[APWG] Ecosystem restoration and the uses of alien species Re: Fw: Ideas for thought.

Thu Apr 14 00:17:44 CDT 2011

APWG and Scott:

"Classical" philosophy may indeed seem separated from science, but principles that seem broad, even fuzzy, can function to focus and maintain discipline in the pursuit of truth that should be science--and "philosophy." But we can all have our own "philosophies." Philosophies, like physical laws and other statements of principle upon which quests for truth are based, are, by their nature, subject to reexamination, to testing, to challenge. My central driving "philosophy," for example has been unchanged since I was fifteen: "To reconcile the needs and works of humankind with those of the earth and its life." It keeps standing up to challenge, but remain open to challenge. 

"Nature," for example, may or may not actually "solve problems," in the sense we are capable of understanding, but in an objective sense, science and scientists should not, cannot, if it/they is/are honest, fail to see the totality of relevant factors within our view. Accordingly, we should not fail to observe and consider the actual effects of, say, a studied organism in all its complexity and relationships. Certainly, then, we cannot remain honest if we select only those aspects related to an organism, a community, an ecosystem that are consistent with some selected "spin" on the facts. To the specific example at hand, "nature's" natural response to change is to match "her" organisms to it. That is, if purple loosestrife happens to be available, and if the conditions of habitat (a given change) happen to match the loosestrife's needs and capabilities, the organism will respond by "doing its thing." Both of these phenomena can be objectively considered; that they may have not is beside the point--that indicates only the limitations of the observer/scientist, not that a conclusion based on fragmentary data is the final, or even an accurate "word" on the subject. 

The operative adjective in my statement about "invasive in ecosystems" is "apparent." If, for example, recruitment of an alien organism is dependent upon some "anomalous" condition in a given "closed" ecosystem, the issue becomes whether or not that organism can continue to survive and thrive, expand, reproduce, and "compete," not to mention displace other indigenous organisms to their ultimate detriment, reduction of population, or extinction. "Continue" deserves more attention too. If, for example, the anomalous condition that enables the alien species to colonize is reduced or ceases, the alien species in question must possess other strategies to persist in any of the aforementioned terms. 

Such objective information can be used by restoration ecologists and others to reduce or eliminate anomalous conditions that enable colonization by the alien species. Mere "bashing" that does not remove the anomalous conditions can be quite limited in its effectiveness, and in some forms (e.g. pulling, digging, spraying etc.) can be counterproductive, increasing rather than reducing or eliminating the aliens. The science of "integrated pest control" has some notable successes, but is not without its own set of problems. While the concept of co-evolved pathogens and predators has intuitive appeal, I'm not sure how much evidence actually validates it, and how much of it is conjecture. Perhaps Lenharth can enlighten us further. We might also consider just how much advantage indigenous species have, and how "disadvantaged" they are in their own native context; evidence is similarly lacking that indigenous, co-evolved species are "controlled" by indigenous pathogens and predators. In addition to predation, an objective look into a species' needs and how well those needs are satisfied by the environment, "natural" or "unnatural" in which they find themselves at any given time or cycle. For example, I was convinced for years that mouse plagues were the result of eradication of their predators, but I now question that hypothesis and wonder how much "good times," either provide by nature or human activities in or near their habitat is perhaps a more important factor. 

With respect to urban parks and open spaces, I have long advocated the preservation and/or restoration and modification of indigenous ecosystems as a first consideration through a process of "project requirements" statements and feasibility, but these realms remain in the domain of whim and desire or "preference." I have also advocated integrating cultural features like "edibility" with ecosystems, but have never been successful. Good luck to all who do. 

I hope that Toby's essay will be discussed point by point, as it contains many that are excellent take-off points for learning more about how we deal with anthropogenic land-scraping, its actual consequences, and the relative values of those consequences and ecosystems. 

WT
  ----- Original Message ----- 
  From: Scott Lenharth 
  To: apwg at lists.plantconservation.org 
  Sent: Tuesday, April 12, 2011 8:27 PM
  Subject: Re: [APWG] Fw: Ideas for thought.

  This essay is about philosophy, so it's difficult to respond to from the perspective of invasive biology or restoration ecology.  Statements such as "purple loosestrife is...nature's way of solving a problem" can't be objectively considered.

  Wayne, you touched on a good point - some introduced plants become invasive in ecosystems that have experienced no apparent human "disturbance".  The essay ignores this critical point:  plants and animals, moved somewhere else, may be biologically released from their co-evolved pathogens, predators, etc.  And that provides the competitive advantage.

  I think the author does illustrate the contrary positions people take regarding urban lands - parks, preserves, green spaces.  Should these be restored into something resembling the historic (pre-settlement) ecosystem?  Or become hybrid "edible landscapes"?  Or just serve as recreation areas with no effort to manage the flora?

  >On Sat, Apr 9, 2011 at 3:10 PM, Wayne Tyson <landrest at cox.net> wrote:

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