Archive for Thursday, July 27, 2006

Frog days of summer

Environment harsh for amphibians

July 27, 2006


As a young girl growing up in Lawrence when Kasold Drive was on the fringe of town, I used to see hundreds of frogs. There are many reasons that I'm seeing fewer frogs where they were once abundant: human infringement onto their territory, pollution and an increase in the UV rays due to the thinning ozone layer are making them disappear.

Frogs and toads can be useful to a garden, playing a key role in squelching the pest population; these little guys are mainly carnivores preying on insects. Amphibians are animals that live on land, but they still need water to mate and to deposit their eggs. Their larvae are known as tadpoles, polliwogs or pollywogs. In their tadpole stage, it is essential that they live in water, and rather than resembling their parents, they look more like fish with a tail and no arms or legs. Amphibians derive a comfortable temperature from their surroundings. They must move to a cooler or warmer location to regulate this, which is why you'll often see an amphibian sunning himself on a rock or gurgling on a ledge in a pond.

The skin of frogs, toads and salamanders is permeable, leaving them highly susceptible to weed and pest killers, detergents and other chemicals we deposit into the environment. Amphibians breathe in part and absorb water through their skin, making it easy for contaminants to enter their bodies. Their skin always needs to be moist; if they dry out, they die.

Frogs and toads aren't seen as often as they used to be in Lawrence. The amphibians are susceptible to pollutants dumped in the water.

Frogs and toads aren't seen as often as they used to be in Lawrence. The amphibians are susceptible to pollutants dumped in the water.

Joseph Collins knows amphibians; he retired from Kansas University's Natural History Museum in 1997 and is now an adjunct herpetologist for the Kansas Biological Survey. He assists with the Kansas Anuran Monitoring Program, a volunteer program coordinated by the Kansas Department of Wildlife and Parks. The program is to help determine the status and population trends of Kansas' 22 species of frogs and toads.

"Having frogs and toads is number one a sign of a healthy environment - the water is good," Collins says. "Number two, it is very pleasant to hear the sounds of frogs calling. Number three, after a long, cold, Lawrence winter, they are the first sign of spring's arrival. And number four, the world would be a frightening place without frogs. I mean, look at Kermit."

Disappearing Act

Collins says it is difficult to assess the decline of frogs and toads.

"Nobody is surveying the abundance of frogs," he says. "If someone is studying a frog, they may notice a decline. The Crawfish Frog for instance, was abundant in the Baker Wetlands through the 1950s, but because someone - and it is unknown who - dug trenches all around the wetlands, that was the beginning of the end of the Crawfish Frog. The last time I saw one was in 1978. It had been hit by a car and was brought into my office."

A pond or water garden will attract frogs and toads.

A pond or water garden will attract frogs and toads.

Collins refers to a book titled "Silent Springs," by Rachel Carson, about the effects of chemicals on the environment.

"'Silent Springs' are happening in some parts of our country," he says. "Western Pennsylvania, for instance - my colleagues and I cannot find chorus frogs in that area any longer. In Michigan, the same problem is occurring with chorus frogs. One species in Kansas, the northern cricket frog, used to be prevalent in the Western quarter of the state, and now they are very difficult to find."

Luring amphibians

Both Collins and Susan Davis, owner of Water's Edge, 847 Ind., agree that the best way to attract frogs and toads to the garden is through a water source. You also may opt to choose nonchemical weed controls whenever possible, like mulch, spading, hoeing and pulling weeds. Another idea is to stop fertilizing your lawn. Instead, leave the grass clippings after you mow to decompose; this is equal to fertilizing your lawn once or twice a year. Keep in mind there are also organic fertilizers on the market. If you do build a pond, ensure that the edges are not too steep so that the amphibians can get in and out easily. Go to the wetlands and discover the gorgeous native plants that you can mimic in your backyard. Provide places for these critters to hide and spots in which to sunbathe. If you build a water garden, they will come.

"Frogs are important in the water garden," Davis says. "The tadpoles graze on algae on the sides of the pond; the adult frogs eat bugs in the garden. They are a part of the 'biology of the pond,' whether it is in natural ponds or in our backyard water gardens.

"For me, the greatest contribution they make is putting smiles on our faces and laughter in our hearts as they sing and jump in the pond," she says. "During the summer, you can find lots of tadpoles and frogs in their various stages of life and metamorphosis in the yard. It is fascinating."

Toad or frog?

If you are fortunate enough to already have amphibians in the garden, how do you know if you have a frog or toad, and what kind, for that matter?

Toads ¢ Toads' hind legs are weaker than frogs; consequently they do not jump as well. ¢ Toads have dry, rough skin, often with many warts. ¢ They are less susceptible of drying out than frogs and are nocturnal creatures for the most part. ¢ When toads feel threatened they may secrete a stink from their glands making them very unappealing to enemies. ¢ They mate in March and oftentimes deposit their eggs in the same water source that that parent toad was born in. Their eggs appear in long lines. ¢ Toads are excellent swimmers and diggers; they eat insects and might live to be 10-15 years old.

Frogs ¢ Frogs are extremely voracious and will do crazy things just to get that nibble to eat. They may make a sudden leap or sneak through the water like a stealth bomber. ¢ They have long, sticky tongues for catching flying insects. ¢ They tend to be skittish and are frightened by sudden movements. If you stay still long enough the frogs will emerge. Source: Kansas Anuran Monitoring Program

Commonly seen in Lawrence

According to Collins, these toads are commonly found in Lawrence. Visit the KAMP Web site,, for more information: Woodhouse toad: Its belly does not have dark spots. The males have throats that are darker than the rest of the belly, and like most toads, they are more active at night. Their calls are explosive and have a nasal tone sounding like "w-a-a-a-a" lasting 1-3 seconds. American toad: These toads grow over 4.5 inches long and are well-known in gardens. They possess a relatively heavy belly and only one wart per dorsal spot. They are active at night and hidden in the day. They have a long, musical trill that lasts from several seconds to 30 seconds. Each male in a chorus sings on a different pitch. They breed from April to June.

Frogs Common frogs in Lawrence: Gray treefrog: These frogs are 1-2 inches in length with rough skin that is green to gray to brown with light spots beneath their eyes. They have bright yellow or orange on the concealed surface of their hind legs with large toepads. Their rough or bumpy dorsal skin usually has darker blotches. Their call is a short, high trill. Northern cricket frog: This frog is wartier, heavier and bulkier than other cricket frogs. They have a dark stripe on the thigh, blending with dark pigment above and in the anal region. They have shades of light brown with gray and green speckles; they sport a rounded snout and have relatively short legs with heavy webbing of the hind foot. The males have a single yellowish vocal pouch under the chin and a dark triangle between the eyes. They often have a bright green or reddish stripe on their backs. Their call sounds like two small pebbles being tapped together. Plains leopard frog: The brown to buff frogs have large spots between yellow dorsal lateral ridges with a light tympanum spot and colored jaw line. Their call is a "chuck-chuck-chuck" that is very abrupt with guttural notes and lasts for 2-3 seconds. If you are interested in hearing these calls they are on the KAMP Web site or if you would like to volunteer to help monitor the frogs and toads of Kansas, there is information on that as well. Water's Edge also will conduct Frog Daze on Aug. 5-6.


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