Supervisor: Stéphanie Pellerin
Wetlands (peatlands, swamps, marshes) cover about 12.5% of the province of Québec. In southern Québec, peatlands have been disturbed since the onset of the european settlement, particularly during the last 100 years. One consequence of these disturbances is the establishment of some species usually not found in peatlands, such as gray birch (Betula populifolia). This is a pioneer species favored by disturbances. The aim of this project is to document the establishment of gray birch in the ombrotrophic peatlands of the Montérégie region, and to examine the factors that contributed to this establishment. The hypothesis is that the expansion of gray birch in peatlands is linked to human activities that took place around peatlands (agriculture, urbanization) which have resulted from drainage. This study will focus on 10 peatlands. For each site, different types of analysis will be conducted: i) plant-macrofossil analysis of surficial peat monolith to show how deep in the organic deposits gray birch macroremains are present; ii) dendrochronological analysis will provide the age of the current living individuals; iii) analysis of aerial photographs will be used to examine temporal changes in land use and to see if the area covered by the peatland has changed through time; iv) analysis of meteorological data will allow determine if the climate favored the establishment of gray birch.