Zoo Zurich, together with the Pro Lutra Foundation, is committed to the natural return of the otter in Switzerland. In this way, the public is continuously informed about sightings and the situation of the otter in Switzerland, so that it is not forgotten by the population and its natural return is well received. In order to document the return of the otter and the relationship between the animals, Zoo Zurich provides the Pro Lutra Foundation with scientific material such as photo traps and video cameras and participates in DNA investigations. In order to successfully advance this project, the Pro Lutra Foundation is working closely with authorities and interested institutions. Dr. Hans Schmid, who is the head of the Pro Lutra Foundation Board, is in charge of the project. At Zoo Zurich, otters are successfully bred within the framework of the European Conservation Breeding Programme and are regularly released to partners of the breeding programme.
Nature conservation in practice
After the Pro Lutra Foundation realised that the otter population in Styria (A) and Savoie (F) was spreading rapidly towards Switzerland, the Foundation set up systematic monitoring of the expected natural immigration in 2007. This monitoring is very complex, as the animals live solitary lives and their territory extends over a water system of 10 to 40 kilometres in length. In addition, the animals live in habitats with a high degree of cover. Through the Lutra alpina research project, the Pro Lutra Foundation is investigating whether and how the habitat conditions for the otter have changed in our country. It also documents all confirmed evidence of otters in Switzerland and in neighbouring countries. On the basis of the knowledge thus gained, it is being examined how and where measures can be taken to enable the otter to return.
The European otter is one of thirteen otter species that were once widespread throughout Europe. From the second half of the 20th century, the otter was considered extinct in Switzerland. Despite extensive research, the causes of extinction have still not been clearly explained scientifically. Discussions have focused on targeted extinction hunting, toxic substances in the waters and a decline in fish stocks. Today, there is increasing evidence that the otter is returning naturally to Switzerland. The habitat of these animals is the dense riparian vegetation along rivers and streams, where they feed on fish, small mammals and birds. In order to positively influence the return of the otter, their habitats, such as floodplain forests, riverbanks and lakeshores, must be ecologically enhanced.
Today, otters live again in rivers of Styria. However, this habitat is characterised by intensive cultural landscapes with multiple uses by humans. Typical examples are diverse industries and all forms of water use up to hydropower plants. Nevertheless, the otter has managed to establish itself. These observations from Austria are particularly important for Switzerland, as the natural return of these areas over the past decade indicates that otters can live in intensively used subalpine and alpine valleys. How otters cope in such habitats, what demands they have on their habitat and refuges, and how they overcome the unavoidable barriers is largely unclear. The Lutra alpina research project aims to shed light on this. The results on how otters live and survive form the most important basis for the return of otters to Switzerland.