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Wednesday, November 13

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Contemporary mass extinctions?

In 2008, my close colleagues, herpetologists David Wake and Vance Vredenburg, used the amphibian crisis to support their invocation of the term the Sixth Mass Extinction. Immediately, I was worried that my friends would be seen as exaggerating, even if I agreed with their argument entirely. Quite the opposite, their phrase was adopted into the vernacular of contemporary conservationists, as has the term Anthropocene—geological epochs, however, require strict geological evidence in order to earn a formal destination, and it’s my understanding that such research is still underway.  Nevertheless, both terms are now used popularly.  But, let’s take a moment to reflect upon what we really are talking about here.

A mass extinction can be loosely defined as a large number of species becoming extinct in a short about of time. We can quibble about what constitutes a “large number of species” and a “short amount of time,” but in retrospect, experts agree on it when they see it. No one argues that the disappearance of dinosaurs and so many other animals of the Cretaceous period was a mass extinction event. My years in the trenches of amphibian conservation saw too many academic arguments in the early years, as some of our colleagues said we lacked the data to declare any amphibian emergency. In retrospect, those unfortunate arguments were valid, but also terribly naïve. The fact of the matter simply was that, while our colleagues in paleontology can identify mass extinctions in history, no modern scientist had any idea how to recognize the onset of a mass extinction. I wrote up some of my feelings on that reality, in a piece about the Rabbs’ fringe-limbed tree frog (linked below). Scientists and conservationists have moved on now and the debates now seem to focus not on “if” a group is experiencing mass extinctions, and less disagreements on the “why” and “how,” but more on the realities of the extent of the problem.

I was prompted to write this blog posting because of the results published recently on the loss of birds. I’ve linked below a thorough review from my favorite science writer, Ed Yong. I’m so happy to report that Zoo Atlanta, through its Mabel Dorn Reeder Conservation Fund, supports two relevant projects to help us monitor and protect native birds. One project has us collaborating with our local Audubon Society’s Project Safe Flight on creating bird-friendly programs to combat the reality of bird collisions with human objects.  The other adds Zoo Atlanta as the only automated Motus monitoring station in the southeastern U.S. for migrating birds. This program is in partnership with Bird Studies Canada. Watch for developments at the Zoo soon on both of these important projects. Kudos to Zoo team members Monica Halpin, Taylor Rubin and Gabe Andrle for leading these successful grant proposals.

We’ve discussed amphibians and their diseases numerous times on this blog. Now it’s birds. Two years ago, I wrote a post about devastating effects of diseases in bats, snakes and starfish. Along the way, I think I neglected to cover what likely is the most alarming of all these recent reports.  Declines in insects: https://www.theguardian.com/environment/2019/feb/10/plummeting-insect-numbers-threaten-collapse-of-nature.

For years, I heard people lament to me about the loss of wonderful frog calls around their properties. Now, I want everyone to stop and compare for a moment your memories of fireflies and junebugs to what you’ve seen in recent years. Ladybird beetles or praying mantis? Environmentally friendlier LED bulbs do tend to attract fewer insects at night, but I see virtually no moths, etc. on my lights at night. Over the summer, I was fortunate to be invited to be a guest-lecturer on a Georgia Tech “Tropical Ecology” course in Costa Rica. I was in pure lowland rainforest, with students, every day and night for a week. I did not get a single mosquito bite, not even in swamps. I don’t like mosquitoes either, but that struck me as a terrible reality. What are my beloved frogs to eat?

Links:

Ed Yong, on the situation of birds:  https://www.theatlantic.com/science/archive/2019/09/america-has-lost-quarter-its-birds-fifty-years/598318/

Atlanta Audubon Society Project Safe Flight: https://www.atlantaaudubon.org/project-safe-flight-atlanta.html

Bird Studies Canada: https://www.birdscanada.org/research/motus/

My blog post from April 2019 on our new work on global amphibians: https://www.sciencedaily.com/releases/2019/03/190328150806.htm

My blog post from November 2017 on wildlife diseases: https://zooatlanta.org/exotic-pathogens-native-wildlife-land-sea/

An article I wrote, reflecting on my own realizations of the amphibian crisis: https://amphibiaweb.org/refs/pdfs/Mendelson_2011_HerpReview.pdf

David Wake & Vance Vredenburg “Are we in the midst of the sixth mass extinction? A view from the world of amphibians”  https://www.pnas.org/content/105/Supplement_1/11466

Joe Mendelson, PhD
Director of Research

Connect With Your Wild Side #onlyzooatl