Foreign Species InfestationsI planted purple loosestrife, a cultured variety obtained from a local nursery in my garden many years ago. The plant grew to maturity as a very tall, attractive stalk with a lovely series of purple flowers. At that time I was very well aware of the nature of the reputation that purple loosestrife enjoyed, accused of being an environmental interloper, a threat to native species. And people were urged to destroy them wherever they saw them.
Years ago I read a report of the purple loosestrife situation in Algonquin Park, where we often enjoyed ourselves canoe-camping for periods of time in the summer and fall. Truth was, I saw very few stands of purple loosestrife, though we did come across wild rice, and we once camped beside an island that had amazing bushes of cranberries which we harvested and then cooked up later, at home. But loosestrife, not one stand. That report? It concluded they were no threat there.
Years ago also, I planted in my garden at the back of the house one single plant of yellow loosestrife. It is reputed, though not a native species, to have been planted in this area since the Victorian era. Presumably brought along with pioneering housewives, just as they brought seeds for their kitchen gardens, introducing non-native species of other types as well.
Over the years I found the purple loosestrife to be a very non-intrusive plant. It stayed where it was planted. It did not propagate, did not spread, did not cause havoc in my garden. It did produce some very lovely flowers and its presence was, while not spectacular, splendid enough in its season. The yellow loosestrife, on the other hand, spread like crazy, and I soon regretted ever having planted it.
And now I read a report from area botanists that the threats of loosestrife thuggishly taking over wetlands and crowding out more valued native species was just wild exaggeration of a prospect that never did occur. It's true that some introduced botanical species can make an awful nuisance of themselves; Japanese-sourced kudzu, for example, introduced in the southeastern U.S. and now overgrowing all other botanical species, impossible to control.
But purple loosestrife? "We were all led to believe that this thing was going to take over the world. Even in the '90s, some biologists were questioning that", said plant biologist Brian Husband of the University of Guelph. But they were considered a dire threat, and governments in Eastern Canada and the Northeastern U.S. in their great wisdom released two European beetles known to eat loosestrife.
Introduce two insects as foreign species to impact on a vegetation as a foreign growth to solve a problem of unwanted presence threatening the security of native species? How utterly clever. Well, it was discovered that after an initial spurt of growth, purple loosestrife settled down to a discreet presence, not crowding out native species after all, but living harmoniously among them. And this appears to be a characteristic typical of many other introduced species.
Now we learn that some experts believe that some hysteria was involved here, that the threat posed by an alien species - purple loosestrife - was overplayed; it was given a bum rap and unnecessarily targeted. In the process two insect species whose long-term effect on the environment likely won't be known for some time were introduced.
A local Ottawa Valley biologist and environmentalist, Dan Brunton is of the opinion that in the first place purple loosestrife was never suited to this region. "I have argued for what it's worth that it never was such a big deal", suitable primarily to wetlands of a certain type: "ideally only seasonally flooded sites like old gravel pits, low pastures, artificially maintained river shores edges, ditches. etc."
As for the beetles; releasing them, as far as Mr. Brunton is concerned, was a poor idea. "We are doing some really risky questionable things. The worst is releasing a non-native bug to reduce the density of stands. Gee, nothing could possibly go wrong with releasing non-native animals in hopes of controlling another non-native animal, could it?"