Covering a surface area of 309 hectares, the nature reserve comprises 157 hectares of forest, 25 hectares of meadows and the remainder falls under the public fluvial domain.


The most remarkable habitat, protected by the reserve, is without doubt the alluvial forest. It is remarkable in more than one respect: it is a rare ecosystem, both nationally and Europe-wide. Its only equivalent in Europe is the Danube alluvial forest, owing to its specific riches and profusion of plant life, which give it more than a passing resemblance to the Amazon rainforest. Like its South American cousin, this forest provides optimal conditions for the development of the species that grow there. The plant life has no factors that really inhibit it: in summer, it can draw water and nutrients from the water table. At one and the same time, it therefore has warmth, humidity, maximum sunlight and rich silt provided by earlier flooding, which brings about a proliferation of vegetation. The forest is also referred to as a "gallery forest" owing to the density of the shrub layer and the presence of numerous climbing plants.

Open habitats

Situated in the north of the island, between the Old Rhine and the high water dyke, the alluvial meadow is an open area where woodland groves alternate with areas of tall plants. It is home to a huge diversity of plant life and was studied in detail in 2008: thirteen different plant communities were identified and a total of 231 species catalogued.

This meadow biotope, which is rare in the Rhine Valley, should be protected by keeping it open.

Aquatic habitats

Aquatic habitats are represented in the reserve in several forms:

  • The former natural course of the Rhine, called the Old Rhine, which borders the reserve to the east between Strasbourg dam and the agricultural dam;

  • The internal water course on the island, called Bauerngrundwasser: this is a former meandering arm of the Rhine;

  • Ten or so ponds and temporarily flooded zones in the low-lying sectors of the reserve.