---------- Forwarded message ----------
Date: Wed, 8 Apr 1998 09:30:11 -0400 (EDT)
From: Faizal Moola <fmoola@julian.uwo.ca>
To: fmoola@julian.uwo.ca
Subject: Herbicide Impacts on Wild Blueberry
I disagree that many silvicultural herbicides are species-specific and have
no adverse impacts on non-target vegetation i.e. vegetation that offers no
evidence of competition with planted trees. In Canada, the most popular
herbicide prescribed for the silvicultural suppression of competing
vegetation is Vision (commerical formulation containing glyphosate).
My lab has studied the impacts of Vision on non-target vegetation for
several years in northwestern Ontario and we have found strong evidence
(which will soon appear in Canadian Journal of Forest Research) that
although not the intended target of vegetation management practices, several
fruit producing species, such as wild blueberry that are important to
wildlife and humans are adversely affected by operational Vision
application. The lowbush blueberry (V. angustifolium) is particularly
sensitive to operational Vision application. This plant exhibits extensive
defoliation and the death of above-ground stems. Our results are similar to
that found by other researchers in Canada and Sweden (Freedman et al. 1993;
Balfour 1989). In addition, moderate to severe damage to foliage and aerial
shoots as well as reduced blueberry cover has been reported in V. myrtillus
L. in Sweden (Lund-Hoie and Gronvold 1987).
I agree that at recommened rates and under normal use scenarios
Vision poses minimal toxicological hazard for terrestrial vertebrates. At
least that's what the published evidence shows so far. Nevertheless,
herbicides do affect populations indirectly by changing their habitat and
wildlife species that are sensitive to microhabitat change may be
vulnerable. Of particular concern to me is what are the impacts of
significantly reduced short-term blueberry production in sprayed areas on
the physical condition and reproductive potential of bears. Major weight
gains in bears coincide with periods of fruit maturation and ripening
(July-August). Rogers (1976, 1987) has reported that blueberry production in
northern Minnesota was critical for black bear growth and reproductive
success. In addition to bears, I have found evidence in the literature that
32 other species depend upon wild Vaccinium spp.
Finally, I would like to argue that protection of wild berry species
is important as these plants are utilized by rural folks in Canada (I have
read that also in Scandinavia and the Pacific northwest of the U.S)
extensively. Indeed, wild berry harvesting is an important non-timber forest
product that supports many families on marginal incomes during the summer in
rural areas. These berries are used in jams, jellies, fruit leathers, and
brilliant wine. Canada's first commercial blueberry wine producer is now up
and running in the town of Markland in Newfoundland.
Cheers
Faizal Moola
Phd. candidate, Dalhousie University
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