Why Illinois Chorus Frogs?
By Mark Alessi, Stan McTaggart, and Mark Phipps of the Illinois Department of Natural Resources
The Illinois chorus frog is considered a Threatened species in Illinois and is a unique amphibian, but it is one that has been able to survive in a predominantly agricultural landscape.
Photo Credit: Peter Paplanus
Rare species and rare habitats are one in the same. Rare species are typically rare because their habitat requirements and/or community types are very specific. Most of the time, very specific habitat requirements by animals and fish requires constant management by land managers/biologists. When you think about the species that are flourishing in Illinois, you think about species that are very adaptable to habitat fragmentation and people; resident Canada geese, white-tailed deer, wild turkeys, and red-winged blackbirds are the first that come to my mind and for the most part, are doing very well from a population perspective. Most anyone can do some good in their yards or on their farms to help Monarch butterflies and other insect pollinators.
On the contrary, landowners need to be in the right place where Illinois chorus frogs exist to have an opportunity to help them survive.
The Illinois chorus frog is considered a Threatened species in Illinois and is a unique amphibian, but it is one that has been able to survive in a predominantly agricultural landscape. One reason we hypothesize why they’ve been able to survive in this landscape is that they are only above ground for a very short period (for a few weeks between February and May) and spend the rest of the year (about 10-11 months) underground. This frog relies on very specific habitat types to both breed and overwinter in: ephemeral wetlands with sandy soils nearby. To be specific, it seems that the most productive wetlands are ones that have water in the spring but then completely dry up mid-summer. This reduces the probability of predators being in the water in future years (fish, salamanders, and bullfrogs). Only limited areas associated with the Illinois and Mississippi River basins have the necessary habitats the frogs require. The Illinois Department of Natural Resources (IDNR) conducts annual surveys from the roadway in areas where we know the right habitat exists. A significant portion of this habitat type is found in agricultural fields, and every year, we come across calling and breeding frogs in these areas. There are more frogs out there than we originally thought, but there are still some serious concerns about their population status and long-term persistence.
This little frog has some cool adaptations for making it’s living. For example, it burrows in the sand with its “front feet,” not its back feet – which is atypical for most burrowing frogs/toads. Their front limbs are thicker and their “fingers” have different adaptations to permit this burrowing behavior. In general, when they burrow underground, they burrow just a few inches below the surface. However, the depth often varies depending upon annual temperature fluctuations. Recent research has identified that this frog consumes prey while underground. During the breeding season, it tends to burrow in the sand during the day and then come out at sunset to call and breed. This critter is full of intriguing adaptations for this ephemeral lifestyle. The eating underground thing makes me happy I am not a frog.
Due to the rarity of ephemeral wetlands associated with sandy soils, there are only a few localized places in Illinois that this species can be found and one of these places is just a stone’s throw from SIU-Edwardsville in Madison County. The Illinois Department of Natural Resources and Heartlands Conservancy have teamed up to protect and manage Illinois chorus frog habitat in the area. For example, Heartlands and the IDNR are collaborating on installing wetlands on IDNR and Heartlands Property. In addition, SIUE scientists and graduate students are studying the life history of this frog so that we can better understand how to manage for it. Since it is found primarily on private lands in Illinois, we also work with private landowners to conserve chorus frog habitat. Conservation of ephemeral wetlands and sand prairies benefit so much more than just the frog. Waterfowl, deer, quail, butterflies, and salamanders are some examples of other species that reside in this habitat type. Due to their small size and home range, even small acres of suitable habitat protected and managed for this species can have outsized benefits.
Lastly, the Illinois Endangered Species Protection Act (IESPA) is a tool to provide additional protections to rare species, and to increase the amount of eligible resources that can be used for species’ management and recovery. One of the goals of the IESPA is to facilitate recovery of species that are classified as threatened or endangered. Since there are greater than 400 species on Illinois’ List of Endangered and Threatened species, the IDNR prioritized species based on the best available science and other variables. The Illinois chorus frog is considered a “recovery priority species” and the IDNR is taking a strategic approach to both management and recovery actions that can be implemented across the landscape. So why is it so important for Illinoisans to preserve and protect rare species like the Illinois chorus frog? Think about the world as a giant jigsaw puzzle. Every piece has its place, and without some of the pieces, the puzzle would be incomplete. In the wild, the continued reduction in “puzzle pieces” will likely someday have devasting consequences to us. It is hard for us to fathom what losing a few species means in our single lifetime, or what losing a little frog means, but the continued reduction, particularly at a fast rate, will certainly negatively impact humans at some point. In addition, frog management includes managing for wetlands. Wetlands have been shown to have very beneficial processes to humans (think clean water, storm storage, etc). Helping the frogs helps us.