Boekelermeer-Zuid, compensatie tussen de bedrijven door

Habitat compensation in an industrial area. Boekelermeer-Zuid is a polder in the province of Noord- Holland, just south of Alkmaar. During the last ten years, land use has changed, agriculture being replaced by industry. As it is an historical site for species protected under the Habitats Directive, such as Natterjack (Bufo calamita), Bitterling (Rhodeus amarus) and Spined Loach (Cobitis taenia), a green structure was included in the plans for the industrial area. This comprised a wet zone at the edge of the polder and a central dry zone, designed with the biotope requirements of the Natterjack in mind. The dry zone was given a sandy soil for overwintering of the toads, and concrete ponds for reproduction. In concrete ponds developed water plants are easy to remove thus providing open, shallow water suitable for Natterjacks. The first successful reproduction of Natterjacks in the concrete ponds occurred after three years. When the urbanization of the polder is complete and their former biotope has disappeared, the Natterjack population will have to rely solely on the artificial ponds. By keeping the ponds in the pioneer stage, we hope that the population will prove to be sustainable. New ditches have been colonised by Bitterling and Spined Loach, so the future of these populations in the polder seems to be assured.