Historical Changes in the Ecological Connectivity of the Seine River for Fish: A Focus on Physical and Chemical Barriers Since the Mid-19th Century

摘要: To understand the long-term fate of fish assemblages in context global change and to design efficient restoration measures river management, it is essential consider historical component these ecosystems. The human-impacted Seine River Basin a relevant case that has experienced extinction diadromous fishes over last two centuries recently witnessed recolonization some species. One key issue evolution habitat accessibility for migratory Thanks unique availability historical, mainly hand-written sources multiple types (river engineering projects, navigation maps, paper-based databases on oxygen, etc.), we documented integrated, geographic information system-based database, changes physical chemical barriers from sea Paris three time periods (1900s, 1970s, 2010s). potential impact runs species have different behaviors—Atlantic salmon, allis shad, lamprey—was evaluated by ecological connectivity modeling, using least-cost approach integrates distance, costs, risks related barriers. We found was contrasted between species, emphasizing crucial role migration type, period, level tolerance low dissolved oxygen values. highest disruption visible when effects large hypoxic areas were compounded those impassable weirs (i.e., without passes). As able reveal relative contribution overall functional connectivity, may constitute model work assessing functioning