Aquatic bryophyte assemblages along a gradient of regulation in the river Rhine

in Hydrobiologia (2000), 410

A study of the zonation of the aquatic bryophyte assemblages from the Anterior Rhine to the Middle Rhine is presented. The typology obtained differs from the hydrogeoinorphological classification because ... [more ▼]

A study of the zonation of the aquatic bryophyte assemblages from the Anterior Rhine to the Middle Rhine is presented. The typology obtained differs from the hydrogeoinorphological classification because the correction of the river has led to the homogenization of habitats. Since the straightening of the river in the course of the 19th century, the embankments have created more stable habitats on which mountain species formerly characteristic of the rapids of the High Rhine appeared. During the 20th century, regulation, the construction of hydroelectric powerstations even the canalization of the river in Alsace. have caused a great change in water level. On the Upper Rhine, the rcgularisation of the water level .'allowed the appearance and the spread of strict hydrophytes such as Octodiceras fontanum which is now common between Rastatt and Bonn. Conversely, species characteristic of variable water levels decreased or disappeared. The industrial development along the river has caused water quality to severely decrease downstream of the industrial areas, hence the decrease or the disappearance of their primary flora in favour of pollution-tolerant assemblages. The former side channels of the Upper Rhine in France that have been disconnected from the main river and fed by groundwater since canalization, possess a bryophyte flora very similar to that of good quality waters in the upstream part of the High Rhine or in the Alpine Rhine. This flora is the last regional relic of a flora that has disappeared from the main channel due to water pollution. These refugia should consequently be preserved from the flooding of alluvial forests, part of the flood management program. [less ▲]

Etude écosystémique d'une gravière de l'ancien lit majeur du Rhin (Krafft-Erstein, Bas-Rhin, France)

in Martinia (1999), 15(1), 3-13

A comparative study of the hydrophyte flora from the Alpine Rhine to the Middle Rhine. Application to the conservation of the Upper Rhine aquatic ecosystems

in Biological Conservation (1999), 87(2), 163-172

A typology of the main channel of the river Rhine according to its aquatic bryophyte and vascular hydrophyte assemblages is presented. The aquatic bryophytes are especially abundant in the main channel ... [more ▼]

A typology of the main channel of the river Rhine according to its aquatic bryophyte and vascular hydrophyte assemblages is presented. The aquatic bryophytes are especially abundant in the main channel, having found stable, rocky habitats with variable water levels in the regulated river, and segregate longitudinally along a gradient of water quality. Conversely, the vascular hydrophytes are restricted to side channels with constant discharges and silt deposits, and segregate laterally along a gradient of connectivity with the main river. The hydrophytes have been affected by water eutrophication which became obvious in the 1960s-1970s. The oligotrophic groundwater-fed side-channels disconnected since the river canalization consequently include a relic reference flora. Important hydraulic works are currently in progress in order to protect the areas located downstream from the canalized Rhine from flooding by retaining the river waters in lateral systems during the discharge peaks and to recreate a functional alluvial floodplain by reconnecting the disconnected side-channels to the main river. The floodpulse caused by the suddent input of surface water in the disconnected brooks will probably wash out most of the hydrophytes and it is very likely that the rare species with their low recolonization strategies will disappear in these conditions. It is highly desirable to preserve from flooding the last oligotrophic brooks with their original hydrophyte assemblages. Those brooks which show a tendency to silt up can be re-dynamized by ecological engineering without disturbing the flowing drains of the watertable. In areas (including flowing drains of the watertable) that have already been designated for flood retention, the hydraulic works should allow, as far as possible, the preservation of the flowing oligotrophy streams by only permitting the input of surface water in the silted-up brooks. The disconnected side-channels could then continue their role as refugia from where the main channel, whose water quality has been improving for a decade, could be recolonized by its primary flora. [less ▲]

Aquatic Bryophyte Assemblages Along A Gradient Of Regulation In The River Rhine

in Hydrobiologia (1999), 410

Typologie bryologique des pelouses calcaires en Petite Camargue Alsacienne (Haut-Rhin, France) appliquée à la gestion conservatoire des milieux semi-naturels

in Ecologie (1997), 28

La cartographie des hydrophytes appliquée à l'étude des écosystèmes fluviaux: un outil d'analyse pour la restauration des anciens chenaux rhénans

in Lejeunia (1997), 153

La bryoflore d'une mosaïque alluviale rhénane: la réserve naturelle de la Petite Camargue Alsacienne (Haut-Rhin)

in Bulletin de la Société Botanique du Centre-Ouest (1996), 27

Etat de préservation et stratégie conservatoire des écosystèmes rhénans en France: bilan et perspective

in Actes du Colloque 'Fleuve Patrimoine': mettre en valeur un fleuve: pourquoi?, Québec 30/9-1/10/1996 (1996)

Evaluation bryologique d'un projet de réinondation par les crues du Rhin: l'exemple de la réserve naturelle d'Erstein (Alsace, France)

in Belgian Journal of Botany (1995), 128