So? Who cares that it has fewer species than tropical ecosystems? An
ecosystem has just as many species as it can support. Compared to other temperate
freshwater systems, the Mississippi Basin is the most diverse in the world. Its
species are unique. When glaciers covered the northern part of the
continent, it was the mighty Mississippi that served as a refugium and major center of
fish evolution. Indeed, the Mississippi is the "mother" of North American
fish diversity.
I think i will have to disagree, glaciers had a very limiting effect on the
fish diversity in the Mississippi. yes, eventually in millions of years you
might get something approaching the number of niches occupied in the
Mississippi that you have in the amazon but you have to remember the
Amazon was-in-one time connected with Africa and so had a bigger pool of
both diversity and disparity to draw from than the Mississippi will ever have.
Michael Hissom
aurea mediocritas
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