species-area curves

[Michael Gochfeld]

I missed the first part of this thread, but there is a phenomenon of a
species area curve, which predicts that the number of species added to
"the list" as you increase the area of coverage, plateaus after a
while.  This has been useful for sampling on a relatively homogeneous
mesoscale (acres, square miles), but it probably applies on the
mega-scale of continents as well Thus even if history had added another
few million square miles to our land scape (if sea level chose to fall
rather than rise) would add disproportionately few new species to the
NAmerican list. Of course it depends on whether the new land had accrued
in the Arctic or tropics. 

If we expanded the definition of "Europe" to an area of Eurasia and
North Africa (often called the western Palearctic) would the species
list reach the same as ours. 

M Gochfeld


"Kondla, Norbert FOR:EX" wrote:
> 
> Well, parts of two continents anyway. For whatever, reason my mind recently
> turned to a quick and crude comparison of Europe as defined in Higgins and
> Riley's field guide to butterflies and then the North American countries of
> Canada and USA. This said crude comparison reveals that Can and USA is
> roughly at least 3 times the size of europe, has a greater latitudinal and
> longitudinal spread and seemingly more environmental diversity as a place
> for butterflies to evolve. Yet, for some reason we only seem to recognize
> about 1.5 times as many butterfly species as in europe. Geographers and
> mathematicians are welcome to fiddle with the crude numbers above but I am
> wondering if the species per area difference is real or if it is a
> reflection of our relatively more primitive knowledge of the taxonomy of NA
> butterflies and history of lumping different looking butterflies into the
> same species. Thoughts are welcomed, and so too would be any literature
> references in the biogeography realm or from other taxonomic groups of
> organisms in case other people have wondered about this.
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Norbert Kondla  P.Biol., RPBio.
> Ministry of Sustainable Resource Management
> 845 Columbia Avenue, Castlegar, British Columbia V1N 1H3
> Phone 250-365-8610
> Mailto:Norbert.Kondla at gems3.gov.bc.ca
> http://www.env.gov.bc.ca
> 
> 
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