The biogeomorphology of cold rivers: exploring the effects of ice dynamics from plants traits to landscapes

Significant progress has been made in the field of fluvial biogeomorphology in the last two decades regarding how vegetation and fluvial landforms co-adjust to shape rivers within different rivers and disturbance regimes. However, the understanding of biogeomorphological behaviors that emerged is largely built on studies made in temperate regions with a focus on flood regime. While over 20% of the worldwide continental surface lay in cold climate, rivers in these regions have been largely underrepresented in biogeomorphology and are worth exploring considering the presence of fluvial ice dynamics. These rivers are subjected to an array of ice forms and processes that are known to affect flow structure, sediment dynamics, fluvial landforms and vegetation through ice-related flood and scour disturbances. Combining previous research results and literature reviews, this presentation aims to integrate fluvial ice dynamics into existing biogeomorphological concepts to generate new hypotheses about river behavior in cold climate. We first present and describe known ice forms and processes and their effects on riverscapes that may have significant implications for river-vegetation co-adjustment mechanisms. Then, we discuss how fluvial ice dynamics may modulate the expression and structure of biogeomorphological interactions. Based on study cases, we emphasize from evidence-based interpretation that ice dynamics do have a significant role to play in the trajectories and evolution of cold rivers. We use core frameworks from the field of biogeomorphology to trace these modulations across scales, from individual plant traits to landscape spatial organization. Reflections and hypotheses that are presented through out this discussion reveal the wide gradient of control ice dynamics can exert on different fluvial contexts and highlight key research gaps and avenues essential to increase our understanding. It is proposed that efforts must be put into long-term monitoring, comparative studies and numerical modeling to test different hypothesis and frame the place of ice dynamics within biogeomorphological frameworks. Not only these suggestions are of particular interest for theoretical advancements in understanding cold rivers behavior, but they would also provide invaluable insights for better prediction and management in a context of climate change.