Friday, December 08, 2006

Are all the frogs really dying?


Scientists agree that frog and toad populations in the United States and around the world are in decline. Of about 100 different species in the U.S., twenty-two are listed as threatened or endangered. Worldwide, there are thousands of species with hundreds nearing extinction. Yikes!

But there is hope. If scientists can figure out why so many species are threatened, then maybe we can save all those peepers and croakers from singing their last tune.

Frogs and toads are amphibians, spending part of their lifecycle in the water, and part on land. And, unlike most landlubbers, they have very thin permeable skin which absorbs both water and air. Because of this feature frogs and toads are good indicators of changes in the earth’s environments and for this reason are considered the global version of the “canary in the coal mine,” only this coal mine is the planet earth! So far scientists have identified several possible changes that could impact survival of frogs: global warming, pollution, disease, and habitat destruction.

From eggs, through the tadpole stage, frogs are surrounded by water. These early life stages are considered the most sensitive to environmental change. Recent studies for example, have found that the most commonly used weed killer in the U.S., atrazine, wreaks havoc on the developing sex organs in male frogs, so much so that some male frogs end up with both male and female organs.

Additionally, parasitic infections in developing frogs are thought to be responsible for formation of excess limbs, and fungal infections in adults have been linked to population declines in other parts of the world. Scientists think that other factors such as global warming, ozone depletion and toxic chemicals may make frogs more vulnerable to infections that otherwise would not have bothered them.

Finally there is wide-spread habitat destruction. As mentioned above frogs and toads require both aquatic and terrestrial habitat, and reduction in either one or both of these habitats could contribute to the decline of frog and toad populations.

But don’t despair! These are not insurmountable problems. Understanding toxicity of pesticides to frogs and toads may lead to greater restrictions on their use (it worked for the Bald Eagle,) and there are currently treaties to prohibit the release of ozone-destroying chemicals. But with over 200,000 acres of land cleared daily (an area equivalent to New York City) habitat destruction seems a thornier issue. So it’s up to all of us, to get on the ball, and help save our amphibious friends.

A good way to begin is to check out the National Wildlife Federations Frog Watch Program at http://www.nwf.org/frogwatchUSA/.

2 comments:

gloria said...

I have a swamp in my neighborhood that might be destroyed for apartments what can I do to save the frogs we are in Mass, and I don't know what I can do to make a difference?

Emily Monosson said...

Hi Gloria, sorry to hear that. This isn't my area of expertise, but you might want to check out the MA Department of Environmental Protection (MA DEP http://www.mass.gov/dep/)and check out their Wetlands Program, http://www.mass.gov/dep/water/resources/wetlands.htm

Someone there may be able to give you advice. Also do you have a local Conservation Commission? I know they are not always helpful (in my neighboring town on Con Comm member was added because he was basically in favor of paving over a wetland so a big box store could be built.) Hopefully yours is on the more protective side.

Finally - I think that vernal pools (defined as contained basins of water without external outlets - which tend to be wet in winter/spring and may be dry by late summer) have a better chance of protection - so if what you have is a vernal pool rather than a swamp you may be in luck.