Flood-meadow project
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A testing and development project aiming at the Restoration of flood-meadows along the northern Upper Rhine and their integration in agricultural utilisation systems.
Iris sibirica, Galium wirtgenii
and Leucanthemum vulgare agg. forming a
colourful aspect on a restoration site in Riedstadt
Iris spuria (here with a swallowtail), a very rare species of Irises with a major occurrence
on the Hessian upper Rhine; here on a restoration site in Riedstadt, proving
the success of plant material transfer as a measure for species-enrichment
The beautiful Gentiana pneumonanthe adds a deep blue to the second
blossoming season of the floodplain meadows in August.
Arabis nemorensis, another very rare and protected species on a
restoration site in Riedstadt
Since October 2000 a project aiming at the recovery of floodplain-meadows has been taking place in the city of Riedstadt, which is situated 40 km south-west of Frankfurt in the Holocene floodplain of the northern Upper Rhine, where species-rich remnant populations of alluvial meadows still occur. Such meadows mainly appear along the big streams in Eastern Europe under the influence of continental climate, moderate human utilisation and an extreme change of water conditions: periods of inundation (usually between winter and early summer) are followed by drought in summer, resulting in a highly specific combination of species. While floodplain-meadows are still fairly common in Eastern Europe, they belong to the rarest habitats in Central Europe. Both types of floodplain-meadows found in Riedstadt (alliances Cnidion on rich alluvial soils and Molinion on rare nutrition-low soils which are the result of former extraction of clay for building purposes) are protected according to appendix 1 of the Flora-Fauna-Habitat directive of the European Union. The floodplain-meadows at the Hessian Upper Rhine are inhabited by a large number of rare and endangered species as e.g. Iris spuria, Arabis nemorensis, Cnidium dubium, Viola pumila or Iris sibirica, Gentiana pneumonanthe, Allium angulosum and Galium boreale.
The project pursues two main purposes: 1) the enlargement of species-rich floodplain-meadows by restoration of ex-arable fields and, to a lesser degree, species-poor meadows and 2) the implementation of an agricultural utilisation system which enables long-term maintenance of the meadows without governmental subsidies.
The restoration area consists of now 58 ha lined up along both sides of the main dyke of the Rhine, thus including areas in the functional floodplain as well as in the fossil floodplain. Of these, 20 ha were bought by the city of Riedstadt from federal subsidies, 14 ha were contributed by the federal state of Hesse, 23 ha by the city itself and 1 ha by a private organisation for nature conservation. Aiming at a species-enrichment diaspores are transferred with plant material from the existing species-rich floodplain-meadows onto the restoration fields with a loader-wagon (with pick-up, cutting knives and proportioning rollers), thus allowing quick and effective work. The transfer takes place in late summer/early autumn, when the majority of the target species bears ripe seeds. Due to a shortage of hay we had to restrain the disposal to 10 to 20 % of the restoration fields; it usually was discharged onto the fields over the whole length in strips of 5 to 10 m width. In case of existing dense vegetation these strips were rotovaded prior to the disposal of plant material to diminish competition pressure and stimulate germination of the target species. Due to a major donation of the Frankfurt Airport it will be able to continue the project, which was meant to end in February 2005, for at least two more years and to increase the dimension of areas actually vaccinated with diaspore containing plant-material.
In order to establish an agricultural utilisation system local farmers were included from the very beginning of the project. Circumstances in Riedstadt are supporting the project as there is a high and long-term demand for hay to feed horses. This serves the conservational aims as horses need late cut hay, which in turn enables most of the target species to finish seed-production. Furthermore, a local shepherd is in need of pastures and hay, too, so that we are able to install a manifold utilisation system and explore its effects on the new flood-meadows.
Another major aspect of the project is to provide information about it for the local community - in order to enhance the acceptance of the undertaken measures not only among the farmers but all citizens - as well as for people working in the field of nature conservation and for the scientific community. A lot of papers and some diploma and doctoral theses have been published in the course of the project (see: www.uni-giessen.de/stromtalwiesen/eng/).
Matthias Harnisch, Department of Environment and Economy, City of Riedstadt, Rathausplatz 1, D-64560 Riedstadt, mail to: m.harnisch@riedstadt.de
Viola pumila on a donor site in the
nature reserve "Riedwiesen von Wächterstadt"
..and Viola pumila on a restoration site.
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