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Response to Purple Loosestrife Gets Bad Rap
by Patricia Story
November 17, 1999

In response to the article posted "purple loosestrife gets a bad rap" I'd like to emphasize the ecological disturbances that the plant does have from an ecological point of view. In eastern Ontario I've seen with my own eyes, in a two to three year period, this plant take over large tracts of wetlands that once were diverse with cattails, and other wetland plant species that hosted bird life, and rapidly create a monoculture field of purple flowers. This plant is an extremely tough competitor and very hard to eradicate. The plant has become a big problem in this region (although I don't deny its attractiveness in a garden setting!)

The problem with a highly competitive plant such as purple loosestrife is that any time a region or ecosystem loses diversity due to invasion and out-competition from an exotic species it is generally not a good thing from a "biodiversity" standpoint. That is to say, more diverse ecosystems generally have more different types of habitats for wildlife, and also can retain more plant cover during changes in weather, hydrology, insect and disease infestation, and therefore be a better environment for birds, insects, amphibians, reptiles, and mammal wildlife, whether that wildlife be suitable for hunting or not. The current monoculture purple loosestrife wetlands of eastern Ontario do not have the same habitat features and food sources that once hosted many species of wetland wildlife, therefore the organisms that depended upon the plant species that were there before the invasion of loosestrife may no longer have homes or food sources - which can have a disastrous effect on these species and the ecosystem in general.

While it may be true that Ducks Unlimited and OFAH are strong anti-purple loosestrife advocates, there are many other organizations including the Ontario Ministry of Natural Resources, and many universities that have studied this species and its damaging effects. There are many professors (who likely do not have any hunting-related or monetary bias in the study of this species) at the University of Guelph who have been researching this plant since the early 1990's. You may try to contact them through the Department of Environmental Biology at (519) 824-4120.

The concern regarding the introduction of the beetle that attacks purple loosestrife is a valid one. While this beetle may help control the purple loosestrife population there also runs a risk that this beetle could become a problem elsewhere in the ecosystem. Since the beetles have already been released (as far as I know) I guess we'll have to just wait and see what happens.

pstory@nrn1.NRCan.gc.ca
Patricia Story, P.Ag
(Horticulturist AND Ecologist!)
Kemptville, Ont.

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