Department of biology, chemistry and geography
Guillaume de Lafontaine (Regular member)
Luc Sirois (External collaborator)
Introduction: Contemporary global changes are altering biodiversity patterns on a planetary scale. While climate warming should favor the invasion of herbaceous tundra by shrub and tree species, ecological disturbances trigger a decline in boreal forest cover associated with an ecosystem shift to a tundra state. Modern-day boreal landscapes reflect the dynamic interactions across wildfires, climate, physical environment variables and forest regeneration. In the Caniapiscau region alpine tundra ecosystems result from a gradual opening dynamic of the forest cover over the last two thousand years, a cold period that was critical to post-fire regeneration. Three hundred kilometers south of this region, alpine tundra ecosystems are also found at the top of the Monts Groulx. However, the origin of these ecosystems remains unknown. Objectives: The project aims to analyze the patterns of floristic biodiversity in a biogeographical framework by comparing the plant assemblages from the alpine tundra ecosystems of the Caniapiscau and Monts Groulx regions with those from the arctic tundra in northern Québec. The project will provide key insights regarding the conservation value of projected protected areas targeted by the Ministère de l’Environnement et de la Lutte contre les changements climatiques (MELCC). More generally, the project will assess whether alpine tundra ecosystems resulting from a regression of the forest cover represent exceptional ecosystems, ecosystems similar to arctic environments or mere degraded forest ecosystems. Study sites: The Caniapiscau region is located at the transition between the open-crowned spruce-lichen woodland and the forest-tundra. The Monts Groulx alpine tundra ecosystems are located in the core of the closed-crown spruce-moss forest. Material and methods: Floristic inventories will be carried out in hundreds of alpine tundra ecosystems in each of the bioclimatic domains: closed-crown spruce-moss forest (Monts Groulx), open-crowned spruce-lichen woodland (Caniapiscau-south) and the forest-tundra (Caniapiscau-north) according to MELCC protocols. These data will be combined with inventories of arctic vegetation already carried out by the MELCC over the past 10 years (unpublished data). A comparison of plant assemblages will be realized by using clustering analyzes of taxonomic, functional and phylogenetic biodiversity (e.g., hierarchical clustering, RDA, dbscan). On each site, mineral soil samples will be collected to perform macrofossil analysis of the wood charcoal particles to assess the age of canopy opening and/or origin of the tundra ecosystem. Expected results: The hypothesis postulates that arctic-alpine plants gradually appear on the alpine tundra ecosystems of the boreal environments. Over time since the inception of a given alpine tundra ecosystem, the plant community has gradually become more similar to arctic tundra communities.
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