These surveys allow us to better understand frog and toad distributions and their relative abundance on BHI over time and will serve as an early warning system for any environmental changes so that action can be taken if necessary.

There are 30 species of frogs and toads in North Carolina. Six species are rare with two being state-listed as Special Concern and one as Threatened. Bald Head Island is within the range of 22 of these species. Frogs and toads have species-specific vocalizations that allow them to be identified and monitored much like birds. However, you cannot count individual frogs and toads and instead must rely on an index of abundance. 

Our North Carolina data will be pooled with data from other states to consider regional and national trends in species distributions and detect changes in frog and toad populations. Understanding these trends will provide us a better understanding of the status and health of our frog and toad populations, and will enable us to protect critical habitats for our frog and toad species.

This is a monumental task that can only be accomplished by dedicated volunteer citizens and we are happy to be a part of such a meaningful citizen science project!