CGRG Bibliography of Canadian Geomorphology
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Author : Green, K.; and Steeger, C.
Date : 2007.
Title : Spatial and temporal variability in riparian function: Case studies from Kootenay–Columbia headwater basins
Publication : Riparian Management in Headwater Catchments: Translating Science into Management. Feb. 20-21, 2007. The University of British Columbia, Vancouver, BC
Issue : Conference Program Abstracts
Page(s) : 13.
Abstract
Spatial variability in riparian ecosystems is linked to the changing dynamics of riparian function with increasing stream size and decreasing stream gradient. In Kootenay – Columbia headwater basins channel widths of 15 meters and channel gradients of 3 percent represent threshold conditions for riparian function. In channels with gradients greater than 3 percent and widths less than 15 metres riparian vegetation plays a crucial roll in determining channel morphology, rate of lateral migration and sediment transport processes. As channel gradient drops below approximately 3% and channel width increases beyond 15 metres, channel morphology and sediment transport are controlled by predominantly alluvial processes. Temporal variability in riparian ecosystems is linked to natural disturbance regimes. Fire and floods are the most frequent disturbance events in Kootenay – Columbia headwater basins, although landslides, bank failure, debris and/or ice flows, snow avalanches, beaver, wind, grazing, diseases and insects can also be significant agents of riparian disturbance. Abrupt changes in riparian vegetation and rates of LWD recruitment during and immediately following disturbance events are typically followed by long term successional changes in riparian stand composition. Physical changes in channel morphology and sediment transport rates reflect the dynamic aspects of riparian function in the decades and centuries following disturbance events. Recognizing and managing towards spatial and temporal variability in riparian function is necessary to ensure longterm sustainability of hydroecological and hydrogeomorphic processes. Mandating fixed width riparian reserves limits the potential for natural variability and could have long-term detrimental consequences. The impacts of early 1900’s logging activities are clearly evident in many Kootenay – Columbia headwater basins a century later. Impacts associated with removal of beaver from many headwater catchments through the 19th and 20th centuries will likely be evident for millennia.
Bibliography of Canadian Geomorphology