Biogeomorphic Interactions in Ice-Driven Fluvial Hydrosystems

Riparian areas are important ecosystems that need to be restored and protected in the Anthropocene era. In Quebec, Canada, conservation laws and management strategies focus on ecological services provided by riparian communities, such as erosion and flood control, carbon sequestration, and pollutants filtration. However, there is a need to incorporate fluvial biogeomophological approaches to improve our understanding of those systems. Biogeomorphology explores both the impacts of flood regime and disturbances on plant structure and composition and the role of plant communities in altering hydrosedimentary processes. Approaches anchored in biogeomorphology have proven to be efficient to understand interactions and feedbacks between fluvial dynamics and plant ecology in many contrasted environments, from temperate to arid regions and from small streams to large rivers. However, those approaches have never been applied to rivers disturbed by ice dynamics. Ice jams and mechanical breakups are known to disturb fluvial systems, both geomorphologically and ecologically. Moving ice during breakups has the potential to severely erode banks and transport sediment, thus destroying riparian habitat and disturbing plant succession dynamics. Feedback dynamics between plants and rivers are thus obviously affected by ice disturbances regime. There is a need to understand how fluvial biogeomorphic systems respond to such disturbances to assess better management strategies and improve prevision models in a context of climatic change. In this poster, we expose a research project aiming at conceptualizing how ice disturbances regime controls the biogeomorphic interactions in two rivers located in eastern Quebec, Canada. To do so, analyses will be held in three distinct spatiotemporal scales: 1) decennial biogeomorphological trajectories, 2) plant community structure and composition on distinct fluvial landforms and 3) functional traits of ice-disturbed indicator species.