February 27, 2012

A Grim Future For Amphibians

As I mentioned in my last post, on February 2 the mountain yellow-legged frog was listed under the California Endangered Species Act. I'm in the process of researching how this listing will affect the management of the frog and its habitat. In the mean time, I thought I'd share a recent story published in Scientific American that serves as a grim reminder of the dire circumstances that amphibians face today. You can view the story here. Let's hope that we can avoid a similar situation with the mountain yellow-legged frog. 
Back to The Mountain Yellow-legged Frog Site.


  1. Hi Ron, I was wondering if you saw this article: http://westernminingalliance.org/?p=1048 ? It talks about where estrogens from contraceptives are released from water treatment plants and even at untrackable levels, it affects the reproductive cycle of frogs. I guess the male frogs loose their "spunk" and aren't interested in mating.


    Have you looked into this at all?

  2. I read the article that you refer to when it was published a couple of weeks ago. It is interesting research but is unlikely to apply to mountain yellow-legged frogs. Most mountain yellow-legged frog habitat is upstream of water treatment plants and so should not be affected by such contaminants.

  3. So, I guess the frogs stay for their whole lives in the area where they were born? I know nothing about frogs, so I guess they don't "migrate" anywhere? What happens in the winter time with the frogs, where do they seek shelter (in the water or on the water's edge)? Especially if it is a big flood year like 1997? Do they get swept away? Or do they instinctively seek higher ground to keep from being swept away.

    Do you have any info on how frogs winter over, typically? Just curious. I never really thought about that before.

    Cool creatures, I can see why you would want to be an expert on them.

  4. As a side note to the previous question, could the effects of estrogen be affecting the frogs DOWNSTREAM (Foothill YLF) from the waste water treatment plants. Also have there been any studies on leeching of contraceptives from septic tanks? As septic tanks (especially old ones) are all over the place in EVERY watershed.

  5. Mountain yellow-legged frogs spend their lives in a relatively small "home range", typically a single lake or short reach of stream. They overwinter underwater, typically in a rock crevice, where they spend months just sitting. In stream habitats, they would certainly be prone to being swept away during large winter floods. Foothill yellow-legged frogs move much more than do mountain yellow-leggeds. They tend to breed in main stem rivers and then migrate back up into smaller tributary streams for the rest of the year. I don't know of any studies looking septic tank leachate, but agree that someone should. The results could be quite interesting.

  6. In your opinion, what environmental factors do you think have the greatest effect on the Mountain YLF? Has anyone done any studies on the atmospheric pollution and it's effect? And an newer, uncharted effect may be fallout from Fukashima- and maybe not in a direct sense, but the tainted water in the Pacific as source for the clouds bringing rain in.

    I guess we are just one big petri dish and as newer factors get added, the environment adapts or it doesn't.

  7. After two or more decades of research, it is clear that fish introductions and disease are the two major stressors impacting mountain yellow-legged frogs. There have been numerous studies on the effects of airborne contaminants, but the results remain equivocal. These factors and others are described in detail at www.mylfrog.info.