Université de Montréal
M.Sc. candidate
Supervisor: Pierre-Luc Chagnon
Sébastien Roy
Start: 2024-05-01
End: 2026-04-30

Project

Plant-soil feedbacks and the impact of microbial communities on plant species coexistence in the ecological restoration of degraded mining sites
Mining activity, although essential to Quebec's economy, generates vast tailings parks that present major environmental challenges, requiring revegetation. The former Gagnon iron mine, abandoned since 1985, is an example, with 95% of its surface still unvegetated. Stress factors limit natural succession and recolonization of this habitat, making it imperative to better understand recolonization dynamics. Among these factors, soil microorganisms play a key role. Indeed, pioneer plants do not colonize new environments alone: their roots interact with a wide diversity of microorganisms, which are essential for plant and soil health. The biodiversity of this microbiome is generally correlated with plant performance and soil quality. However, most knowledge on these interactions comes from natural or semi-natural ecosystems, and few studies concern primary successions like those observed in mining tailings parks. It is therefore crucial to better understand these habitats to ensure their sustainable management and to select optimal plants and microorganisms to effectively restore the Gagnon mine. This project aims to characterize the influence of microorganisms on the recolonization of mining tailings parks. We will analyze two types of microbiomes: that of uncolonized soils and that of the rhizospheric soils of the five plants present on the site, using advanced biomolecular approaches. This analysis will distinguish microorganisms present in the soil in the absence of plants from those specifically associated with plant soils. We will also conduct an in vitro greenhouse experiment to measure plant-soil feedback between different species and rhizospheres at the site. By correlating these data with microbiome diversity, we will identify the microorganisms that have the greatest impact on plant performance and how plant microbiomes affect coexistence between plants. This information will be essential to understanding how the microbiome of these plants has enabled them to colonize and coexist in this hostile environment. This research will allow us to identify which plant species have microbial communities with complementary functions. We can then propose synergistic plant assemblages to accelerate the ecological recovery of sites disturbed by mining activities. More broadly, this study will contribute to understanding the role of the microbiome in the restoration of damaged habitats.