Within the former German-Soviet Environmental Agreement in the years 1989-1991 3 biological expeditions to the Taimyr peninsular in northernmost Siberia were performed. They laid the ground for a partnership agreement between the Taimyrsky Zapovednik (nature reserve) and the Schleswig-Holstein Waddensea National Park and later the establishment (1993) of the Great Arctic Reserve (Zapovednik). The Taimyr peninsular is covered by the most extensive and northernmost tundra habitats in Siberia. These enormous wetlands are used during the short Arctic summer by millions of waterbirds, which winter in Southern Europe, Southern Asia and Africa. The biodiversity of the Taimyr peninsular is with 20% well covered with different kinds of protected areas. However, there may be need to connect them by South-North corridors to secure adaptation of biodiversity moving North with climate change. With increased warming and thawing of tundra massive release of methane stored in the ground could trigger further climate change.