Pheonix, "designer ecosystems", and new selection pressures

Thought this might be interesting. Several of you ecologists have probably heard of this, but I just found out.On livescience.com today, they had an article on how Pheonix was changing the local ecosystem. Just recently, there was one on how New York City is doing the same, and it's though that almost all of the major cities are affecting the ecosystem, creating waht some call "designer ecosystems".Pheonix is the interesting case--the animals and plants starting to live around Pheonix are new to the area, or at least several are. ANd this is a new ecosystem, the effect beginning with the post-WWII buildup of suburbs. What I'm wondering is this:Populations change relatively little in an environment that they are well adapted to. However, the ecosystem is in te process of radically changing in Pheonix. I'm wondering--are we building an evolution factory by changing the selection pressures?

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All a man's knowledge comes from his experiences

Thread moved here from the Proposed New Topics forum.

When I lived in Phoenix in the mid sixties that was a big issue.

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Aslan is not a Tame Lion

Yes, we are.Do we consider this some kind of 'un-natural' selection evolution, natural selection evolution, or neither?Edited by Catholic Scientist, : changes evolution to selection

For those who don't get the reference, the article in question is: The New Nature: Cities as Designer Ecosystems. Not necessarily. Although speciation could be increased by the new developments (you can get snails speciating with a new two-lane country road), the organisms moving into the cities are those which are mostly already adapted to urban environments. Those "native" species that find urban areas conducive (like coyotes) are often opportunistic generalists (what some of my friends call "tramp" or "weed" species - rather unfairly, IMO).We're not likely to see "evolution" per se, primarily because the new selection pressures acting on existing species operate at a vastly more rapid rate than natural selection writ large. What we see when "natural" landscapes are turned into urban landscapes is massive local population extinction or habitat tracking as native species are squeezed out or move away. Except, of course, for the opportunists. In other words, we see mostly ecological turnover, not evolution.

Apparently it pays to have an ecology degree.However, what happens to the original (I daren't say endemic, though there might be some) species? I would guess that as Pheonix expands, we're going to put pressure on those species, not only by changing the local environment, but also by adding better-adapted species.Just re-read your post, and noticed the last statement--the whole turnover thing. Guess that answers my question.

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All a man's knowledge comes from his experiences