title: Gravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes.
abstract: Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologic-altering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth.
authors.affiliation: Center for Integrated Research on the Environment, University of Montana, Missoula, MT 59812, USA.; Flathead Lake Biological Station, University of Montana, Polson, MT 59860, USA.
authors.forename: F Richard
authors.identifier: 0000-0002-8274-8148
authors.initials: FR
authors.lastname: Hauer
authors.affiliation: Yellowstone to Yukon Conservation Initiative, Box 4887, Banff, Alberta T1L 1G1, Canada.
authors.forename: Harvey
authors.identifier: 0000-0002-0375-8824
authors.initials: H
authors.lastname: Locke
authors.affiliation: Wildlife Biology Program, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA.
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Dreitz
authors.affiliation: Wildlife Biology Program, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA.; Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Hebblewhite
authors.affiliation: Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA.; Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA.
authors.forename: Winsor H
authors.initials: WH
authors.lastname: Lowe
authors.affiliation: Flathead Lake Biological Station, University of Montana, Polson, MT 59860, USA.; U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT 59936, USA.
authors.forename: Clint C
authors.initials: CC
authors.lastname: Muhlfeld
authors.affiliation: Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA.
authors.forename: Cara R
authors.identifier: 0000-0001-7508-0859
authors.initials: CR
authors.lastname: Nelson
authors.affiliation: Birchdale Ecological, PO Box 606, Kaslo, British Columbia V0G 1M0, Canada.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Proctor
authors.affiliation: Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta T1K 6T5, Canada.
authors.forename: Stewart B
authors.initials: SB
authors.lastname: Rood
mesh_terms: D000818:Animals; D044822:Biodiversity; D003247:Conservation of Natural Resources; D004463:Ecology; D017753:Ecosystem; D055868:Floods; D005843:Geography; D019015:Geologic Sediments; D055593:Geological Phenomena; D006801:Humans; D046448:Ice Cover; D045483:Rivers
keywords: Gravel-bed rivers; biodiversity; complexity; connectivity; coupled natural and human systems; disturbance; ecosystem conservation; floodplains; hydrogeomorphic