When 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?