March 16, 2009

Anybody Have a Spare Pond?

The ongoing severe declines of mountain yellow-legged frogs in the Sierra Nevada make it all but inevitable that these populations will eventually be listed under the federal Endangered Species Act. Such a listing will trigger the writing of recovery plans for Rana sierrae and Rana muscosa, plans that will undoubtedly call for the development of captive breeding programs. If successful such programs could provide frogs for reintroductions back into the wild and for experiments that are critical to our understanding of important issues related to frog conservation.

As I've discussed in previous posts captive breeding has an increasingly important role to play in species conservation programs but because maintaining frogs in artificial environments (e.g., indoor aquaria in zoos) is very labor intensive (think of the time required to feed 100 frogs every day, change their water, and clean their enclosures), this gets expensive in a hurry. A cheaper and potentially more productive route would be to hold frogs in natural or semi-natural ponds outdoors. This would greatly reduce the resources needed to maintain these populations because the frogs could feed themselves. All we need are some ponds that would provide suitable habitat for mountain yellow-legged frogs. Ideal ponds would be located at elevations above 6000', be deep enough to allow frogs to overwinter (>10 feet), and have reasonable access. Ponds would also need to be surrounded with a frog-proof barrier to ensure that frogs don't wander off.

If we can't locate such ponds we need to consider constructing them. As I write this I'm staring out the window at my back yard, wondering if maybe we could replace that useless lawn with a frog pond. But seriously, we need to engage any interested agency or member of the public and provide the resources necessary to make this happen. Might there be a national forest ranger district out there with a pond near a district office that could be turned into a frog pond? Are there any private landowners who might be willing to have one of their ponds put to such a use?

If any of you readers have any ideas I'd love to hear them.

Back to The Mountain Yellow-legged Frog Site.


  1. I love your idea about finding "spare ponds."

    Years ago I tried to "raise" a few small toads I'd discovered on my doorstep in North Carolina. Trying to find enough small insects for them was a full-time job! Concerned they'd starve, I let them go—to find their own food!

    So you are right. The effort and expense involved in attempting to recreate what nature does... naturally... is huge.

    Your idea—to use ponds already settled into the countryside—is a great idea. I wish I had a spare pond. Alas, now in Maryland, we have no ponds and do have... cats.

    However, I can report that in Patapsco State Park the frog and toad populations appear to be healthy.



  2. Does this assume the ponds have to be fungus free?


  3. Ideally ponds would be chytrid-free, but I don't think we can assume that any habitats are chytrid-free these days. If frogs in the ponds became infected with chytrid we could at least easily treat frogs to clear them of the chytrid before the infection caused frog mortality.

  4. I hope i'm not being a pest, but if we can treat a pond for the fungus, why cant we treat a lake? If DFG can drop fish in a lake, can't they just as well drop treatments into an infected lake?

    Just curious,


  5. We can treat frogs to clear them of Batrachochytrium but we cannot treat entire ponds or lakes. The drugs used to clear Batrachochytrium are anti-fungal in their action and kill all fungi. The vast majority of fungi are not pathogenic and play important roles in lake ecosystems as decomposers. So we wouldn't want to wipe out all the whole fungal community in our attempt to rid habitats of the chytrid fungus. We have to accept that Batrachochytrium is here to stay. Therefore the only hope for the long-term persistence of frogs is evolution between frogs and Batrachochytrium. My hope is that we can keep frogs on the landscape long enough (through various conservation measures) for Batrachochytrium to evolve lower virulence (this is the expected course of evolution in this case because it would hardly be adaptive for Batrachochytrium to wipe out its host) and frogs to evolve greater resistance.

  6. [ Saw this today... Cat ]

    Mar 25: Frogs, Salamanders, & Vernal Pools in your Backyard

    Wednesday, March 25, 2009, 7pm National Zoo Conservation & Research Center, Conservation Dr & Research Dr, Front Royal, VA 22630

    The Appalachian Mountains are a hot spot for amphibians, being home to more salamanders than anywhere else in the world. This means that your own backyard could be vital habitatfor a group of species (frogs and salamanders) that are rapidly disappearing world-wide. Vernal pools are fishless and seasonal sources of water, which are essential to amphibian reproduction. As spring blossoms and choruses of peeping frogs fill the night air, Matt Evans, herpetologist and biologist from the Smithsonian's National Zoo, will discuss ways that you can help protect amphibians and their habitats. Admission is free.

    Please contact the Conservation Research Center with questions at 540-635-6540.

  7. Just found this after seeing your incredible work on PBS last night. We have a 1-acre pond at 3,100 feet in the Sierra on a seasonal snowmelt creek, just outside of Mariposa and ~ 7 miles from Yosemite as the frog hops. We've been wanting to reintroduce the native frogs, such as the yellow-leggers. Not your ideal venue, and we couldn't really do frog barriers, but we'd sure try and keep them alive and happy via habitat and food-source cultivation. We do have some bullfrogs and bass though (along with many toads and tree frogs). Is there a place where we can get Cal natives to introduce w/o taking them out of the wild?

  8. Thanks for the post, RandomTruth. Based on the photos of the pond on your blog this could be great habitat for California red-legged frogs. That would only be the case if the pond is fishless and lacks crayfish and bullfrogs. Keeping bullfrogs out would likely take some vigilance on your part. If you are interested in pursuing this further, send me an email.