D^L wrote: ↑
Mon Dec 03, 2018 12:15 pm
One thing I recall from Nigel Taylor, which I agree with, is that ex-situ conservation has to have a re-introduction strategy. A species without a habitat, separate to a few greenhouses, is "gone" as far as biodiversity is concerned.
Sorry, Dave, but I disagree. A clear counterexample is the Ginkgo tree, which is a much appreciated tree planted across the world. The few populations which are possibly wild are pretty genetically uniform anyway, and it wouldn't matter at all (except sentimentally) if they died out, either to preserving the genes, or to the species continued existence. On the other hand, the Gingko has never become naturalised anywhere, which argues that reintroduction of this tree is unlikely to be successful. However, given that it is only distantly related to any other living plant, it is very important to biodiversity that this plant should continue to exist.
An even better counterexample to reintroduction is given by a succulent: Brighamia insignis. Its pollinator is extinct. Reintroduction clearly cannot work in such a case.
Indeed, reintroduction is often unlikely to be a solution. If a plant is rare in the first place, there are typically underlying reasons, e.g. specialised environmental requirements, it is a poor competitor, etc (even attractiveness to human collectors). In such cases, reintroducing it is only going to leave it vulnerable for the same reasons as before. Yes, there have been some successful reintroductions, but they do not invalidate the general point, and like paying people off, are not necessarily a long term solution.
We need to face up to the fact horticulture may be the best, and indeed only future for some species.