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Reminds me of Chatham Island black robin conservation efforts that turned out not so good: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0

Reminds me of Chatham Island black robin conservation efforts that turned out not so good: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0079066 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna... Conservation management often focuses on counteracting the adverse effects of human activities on threatened populations. However, conservation measures may unintentionally relax selection by allowing the ‘survival of the not-so-fit’, increasing the risk of fixation of maladaptive traits. Here, we report such a case in the critically-endangered Chatham Island black robin (Petroica traversi) which, in 1980, was reduced to a single breeding pair. Following this bottleneck, some females were observed to lay eggs on the rims of their nests. Rim eggs left in place always failed to hatch. To expedite population recovery, rim eggs were repositioned inside nests, yielding viable hatchlings. Repositioning resulted in rapid growth of the black robin population, but by 1989 over 50% of all females were laying rim eggs. We used an exceptional, species-wide pedigree to consider both recessive and dominant models of inheritance over all plausible founder genotype combinations at a biallelic and possibly sex-linked locus. The pattern of rim laying is best fitted as an autosomal dominant Mendelian trait. Using a phenotype permutation test we could also reject the null hypothesis of non-heritability for this trait in favour of our best-fitting model of heritability. Data collected after intervention ceased shows that the frequency of rim laying has strongly declined, and that this trait is maladaptive. This episode yields an important lesson for conservation biology: fixation of maladaptive traits could render small threatened populations completely dependent on humans for reproduction, irreversibly compromising the long term viability of populations humanity seeks to conserve

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wdewind 12y ago
This sounds like a success story to me, not a failure, despite the unintended consequences. I feel like the stories not finished though. Was the population able to survive without humans going forward? Or has it entirely died? Or something in between?
bayesianhorse 12y ago
I think the lesson should be: If a species is hovering over the brink of extinction, it's a better idea to do whatever it takes and only worry about the consequences later... Of course, if rim-laying had been fixated, the species would still have become extinct...
- shostack 12y ago
  Or perhaps to dig deeper as to WHY they are on the brink of extinction. If they develop a trait that causes them to lay their eggs on the rim (which can be directly linked to the species decline), isn't that just Darwin at work? Who are we to step in an say "yep, they're idiots for doing it, but we should still save them."
  - vanderZwan 12y ago
    That kind of trait doesn't just come out of the blue - there always is some form of selection pressure involved. Most likely caused by us in some way. That's why we need to step in. But yes, ideally at the point that causes this selection pressure to exist in the first place.
  - bayesianhorse 12y ago
    Charles Darwin was a scientist, not a super-natural deity responsible for evolution. He can't be "at work". Extinction events for natural reasons shouldn't be as frequent. Otherwise there would be far fewer species left. Therefore any extinction process we witness, especially with a species starting out with a healthy population, probably isn't natural.
- brownbat 12y ago
  > If a species is hovering over the brink of extinction, it's a better idea to do whatever it takes... With the caveat that some species don't qualify for protection. Variola major, for example, or Plasmodium malariae. I'd even go so far as supporting the complete elimination of Anopheles albimanus and several of its relatives, and I don't think I'm the only one. Not trying to detract from your point, just... this area has a lot of weird wrinkles that are hard to navigate. Radiolab reminded me of that last week, discussing some measures used to preserve the Galapagos: http://www.radiolab.org/story/galapagos/ http://www.radiolab.org/story/galapagos/ It added an addendum, a heartbreaking story about bird preservation, and how difficult it is to preserve species that fare better without human contact in a world now utterly full of humans: http://www.radiolab.org/story/birds/ http://www.radiolab.org/story/birds/
jimworm 12y ago
Natural selection isn't some benevolent deity. Its MO is to drive species to extinction, it's just that when some individuals find a way around it we call that evolution. Without knowing which traits a species "needs", the best conservationists can do is to increase numbers while preserving diversity. The "50% of all females laying rim eggs" is just a reflection of the single breeding pair's genomes. If rim eggs had been discarded, only copies of the "good" genes could have been tossed along with those eggs, and "bad" genes inadvertently selected by virtue of not being linked to the rim egg gene - which was exactly how the rim egg gene itself came to be in the last breeding pair. Increasing numbers while preserving diversity will give the bottlenecked gene pool a chance to mix into as many combinations as possible before being released back into the wild, without natural selection driving the species to extinction. It doesn't always work, but if it doesn't work the species was done for regardless of our efforts.

deleted 12y ago

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wdewind 12y ago

This sounds like a success story to me, not a failure, despite the unintended consequences. I feel like the stories not finished though. Was the population able to survive without humans going forward? Or has it entirely died? Or something in between?

bayesianhorse 12y ago

I think the lesson should be: If a species is hovering over the brink of extinction, it's a better idea to do whatever it takes and only worry about the consequences later... Of course, if rim-laying had been fixated, the species would still have become extinct...

shostack 12y ago
Or perhaps to dig deeper as to WHY they are on the brink of extinction. If they develop a trait that causes them to lay their eggs on the rim (which can be directly linked to the species decline), isn't that just Darwin at work? Who are we to step in an say "yep, they're idiots for doing it, but we should still save them."
- vanderZwan 12y ago
  That kind of trait doesn't just come out of the blue - there always is some form of selection pressure involved. Most likely caused by us in some way. That's why we need to step in. But yes, ideally at the point that causes this selection pressure to exist in the first place.
- bayesianhorse 12y ago
  Charles Darwin was a scientist, not a super-natural deity responsible for evolution. He can't be "at work". Extinction events for natural reasons shouldn't be as frequent. Otherwise there would be far fewer species left. Therefore any extinction process we witness, especially with a species starting out with a healthy population, probably isn't natural.
brownbat 12y ago
> If a species is hovering over the brink of extinction, it's a better idea to do whatever it takes... With the caveat that some species don't qualify for protection. Variola major, for example, or Plasmodium malariae. I'd even go so far as supporting the complete elimination of Anopheles albimanus and several of its relatives, and I don't think I'm the only one. Not trying to detract from your point, just... this area has a lot of weird wrinkles that are hard to navigate. Radiolab reminded me of that last week, discussing some measures used to preserve the Galapagos: http://www.radiolab.org/story/galapagos/ http://www.radiolab.org/story/galapagos/ It added an addendum, a heartbreaking story about bird preservation, and how difficult it is to preserve species that fare better without human contact in a world now utterly full of humans: http://www.radiolab.org/story/birds/ http://www.radiolab.org/story/birds/

jimworm 12y ago

Natural selection isn't some benevolent deity. Its MO is to drive species to extinction, it's just that when some individuals find a way around it we call that evolution. Without knowing which traits a species "needs", the best conservationists can do is to increase numbers while preserving diversity. The "50% of all females laying rim eggs" is just a reflection of the single breeding pair's genomes. If rim eggs had been discarded, only copies of the "good" genes could have been tossed along with those eggs, and "bad" genes inadvertently selected by virtue of not being linked to the rim egg gene - which was exactly how the rim egg gene itself came to be in the last breeding pair. Increasing numbers while preserving diversity will give the bottlenecked gene pool a chance to mix into as many combinations as possible before being released back into the wild, without natural selection driving the species to extinction. It doesn't always work, but if it doesn't work the species was done for regardless of our efforts.