Amphibian Week Day 4

May 6, 2021 • 2:15 pm

by Greg Mayer

The theme of today’s post is threats to amphibians.

In the above graphic, “41%” of amphibians are threatened”, may seem improbably precise, since threatened species are usually identified by the realization that some species is under threat, which then gets the species added to the IUCN’s Red List, an authoritative compilation. But the Zoological Society of London‘s Institute of Zoology has for a decade been implementing a “Sampled Red List Index“, which, instead of seeking out threatened species, assesses a large, random, sample of an entire higher taxon, thus giving a valid estimate of the proportion threatened. (I worked on the reptile SRLI, which assessed 1500 species).

One major threat to amphibians has been the global spread of the chytrid fungus, Batrachochytrium dendrobatidis, which infects amphibians and can wipe out whole populations and species. Chris Petersen, of Department of Defense Partners in Amphibian and Reptile Conservation, sent me links to the following reports on surveys and assessments that have been conducted concerning the chytrid threat to amphibians inhabiting military lands.

Report 1: Do Frogs Get Their Kicks on Route 66?

Report 2: From the Mountains to the Prairies Seasonal Bd Responses Differ by Latitude and Longitude at a Continental Scale

Report 3: Salamander Chytrid Fungus Risk Assessment on Department of Defense Installations

I especially liked the first survey, a transcontinental transect study from California to Virginia; it found chytrid at all but one location.

Figure 1 from Petersen et al. (2011).

This and the second study were coauthored by, among others, my colleagues Rob Lovich and Mike Lannoo; Rob has previously treated WEIT readers to World Snake Day, and Mike has authored or coauthored several major works on amphibian conservation, including the monumental Amphibian Declines: The Conservation of United States Species. (The titles of these two reports also show the authors’ knowledge of song lyrics!)

We’ll finish off today’s installment with the non threatened Wood Frog (Rana sylvatica), which is widespread in North America. A northern species, a number of relict populations have survived in mountains south of the main range, left behind as the species followed the retreating glaciers north. This fellow’s from the main range in northern Minnesota, near Lake Superior.

Wood frog, Lutsen, near Lake Superior, Minnesota, 6 June 2014.

h/t C. Petersen, G. Wood

Böhm, M., B. Collen, … G.C. Mayer… et al. 2013. The conservation status of the world’s reptiles. Biological Conservation 157:372-385. pdf(MS)

Lannoo, M.J., ed. 2005. Amphibian Declines: The Conservation of United States Species. University of California Press, Berkeley. publisher

Petersen, C., R.E. Lovich, M.J. Lannoo, and P. Nanjappa. 2011. Do Frogs Still Get Their Kicks on Route 66? A Transcontinental Transect for Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) Infection on U.S. Department of Defense Installations. Proj. No. 09-246, Department of Defense Legacy Resource Management Program. pdf

Petersen, C., R.E. Lovich, C. Philips, M. Dreslik, P. Nanjappa, and M.J. Lannoo. 2013. From the Mountains to the Prairies—Seasonal Bd Responses Differ by Latitude and Longitude at a Continental Scale. Proj. No. 10-426, Department of Defense Legacy Resource Management Program. pdf

Petersen, C., K.L.D. Richgels, G. Lockhart, and R.E. Lovich. 2019. Salamander Chytrid Fungus Risk Assessment on Department of Defense Installations. Department of Defense Legacy Resource Management Program. pdf

10 thoughts on “Amphibian Week Day 4

  1. I love the Greg posts – always so well referenced!

    I think there should be a book of The Best of Weit…

    1. How would PCC(E) decide on “the best”?
      – Comment count?
      – Average comment length (so the “sub” comments barely show)?
      – Length of time between first and last comment? (That’s going to need some manipulation – recent posts have a shorter window than older posts.)

      1. I was thinking biology posts. Based on whatever. I prefer books to on screen reading.

        Anyway, if you total up the wordage, he is as prolific as a Trollope I reckon! 🤓

        1. Someone, somewhere, is probably running a Twitter (InstaPin, FacePage, WhatEver) account as Trollope, endlessly complaiing about how keeping up with social media leaves him too little time to churn out the thousand-page bodice-rippers.
          I may be mischaracterising Trollpop. They may be two-thousand page bodice-rippers.

  2. Thanks for this post. The intricacy of species decline is difficult to comprehend.

  3. It’s difficult to grasp the severity of amphibian decline for us non-scientists. Even if taking into account the effects of a moving baseline, how many regular people pay attention? I FEEL like I see fewer frogs than I used to but without data for where I grew up, it’s nothing more than just a feeling. Same for insects. Unfortunately, since people like Greg ARE paying attention and ARE collecting the data, my feelings are confirmed. To misquote Pete Seeger, where have all the frogs and insects gone?
    Where I grew up the water is cleaner, mostly, but the woods have been bulldozed, fields are full of houses, roads cutting through everything, and everyone is mowing, spraying, and chainsawing everything into oblivion. Of course, habitat destruction isn’t OUR problem, it’s only happening in the rainforest, right? Our sterile lawns and new strip malls and parking lots could never be a problem, right?

    1. As such declines are gradual it is hard to relate that to people who see their youth as a baseline. The decline of birds in the countryside is huge since I was a child.

      The lapwings – where are they???

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