Geomorphological concepts and tools for sustainable river ecosystem management

Abstract

ABSTRACT1. Under definitions of 'strong' sustainability, ecosystem protection and the valuation of natural goods and services figure prominently. These priorities also lie at the heart of the EC Water Framework Directive (WFD).2. This paper explores the ability of fluvial geomorphology to describe, monitor and predict river channel conditions and behaviour at the basin and smaller scales. It also examines how geomorphology can help to create management 'tools' and work in interdisciplinary frameworks with freshwater ecology to assess instream physical habitat.3. Systematic views of river basins and predictive techniques based on system drivers have been popular in fluvial geomorphology for 50 years. System states are seen as resulting from the balance between all relevant processes. However, channel dimensions and forms at a site are much harder to predict and their dynamic adjustment can occur rapidly, exhibiting 'threshold' behaviour.4. Direct human impacts have been a focus of research but long-term monitoring of channel states and adjustments has been neglected; River Habitat Survey offers major opportunities in this respect, even though it was not designed specifically for geomorphological interpretation.5. In the UK, local or 'reach'-scale channel adjustment is widespread, justifying a major empirical survey effort in support of management decisions. Channels are supply-limited in sediment terms, polycyclic in profile, confined within glacial and periglacial sediments and extensively manipulated by engineering modifications. Whilst system properties are vital to the choice of management options over long timescales, conditions on a hierarchy of smaller scales can confound the systematic attempts of geomorphologists to classify and predict channel states.6. Freshwater ecologists have long appreciated the need for a scaled approach to river systems. This paper argues for extensions to shared data collection and analysis programmes before immutable policy becomes established around unfinished management tools. Adaptive management creates a more realistic medium for the use of uncertain geomorphological and ecological predictions.

Benthic and hyporheic macroinvertebrate distribution within the heads and tails of riffles during baseflow conditions

“…Although the processes which structure invertebrate communities at varying spatial scales have been examined Newson, 2002;Chessman et al, 2006), knowledge regarding the sediment characteristics and patterns of vertical hydrological exchange at the habitat/geomorphic unit scale (small-scale morphological features) and their associated relationships with macroinvertebrates requires further examination through field investigations. It is widely acknowledged that geomorphic units and river bed sedimentary characteristics influence the structure and functioning of macroinvertebrates, but community variation across individual morphological units (e.g.…”

Influence of morphohydraulic habitat structure on invertebrate communities (Ephemeroptera, Plecoptera and Trichoptera)

“…These tasks lead to the cooperation of several branches of science such as fluvial geomorphology, ecology, zoology, botany, etc. Contribution of fluvial geomorphology represents understanding and analysis of processes which form the river channel and methods of assessment of physical habitats (Newson & Newson 2000;Newson 2002;Gordon et al 2004;Clifford et al 2006). It was recognised in stream ecology that the diversity of stream communities is directly influenced by the heterogeneity of abiotic environment (Hynes 1970).…”

Caracterización geomorfológica de los ríos de Galicia mediante unidades litotopográficas

“…Las ULT contienen toda la carga explicativa de la estructura (litología y tectónica), mientras que la cuenca vertiente se caracteriza únicamente por su tamaño. En cualquier caso, ambos factores son complementarios y nunca excluyentes: la ULT refuerza el análisis de la influencia geomorfológica en los ecosistemas (Montgomery, 1999;Ibisate et al, 2011); en cambio, la cuenca, explica los procesos ligados a su tamaño y, además, delimita un sector lógico para evaluar los impactos geomorfológicos sobre los procesos ecológicos, de ahí que proporcione un marco de gestión y análisis ideal en la dirección de recursos naturales (Newson, 2002).…”