Subject: Re: pernicious plants
Date: Feb 17 13:48:45 1995
From: Don Baccus - donb at Rational.COM


> That was a good list, Don, with good information; thanks.

Thank for the kind words!

> I would add
> PURPLE LOOSESTRIFE to the list without hesitation...

Maybe I would too, if I were familiar with it! Is it widespread throughout
the PNW? Is it easy to describe? This may be one of those things I'm
familiar with visually without knowing the name.

> It's clear that there are hundreds of weedy species that effect relatively
> minor changes on ecosystems, but the ones named have the unpleasant
> propensity to take over large stretches of (often disturbed) habitat by
> successfully outcompeting native and other weedy species, and, for the most
> part, they don't have much value to wildlife.

Our wildlife, at least. Of course, if we imported entire communities
rather than individual species the situation might be different (most
likely vastly worse, but my point is that the monoculture that arises so
often with imported pests isn't normally reflected in their habits at
home).

> Himalayan blackberry
> probably is an exception to this, as it furnishes habitat for a lot of
> thicket-inhabiting small birds and mammals, and the fruits are eaten by
> quite a few species.

That's a good point, though their propensity to take over open space
is a matter of exchanging one habitat for another. But, your point
that this replacement habitat has value for a lot of critters is
well-taken.

> We definitely should distinguish weeds that are damaging to natural
> ecosystems from weeds that are inconveniencing to us. I think bracken
> would only fit in the latter category, if at all. As would Russian
> thistle, Canada and bull thistles, and some other species.

And, of course, the same is true in the avian world: chukar vs. starling,
etc. Some critters have more impact in some regions than others: nutria
are mostly a nuisance here, but a genuine menace in the Mississippi Delta.

> At least we
> don't have pernicious TREES, as do many areas of the tropics.

And subtropical Florida, i.e. Everglades NP, I might add.

Austrailian Causarina (sp). Comes from the "red center" where it
rains 5-10 a year. Thrives in the 'glades, interestingly enough,
where it rains buckets. The 'glades shares one feature though: nutrient
poor growing medium. Oh, the (sp) above meant spelling, not species!

Brazilian Pepper is a plague there, too.

-Don Baccus-