title: Floodplain forest succession reveals fluvial processes: A hydrogeomorphic model for temperate riparian woodlands.
abstract: River valley floodplains are physically-dynamic environments where fluvial processes determine habitat gradients for riparian vegetation. These zones support trees and shrubs whose life stages are adapted to specific habitat types and consequently forest composition and successional stage reflect the underlying hydrogeomorphic processes and history. In this study we investigated woodland vegetation composition, successional stage and habitat properties, and compared these with physically-based indicators of hydraulic processes. We thus sought to develop a hydrogeomorphic model to evaluate riparian woodland condition based on the spatial mosaic of successional phases of the floodplain forest. The study investigated free-flowing and dam-impacted reaches of the Kootenai and Flathead Rivers, in Idaho and Montana, USA and British Columbia, Canada. The analyses revealed strong correspondence between vegetation assessments and metrics of fluvial processes indicating morphodynamics (erosion and shear stress), inundation and depth to groundwater. The results indicated that common successional stages generally occupied similar hydraulic environments along the different river segments. Comparison of the spatial patterns between the free-flowing and regulated reaches revealed greater deviation from the natural condition for the braided channel segment than for the meandering segment. This demonstrates the utility of the hydrogeomorphic approach and suggests that riparian woodlands along braided channels could have lower resilience than those along meandering channels and might be more vulnerable to influences such as from river damming or climate change.
authors.affiliation: Institute of Floodplain Ecology, Karlsruhe Institute of Technology, Josefstrasse 1, D - 76437 Rastatt, Germany; Environmental Consulting Ltd., Bahnhofstrasse 39, 9020 Klagenfurt, Austria.
authors.forename: Gregory
authors.initials: G
authors.lastname: Egger
authors.affiliation: University of Trento, Department of Civil, Environmental and Mechanical Engineering, Via Mesiano 77, 38123 Trento, Italy. Electronic address: emilio.politti@umweltbuero.at.
authors.forename: Emilio
authors.initials: E
authors.lastname: Politti
authors.affiliation: Environmental Consulting Ltd., Bahnhofstrasse 39, 9020 Klagenfurt, Austria.
authors.forename: Erwin
authors.initials: E
authors.lastname: Lautsch
authors.affiliation: Center for Ecohydraulics Research, University of Idaho, 322 E. Front Street, Boise, ID 83702, USA.
authors.forename: Rohan
authors.initials: R
authors.lastname: Benjankar
authors.affiliation: University of Lethbridge, Department of Biological Sciences, Alberta, T1K 3M4, Canada.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Gill
authors.affiliation: University of Lethbridge, Department of Biological Sciences, Alberta, T1K 3M4, Canada.
authors.forename: Stewart B
authors.initials: SB
authors.lastname: Rood
mesh_terms: D001955:British Columbia; D057231:Climate Change; D017753:Ecosystem; D004777:Environment; D055868:Floods; D065928:Forests; D060587:Groundwater; D007061:Idaho; D008962:Models, Theoretical; D009009:Montana; D011210:Power Plants; D045483:Rivers; D014197:Trees
keywords: Black cottonwoods; Floodplain vegetation; Fluvial processes; Forest succession; Habitat indicators