Producer's Notes: Disappearing Frogs
A Pacific Chorus FrogWhen I was growing up in the Bay Area the chirping croaks of native tree frogs often serenaded us to sleep. The sound of those little Pacific Chorus frogs calling to each other was always familiar background music to long summer nights. Those were days of catching pollywogs down at the creek and finding Western Toads in our backyard garden. My brother and I knew exactly where the toads liked to sit during the hot summer afternoons. And like most young boys it was nearly impossible to resist picking them up and interrupting the poor animals' siestas. Of course the toads always expressed their irritation in the same way, leading us to immediately put them back down in gleeful disgust. This was a wonderful part of each summer's routine.
I'm sad to say my daughter probably won't share those same experiences I had. I could say it's because we live in San Francisco and cities aren't as amphibian-friendly as the suburbs. But my parents still live in the same house where I grew up. Unfortunately, it has been years since we've seen toads in the garden there. And the quiet singing of the tree frogs seems much lonelier today.
Amphibian decline is happening all over the world. And as depressing as it is not to have those fun childhood experiences of catching, playing with and hearing frogs in the garden, there is a much more serious problem going on. This can have some serious consequences to local food webs. It is also an alarming sign that there is something really unusual happening with the world's environment.
There are many reasons for the decline in the world's amphibian populations. And it seems that each region of the globe, and maybe even each species, may have its own ticking time bomb. Some places may be experiencing rapid habitat decline. There is pollution in the rainwater and chemical run-off in lakes and streams. Some places are seeing a sharp increase in parasites and diseases. Scientists are even looking at increased UV radiation. Or maybe it's a combination of multiple factors. The result is part of what some scientists are now calling the "sixth wave of extinction."
That’s a lot of doom and gloom. Luckily, scientists are racing to understand this decline and hopefully may come up with a means of curbing it before it is too late. We were fortunate to meet some of the best. We joined herpetologists Karen Swaim and Vance Vredenburg out into the field to learn more about what is happening to our local California red-legged frogs. We also visited the laboratory of Professor Tyrone Hayes at UC Berkeley to learn what his team is discovering about the connection between agricultural pesticides and frog decline. (See our additional web-only interview with Professor Hayes) You can test your amphibian knowledge by taking our QUEST quiz. Do you know why my brother and I always put down those toads?
Watch the "Disappearing Frogs" TV Story online, as well as find additional links and resources.
Chris Bauer is a Segment Producer for television on QUEST.
6 Comments
Tyrone Hayes spoke at Down to a Science in March. His argument (well articulated in the web only feature) is persuasive, startling, and motivating. In fact, Tyrone has "crossed the line" in advocating the ban of atrazine. More info can be found on his website: http://www.atrazinelovers.com
If you're interested in seeing Tyrone rap (that's right I said rap) more on this topic, check out this video I posted on YouTube: http://www.youtube.com/watch?v=3MxrH4lN0-A
News update:
Bacteria could stop frog killer
With amphibian populations collapsing all over the world, researchers are fighting to stop what some are calling the "6th wave of extinction."
One finding, presented at the American Society for Microbiology and reported by the BBC suggests that the chytrid fungus that has been devastating amphibian populations around the world may be treated using a fungus fighting bacteria. According to the article, "Scientists have found that certain types of bacteria which live naturally on amphibians produce chemicals that attack the disease-causing fungus."
To learn more about this, log onto:
http://news.bbc.co.uk/2/hi/science/nature/7438205.stm
A new study that came out last month confirms what Tyrone Hayes had found- that agricultural pesticides cause reproductive abnormalities- including hermaphroditism- in frogs:
http://thebirdsandthepcbs.blogspot.com/2008/08/bad-news-to-start-work-week-dude-looks.html
We should all wake up to the fact that we entering a part of the cosmos that the ancients new very well its destructive force. It all has to do with the increased radiation etc. coming form our sun which is being influenced by the blast coming from the galactic center of our universe. The Mayans were very well versed regarding the effects of the cosmos and went to great lengths to pass their knowledge on to future generations. This is just the beginning of more cataclismic events yet to come. Also note the increased earthquake activity in Yellowstone. Note the changing migration patterns of many animals. We have roughly three years left of civilization as we know it. Thanks for the opportunity to discuss.
There may be a new way to combat the fast spreading and lethal chytrid fungus that has wiped out entire frog and other amphibian species throughout the world. According to a recent AP report, The Smithsonian Institution is leading six other zoos and institutes in the Amphibian Rescue and Conservation Project, which aims to raise $1.5 million to fight the fast-spreading chytrid fungus.
Recently published research from James Madison University, suggests a benign, fungus-fighting bacterium in frogs' skin can be used to fight the fungal infection. In the study, frogs bathed in a mixture containing the bacteria and then exposed to the fungus had a 100 percent survival rate. Now they just need to get it out there to the frogs in need.
For more information, see:
Amphibian Rescue and Conservation Project: http://amphibianrescue.com
Press Release
FOR IMMEDIATE RELEASE
Long-range transport of insecticide residues linked to amphibian population declines
Lawrence, Kan. — Two pesticides used in highly populated agricultural areas of California appear to be killing frogs that live and breed in the Sierra Nevada, according to results from a study published in the August 2009 issue of Environmental Toxicology and Chemistry.
The study examined how two insecticides—chlorpyrifos and endosulfan—used in the fertile Central Valley of California affect amphibians that breed in the Sierra Nevada Mountains to the east. Toxicity was measured to larval Pacific treefrogs (Pseudacris regilla) and foothill yellow-legged frogs (Rana boylii), which are among the amphibians with declining populations that often live and breed in meadows surrounding the Sierra Nevada. Winds blow insecticide residues into the mountains, and they fall as rain or snow. In these regions, insecticides have longer half-lives because of cooler temperatures and can be spread by melting snow to areas where amphibians live and breed.
As outlined in the article, “Toxicity of Two Insecticides to California, USA, Anurans and Its Relevance to Declining Amphibian Populations” by Donald W. Sparling and Gary M. Fellers, the study used laboratory testing to examine how the insecticides affected the two frogs at environmentally realistic concentrations. During testing, tadpoles were observed at various stages of development to see how the insecticides affected their growth and health.
Endosulfan was more toxic than chlorpyrifos to both species, according to the research, and tadpoles of both species developed abnormalities when exposed to high endosulfan concentrations. Endosulfan also affected the growth and development rates in both species. The researchers say this affects the amphibians’ behavior and increases their vulnerability to predators and hydrological events such as floods and droughts.
The study also shows that chlorpyrifos and endosulfan are highly toxic to both amphibians, with the yellow-legged frogs more sensitive than the Pacific treefrogs to these insecticides.
“The difference in sensitivity is important, because P. regilla populations are still comparatively stable in California, even in montane areas, whereas R. boylii is one of the species that has declined in recent years,” according to Sparling and Fellers.
The yellow-legged frogs, which rely more on standing water during reproduction, have seen higher population declines compared with other species.
“Concentrations of insecticides in the Sierra Nevada Mountains of California may have the ability to inflict serious damage on native amphibians,” Sparling and Fellers write. “The present study adds to the increasing evidence that pesticides are very harmful to amphibians living in areas that are miles from sources of pesticide application.”
To read the entire article, visit http://www.allenpress.com/pdf/ENTC_28.8_1696_1703.pdf