Here's a message that did not make it through the ether initially.
Stefanie
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Helen wrote concerning 'weeds' in natural ecosystems (see below
for full text) and that it is natural for species to move into each
other's territories.
True - but humans have changed the rate extrodinarily and in many
cases are introducing species to places they would never have
reached otherwise. As a result, our activities are drastically
changing millions of years of evolution. The reason that New Zealand
has (or had) such fantastic and different flora and fauna
is because it is geographically separated from other land masses and
therefore the plants and animals evolved differently. I've heard
that over half the vascular plant species (i.e. not mosses or lichens
or algae) in New Zealand are now introduced species. Many of the
worse invaders are introduced garden plants.
If we allow the spread to continue, we will end up with a world full
of species that are either very tolerant of humans and/or outcompete
every other species. A very unattractive prospect for many of us that
share Aldo Leopold's sentiment that we cannot live without
wilderness. Introduced species are decreasing biodiversity worldwide,
many extinctions have been caused by these biological invasions. This
impoverishment of the worlds flora and fauna is deplorable for both
practical and ethical reasons.
In New Zealand it is still possible to buy exotic garden plants that are known
aggressive 'weeds' (in the ecological sense) at nurseries and garden shops. The
New Zealand Forest and Bird conservation group has just launched an
initiative to encourage nurseries to remove those species from their
inventories. I hope it will be extrodinarily successful.
> In New Zealand noxious weeds are often so designated for ecological reasons.
> These are non-indigenous plants which are likely to spread in areas reserved
> for indigenous species and to crowd out, strangle or otherwise diminish
> indigenous species.
>
> I think some of this does need to be controlled but I also tend to feel that
> it is natural for species to spread into each other's territories and often
> enjoy seeing these 'weeds' thriving in spite of human efforts to restrain them.
>
> Humanity has caused faster and more distant intermingling of species. Some
> species may be lost but perhaps interbreeding will enable adaptations to
> environmental changes which are also more drastic because of the activities
> of our species.
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Frances Schmechel
[EMAIL PROTECTED]
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Stefanie S. Rixecker
Department of Resource Management
Lincoln University, Canterbury
Aotearoa New Zealand
E-mail: [EMAIL PROTECTED]
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