James Ward, Surnadal 2002
TOWARDS A HOLISTIC PERSPECTIVE OF
RUNNING WATER ECOSYSTEMS
J. V. Ward
Professor of Aquatic Ecology
ETH - Zurich
Running water ecology is a young science, the conceptual foundations of which were derived largely from studies conducted in regions where river corridors had already been regulated for many decades (North America) or even centuries (Europe). Therefore, there is a general impression of rivers as being much less heterogeneous and much more stable than they are in the natural state. Due to a lack of fundamental knowledge of the structural and functional features of morphologically intact river corridors, established research and management concepts may fail to fully recognize the crucial roles of habitat heterogeneity and fluvial dynamics. This is especially true for floodplain segments, where river corridors formerly characterized by dynamic interactions and complex environmental gradients between lotic, lentic, riparian, and groundwater systems have been regulated to supress fluvial dynamics and trained to form straightened, artificially-constrained single thread channels. Unfortunately, many rivers are in such a state, but it should be recognized that this is not the natural condition. An incomplete appreciation of the complex nature of ecological patterns and processes in natural river ecosystems, including the critical role of natural disturbance, has constrained both theoretical advances in the discipline and the effectiveness of river conservation and restoration initiatives. Results from research on European river ecosystems where natural ecological processes still operate on a relatively large scale are presented to demonstrate the insight to be gained from such investigations. Examples are given of the high level of spatiotemporal heterogeneity that may be attained in such rivers. The goal is to promulgate a broader and more integrative understanding of natural processes in river corridors as a necessary prelude to effective river conservation and management. Reconstituting the functional integrity that characterizes intact river corridors should perhaps be the major goal of river conservation. Understanding ecological processes at the landscape scale is essential in this regard.
Ämne: James Ward, Surnadal 2002
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