Edwards studied the effects of grazing by moose (Alces alces andersoni) on the demography of the perennial herb (Aralia nudicaulis), an important component of the herbaceous flora in the boreal forest on Isle Royale National Park, Michigan, using the frequency and pattern of herbivory. Survivorship and reproduction of shoots of plants clipped experimentally was also measured. Moose browsed 63% of flowering shoots and 33% of vegetative shoots; the proportion of shoots eaten increased with shoot density from 11%, in quadrants with less than 9 shoots per square meter, to 77% in quadrants with over 20 shoots per square meter. Clipped shoots resulted in smaller fruits and leaves and a lower flowering rate than intact shoots, but no effect was observed on survivorship. The author concludes that grazing significantly alters the population structure of A. nudicaulis by reducing the total number of flowering shoots and decreasing fruit production.
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