Sielmanns Naturlandschaft Wanninchen, Nature reserve in Luckau, Germany.

Sielmanns Naturlandschaft Wanninchen is a 3,300-hectare nature reserve in the former Schlabendorfer Felder open-cast lignite mine, southwest of the Spreewald. Its terrain combines flooded pits, sand dry grasslands on spoil tips, and steep banks where sand martins nest. The Heinz Sielmann Stiftung has acquired the land since 2000 to allow undisturbed wilderness development.

From 1957 to 1991, excavators and conveyor bridges extracted lignite from the Schlabendorfer Felder open-cast mine, altering the landscape and regional water balance. Mining ended in 1991, and rising groundwater gradually filled the residual pits. In 1996 the Oberspreewald-Lausitz district placed the first parts under nature protection, and since 2000 the Heinz Sielmann Stiftung has acquired over 3,300 hectares for undisturbed development.

The nature experience center teaches people about the environment through displays about water, plants, and animals found in the region. Visitors can see how education happens through interactive exhibits and outdoor spaces.

Access to trails and observation areas is available year-round, with the best conditions during warmer months. The terrain is flat and easy to walk, though sturdy footwear helps in wet sections.

Hundreds of whooper swans from Scandinavia and the Baltic region stop here during migration. Some pairs have settled and nest regularly within the reserve.