Bermuda is a small island far off the coast of the US. It is only about 20mi2 and has a tropical climate (you may think it is redundant to state that it's climate is tropical, however, this is not a trivial fact when it comes to discussing the marine algal species present). Dr. Schneider's talk was a summary of many years of work, spread out over several publications that have compared an initial report of all marine algal taxa present on the island (published in the 1920's) to a modern-day analysis of the taxa present.
First the unimpressive news: After sampling and sampling and sampling for many years in Bermuda, the algal species richness has not changed a whole lot from the 1920's to modern day. There were only about 20 new species added to the list. You would think there would have been more since overall lots of new algal species have been added to the roster and the methods for identifying them have gotten better. But no, just a handful of new ones.
Now for the impressive news: On the initial species roster, over 80 of the algal taxa listed were species that had been initially described in countries like England, Scotland, Norway, Denmark, etc. Doesn't that set a flag off in your head? Why would an algal species from frickin' freezing Norway be happy in warm, sunny Bermuda? And aren't all those places REALLY far away from Bermuda? Island Biogeography says that mainland species can come to inhabit islands, but doesn't 3371 mi seem really far, even for Island Biogeography? And this is exactly the sort of thoughts that Dr. Schneider had. So when he and his team looked at the algal species they collected with their modern day keys and microscopes and DNA barcoding rosters, this is exactly the sort of thing they found. These species are not the species they claim to be. So who are they? Where are they more likely to be from? If you answered that they're probably from somewhere closer and warmer, you'd be right! A lot of the species found at Bermuda were in fact from closer places like Jamaica (1253 mi), Mexico, Florida, Georgia, and South America. Over 100 species were re-identified to be different species from these tropical locations. So while the total species richness didn't change a whole lot, the identities of those species changed quite drastically.
In other interesting news, there is the matter of obvious species. An obvious species is one that is big and/or everywhere and you've put any effort at all into sampling, you'll have seen it. Trouble is, this new survey missed some of the really obvious species that the 1920's list indicated were there. And the new list indicates some obvious species the 1920's list didn't find at all....what's going on here? While re-naming things that were previously labeled incorrectly isn't really a shift in community composition, this is! And a shift in composition is something you'd expect after an island has been isolated for a long time. I think this is where that graph from E.O. Wilson comes in handy....
So we went from a list created by Europeans in the 1920's who identified these tropical algal taxa based on the temperate species they were more familiar with, to a whole new species list comprised of taxa from other tropical mainlands, a changing of the guard of obvious species, and some new ones. Those are some big changes. But if you just looked at richness? Meh...not too much going on. I guess we'll have to leave Dr. Schneider to continue his dreary work in Bermuda, continuing to catalog the algal species composition of that far-off island!
http://www.trincoll.edu/~cschneid/bermuda.html
Craig W. Schneider – An assessment of the island biogeography theory using a century of floristics in Bermuda—immigration and extirpation or simply systematics? 49th Northeast Algal Society Meeting. April 16-18, 2010.
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