Thursday, December 27, 2018

The Species That Went Extinct in 2018

    Since 2012 I have gathered in one place a list of all the animals that went extinct in the previous year. Click here for the 20172016201520142013, and 2012 editions. I started this series because I didn't know of anybody else summarizing this kind of important information. Interestingly, now I keep getting e-mails from people that found one of my lists and want to know if I know of a website that compiles lists of species that have recently gone extinct. Yes there is; you are reading it.

Let's get into it.

All the animals thought to be European Wildcats (Felis silvestrus) in Scotland appear to have domestic cat genes (due to interbreeding). So, although they still fill the same niche, the pure wild animal (a subspecies) is probably gone.

Photo: Justin Shoemaker
Breeding populations of cougars in the northeastern United States probably blinked out in the first half of the 20th Century, long before the Endangered Species Act even existed. But, this year the U.S. Fish and Wildlife Service felt confident saying that what we considered the eastern subspecies is extinct, and therefore should be taken off the list of endangered species (the Florida panther is considered a separate subspecies). The eastern subspecies may be gone but who knows, there is limited compelling genetic evidence to say we should break this species up into different subspecies, and western cougars are slowly making their way back east.

It is hard to know when a species is gone or just rare and hard to find. So, scientists sometimes employ statistical analyses that incorporate how often a species used to be found, the last time they were seen, and an assessment of conservation threats to estimate whether they are likely to be extinct now. Alex Bond gave me a heads-up that this year a group of scientists used these methods to conclude that cryptic treehunter (Cichlocolaptes mazarbarnetti), Alagoas foliage-gleaner (Philydor novaesi, both forest dwellers of Brazil), and poo-uli (Melamprosops phaeosoma, a Hawaiian honeycreeper) are now extinct.

After this blog was posted, John Platt at The Revelator tipped me off about a few notable extinctions that I missed.We knew that Macclear's Rat (Rattus macleari) from Christmas Island went extinct over a century ago. But, a study published this year says we lost a flea at the same time. The Christmas Island Flea was so closely linked to this species of rat, that it could not exist with its host.

John also tipped me off about the Ozark Pyrg, a snail from Arkansas and Missouri. None have been found since 1915 and the US Fish and Wildlife Service said they're probably extinct, so they're not going to get protection under the Endangered Species Act.

There was not a lot of wildlife extinction news this year. That's good news! But it leaves without much to talk about. So, let's highlight some plants.

John Platt writes a eulogy for Adenocarpus faurei, declared extinct after five years of fruitless searches, "this yellow-flowering shrub was native to the Oued Sidi Khaled valleys of northern Algeria, where it lived at altitudes of around 3,600 feet. It was first described scientifically in 1926 — which, coincidentally, was the last time it was ever officially seen."

John also pointed out to me that a similar fate has been experienced by Vepris bali, a rare tree from Cameroon. Scientists describe the species and announce it is probably extinct in the same scientific study.

Goodbye Amaranthus brownii, a Hawaiian herb that was last seen in 1983. This plant took a major hit from introduced grasshoppers, and inbreeding was a problem for the few plants left.


Photo Courtesy: Turtle Survival Alliance.
Things to watch in 2019. I expect caribou are about to vanish from the lower 48. There may only be four Yangtze Giant Softshells (Rafetus swinhoei) left in the world. This year the last male Northern White Rhinoceros (a subspecies) died at age 45; there are two females left: his daughter and granddaughter.
Simply listing the species that went extinct in a given year is surprisingly tricky. Here are my answers to some commonly asked questions.

1. Just because we are always discovering "new" species doesn't mean we are offsetting extinctions somehow. When we discover a new species it is not actually new to Earth, it is just new to us. In other words, a new life form was not just created, we just happened to learn about it. There is a limited pool of species and the total number of species is decreasing. Evolution leads to the creation of new species but not on a time scale that is relevant to this conversation.


2. Human beings are one of the species on Earth. I do not feel that this means that anything and everything we do is natural and therefore okay, even if it means causing species to go extinct. Other species have value and we should act accordingly to keep them around. With great power comes great responsibility.


3. In my list I include species that went extinct in a globally significant region even if the species might still exist somewhere else. I think these local extinctions (called extirpations) are important. You might decide not to include them in your list of extinctions.


4. I include in my list species that went extinct in the wild, even if some individuals may still exist in captivity. See above.


5. It is often impossible to know when a species went biologically extinct. That is, there is often no way of knowing when the last individual of a given species dies. So, I often include in my list species that were declared extinct, this official designation often occurs many years after the last actual death. Again, you may not include them in your list of extinctions, but I do.


6. It is not unusual to "rediscover" a species that we thought was extinct. That is always great news. But, they are usually still critically endangered and often "really" go extinct afterwards.

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