Flood-meadow project
Participants
Land Hessen
Justus-Liebig-Universität Giessen
Stadt Riedstadt
Sponsor
Fraport AG
Supporters
Hessische Industriemüll GmbH
Claas KGaA mbH Landmaschinen
Seippel Landmaschinen
Restoration of floodplain meadows along the northern Upper Rhine and their integration in agricultural utilisation systems
Matthias Harnisch, Department of Environment and Economy, City of Riedstadt, Rathausplatz 1, D-64560 Riedstadt
- Introduction
- Project area
- Restoration Measures
- Agricultural use
- Public relations
- Financing
- Results / Conclusions
- Contact / Links
Introduction
Ecological conditions
Floodplain meadows are characterised by very specific conditions:
In the project area we have a very warm and dry climate.
Most important is an extreme change of water conditions with more or less regular inundation (usually in the winter half year) followed by warm and dry periods in the summer half.
Extreme change of water conditions in the project area, high level inundation (winter 2002/2003) followed by drought (Summer 2003)
In interaction with a non-intensive agricultural management this leads to a highly specific combination of species.
In the project area along the northern Upper Rhine there are still species- and individual-rich remnant stands of floodplain meadows, belonging to alliances Cnidion and Molinion, both protected by the Flora-Fauna-Habitat directive of the EU.
In Central Europe Cnidion-meadows are one of the most threatened plant communities. Many typical species reach in the study area the north-western limits of their distribution (e.g.: Allium angulosum, Cnidium dubium, Scutellaria hastifolia, Viola pumila).
Some species
Below, you can see some pictures taken on our meadows.
Viola elatior |
Viola pesicifolia |
Viola pumila |
Iris sibirica |
Iris spuria and Galium wirtgenii |
Iris spuria with a swallowtail |
Pseudolysimachion longifolium and Genista tinctoria |
Pseudolysimachion longifolium |
Allium angulosum and Molinia caerulea |
Allium angulosum |
Cnidium dubium |
Scutellaria hastifolia |
Serratula tinctoria |
Gentiana pneumonanthe |
Succisa pratensis |
Starting Point
In 1983 the inner dyke-system in the natural reserve "Kühkopf-Knoblochsaue" was demolished by a big flood.
In consequence were 300 ha of former arable land changed into woods (150 ha) by natural succession and grasslands (150 ha) by means of controlled succession (just cutting the upcoming vegetation once a year).
Now, after more than 20 years and in spite of suitable ecological conditions on these new meadows there are:
- still a low number of species,
- only trivial and common species and virtually
- no rare floodplain-meadow species.
So, as
- the ecological site conditions are favourable and
- highly valuable species-rich floodplain meadows are to be found nearby (distances lower than 1 km) and
- the new meadows are - after the partly destruction of the dykes in 1983 - regularly flooded and
- the management of the new meadows aims at the development of floodplain-meadows
Why did no target species occur after more than 20 years?
and
What are the limiting factors?
- Many of the target species do not build up a persisting soil seed-bank
- Many of the target species are characterised by very small dispersal distances (usually less than 1 m per year)
- Seemingly no effective transfer of diaspores and/or propagules through regularly occurring floods, in spite of stands with target species nearby
- Old means of dispersal do not exist anymore in modern agricultural landscapes (as e.g. random dispersion through loss of seeds in course of haymaking/ transport, transfer with cattle ect.)
So, we can say that the limiting factor is a lack of effective dispersal of target species.
Aims
The aims of the project are:
- The enlargement of highly rare species-rich floodplain meadows by restoration of ex-arable fields and, to a lesser degree, species-poor meadows
- The testing of diaspore transfer with plant-material as a restoration measure
- The implementation of an non-intensive agricultural utilisation system which allows the farmers to gain a decent income and at the same time enables long-term maintenance of the meadows
- Monitoring of the applied restoration measures as well as the assessment of ecology and population biology of flora and fauna in floodplain meadows.
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