If you happen to see a frog hopping around in your back yard, take a good look— it might not be around for much longer. Ecologists are increasingly warning that due to habitat destruction, widespread infectious disease and climate change, amphibians are facing "extinction in real time."
As many as 40 percent of amphibious species, which include frogs, salamanders and newts, could be facing "imminent extinction," according to David Wake, a researcher at the University of California Berkeley.
"It's happening around the world … we're seeing it on our watch," he says. "People talk more about birds or mammals because they are charismatic, they're in the public eye. I'm concerned about rhinos and tigers, too, but in the meantime, we're losing the things that are in our backyard."
Scientists first began noticing the decline in the late 1980s, but despite increased awareness, amphibious populations haven't grown.
"If anything, the problem has gotten worse," Wake says. "The attention we've given to it has led to some surprising discoveries," such as Chytridiomycosis, an infectious disease caused by a fungus that lives around the world and has a near 100 percent mortality rate in amphibious animals. So far, biologists haven't been able to stop the disease.
Researchers disagree, however, on why we might soon have to say farewell to frogs forever. A controversial paper published in November by Christian Hof, a researcher at the University of Copenhagen, asserted that climate change is one of the biggest reasons the amphibian population is in worldwide decline. In an analysis released Friday in Science Magazine, Wake admits amphibians might be susceptible to changing climates, but their survival over millions of years points towards adaptability.
"With their moist and seemingly delicate skins, amphibians might be highly susceptible to climate change, but they are long-term survivors, having gotten through the end-Cretaceous extinctions and Pleistocene climate changes," he writes. Habitat destruction and Chytridiomycosis are more imminent problems, he says.
"It's not that climate change isn't going to have an effect, it's that the most acute things [habitat destruction and disease] are here right now, hitting amphibians hard," he says. "Climate change is a little more remote and more controversial."
Wake points to the Sierra Nevada frog, which lives high in the northern California mountains. Less than 100 years ago, the frog was the "most common vertebrate" in the area. Commercial development and disease ravaged the area's frog population. The species is now 99 percent extinct, with a few hanging on in highly protected national parks.
Most likely, a combination of the three factors is to blame for amphibian decline. Wake says all three factors contribute to a "witches' brew" that spells almost certain doom for thousands of amphibious species.
Whatever the reason for the decline, scientists appear powerless to stop it.
"When I was a kid, I went down to the stream and caught tadpoles," Wake says. "That's impossible now. You can't raise tadpoles anymore."