PROJECT DESCRIPTION
BACKGROUND
The river Rhine is a very busy shipping route in Europe and flows through densely settled terrain, so regulation of its hydrology began long ago and has continued until today. Some impacts of these interventions on the natural river and floodplain ecosystems are immediate and obvious; others such as desiccation and stagnation are long-term and insidious. Along the upper Rhine around Karlsruhe, about 7 500 ha of floodplain still has a high nature value, such as former tributaries and side channels of the Rhine river, wet meadows and calcareous fens and woodland subjected to summer floods. However, the hydrological regulation of the river had reduced dynamics to the point where pioneer communities were disappearing and standing waters were terrestrialising (infilling). Land use changes were affecting the woodlands and wet meadows. Besides these physical threats to the area, the recreational demands of the inhabitants of the Karlsruhe urban area were causing increasing disturbance to wildlife.
OBJECTIVES
The project’s overall objective was to implement a series of measures aimed at improving the conservation status for species and habitats of the river Rhine floodplain. Although river dykes had to remain in place, the project aimed at a substantial improvement to the hydrological dynamics of the area which, after the initial work, could be left to its own devices. Particular attention would be paid to reversing the silting up of former river arms, and to boosting water flow through the extensive ditch system so that this would act as an interconnecting network linking floodplain wetlands.
An important aspect was to ensure broad local support. Therefore the beneficiary assembled no less than 17 partners, from municipalities and district authorities to angler associations and nature conservation NGOs.
The gradual disappearance of the white willow and black poplar, two crucial elements of the alluvial forest vegetation, was one of the main problems addressed by this project. Allowing more natural flooding was one aspect, but others included planting trees and preparing appropriate sites for natural germination of the seeds. Other plants such as great fen-sedge (Cladium mariscus) and its habitat of calcareous fens and wet grasslands, water clover (Marsilea quadrifolia) and water chestnut (Trapa natans), would also be nursed back to a healthy conservation status, in part by employing free-range pigs.
Due to the huge recreation demands, a significant part of the project would focus on new information and visitor guidance strategies such as an electronic mobile nature guide besides equipment for guided tours such as boats and bikes. Live broadcasting from the project area into schools and the on-site information centre would be launched, to bring a special live ‘LIFE’ element.
The following main actions were planned:
RESULTS
Overall, the project was successfully implemented. In most cases the actions were carried out as planned, resulting in some 100 different project measures carried out in the project area (a total of 7 665 ha). All the project measures aimed to improve the conservation status for species and habitats of the river Rhine floodplain area. However, specific actions were extremely varied, from the protection of a single species (e.g. water chestnut) to the initiation of ecological processes, such as flooding and erosion.
Also as envisaged, all project measures were intensively discussed with various experts of different areas, before they were carried out. This sometimes slightly delayed the project implementation, but nevertheless led to an improved project implementation.
The most relevant project achievements include the following: Habitat improvements:
Small-scale measures: A high number of small-scale measures were successfully implemented. These works (e.g. reshaping of drainage channels, creation of new ponds and actions for species protection) have created new valuable habitats. Separately, these actions had a relatively small impact. But, overall, due to the high number of on-site measures, there has been a large-scale, positive conservation impact.
Public relations: The project carried out a very intensive public relations campaign that involved the organisation of 150-200 events/ year attracting more than 10 000 visitors/ year. A book on the ecology of the project area and the LIFE measures was also published at the end of the project.
Positive ecological impacts: The transformation of habitats and the improvement of habitat conditions requires many years. Nevertheless, over the project period some remarkable positive ecological effects could already be observed. These included: (i) In 2005, a pond was created at the Fritschlaich site. Only two years later (in 2007) 37 different dragonfly species were observed. 20 species were successfully reproducing, including the rare dragonfly species, Gomphus pulchellus and Leucorrhinia caudalis; (ii) The removal of silt in the Eggensteiner Altrhein resulted in a substantial increase of the number of mollusc species. At the end of the project, the number of mollusc species had almost doubled. One of the species (Pisidium pseudosphaerium) was recorded during the monitoring surveys for the first time in South-West Germany. (iii) The reshaping of the drainage ditches also had a very rapid positive ecological impact. At one ditch (Neugraben) the population size of the target species, Coenagrion mercuriale, was ten times higher than before, after the re-profiling of the ditch, which is an extremely good result.
