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permaculture - Re: [permaculture] nitrogen fixing trees/shrubs that feed livestock

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  • From: Toby Hemenway <toby@patternliteracy.com>
  • To: permaculture list <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] nitrogen fixing trees/shrubs that feed livestock
  • Date: Sun, 26 Dec 2004 11:49:07 -0800

On 12/26/04 8:04 AM, "Clint Popetz" <clint@cpopetz.com> wrote:

> Aiee, be very careful about russian olive (and its relative autumn
> olive.) They are both very invasive. [snip] They're swarming
> all over the place, steadily shading out or strangling other species.
> In the west, they're eating away at riparian woodlands.

You might find "Invasion Biology: Critique of a Pseudoscience" by David
Theodoropoulos a useful counter to unfounded claims that invasive species
are a major cause of ecosystem damage. David cites an immense amount of data
showing that most "damage" by "invasive" species occurs on land that has
been logged, grazed, or as in the case of SW US riparian systems,
channelized by Corps of Engineer projects and disturbed by dams and the
massive native willow and cottonwood killing projects of the past. He also
cites data showing that wherever scientists have bothered to check, "exotic"
species almost always support the same number and kind of native partners as
the species they "replace."

I've observed a terrible invasion in the US west, the near-complete loss of
of native prairie and savanna to a ferociously invasive species that shades
out and strangles all competitors--a single individual can kill off hundreds
of prairie species. The invader: Douglas Fir, moving into prairie ecosystems
where it has not existed before or has only been a minor component.
Shouldn't we eradicate this menace to native species? Oh, I forgot; Doug fir
is a native. But it's still killing prairie species--doesn¹t that make it
evil?

I use this silly example to show that nature doesn't distinguish between
native and exotic species; only humans do that. Massive species movement and
redistribution have always been a part of ecosystem dynamics. We need to
learn to get comfortable with it instead of engaging in bound-to-fail
projects like Russian-olive pulling. If the conditions that favor the
"invader" over the "natives" aren't changed, the "invader" will simply come
right back the minute we stop pulling it. Most "restoration" projects fail
for this reason. What leads us to assume nature is being stupid when she
lets species such as Russian olive thrive?

Like the an said, "I'm tired of growing plants that want to die and killing
plants that want to live."

Toby
www.patternliteracy.com






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