Ecolog: There is such a fundamental and pervasive misunderstanding of this point that to challenge the ecoillogical concept of "pristine" is broadly considered treasonous heresy. Freezing ecosystems in time has strong roots in the presumption that gardening and landscaping are related to ecology. I tried to make this point at a 1986 meeting (in Berkeley?) called "Conservation and Management of Rare & Endangered Plants." The reception ranged from chilly to freezing. One highly respected professor objected to my being permitted to speak at all. I no longer have an electronic copy (The Restoration of California: A Practical Guide), and I couldn't find one on the Internet, but I did find an old draft in my files. The book is available through bookfinder.com for fifteen bucks or so (one site has it for $240+!). Here's an excerpt, laboriously pecked out on my keyboard: "What's wrong with landscaping? Nothing is really wrong with it, but it is only cosmetic. The trouble is, most people think that it is natural, just like Yosemite Valley, and don't recognize it for what it is--an artificial decoration on the land that happens to be constructed of living organisms. The fact that the plant assemblage does not function biologically [ecologically] is lost in the simple lust for the desired [sic] phantasy."
It is simply not widely recognized, as Cruzan points out, that ecosystems are not static. Many biologists and not a few ecologists apparently believe that they are. Again, as Cruzan says, ". . . we should focus on conserving natural processes, not entities." I might only add that where conditions that match an organism's requirements exist, the major problem will not be getting them to occupy such sites, but keeping them from occupying them, given the presence of viable propagules. But it would be the epitome of arrogance to declare that we know enough about ecosystems to prescribe what they should be--or, for that matter, what they were in the past. All we can do is to modify damaged sites to enable adapted (preferably indigenous) organisms to (re)colonize either by introducing their propagules or by watching the inevitable invasion. WT ----- Original Message ----- From: "Mitch Cruzan" <[email protected]> To: <[email protected]> Sent: Sunday, September 11, 2011 11:09 AM Subject: Re: [ECOLOG-L] a non Ivory Tower view of invasive species > I'm only asking for a quantifiable description of 'invasive' - we can't > do it based on where organisms originally evolved. Distributions of all > biota has changed dramatically in the last 18,000 years, so drawing > lines based on where species originally came from does not make a whole > lot of sense. The policy at some national parks has been to try to > preserve based on what we think the composition was like before the > arrival of Columbus to the New World. Such a view does not take into > account the fact that these communities are dynamic - distributions are > still changing in response to climate change since the last glaciation > (not counting human effects on climate). Distributions and community > composition will continue to change - these systems are naturally > dynamic. But this reality does not jive well with current views of > conservation biology whose main purpose seems to be an attempt to freeze > systems in time or to return them to some state that we think they use > to have. As conservationists we should focus on conserving natural > processes, not entities. Those processes lead to changes in > distributions, hybridization, change in community structure, and even > extinction. Fire policy is a great example - look at how are view of > the role of fire in ecosystems has changed over the last 100 years. We > need to have a similar recalculation of our policies for other aspects > of conservation biology - a focus on allowing natural processes to run > their course no matter where they might lead. South Florida is just a > great example of a dynamic system. > > So perhaps a definition of 'aggressive behavior' no matter what the > origin of the aggressor would be appropriate. Even then we have to make > decisions on if and when it would be appropriate to intervene. > > > > On 9/11/2011 10:42 AM, [email protected] wrote: >> ---- Mitch Cruzan<[email protected]> wrote: >> >> (stuff cut) >> >> What about the South Florida tropical flora/fauna? Many >>> species in those systems only arrived on this continent only within the >>> last 5000 years - are they invasive? Are entire communities in the >>> everglades invasive? >> Hmmm. How long ago did Florida emerge? >> >> Are you suggesting we should not be concerned about pythons in Florida, >> because though they are relative newcomers by Florida standards, all of the >> Floridian biota constitututes newcomers by geological standards? As another >> poster said, perhaps it is invasive behavior that matters. But of course, >> these snakes are not invasive -- they are tightly tied to the conditions >> where they evolved. They were brought by people, then released. But they >> do wreak havoc on native fauna once present. Not a problem, since Florida >> is recently emerged, so has only recently arrived biota? >> David McNeely >> > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1392 / Virus Database: 1520/3890 - Release Date: 09/11/11 >
