Roland Carbiener

Aquatic macrophyte communities as bioindicators of eutrophication in calcareous oligosaprobe stream waters (Upper Rhine plain, Alsace)

The results cover a statistical analysis of the correlations between aquatic macrophyte communities and chemical parameters (N−NH4, N−NO3, P−PO4, COD, Temperature, dissolved O2, Cl) in unpolluted hard waters (upper Rhine rift valley). This study was based on a table of phytosociological relevés for six plant communities, named A, B, C, CD, D and E. The ecological determinism of the communities were defined from: The study of the seven foregoing physico-chemical parameters for 29 groundwater streams on periodical samples of water. The study of the change with time in the aquatic vegetation after change of the trophic status, confirmed by analysis. The comparative study of the vegetation of the streams and parts of the streams with different trophic statuses but fed by the same groundwater table of the Wurmian Rhine gravels. Analysis of the main components showed the good correlation between the macrophyte communities and the trophy (N−NH4, P−PO4). These six communities were classified according to the trophic scale. Discriminant analysis was used to compare the classification of the phytosociological sequence with that based on the statistical analysis. The authors give a very precise bioindication scale (based on the macrophyte community) for the eutrophication degree in unpolluted hard waters.

Evolution of major pattern models and processes of alluvial forest of the Rhine in the rift valley (France/Germany)

In the rift valley (North-East of France/South-West of Germany), the Rhine runs freely for 300 km from South to North. The absence of natural obstacles allows the development of a very regular profile of the river. We have therefore an opportunity to study very gradual modifications of the alluvial forest communities of the fluvial corridor from upstream to downstream, according to the gradual evolution of the ecological factors, related to slope decrease and hydrological modifications. We describe, from Basel to Mainz: 1) modification of dynamic processes in the forest communities such as successional sequences or sylvigenetic mosaïcs of the terminal stages. 2) modification of species richness. 3) reduction of species diversity. 4) simplification of the forest stratification. 5) modification of efficiency of the biogeochemical cycling. 6) ecological vicariances. 7) modification in species behaviour. modification of dynamic processes in the forest communities such as successional sequences or sylvigenetic mosaïcs of the terminal stages. modification of species richness. reduction of species diversity. simplification of the forest stratification. modification of efficiency of the biogeochemical cycling. ecological vicariances. modification in species behaviour.

The exchange process between river and groundwater on the central Alsace floodplain (Eastern France). II: The case of a river with functional floodplain

The floodplain of the river Ill in the Alsace Rhine valley is used as a model to study river-groundwater exchange process. Groundwater-fed streams located in the Ill floodplain are analysed using three methods: an analytical method based on hydrochemical variables (Cl− NO3−, PO43−and NH4+), a phytosociological one based on surveys of aquatic macrophyte communities and a biological method based on the accumulation of mercury in the moss Fontinalis antipyretica. The results show that the eutrophicated and polluted river Ill (660 µg l−1 N-NH4+, 500 µg l−1 P-PO43−, 0.3–0.4 mg Hg kg− dry weight of moss) has a negative effect on the groundwater via the bed, depending on the level of the river bed in relation to the groundwater table level. Upstream of Colmar in the south of the Alsace floodplain, the Ill waters infiltrate and contaminate the groundwater, but this is not the case further downstream. Along a stretch of the Ill (40 km) annual floods provide eutrophicated and polluted waters to the aquifer. However these waters are purified during their transfer through the soil-vegetation system. Thus in the groundwater-fed streams the water is characterised by a low level of phosphate, ammonium nitrogen and mercury (10–20 µg l−1 N-NH4+ and P-PO43−, < 0.05 mg Hg kg−1 dry weight of moss). We demonstrate the importance of a functional floodplain in replenishing the aquifer with poor-nutrient waters. The aquatic vegetation of groundwater-fed streams reflects the water quality and thus can be used as a bioindicator and descriptor of river-groundwater exchange process.

Changes in aquatic vegetation in Rhine floodplain streams in Alsace in relation to disturbance

Abstract. Changes are described in aquatic vegetation in oligotrophic, groundwater-fed Rhine floodplain streams in Alsace (eastern France), resulting from disturbance. Disturbance factors include changes in nutrients, either permanent ones - effluent from a waste water treatment plant or trout hatcheries - or periodic ones: flooding. Regular inputs of high levels of phosphate and ammonia modified the macrophyte vegetation in these streams. The floristic composition, which was characteristic of oligotrophic waters upstream of the eutrophicated sector, changed to that of a eutrophic situation as originally found downstream. Periodic disturbance by floods which normally occur once a year, irregularly eutrophicates the small streams, causing the development of a mixture of eutrophic and oligotrophic species. Six macrophyte communities are distinguished, indicating different trophic levels. The aquatic vegetation is adapted to the variations of phosphate and ammonia levels. Hence, aquatic macrophytes can be used as bio-indicators of fluctuations in water nutrient levels in relation to the type of disturbance.

Végétation des eaux courantes et qualité des eaux: une thèse, des débats, des perspectives

Summary The macrophytes in running waters are good bioindicators for using either water or sediment-water interactions. The bioindication is realized at the species level by stenoecic species in relation to the factor considered (mineralisation and trophy), or at the level of phytocenoses. Several conditions have to be met to obtain bioindication scales which are quantified and reproducible. These are the a) hydrological sampling, b) definition of the water qualities, c) existence of a complete range of variations of these qualities, d) integration of rheological, sedimentological and morphometric facies in the vegetation sampling. Condition a) is met in the alluvial alsatian floodplain of the Rhine, which is characterized by highly mineralized, calcic bicarbonated waters and the large plateau of triassic sandstone of the Northern Vosges with poorly mineralized waters. These two sectors will be used as model for our demonstration. Saproby and trophy will be distinguished. Moreover the trophic quality need...

Synsystematic division and syndynamics of the Potamogeton coloratus community in flowing waters of Southern Central Europe

Summary Phytosociological surveys of the Potamogeton coloratus-commurity were made in 19 flowing waters of Southern Central Europe (Alsace, south of Germany, Central Switzerland) to study the status of this community; it is characteristic of oligotrophic hard waters and to a large extent independent of morphometry and current velocity. The synsystematic analysis of 63 releves showed that this community maintains a well defined floristic composition in flowing waters; it was divided into 3 subunits, according to floristic and ecological criteria. Studies of the succession after clearing in two Alsatian waters (and numerous releves which have been made over long periods in some other waters) showed that the community regenerates easily and recovers the typical former floristic composition after three to four years if the water quality remains constant or recovers its oligotrophic status. It may have a pioneer behaviour. This study confirms its total destruction by even a slight eutrophication.