Frogs and Toads in the Garden
Green Frog Sighting
The green frog (Lithobates clamitans) spends most of its life in water and, during the winter, it will bury itself in the substrate at the bottom of ponds and pools until spring. When they are startled by potential predators, green frogs will make a high-pitched peep as an alarm to other frogs before fleeing to safety.
Image courtesy of National Wildlife Federation, photo by Paula Stone-Buckner
If you enjoy a garden or backyard that attracts wildlife and consider yourself a fan of amphibians, what could be better than creating a habitat for frogs and toads? Installing a small pond is easier than you think and you can enjoy the many benefits that pond dwellers provide. For one thing, frogs and toads are a great asset in pest control. They devour mosquitos, flies, cockroaches, moths and other insects. And toads, in particular, have a voracious appetite for slugs. They'll also serenade you at night in warmer weather with their unique songs and sounds.
There are also other important reasons to want them in your area. "Biodiversity, for one thing," states Ron Skylstad, the director of Tree Walkers International, a grass-roots organization that supports the protection, conservation and restoration of wild amphibian populations through hands-on solutions like building community ponds. "If you have amphibians, it's a good sign," Skylstad says. It means you are living in an area with a rich ecosystem. "If you're in an area and there aren't many amphibians," he adds, "that should be a red flag about the general ecosystem health there." The removal of amphibians from any habitat can drastically affect predator dynamics, nutrient cycling, algae communities and other vital components in the ecosystem, resulting in an unpredictable imbalance.
The biggest threat to amphibians right now is habitat destruction and pollution. In her new book, The Sixth Extinction: An Unnatural History, author and environmental reporter for The New Yorker, Elizabeth Kolbert writes that, "It is estimated that one-third of all reef-building corals, a third of all freshwater mollusks, a third of sharks and rays, a quarter of all mammals, a fifth of all reptiles and a sixth of all birds are headed toward oblivion." Skylstad believes that Kolbert's predictions, which are based on solid scientific research and documentation, need to be urgently addressed. Skylstad is doing his own part to educate the public about the importance of amphibians and providing solutions to people who want to help reverse the species' decline.
The main objective of Operation Frog Pond, a conservation project by Tree Walkers International, is to provide new habitats for amphibians pushed out of their breeding and living spaces by new building developments and toxic man-made pollutants in their environment. A pond-building guide is available on the organization's website but Skylstad lists the important points to consider below for those interested in creating a backyard pond.
The pond should be situated in a part of the yard that is partially shady but receives some sunlight.
Shallow, Sloping Sides
The most desirable pond for amphibians is one that is fairly swallow and no deeper than 18-20 inches at the center and as shallow as 8 inches around the edges. The sides of the pond should slowly slope down and not sharply drop off at the edge.
The ideal vegetation for frog ponds are thin, vertical stemmed plants like spike rushes, reeds and sedges. Amphibians like to attach their egg sacks to the bases of these plants below the water surface after breeding.
After you dig out the dirt from the area where you'll create your pond, put down a rubber liner such as an EPDM rubber or polyethylene that will create a tight water barrier. Then add back in all the soil you removed. This creates a nice, soft bottom. "Tadpoles of some species like to lay down in that muck," Skylstad notes. "They filter feed through that muck so they'll pick up all kinds of organisms and algae," which are beneficial to their growth.
It is best to not have any water movement in the pond. Amphibians like quiet, still water.
Keeping fish in separate ponds from frogs and toads is recommended because fish, even the smaller species, will feed on amphibian eggs, larvae and adults. If you want to introduce any other species into the pond, you should consult your local fish and game department. They may be able to recommend a local species of darters or minnows that wouldn't be a threat to tadpoles and would help in the consumption of mosquito larva.
Dogs and cats are potential threats to amphibians so if you have pets, you should limit their access to the pond by putting up a wire fence or barrier around it. Broken dishes or clay pots turned on their side and scattered around the edges of the pond also offer additional shelter for frogs and toads in a cool, damp safety zone.
Practices to Avoid
Do not stock your pond. Let the amphibians in your area find it on their own and populate it. Buying and stocking it with amphibians that are not native to your area could introduce disease, predators and other problems into the local habitat. Bullfrogs, in particular, are a problem because of their size. "They literally eat native species of amphibians," Skylstad warns. "They're so big they can eat a native salamander or a native frog. They're decimating some native amphibian populations because there is nothing that can compete with them."
Do not plant cattails in your pond even though it's a common sight in many natural ponds. Cattails have thick stems and skin and are of little use to amphibians in their breeding and development. They also proliferate quickly and can crowd out other types of beneficial vegetation in your pond.
Avoid using insecticides or garden chemicals in your backyard or you run the risk of poisoning and killing your pond inhabitants. You also need to keep in mind that you should never handle an amphibian without rinsing your hands first. The skin of a frog is very porous like a sponge so if your hands were covered in mosquito repellent it would be absorbed directly into the frog's body and poison it.
By observing all of these dos and don'ts, you can create the perfect amphibian pond and do your part in this international conservation effort. For more information about Tree Walkers International, visit their website.