We ecologists define the niche. We can stick with the Hutchinsonian definition, or we can modify it in ways we might find more useful.
Niches, empty or not, are not fixed. If there is a lot of breadth, then organisms will tend to partition the "hyperspace" among themselves. Consider David Lack's warblers, who ended up occupying the same trees but at different heights above the ground. I think he identified three species. I suspect that if the trees were shorter he might have found just two, and if they were taller, more than three. The concepts of niche and speciation are complicated and we are still working on them. To do so effectively, we should try to free ourselves from rigid definitions, although of course we always have to be clear what we mean. The reason I like the term "empty niche" is not that I am against Hutchinson and his disciples, but because it is a useful concept. If we reject it, and insist instead on circumlocutions like "potential resource manifold in hyperspace not currently fully exploited by any species" then it interferes with our doing science. Bill Silvert ----- Original Message ----- From: "Warren W. Aney" <[EMAIL PROTECTED]> To: "William Silvert" <[EMAIL PROTECTED]>; <[email protected]> Sent: Friday, November 23, 2007 6:18 PM Subject: RE: "unoccupied" niches and 'competitive exclusion" > Does the species define the niche? Or (in evolutionary terms) does the > niche > define the species? David seems to be saying that the species defines the > niche and Bill seems to be arguing that the niche exists independent of > the > species filling it. Did Darwin's Galapagos finches evolve to fit > pre-existing niches, or did they define the niche as they evolved?
