Re: POND life vs. aquarium life

["stephan Mifsud" <valerandi at nextgen_net.mt>]

I said in part:

> I live in the middle of a town so there is no danger of
> anything escaping in to the wild.
>

Scott asked:

No pollen, no insects, no birds, no mammals, or other
sources of distribution?

There are no birds except the odd sparrow and robin, and
they only drink from the pond without wetting their feet.
Ducks and water fowl might carry vegetation and seeds but my
6 foot pond never interested any. I wonder why? No mammals,
except the two legged ones and the odd rat that unluckily
for it attempted to enter my domain through the drain.

But why do you ask about insects and pollen? How can they be
a source of spreading of invasive plants? Isn't it the seeds
or vegetative parts that are responsible for this in the US?
Even if there is another plant of the opposite sex waiting
to be fertilized by my plants in the wild, why worry? Its
already there.

The only problem I envisage with pollen, and its
distributers, be it wind or insects, is if it fertilises a
different variety or subspecies of a species already
existing in the wild. Thus potentially creating a hybrid
that can outcompete the native wild plant. The only plant I
have which might do that is Samolus valerandi. I have both
the aquarium variety (ssp parviflorus from America) and the
Maltese/ European subspecies (ssp valerandi) at home. I keep
them well seperated, but it is for the American variety I'm
worried about. The European subspecies is much more
aggressive and competitive. In the US this plant has escaped
into the wild and is now found in a number of states.

Here in Malta 99% of the streams and ponds dry up in summer,
the rest are too far away, so don't worry about my plants.
But I guess you are right in worrying about invasive aquatic
plants elsewhere. Just hope that people will learn one day
what harm they do to their own environment with the
introduction of aggressive alien species/subspecies.

regards

Stephan



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