> Jay:
>
> My God.......it looks like the natural monsters are worse than anything
> Dr. Frankenstein could ever dream
> up . I don't know what the answer
> is but the ecological future looks
> rather grim .
In some circumstances this is true. I just hope that we don't get swept up into
some wave of hysteria that prompts us to over react and do even more damage
trying to spray exotic weeds and kill the native flora and fauna too. Often times
we assume a species to be invasive and find out that it is more than just the
species at fault. This is especially true of plants - aquatic species in
particular. In my recent study of literature on Water Milfoils - genus
Myriophyllum I have found it is possible to have a species that is listed as
imperiled in one state and an aquatic nusince species in the next. I was quite
disturbed when I came across recommendations for applying aquatic herbicides to
control not the exotic Eurasian Milfoil but a native species - M. hetophyllym in
its native range.
Often times when an aquatic plant species gets out of hand, it is because excess
nutrients are leaching into a lake or river. Agricultural runoff and septic tank
leachates are the major culprits fueling the growth of aquatic vegetation - even
native species to the point that it degrades waterways.
Sometimes our scorched earth tactics to control exotics backfire really badly.
This has been the case with the Federal Government's war against the Fire Ant
which seemed to just exacerbate the problem. This particular insect just happens
to hail from seasonally flooded savannahs in South America - a very unstable
environment and had evolved quite a few talents for suviving such upheval. They
were taylor made for moving into areas of large-scale mechanized farming.
Spraying the hell out of everything just killed off the native insect fauna and
made it all the easier for Fire Ants to recolonize.
> Hopefully the answers
> will be found before it becomes
> impossible to reverse the consequences
The answers are all around us.
We can do many things right in our own backyard that will help to alleviate this
problem. First of all - avoid using plants with a demonstrated bad track record
in our landscaping. Things like Japansese honeysuckle can be replaced with more
benign counterparts - ie the native red trumpet honeysuckle. Using native plants
in home landscapes also enhances wildlife habitat and uses less resources to
maintain because the plants are better adapted to local conditoions and require
less coddling than generic garden shop plants. Also there are alternative ways to
maintaining lawns using organic fertilizers or even no fertilization and avoiding
the impulse to use herbicides. That and being a little more tollerant of lawn
weeds can help improve the quality of our waterways and native fish life as well!
As hobbyists - be it fish, reptiles or horticulture - we should promote the
responsible keeping/cultivation and disposition of non native species. Spread the
word in the community of your peers about what some species are capable of doing
when they are turned loose outside their natural range. Sportsmen and native fish
collectors should be careful to decontaminate gear when moving from one water
body to the next. All it takes is a fragment of Milfoil of bilge water filled
with Zebra Mussel larvae to start a new outbreak elsewhere.
There are some cases where really acute infestations have been unleashed that for
now will defy our ability to control. But a doom and gloom outlook is
counter-productive. There are emerging technologies that may allow us to taylor
species specific agents that can eradicate infestations without as much colateral
damage as is often wrought by biocides and conventional biocontrols.
Also there are natural processes at work that can limit exotic pest species.
Native life forms may learn to use the newcomer in some way which will limit it.
Sometimes what we are really seeing is a crash- outbreak population effect that
in time will pass. The River Thames in Britain was for a while choked to the
point of being unnavigable by the American Elodia canadensis introduced as a pond
or aquarium plant. But after a brief period of dominance it went into decline.
Possibly due to modern efforts to clean up rivers which reduced the sewage
effluents that often provoke such rampant growrth.
The Elodia is there to stay but no longer choking the rivers. It has found a
niche among the local flora.
Jeff
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