Coastal wetlands play crucial ecological, economic and social roles that stem from their rich biodiversity. They provide essential habitat for a large variety of species, mitigate climate change and offer coastal protection and water purification. However, the Great Lakes (GL) wetlands are being degraded at an alarming rate due to anthropogenic stressors, climate change and invasive species. Exotic and invasive plant species are particularly problematic, and are suggested to be responsible for many ecosystem changes in the GL. An up-to-date analysis of the current distribution of wetland species is now of critical need. Working with the Great Lakes Protection Initiative (GLPI), this study examines the current biodiversity and distribution of plant species along the Canadian GL wetlands' hydrosere. We used an impressive dataset collected by Environment and Climate Change Canada during the summer of 2018-2019. This dataset includes 26 sites and more than 8500 quadrats across four GL. We adopted a multiscale approach to perform alpha-, beta-, and gamma-diversity analysis of this dataset. We showed that the northern lakes (Superior and Huron) are richer, more diverse and less invaded by exotic species than the southern lakes. The southern lakes (Erie and Ontario) are strongly human-impacted by showing a lower richness, a high cover in exotics and a more homogenous plant community. We also showed that the emergent marsh vegetation community is the most impacted along the hydrosere. This study offers an opportunity to develop a conceptual framework to assist wetland managers in their conservation and restoration efforts