68
I
LIFE improving the conservation status of species and habitats
Though often only a few square metres in area, petrifying springs with tufa formation and their immediate surroundings are a valuable and unique habitat for certain species.
LIFE conservation of a special habitat: petrifying springs with tufa formation
M
any petrifying springs have suffered from human interference such as attempts to make them more attractive by encasing them in constructions, draining and their use as rubbish dumps. They are also highly sensitive to changes in their surroundings. This particular type of spring is formed where spring water with high calcium carbonate content comes out of the ground. On contact with the air, carbon dioxide is lost from the water and a hard deposit of calcium carbonate (tufa) is formed. Tufa-forming springheads are characterised by the swelling yellow-orange mats of the mosses and algae of the phytosociological alliance Cratoneurion, with the mosses from the genus Cratoneuron dominant. Many rare, lime-loving (calcicole) species live in the moss carpet. Threats resulting from direct human intervention include the discharge of liquid manure and pesticides in adjacent catchment areas and the inflow of warmer drainage water from farmland. Moreover, the mosses and algae on which the habitat depends decline if conditions concerning shade, microclimate and pH of the water are not perfect. LIFE projects have demonstrated that restoring the natural conditions for this unique micro-habitat can have a beneficial effect on its long-term survival. A wide range of site-specific hydromorphological actions have been carried out at strategically important sites in Europe.
LIFE actions One of the largest concentrations of petrifying springs in the EU is located in the Franco-Swabian Jura region of southern Germany. A particular threat for the tufa springs in the region is the substitution of native deciduous forests with monotonous stands of planted spruce. A LIFE project (LIFE03 NAT/D/000002) helped restore 56 spring habitats, carrying out a number of small-scale initiatives to ‘renaturalise’ individual springs. Various actions were carried out at specific sites. For example, a spring near Hohenstadt was used by the local community. Households were connected instead to the central drinking water supply and the concrete shafts to the spring were removed and the downstream area restored. Other actions included removing a concrete wall acting as a dam at one site to restore the free-flowing character of the stream fed from the spring. Around another spring a spruce monoculture was cleared from an area of around 2 000 m2. The exposed slope was then planted with more appropriate trees.
Protection of the spring with fences is another common conservation action. A spring in the community of Dittenheim, which has suffered from contamination and damage resulting from the grazing and excrement of sheep, was protected by a fence built by a youth welfare organisation. Also at a site near Rohrbach, in addition to the removal of spruce trees, the area around the spring was fenced off. LIFE projects have also increased our knowledge of the micro-habitat. For example, the Italian project, ‘V. Curone - V. S. Croce : protection priority habitats’ (LIFE98 NAT/IT/005037), carried out a study of the petrifying springs in the Valle San Croce Valle del Curone area close to Milan and undertook various measures in order to stabilise their hydrology, reduce visitor pressure and increase their stability. Detailed mapping of springs with tufa allowed new localisation in several sites within the target pSCI, evidencing a wider distribution than expected. These key conservation measures have demonstrated how the conservation status of petrified springs can be improved in Europe.
LIFE has restored petrifying spring habitats by restoring the spring flow and by fencing off the habitat area to avoid grazing and contamination.
Photo: Landesbund für Vogelschutz (LBV) Bayern
OTHER WETLANDS : PETRIFYING SPRINGS
LIFE Focus