How many times have we heard the (para-) phrase: “It’s simply impractical to bring populations of critically endangered species up into the thousands”?
Well, my friends, if you’re not talking thousands, you’re wasting everyone’s time and money. You are essentially managing for extinction.
Ouch.
Thanks for the coverage, Luigi.
I did NOT want to see this.
Of course, they are NOT talking about “adult specimens” in the sense of plants: adult specimens of e.g. felines can be assumed to differ genetically from each other at least a bit (Cheetahs being a BAD example)(and you must include both genders), but didn’t they find that all the specimens of Cosmos atrosanguineus in cultivation are the same self-incompatible clone, despite the digging that has apparently extirpated it in the wild?
Clones can also be different in their degree of heterozygosity as well as in their relatedness: if you were optimally choosing the specimens for your “Ark,” you would want as much genetic diversity as possible, with choosing specimens from all over the natural range being a practical approximation. So the “magic number” depends on how the specimen clones were chosen, and the genetic nature of the population they were chosen from. This is also part of the problem with “Ex-Situ” efforts: it’s all to easy to select for greenhouse adaptation, aesthetic appeal, etc instead of retaining diversity.
Also, obviously, the “magic number” is not a discrete cut-off: I’m pretty sure it represents the calculated population size at which some criterion like “likely to survive for 1000 years” falls below a threshold like “20%”
I hope the real numbers for plants are lower than this report implies, just as I hope that some of the plants thought to be extirpated still persist in refugia somewhere. I guess that makes me an optimist?
purpurea