Climate change and nutrient enrichment altering sedimentary diatom assemblages since pre-industrial time: evidence from Canada’s most populated ecozone

Lakes worldwide are under threat by a myriad of environmental stressors that have been increasing in number and magnitude. These can be regional such as climate change, or local nutrient-rich runoff, invasive species, road salt contamination, to name but few. To protect lake ecosystems from further deterioration, we need long-term data define pre-disturbance baselines identify causing the greatest ecological changes. Paleolimnology is an effective approach reconstruct limnological history, providing important window into past Here, applied paleolimnological tools explore pre-industrial contemporary diatom assemblage changes 27 lakes located most populated ecozone Canada, Mixedwood Plains. We also examined full sediment core for Lac des Chicots (Southern Québec), aiming disentangle impacts natural versus anthropogenic interactions assess their relative effects on lake’s biotic structure. Our ordination analysis suggests Plains experienced varying lake-specific over ~150 years, with two major trends across study lakes: (1) prevalent increase planktic (2) rise mesotrophic/eutrophic taxa receiving high human impacts. case identifies both historical events recent activities, cultural eutrophication warming. Overall, our demonstrates marked mainly associated