Dynamique végétale récente du complexe tourbeux des Tourbières-de-Lanoraie (Québec)
Worldwide, wetlands are among the most threatened ecosystems by human exploitation, drainage and climate changes. In a conservation perspective, understanding the processes throughout a temporal perspective is an important issue. In this master, I aimed (1) to describe the dynamics of vegetation communities in two bogs of the Tourbières-de-Lanoraie wetland complex during the last three millennia and (2) to determine the impacts of human disturbances on that dynamics on the last 500 years. To achieve this objective, I used a multiproxy paleoecological approach. Vegetation dynamics was similar in the two studied sites. After an ombrotrophication of the wetland, the open bog with Sphagnum and Ericaceae became gradually a forested bog. The transition from minerotrophic to ombrotrophic conditions happened before the Little Ice Age (1570-1850 AD) when climatic conditions were relatively cooler and drier. The forested stage developed much later, at the beginning of the XXth century. Human activities seem to have triggered the shift. Indeed many disturbances like drainage increased during the last century. This study shows that human disturbances are the main drivers of recent vegetation dynamics over the two studied bogs.
Tourbières Paleoecology Vegetation dynamics Anthropogenic disturbances Peatlands Quebec