Saturday, 30 December 2017

Endangered Species: Examining the Numbers

How many animals in New Zealand are actually endangered, and how much can poisoning our environment save them? A Facebook friend posted a comment on one of my Facebook posts today citing the sometimes-touted "fact" that 11% of the world's endangered species are endemic to New Zealand. I am skeptical--the world is a big place, and NZ is a small one--so I went looking for some numbers. Here's what I found:

Archie's Frog, an ancient species. Photo from DOC.
The International Union for Conservation of Nature (IUCN) lists 2464 endangered animals worldwide. Of the world's top 100 most endangered species, including plants, on the IUCN red list posted on Wikipedia, only Archie's Frog is endemic to New Zealand. (That would be 1%). But Archie's frog is an odd pick for the Top 100. After an 80% decline in the Archie's Frog population last century, possibly due to disease/fungus, Archie’s frog has now stabilized in three locations and they are also being successfully captive-bred—so is it really one of the world’s top 100 most endangered species? 

NZ's national heritage site lists 2788 endangered species in New Zealand including plants, insects, and fish. The top 10 most endangered animal species in NZ, according to a 2012 Herald article, are Maui's dolphin, the NZ fairy tern, the kakapo, the white heron (noted in the article as "common" in Australia), the black stilt, greater short-tailed bat, Bryde's whale, southern elephant seal, and the NZ sea lion (there are also populations in Australia).

Maui's dolphin, photo from Wikipedia
New Zealand's Endangered Species Foundation (ESF), in conjunction with the NZ Department of Conservation (DOC), compiled their own list of the 10 most threatened New Zealand species. These are the Maui’s dolphin, Canterbury knobbled weevil, Mokohinau stag beetle, quillwort (an aquatic fern), fairy tern, limestone cress, Chesterfield skink, coastal peppercress, eyelash seaweed, and the dune swale Daphne. The ESF claim there are 4000 New Zealand species “in danger of being lost”. Their website gives cost estimates for saving each of the top-10 species, and it's not trivial money; they’re a non-profit organisation raising money for “targeted intervention”.

When you really start looking at the actual lists of endangered species, they’re all over the place. A lot of animals and plants are cited as "possibly extinct", so the "most endangered" list becomes somewhat meaningless as these are rarely included on those lists. These are animals like the Haditha cave fish (only in Iraq--nobody's monitoring at the moment), and Bachman's warbler (US/Cuba).

Public profile matters a lot too. In New Zealand we hear a lot about kiwi being at risk (estimated count around 100,000) and wood pigeons (not threatened, no number available), but not so much about fairy terns (40 individuals) or the Chatham Islands oystercatcher (est. 300 birds) or grey ducks (“nationally critical” but no estimated headcount available and they're legal to hunt). Could the skew be due to a desire to emphasize forest birds over shore/sea birds promotionally because poisoning the forests--ostensibly to kill the feral mammals and “save the birds”--is a big industry in New Zealand? Could it be that easily-recognized, appealing species perceived as at risk are more likely to generate cash donations and government conservation money than weevils and quillwort?

Incidentally, and just as an ironic side note, the IUCN lists the southern bluefin tuna as "critically endangered" (on their "red list"). The NZ commercial annual catch quota of southern bluefin tuna is set at 1000 tonnes; Australia's quota is 5665 tonnes, similar to Japan’s. I guess a "critically endangered" label doesn't seem to count for much if there's money to be made. (Rhino poachers and conservationists in Africa would agree.)

Clearly, these lists and numbers are somewhat arbitrary. For most species, there is no clear idea how many individuals are remaining in the wild. Mostly lists don’t include probable extinctions, and some include plants and animals that are being successfully bred in captivity. Some endangered species, like the tuna and the grey duck, are actively hunted/harvested. Some New Zealand lists of endangered animals include species that are also endemic—and not so endangered--elsewhere, like the white heron and the New Zealand sea lion.

So…does New Zealand really have 11% of the world’s endangered species? I didn't find  11% mentioned anywhere, and I don’t believe that figure for a minute. Can we “save” our most vulnerable species by dropping 1080 or brodificoum poison in our forests? Given most of our endangered species are not forest dwellers, that seems unlikely, even supposing poisoning an animal's or plant's environment is helpful--and that's a pretty big supposition.

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