This leopard frog is missing a limb. It was attacked as a tadpole by a nematode parasite - Ribeiroia ondatrae. (Photo by Pieter Johnson)
This frog has extra legs as result of the parasite attack. (Photo courtesy of Pieter Johnson)
The parasite: exycsted metacercaria of Ribeiroia ondatrae. To propagate it relies on snails, amphibians, and birds in different stages of its lifecycle. (Photo couresty of Pieter Johnson)
Ecologist Pieter Johnson, who has published research on the link between frog deformities and Ribeiroia ondatrae, and how fertilizer pollution drives increases in these parasites. (Photo courtesy of Pieter Johnson)
New research says farm pollution is leading to an increase in frog
deformities. As Mark Brush reports, biologists say the pollution
causes an increase in harmful parasites:
Transcript
New research says farm pollution is leading to an increase in frog
deformities. As Mark Brush reports, biologists say the pollution
causes an increase in harmful parasites:
Water running off farm fields can carry fertilizers into nearby lakes
and rivers. Those fertilizers can then fuel algae growth. Researchers have found that a frog-
deforming parasite thrives in this algae rich environment.
Pieter Johnson is an ecologist at the University of Colorado. He
published his research in the Proceedings of the National Academy of
Sciences. He says these microscopic parasites go after tadpoles:
“And those parasites swim around in the water and they’re specifically
looking for tadpoles and when then find one they burrow in, right around
the limbs, where the developing limbs are.”
The parasite attack can kill the tadpole or result in a frog with an
extra or missing leg. Johnson says these amphibians become easy prey
for birds or other animals. He says this cycle contributes to the
overall decline in amphibian populations worldwide.
Ed Herrmann tries to hear some frogs through the
traffic near the Rouge River. (Photo by Ed Herrmann)
The middle branch of the Rouge River in suburban Wayne
County, Michigan. (Photo by Ed Herrmann)
Each Spring, thousands of people spend their evenings listening to frogs and toads. It’s not just for fun. They’re helping assess the water quality of rivers and wetlands around the country. The Great Lakes Radio Consortium’s Ed Herrmann joined the search for amphibians, and has this essay:
Transcript
Each Spring, thousands of people spend their evenings listening to frogs and toads. It’s
not just for fun. They’re helping assess the water quality of rivers and wetlands around
the country. The Great Lakes Radio Consortium’s Ed Herrmann joined the search for
amphibians, and has this essay:
I’ve always enjoyed being outside and listening to nature. Recording nature sounds is a
hobby of mine. So when I saw an ad asking for people to listen for frogs and toads, I
thought, “All right. Beats watching campaign commercials.”
I called up Friends of the Rouge…(that’s a local group dedicated to helping out the Rouge
River watershed) and a few days later I got a package in the mail. It was full of maps and
information, and had a CD with the songs of the local frogs and toads. I studied my area,
and found some good looking wet spots where I thought they might live.
I memorized the sound of the Wood Frog (sound), Chorus Frog (sound), Spring Peeper
(sound), and American Toad. Then, on the first night when the temperature and wind
conditions were just right, I headed out to hear some frogs.
(sound of traffic roaring by)
I don’t know what I was thinking. This is suburban Detroit, not exactly a wildlife refuge.
In fact, the only animal I see is a rabbit dodging traffic. And the only thing I hear is…
(more traffic sound)
The Rouge River flows into the Detroit River and then Lake Erie. It used to be one of the
dirtiest rivers around, mainly from all the industry down by the mouth. That problem is
more or less under control but now there’s a larger one.
If you look at a map from the 1970s, you see miles of wetlands, small farms and
orchards. Today you see nonstop subdivisions and shopping malls. It might seem like
progress to you, but for the river, the constant barrage of fertilizers, pesticides, soap and
other chemicals that everybody uses to keep their suburbs looking pretty is a lot worse
than an occasional dose of battery acid from a factory. Also having acres of concrete
instead of wetlands means there’s nothing to soak up and filter the water, which means
after a big rain, it floods. It’s obvious this river needs some help.
(sound of river)
In 1998, volunteers began surveying the frogs and toads in the Rouge watershed. These
creatures were chosen because they sing, so they’re easy to track. The reason they’re
good indicators is that, like other amphibians, they absorb water through their skin. That
means they get poisoned by everything that we in the civilized world pour into the water.
Plus, their eggs hatch in water and their larvae (the tadpoles) live in water. It’s pretty
simple: if the water is good, there’s plenty of frogs and toads. If not, they disappear.
So, night after night, I’m out there listening. Listening in the dark. Listening hard.
Not a peep.
I’m beginning to think that the price of all these well-manicured lawns is a silent spring.
Then finally one night, (sound of American toads) the good old American toad! All
right, it is the most common species around, but at least it’s a start.
(sound of chorus frogs and green frogs)
A few weeks later, I join a group at a “mitigated” wetland. That means that when a
developer decided that a real wetland would be the perfect place to build condos and a
golf course, the government said, “Sure, go ahead. Drain it. Just be sure to dig a hole
over here and fill it with water.” Now, five years later, some frogs have moved in and
seem to be fine.
But they still have a little problem…
(jet roars overhead, followed by a few green frogs)
Ah, location, location. This new wetland is right
next to the airport.
Now, the reason these frogs sing is to attract a mate. So if nobody hears them, there are
not going to be any tadpoles to make next year’s frogs. In order to survive, they need not
only to sing, but to be heard.
For the Great Lakes Radio Consortium, I’m Ed Herrmann.
This leopard frog is missing a limb. It was attacked as a tadpole by a nematode parasite - Ribeiroia ondatrae. (Photo by Pieter Johnson)
