So, Mr. Patton, if you could, would you re-introduce smallpox and polio? It
took nature millions of years to get them working properly on the human
population.
Martin Meiss
2010/5/12 Jan Ygberg <jygb...@gmail.com>
> Humans are not part of nature? No wonder the planet is sick.....
>
> On Tue, May 11, 2010 at 10:15 PM, Geoffrey Patton <gwpatt...@yahoo.com
> >wrote:
>
> > This has been an especially interesting and worthwhile discussion,
> > particularly on the ethics front. My ethics derive from an ecologist
> whose
> > name I can no longer recall but whose mantra was that Nature took
> millions
> > of years to sort out the current state and any human-caused change is, by
> > definition, adverse. Where people have a hand in it, it is bad,
> regardless
> > of any perceived shot-term benefit. Pedagogical but true in my view.
> >
> > Cordially yours,
> > Geoff Patton, Ph.D. 2208 Parker Ave., Wheaton, MD 20902
> 301.221.9536
> >
> > --- On Tue, 5/11/10, James Crants <jcra...@gmail.com> wrote:
> >
> > From: James Crants <jcra...@gmail.com>
> > Subject: Re: [ECOLOG-L] Ecology Terminology and associated phenomena
> > Colonizing species etc
> > To: ECOLOG-L@LISTSERV.UMD.EDU
> > Date: Tuesday, May 11, 2010, 10:47 AM
> >
> > I think I have not made my arguments clearly enough. I merely intended
> > to summarize my moral case for suppressing invasives as part of my
> summary
> > of the off-forum conversation. My numbered paragraphs were intended to
> > address the claim that there is no ecological difference between native
> and
> > exotic species, and the claim that there is no ecological difference
> > between
> > human-mediated dispersal and dispersal by any other agent. My responses
> to
> > Matt's responses to those paragraphs are below:
> >
> >
> > JC(1) Exotic species, on average, interact with fewer species than native
> >
> > > species, and their interactions are weaker, on average. In
> particular,
> > > they have fewer parasites, pathogens, and predators, counted in either
> > > individuals or species. This is especially true of plants, and
> > especially
> > > non-crop plants. I suspect, but have not heard, that exotic plants
> also
> > > have fewer mycorrhizal associates than native ones, but I doubt that
> they
> > > have significantly fewer pollinators or dispersers. Meanwhile, back in
> > > their native ranges, the same species have the same number of
> > associations
> > > as any other native species.
> > > MC(1) Natural selection only produces interactions good enough to
> persist
> > > under prevailing conditions; there is no gold standard. By definition,
> > 50%
> > > of all species interact with fewer species than average, and 50% of
> all
> > > interactions are weaker than average. Preferring stronger, more
> complex
> > > interactions means preferring more tightly-coupled (and therefore)
> > > 'riskier'
> > > systems with a higher likelihood of failure.
> > >
> > JC (1b) The argument about how many species interact with fewer species
> > than
> > average misses my point. I'm saying that, if you counted the biological
> > interactions for each native species and each exotic species in some area
> > (could be a square meter, could be the world), I believe you would find
> > that
> > the average number for exotic species would be significantly lower than
> the
> > average for exotic species. Thus, exotic species are ecologically
> > different
> > from native species.
> >
> > Actually, having more interactions may mean greater stability, on
> average,
> > since some of those interactions are functionally redundant. I would
> have
> > to brush up on my community ecology to be sure I'm not being overly
> > simplistic, but I know this is true in pollination systems; pollinators
> > that
> > interact with more angiosperm species have greater population stability,
> on
> > average, and angiosperms with more pollinator species have greater
> > reproductive stability, on average (though I don't know if this leads to
> > greater population stability for long-lived species).
> >
> > I'm not sure what you mean by "systems with a higher likelihood of
> > failure." It seems to me that failure is a matter of human values not
> > being
> > realized. If, by "failure," you mean "rapid change," well, that hardly
> > seems to be a problem for you. I would have to agree that systems
> managed
> > to promote natives at the expense of exotics are more prone to failure
> than
> > those where any and all ecological outcomes are deemed acceptable, but
> > that's only because "failure" in the former group means invasion and
> > domination by exotic species, while there is no such thing as "failure"
> in
> > the latter group.
> >
> > >
> > > JC(2) Very-long-distance dispersal by humans confers a fitness
> advantage
> > > over very-long-distance dispersal by other agents, on average, for two
> > > reasons. First, humans often disperse organisms in groups, such
> > > as containers of seeds, shipments of mature plants and animals, or
> large
> > > populations contained in ballast water, allowing them to overcome the
> > Allee
> > > effects (lack of mates, inbreeding depression) their populations would
> > face
> > > if introduced as one or a few individuals. We also often take pains to
> > > maximize the establishment success of organisms we disperse, by
> shipping
> > > healthy, mature plants and animals and propogating them when they
> arrive,
> > > while non-human dispersal agents usually introduce small numbers of
> > > organisms, often nowhere near their peak fitness potential (e.g.,
> seeds,
> > > spores, starving and dehydrated animals).
> > > MC(2). JC appears to be arguing that once rare occurrences are no
> longer
> > > rare. I agree. But I draw the opposite conclusion, because he is
> > arguing
> > > that to generate such changes is morally wrong, while I am just saying:
> > > when
> > > these conditions prevail, long distance dispersal becomes normal.
> > >
> > JC(2b) I'm not saying anything (here) about whether the recent commonness
> > of
> > previously-rare dispersal events is morally wrong. I'm countering the
> > argument that human-mediated dispersal confers no fitness advantage
> > over dispersal by any other agent. Others may be aware of an invasive
> > exotic species that was not imported by humans in far greater numbers
> than
> > we could reasonably expect from any other agent, even if it had 100,000
> > years to work, but I am not.
> >
> > Furthermore, most invasive species were carefully planted and tended
> across
> > large areas. Others may know of a dispersal agent that takes such care
> of
> > the species it disperses AND has any realistic potential of dispersing
> > something over 1,000 miles, but I do not. Human-mediated dispersal is
> > unlike dispersal mediated by any other agent.
> >
> >
> > > JC(3) Although the population dynamics of invasive species do not
> differ
> > by
> > > what agent introduced them (whether humans brought them, some other
> agent
> > > did, or they evolved in situ), it is ecologically consequential that
> > human
> > > activities are generating so many more invasive species than natural
> > > processes usually do. Aside from maybe continents or oceans merging
> > > through
> > > plate tectonics, nothing non-human introduces such a flood of new
> species
> > > to
> > > new environments as we humans have in the last several centuries.
> > > MC(3). See MC(2). What was once normal is no longer normal.
> > 'Ecologically
> > > consequential' in this context is standing in for 'morally
> > consequential'.
> > > Ecologically, change is change.
> > >
> > JC(3b) By this logic, ice ages are ecologically inconsequential. I'm not
> > making a moral judgement (here). I'm only pointing out that humans have
> > accelerated the frequency of invasion by new species by many orders of
> > magnitude, and that this is having the sort of dramatic ecological
> effects
> > you would, in theory, expect it to have. Again, this goes toward
> > countering
> > the claim that there is no ecological difference between human-mediated
> > dispersal and dispersal by other agents. If we are increasing the
> > probability of intercontinental dispersal by many orders of magnitude
> over
> > what you find for all other agents combined, there is an ecologically
> > important difference between human-mediated dispersal and dispersal by
> > other
> > agents.
> >
> > >
> > > JC(4) To arrive at the conclusion that the terms "native" and "exotic"
> > (or
> > > "alien") are ecologically meaningless, you must approach the issue this
> > > way: if there is no set of criteria by which one can reliably
> categorize
> > > an
> > > organism as native or exotic in the absence of historical evidence, the
> > > distinction is meaningless. I think the valid approach is this: if
> > there
> > > is no set of criteria by which one can reliably distinguish the
> category
> > > "native species" from the category "exotic species" (*after* the
> > > categorization is done based on geographic history), the distinction is
> > > meaningless. By analogy, the first approach is like saying that there
> is
> > > no
> > > difference in height between men and women because one cannot reliably
> > > identify the height of a person by their sex, while the second approach
> > is
> > > like saying that there is a difference in height between men and women
> > > because men are, on average, significantly taller than women.
> > > MC(4). JC undermines his argument here by trying to make the
> difference
> > > between natives and aliens morally inconsequential. I think we can
> > assume
> > > that he sees no moral imperative emerging from the statistical
> likelihood
> > > that men are (and have been) taller than women. But we know he
> believes
> > a
> > > moral imperative emerges from the claims he makes in (1-3). So his
> > analogy
> > > isn't really an analogy. A better analogy would be a claim that men
> > are,
> > > on average, more politically powerful than women, evaluated in light of
> a
> > > moral claim that no such difference should exist. But even that
> analogy
> > > would only recommend equalizing average fitness; leveling the playing
> > > field.
> > > And it flies in the face of the "past = desired future" formula
> inherent
> > in
> > > anti-alien sentiment. Finally, if Williamson's legendary '10s' rule is
> > > even
> > > remotely accurate, the aliens are already disadvantaged by multiple
> > orders
> > > of magnitude. Long distance transport is now vastly more likely, but
> > > establishment at the other end is still a long shot.
> > >
> > JC(4b) Again, I'm not making a moral argument at all. You (and others)
> > have
> > said that native and exotic species cannot be distinguished ecologically.
> > One way I've seen other people arrive at this conclusion is by observing
> > that there are no ecological criteria that can perfectly predict whether
> a
> > species is native or exotic (e.g., there are invasive natives, there are
> > exotic plants with more insect herbivores than related natives, etc.).
> I'm
> > saying that this approach is like trying to predict people's sex based
> > on their height, noting that you often guess wrong this way, and
> concluding
> > that sex is not relevant to height.
> >
> >
> >
> >
> >
>
>
> --
> Jan Ygberg
> Juan Fanning 380
> Lima 18
> Peru
> INT+(511) 446 1099
>
