Browse by author
Lookup NU author(s): Emeritus Professor Malcolm Newson
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
© Arnold 2000. The physical component of river channel (mstream) habitat is of acknowledged significance, particularly in headwater streams; furthermore, physical habitats have been heavily impacted by human needs for river services: principally flood defence (channel modification) and water resources (flow regulation). Despite the control exercised on physical habitats by fluvial geornorphology (channel shape, bed material size, bedforms and bars) and flow regime (including the varying hydraulics of flow around these forms), their interaction has hitherto lacked a distinctive spatial formulation and biological validation. This article describes the challenges faced by a need (in both theoretical and practical areas) to understand the detail of physical habitat conditions in stream channels. A number of mesoscale approaches are emerging, both from ecology and geomorphology. We outline the field validation of a 'habitat hydraulics' approach to the interaction between river discharge and channel form. Qualitative 'flow types' are shown to be representative of discrete hydraulic conditions within mesoscale units of the channel bed described as 'physical biotopes'. The approach is compared with parallel ecological research on 'rnesohabitats' and 'functional habitats'. The extent, pattern and discharge-variability of physical biotopes can be surveyed in the field and used as a spatial guide to biological sampling (in this case for benihic invertebrates). Biological patterns (at the scale sampled here) appear to respond first to the river continuum concept's longitudinal zonation of the channel, but there is a marked secondary signal in statistical analyses from the pattern of biotopes. Given the promise of the physical biotope approach, its logical extension in predictive mode is via the hierarchical concepts shared by freshwater ecologists and geomorphologists; however, there is little agreement or. scale terminology, hierarchical principles and, above all, a truly geomorphological channel classification, based on reaches, into which mesoscale habitat typologies could be fed. Assuming a relationship between biological diversity and that of physical biotopes it should be the aim of river managers, whether intervening in the channel form or its flow regime, to optimize certain parameters of the pattern of biotopes; these parameters should be a focus for future research. Both the rapid survey and proper description of these patterns will benefit from the application of remote-sensing technology, improved instruments for microscale hydraulic studies and a G1S approach based upon the spatial principles of landscape ecology.
Author(s): Newson MD; Newson CL
Publication type: Article
Publication status: Published
Journal: Progress in Physical Geography
Year: 2000
Volume: 24
Issue: 2
Pages: 195-217
ISSN (print): 0309-1333
ISSN (electronic): 1477-0296
Publisher: Sage Publications Ltd.
URL: http://dx.doi.org/10.1177/030913330002400203
DOI: 10.1177/030913330002400203
Altmetrics provided by Altmetric
