I realize that this interesting thread (which I have mostly just = skimmed) has been largely in search of hard data on = extinctions/extirpations.
But for the longer-term view, I keep thinking of that paper (I'm sure = someone can supply the reference) that somehow used species-area curves = for different-sized portions of the globe in order to suggest what the = planet's ultimate species richness would be if species' distributions = were homogenized so that "everything occurs everywhere". The prediction = was, of course, shocking. A major reason that global species richness is = as high as it is, is that different species occur in different areas. While we can debate the quality of evidence, and it is certainly = worthwhile to study the mechanisms involved, does anyone doubt that the = truly long-term result of the continued spread of exotics will be many = extinctions? Dave Whitacre
