Wernsdorfer See Nature Reserve: A Detailed Atlas of Protected Wetland Landscapes in Brandenburg

The landscape around Wernsdorfer See began to take shape at the end of the last Ice Age, when meltwater of the Berlin Urstromtal carved a long west-east running lowland, leaving behind sandy deposits that gradually built dunes. Over thousands of years, sand, flood-borne sediment, and dead plant material filled in the lake basin, converting parts of the original open water into fen and wet grassland between Erkner and Wernsdorf.

Humans have shaped the area for a very long time. Archaeological evidence shows that the region was inhabited during the Middle Stone Age, and Slavic settlement traces from around the fourth century remain preserved as protected ground monuments. The village of Wernsdorf itself was first documented in 1460, while neighbouring Gosen appeared in records later. On Schmettau's historical map of Brandenburg from 1575 to 1787, the lake was shown as a single, considerably larger body of water.

From the late nineteenth century, several reed-processing factories operated in the area and harvested large quantities of reed from the lake margins. As Berlin expanded in the 1920s, tourism began to replace reed harvesting as a dominant local use of the landscape. A first effort in 1936 to secure protection for the area was interrupted by the Second World War, but the district administrator of Beeskow-Storkow resumed the process in 1946. Between 1950 and 1956, Berlin household waste was dumped directly into the lake, a practice halted by conservationists in 1956. Their efforts led to the formal designation of the Naturschutzgebiet on 19 October 1967. During the 1950s a separate landfill was established east of the reserve, which was closed in 2005 due to a missing base seal and is being sealed and remediated in the 2010s. In 2004 the European Union confirmed the area as an FFH site, anchoring its protection within the Natura 2000 framework.

Wernsdorfer See sits in a lowland valley shaped by glacial meltwater, where the Spree and the Oder-Spree Canal run roughly parallel in a west-east direction through an otherwise gentle landscape. Elevations across the reserve range from about 30 to 45 metres above sea level, giving the terrain only modest relief but considerable ecological variety.

The most striking element is the lake itself, a shallow eutrophic waterbody that now covers roughly 75 hectares, having lost around a quarter of its former surface area to sedimentation and post-war dumping. The lake reaches maximum depths of only about 1.0 to 1.5 metres in the south and around 0.8 metres in the north, with an average surface elevation near 32.3 metres above sea level. Water enters the lake from a spring-fed pool in the north, the Kappstrom stream, and the Mühlenfließ, while the southern end connects to the nearby Krossinsee through the Oder-Spree Canal.

Around the lake, the landscape shifts quickly between habitats. Inland dunes carry open and partially open sandy grasslands with low-growing herbs, while lower-lying ground carries wet meadows, tall herb communities, and reedbeds. The interplay of dry dune sand, still water, and seasonally flooded meadows within a few hundred metres is one of the reserve's defining features and supports the diversity of plants and animals found here.

Ecologically, Wernsdorfer See is best understood as a small but layered wetland complex where glacial sand, shallow open water, reed margins, and managed grassland coexist. The combination of dry dune grassland, wet meadows, and eutrophic shallow water creates overlapping habitat types that would not normally be found side by side in lowland Brandenburg.

The reserve contains dunes with open grassy vegetation, eutrophic lakes and ponds, damp tall-herb communities, and species-rich lowland meadows that are partly maintained through traditional use. The wet meadows and stands of tall herbs are also inhabited by beaver, whose activity continues to reshape small stretches of the shoreline. As in many Spree valley reserves, water levels are partly governed by the Oder-Spree Canal, so the management of the canal has direct ecological consequences for the lake.

The botanical interest of the site is unusually high for its size. Dune and dry grassland species grow alongside wetland and aquatic species on the lake margins. Plants of conservation interest include water caltrop, the floating aquatic fern Salvinia, the fen orchid Liparis loeselii, the early marsh orchid and the broad-leaved marsh orchid, the grass-like sand sedge with dark tips, marsh gladiolus, amphibious bistort, and a range of small marshland herbs. The mixture of sand-loving and wetland-loving species in the same reserve is one of the reasons the site has been afforded both national and European protection.

Wernsdorfer See is primarily known as a bird reserve. The shoreline, open water, reeds, and surrounding meadows support a wide range of breeding, resting, and feeding birds. Among regularly recorded species are hobby, bluethroat, wood sandpiper, common kingfisher, osprey, little ringed plover, common sandpiper, woodlark, northern lapwing, little crake, garganey, common crane, teal and northern shoveler, red-backed shrike, golden oriole, bittern, marsh harrier, red and black kite, black woodpecker, white-tailed eagle, great egret, barred warbler, common pochard, black tern, spotted crake, and hoopoe, reflecting a remarkably diverse mix of woodland, farmland, reedbed, and wetland species.

Mammals are represented chiefly by beaver, which is active along the wet edges of the meadows and reeds. Amphibians include moor frog, and reptiles include sand lizard. The lake itself supports fish species such as asp and bitterling, which are characteristic of slow-flowing lowland waters in the Spree system.

Conservationists have worked actively to restore two species at the site. Since 2016 artificial nest platforms have been used to encourage black terns to breed, with the first year producing a substantial count of breeding pairs that subsequently declined. From 2005 onwards, individuals of a regionally extinct butterfly, sometimes referred to as the golden checkerspot, were translocated here from a larger population near Pasewalk, and by 2009 several thousand individuals had been recorded, with the population now considered stable.

Wernsdorfer See is protected under both German and European conservation frameworks. As a Naturschutzgebiet designated in 1967, it carries the strongest level of habitat protection available under Brandenburg law. Its confirmation as an EU Fauna-Flora-Habitat site in 2004 placed it within the Natura 2000 network and tied its management to European protection objectives.

The formal conservation aims of the reserve centre on preserving the shallow lake as a refuge for water and marsh birds, maintaining habitat for feeding and breeding across many animal groups, and securing the populations of protected plants such as water caltrop, the floating fern Salvinia, and several threatened orchid species. A first draft management plan for the FFH area, produced in July 2019, reviewed the condition of habitats and species and identified fishing and angling as issues requiring clearer coordination between stakeholders.

A significant part of the conservation story is remediation. Decades of post-war dumping reduced the open water surface, while an adjacent landfill operated from the 1950s and was shut in 2005 for lacking a proper base liner, with sealing and aftercare continuing in the following decade. Active species recovery projects for black tern and the regionally extinct checkerspot butterfly show that the reserve combines passive habitat protection with more direct intervention aimed at restoring biodiversity.

The region around Wernsdorfer See has been continuously occupied for thousands of years. Archaeological evidence indicates settlement during the Middle Stone Age, and Slavic settlement traces from around the fourth century remain protected as designated ground monuments. The nearby village of Wernsdorf itself was first recorded in 1460, while the village of Gosen appears in later sources. Schmettau's late-eighteenth-century map still shows the lake as a single, larger waterbody, providing a historical baseline for understanding how dramatically the landscape has changed since then.

The name Wernsdorf and the name of the lake survive as the principal cultural reference points for the reserve. While the lake is no longer used for bathing, traditional uses of the surrounding landscape, including reed harvesting in earlier centuries and the long-running agricultural use of part of the grassland, continue to shape how the area is managed today. A roughly six kilometre circular trail allows visitors to encounter these historical layers through the landscape itself.

Within its compact footprint, Wernsdorfer See packs together sand dunes, dune grassland, wet meadows, reedbeds, and a shallow lake, producing a habitat mosaic that is unusual for lowland Brandenburg and particularly rich in wildlife for its size.

The reserve is a strong year-round birdwatching destination in the Berlin-Brandenburg region, combining sightings of raptors, marshland waders, and reedbed species in a single walk. Active species recovery projects, including nesting aids for black terns and a successful reintroduction of a regionally extinct checkerspot butterfly, make it a useful example of modern habitat management in action.

Because Wernsdorfer See is a lowland wetland reserve rather than a mountain or coastal park, the character of a visit changes most noticeably through the bird calendar. Spring and early summer bring the widest range of breeding birds, including cranes, bitterns, common kingfishers, and black woodpeckers, as well as flowering orchids and other dune and meadow plants on the drier ground. Late summer and autumn are often rewarding for migratory waterbirds and raptors gathering over the reeds and wet meadows, and for clearer views across the wetland as vegetation begins to die back.

Walking conditions on the roughly six kilometre circular trail are generally easiest in the drier months from late spring through early autumn, when the meadow paths are firmest. Bathing in the lake is prohibited, so visits at any time of year are best framed around walking, observing wildlife, and exploring the dunes and reed margins rather than water-based recreation.