According to the 2007 IPCC report, the alpine tundra ecosystems found on low mountains of the northern hemisphere are amongst the most threatened by climate change. A treeline advance or a significant erect shrub expansion could result in increased competition for the arctic-alpine species usually found on mountaintops and eventually lead to their local extinction. The objectives of our study were to identify recent changes in the cover and growth of erect woody vegetation in the alpine tundra of Mont de la Passe, in the Parc National de la Gaspésie (Québec, Canada). The comparison of two orthorectified aerial photos revealed no significant shift of the treeline between 1975 and 2004. During the same period however, shrub species cover increased from 20.2% to 30.4% in the lower alpine zone. Dendrochronological analyses conducted on Betula glandulosa Michx. sampled at three different positions along an altitudinal gradient (low, intermediate and high alpine zone) revealed that the climatic determinants of B. glandulosa radial growth become more complex with increasing altitude. In the lower alpine zone, B. glandulosa radial growth is only significantly associated positively to July temperature. In the intermediate alpine zone, radial growth is associated positively to July temperature but negatively to March temperature. In the high alpine zone, radial growth is positively associated to January, July and August temperature but negatively to March temperature. The positive association between summer temperatures and radial growth suggests that B. glandulosa could potentially benefit from warmer temperatures, a phenomenon that could lead to an increase in its cover over the next few decades. Although alpine tundra vegetation is not threatened in the shortterm in the Parc National de la Gaspésie, erect shrub cover, especially B. glandulosa, could likely increase in the near future, threatening the local arctic-alpine flora.

Il est reconnu en droit canadien qu'une disposition imprécise, au point de ne pas tracer une sphère de risque permettant un débat judiciaire, peut être invalidée puisqu'elle contrevient ainsi à la Charte canadienne des droits et libertés. Dans ce contexte, à quelle considération a droit le citoyen dans sa compréhension de dispositions pénales souvent obscures? Dans cet article, l'auteure examine la théorie de l'imprécision tel qu'elle est actuellement appliquée par les tribunaux canadiens, dans le contexte des dispositions criminelles et pénales. Par la suite, une analyse critique de cette théorie s'articule en trois axes principaux : la position précaire du citoyen, la situation privilégiée du législateur et la mise en péril de la séparation des pouvoirs. Enfin, l'auteure propose une norme plus respectueuse du citoyen : l' intelligibilité civile.