Peter O'Byrne wrote: >Or the species didn't exist before 1066, and it's precursor has > speciated over the last ~ 900 years by adapting to an environment with > rabbits.
Good point. It would certainly be ironic if an endemic species was completely dependent on an exotic, invasive species for its continued existence. However, the news reports mention that Epipactis sancta is closely related to the dune helleborine, Epipactis dunensis, which inhabits very similar sandy habitats elsewhere in the UK. There are also other endemic species that are found in U.K. dunes. I have a hard time believing that all these species evolved since the introduction of rabbits. Since dunes are by nature dynamic, with older dunes becoming grassy as new dunes are forming, I have a suspicion that the Lindisfarne helleborine is adapted to colonize new dunes as the older ones become choked with grass. Aren't there other orchids that are adapted to disturbed or ephemeral habitats? The helleborine may well thrive when rabbits alter the landscape, but that's not the same as being dependent on rabbits. On the other hand, perhaps Lindisfarne didn't contain any suitable habitat until rabbits moved in. Presumably one could analyse rapidly evolving regions of the helleborine's genome and come up with an estimate of the time since it diverged from Epipactis dunensis. Nick -- Nicholas Plummer [EMAIL PROTECTED] _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
