PARENT SESSION
Contributed Oral Session 101: Mammalian Herbivory
Wednesday, August 10, 1:30 PM - 5:00 PM, Meeting Room 520 A, Level 5, Palais des congrès de Montréal
Long terme effects of deer browsing and trampling on the vegetation of peatlands.
Pellerin, Stéphanie*,1, 2, Côté, Steeve2, 3, 4, Huot, Jean2, 3, 4, 1 Institut de recherche en biologie végétale, Montréal, Canada2 Chaire de recherche industrielle CRSNG-Produits forestiers Anticosti Inc., Québec, Canada3 Centre d'études nordiques, Québec, Canada4 Université Laval, Québec, Canada
ABSTRACT- Overabundance of wild large herbivores, especially exotic species, is a major threat to several ecosystems worldwide. While the response of forest vegetation to high density of herbivores has been well studied, far less is known about peatland vegetation. In this paper, we aim at assessing the long term impact of white-tailed deer on plant communities of ombrotrophic (bog) and minerotrophic (fen) peatlands in eastern North America. Vegetation of five peatlands that have experienced high deer densities for at least 75 years was compared with that of five peatlands situated at proximity but where deer were absent. We investigated deer impacts on plant species composition and cover, shrub height and cloudberry fruit/flower production and morphology. In bogs, white-tailed deer had no long term impact on plant species assemblages, but reduced lichen cover and increased the surface area of bare peat. On the other hand, the floristic composition of fens differed significantly between sites where deer were present or absent. Plant diversity was greater in undisturbed fens than in disturbed fens, especially for shrubs, sedges and liverworts. No detrimental effects of browsing on shrub height were observed. Conversely, deer browsing seemed to have deleterious impacts on cloudberry fruit/flower production. Browsing also significantly reduced the number of leaves per individual. Overall, our results suggest that white-tailed deer had some important impacts on the vegetation of peatlands, especially on lichen cover, that could be harmful for the long term conservation of peatland plant biodiversity.
Key words: Anticosti Island, Bogs, Fens, Plant community