PROJECT DESCRIPTION
BACKGROUND
The bittern (Botaurus stellaris) prefers nesting in broad stretches of reeds and rushes, but will settle for small fish ponds, when these are part of a more extensive complex of surface waters. The brown speckled bird with its distinctive long claws has been decimated by habitat loss throughout southern and western Germany, and Western Europe in general. One of the most important nesting areas remaining in Bavaria is the Charlottenhof pond complex, a 900 ha area mainly used to farm carp. Between four and six bittern nesting sites are occupied here each season and there is a potential, assuming appropriate management of the ponds, for more nesting sites. The polygamous bittern requires reeds or rushes which are not too dense and are free from disturbance, as well as good foraging opportunities (fish, amphibians, invertebrates, etc.). On the other hand, intensive fertiliser application, high fish stocking densities, artificial feeding, continual removal of the reeds and any inflow of nutrients and pesticides must all be avoided. The project was an attempt to develop a model for boosting bittern populations by combining protection with the application of specific forms of fish pond exploitation: areas of rushes suitable for bittern have to be preserved and, to keep them in good shape, mowed at regular intervals,while extensive fish farming in the ponds has to be ensured.
OBJECTIVES
The project was an attempt to develop a model for boosting bittern populations by combining protection with the application of specific forms of fish pond exploitation: areas of rushes suitable for bittern have to be preserved and, to keep them in good shape, mowed at regular intervals, while extensive fish farming in the ponds has to be ensured. To implement the project, about 10 ha of ponds around existing bittern populations were to be acquired by purchase or long-term lease and extensificiation contracts concluded with the fish farmers. These contracts would compel them to keep terrestrialization zones (40-50% of total surface area taken up by such zones per pond is ideal) and to guarantee that there will be water in the ponds all year. They would also prohibit them from applying fertiliser, lime or artificial feedstuffs to the pond or mowing aquatic vegetation. Because market prices for carp were very low in the mid-199Os, it was expected that the fish farmers' attitudes towards such contracts would be positive, as on the one hand less effort and input would go into fish farming (so production costs are lower) while on the other income rises on account of the compensation payments which go together with the contracts. In addition to all this, one-off measures to improve habitats were to be taken: flattening the gradient of pond banks to stimulate terrestrialization, bringing more structure to the reedbeds and - along the edges of intensively used farmland- laying out buffer strips and ditches to carry off polluted water.
RESULTS
The project had to confront unexpected changes to the attitude of fish farmers and fishpond owners, whose willingness to sell or conclude management agreements lessened drastically as market prices for fish rose due to BSE scares and stronger consumer demand for this aquatic food product. This necessitated an additional clause redefining some of the targets and measures in the project. Management plans were made for the following ponds: Hofbauerweiher, Löchelweiher and Altenweiher. The 6 ha Altenweiher pond was purchased. Because work could only be done on ponds owned by the beneficiary or with permission of the private owners, the availability of sites to work on was limited. The main actions took place at the pond Altenweiher where two ponds were merged together and a totally new design of the pond with gradually sloping banks, newly planted reedbeds and deep channels to separate refuge islets and reedbeds from the mainland (against terrestrial predators) was created. Further habitat improvement actions took place in the ponds Forstweiher, Löchelweiher, Landsknechtweiher and Hofbauerweiher, where permission was given by the owner and agreements for long-term use were concluded. These actions consisted of measures to raise water levels in reed beds; cutting out of pines, willows and birches; removal of the top layer of soil to boost conditions for reed growth, etc. Recurring management depended on agreements with the pond owners, but was initiated at some places, e.g. as a follow-up measure (coppice shoot cutting) in the ponds where habitat improvement took place, and will be continued. Permission from owners to expand management will continue to be sought in the future. Information panels were erected on site to inform about the project aims, and international networking with similar projects, e.g. in Belgium and Austria, took place. One project manager was assigned to manage the work, negotiate with private owners, plan actions and monitor the bittern population. Monitoring of the project sites recorded four booming males in 2001 and again in 2002, a quarter of the total bittern population of the SPA, showing that stability had been achieved. The habitat improvement work is expected to lead to an increase in bitterns, but this will only become apparent in the years after project completion in 2002. The LIFE project is to be followed by a regionally-funded project to continue the work for Botaurus stellaris in the Charlottenhofer Weiher and expand it to other bittern habitats in northeast Bavaria, building on the experience gained via LIFE.The project had to confront unexpected changes to the attitude of fish farmers and fishpond owners, whose willingness to sell or conclude management agreements lessened drastically as market prices for fish rose due to BSE scares and stronger consumer demand for this aquatic food product. This necessitated an additional clause redefining some of the targets and measures in the project. Management plans were made for the following ponds: Hofbauerweiher, Löchelweiher and Altenweiher. The 6 ha Altenweiher pond was purchased. Because work could only be done on ponds owned by the beneficiary or with permission of the private owners, the availability of sites to work on was limited. The main actions took place at the pond Altenweiher where two ponds were merged together and a totally new design of the pond with gradually sloping banks, newly planted reedbeds and deep channels to separate refuge islets and reedbeds from the mainland (against terrestrial predators) was created. Further habitat improvement actions took place in the ponds Forstweiher, Löchelweiher, Landsknechtweiher and Hofbauerweiher, where permission was given by the owner and agreements for long-term use were concluded. These actions consisted of measures to raise water levels in reed beds; cutting out of pines, willows and birches; removal of the top layer of soil to boost conditions for reed growth, etc. Recurring management depended on agreements with the pond owners, but was initiated at some places, e.g. as a follow-up measure (coppice shoot cutting) in the ponds where habitat improvement took place, and will be continued. Permission from owners to expand management will continue to be sought in the future. Information panels were erected on site to inform about the project aims, and international networking with similar projects, e.g. in Belgium and Austria, took place. One project manager was assigned to manage the work, negotiate with private owners, plan actions and monitor the bittern population. Monitoring of the project sites recorded four booming males in 2001 and again in 2002, a quarter of the total bittern population of the SPA, showing that stability had been achieved. The habitat improvement work is expected to lead to an increase in bitterns, but this will only become apparent in the years after project completion in 2002. The LIFE project is to be followed by a regionally-funded project to continue the work for Botaurus stellaris in the Charlottenhofer Weiher and expand it to other bittern habitats in northeast Bavaria, building on the experience gained via LIFE.