Skip to main content

Physical and Human Factors Influencing Potential Fish Habitat Distribution along a Mountain River, France

Buy Article:

$51.00 plus tax (Refund Policy)


Potential fish habitat along the Drôme River, France, is a function of the distribution of large woody debris, boulders, undercut banks, gravel substrate, and pools. The distribution of these features is, in turn, a function of channel geomorphology, watershed and riparian forest characteristics. We conducted field work and analysed aerial photographs for 190 elementary segments of 500 m length along the Drôme River's 95 km course from the Alps westward to its confluence with the Rhône River near Loriol. The Drôme River does not follow the classic pattern of a monotone downstream decrease in gradient and change in channel characteristics. Although channel gradient, braided index and channel incision all decrease downstream, stream power is independent of longitudinal distance. These variables are largely controlled by geomorphic, human or hydrologic factors at the reach scale. Potential fish habitat richness decreases downstream, but individual habitat variables affecting habitat richness do not necessarily decrease downstream, many being controlled by local factors rather than by position along the continuum. Large woody debris is more abundant in braided reaches located directly downstream of confluences with main tributaries or downstream input sites. Boulders are most abundant downstream of failed bank protection works or in gorges. To improve fish habitat in the Drôme River, we recommend taking a long-term and large-scale perspective. Because structures placed in this unstable channel are likely to be washed downstream, we propose to emulate natural river dynamics and to permit large woody debris to enter the channel in unstable reaches via bank erosion, and that this debris not be removed (as is routinely done now) but permitted to migrate downstream through the system, creating fish habitat en route.

Keywords: boulders; ecological management; fish habitat potentiality; fluvial continuum; geomorphological pattern; large woody debris; network; pools

Document Type: Research Article


Affiliations: 1: CNRS–UMR 5600 ‘Environnement–Ville–Société’, France, 2: Division ‘Biologie des Ecosystèmes Aquatiques’, CEMAGREF de Lyon, France, 3: University of California at Berkeley, USA

Publication date: April 1, 2000


Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more