Ölbachtal mit Augustdorfer Dünenfeld, Nature reserve in Augustdorf, Germany.

The Ölbachtal mit Augustdorfer Dünenfeld is a 169-hectare nature reserve between Stukenbrock and Augustdorf, adjoining the Senne military training area. Its core is the box-shaped valley of the spring-fed Ölbach and an adjoining dry valley, set among extensive pine woods with scattered open heath and sandy grassland. Dune crests up to twelve metres high rise in the dune field, and a seven-hectare former sand pit, worked until 1975, now holds shallow ponds.

The inland dunes of the Augustdorf dune field formed mainly during the Weichsel glacial period, when wind blew the bare Senne sand into ridges up to twelve metres high. Later dunes arose from human activity such as forest clearance, ploughing and heath plagging. The 169-hectare reserve, split between Oerlinghausen and Augustdorf (168 ha) and Schloß Holte-Stukenbrock (1 ha), adjoins the Senne military training area.

The name Ölbachtal comes from the Ölbach stream, whose spring-fed box valley cuts through the reserve; the sand quarry near the dunes was worked until 1975. The surrounding Senne heath was shaped by plaggen, the stripping of turf and heather for livestock bedding, which helped expose sand for younger dunes.

The reserve lies between Stukenbrock and Augustdorf and borders the Senne military training area, so access points are reached from these two places. The 168-hectare main section with the code LIP-002 is in Oerlinghausen and Augustdorf, while a separate 1-hectare piece, GT-027, belongs to Schloß Holte-Stukenbrock. The former sand quarry, about seven hectares, holds many small shallow pools, so expect wet ground there.

The former sand pit covers about seven hectares and was worked commercially until 1975. Because the sand was dug only shallowly, a mosaic of small shallow pools and damp hollows formed after renaturation. Look for the round-leaved sundew at the edges of these pools, and listen for the natterjack toad, which lives here.