Grant: Discovery Launch Supplement

The high ecological value of old-growth forests is now fully recognized, as they harbor a biodiversity distinct from young or managed forests. However, old-growth forests are under pressure from human activities, causing continuing area loss and fragmentation. Implementing effective strategies to protect old-growth forests is one of the main objectives of sustainable forest management in Canada. Old-growth forests are highly heterogeneous in terms of structure and composition, and therefore in terms of habitats, even within the same territory. To be effective, protection strategies must be able to maintain this diversity of old-growth forests, but few tools are available. The aim of this project is therefore to assess the relevance of tree-related microhabitats as innovative indirect indicators of biodiversity in Canada's boreal mixedwood forests. Tree-related microhabitats refer to the small-scale structures found on trees (e.g. cavities, cracks, epiphytes), which are home to numerous and diverse species. However, the importance of tree-related microhabitats in Canada's old-growth boreal forests, and in particular their ecological role, has not been studied to date. We aim to (i) identify the factors at the scale of the tree, its immediate environment and the stand that explain the development of tree-related microhabitats in boreal mixed forests (PhD1), and (ii) assess the role of tree-related microhabitats as indicators of biodiversity, with a particular focus on understudied taxa, in boreal mixed forests (PhD2). The project will take place in the Lake Duparquet Research and Teaching Forest, located in western Quebec. Tree-related microhabitats will be sampled in a network of 6 1-ha plots in old growth forests monitored since 1994. Metrics of structure, composition and dynamics will be surveyed at the scale of the tree, its immediate surroundings and the stand. Samples of epiphytes (bryophytes and lichens) and environmental DNA (eDNA) will then be taken from a sub-sample of representative tree-related microhabitats. Soil eDNA data will also be sampled regularly in these plots. Analysis of these data will enable us, for the first time, to identify the factors explaining the development of tree-related microhabitats and the biodiversity associated with them in the mixed boreal forests of eastern North America. The results will provide a new insight into the biological diversity of Quebec's old-growth forests, and pave the way for concrete applications contributing to sustainable forest management. Tree-related microhabitats could thus become one of the essential tools to ensure the success of old-growth forest protection strategies.