Below-ground facilitation between tree species in the re-vegetalization of a post-mining site

Master Project of Supun Madhumadhawa Pawuluwage

Directors: Nicole Fenton (UQAT-IRF) and Philippe Marchand (UQAT-FIR)
Collaborators: Mélanie Roy (Paul Sabatier University)

Canadian boreal forests are under threat due to anthropogenic activities such as logging, mining, hydroelectric development and oil and gas extraction etc. Based on the status of the boreal forests in Quebec, they experienced, over last twenty years, significant mining development that required the construction of many tailing facilities. In the boreal region, the abandoned mining sites and post-mining sites are slowly being colonized by lower plants, herbs and eventually with trees, which create recolonizing and regenerating stages. These mine tailings are surface deposits recently established and are poor in organic matter and nitrogen. Therefore, post-mining lands offer the opportunity to study the first steps of colonization of boreal forests on bare soil low in organic matter and nitrogen.

The general goal of this project is a comprehensive study of seedling survival and establishment through belowground facilitation by mycorrhizal networks. For that we conducted a study to determine whether seedling growth and survival at this early succession stage on a former mining site depend on intraspecific and interspecific interactions and then determine whether this facilitation is due to mycorrhizal networks or due to other factors, if evidence of facilitation is found. Also, we determined taxonomic diversity, richness and abundance of mycorrhizal fungi and mycorrhizal community comparison was carried out using molecular analysis. Plant inventories, sampling of soils, mycorrhizae, leaf analysis and genetic analysis of mycorrhizae will be carried out to answer those questions. Sampling was done in the former Beattie mining site near the Lake Duparquet Teaching and Research Forest (FERLD) of UQAT during summer 2019. Molecular analysis was carried out using Illumina - MiSeq to identify mycorrhizae in Paul Sabatier University, Toulouse, France under supervision of Professor Melanie Roy. After following the bioinformatics analysis and statistical analysis we compared mycorrhizal communities among host plants to identify specific hosts which are related with similar mycorrhizae. According to obtained results, there were no host specific mycorrhizal communities among our samples. Main expected outcomes of this research will be an understanding of belowground facilitation of plants in a degraded site through plant-plant interactions.