Biesenhorster Sand Nature Reserve: Exploring the Glacial Sand Landscapes of Berlin

The landscape of Biesenhorster Sand was originally shaped during the ice age, when the Warsaw-Berlin Urstromtal filled with up to ten meters of glacial meltwater sand, creating the broad sand plain that dominates the area today. The original woodland cover was cleared in the mid-19th century, and the cleared land was used for agriculture for several decades.

In the early 20th century, the site took on a military-airfield character. From 1907, the area hosted a Siemens airship hangar, and from 1917 onward it was part of the Berlin-Karlshorst military aviation station. After 1918, parts of the open land were converted into allotments. In the 1930s, these allotments were displaced by the construction of the Berlin outer freight ring railway (Güteraußenring), and additional sand was used to infill land for the surrounding rail infrastructure.

During the GDR era, the site became part of an even larger military-rail complex. The Wuhlheide marshalling yard, in operation since 1953, occupied adjacent land, and a Soviet Army barracks with its own loading yard stood on the site itself. Withdrawals of Soviet troops in 1994 ended the military use, and in the same year the marshalling yard was decommissioned and its installations gradually dismantled. Since then, the open ground has developed largely undisturbed, although traces of its past use, including the ruin of a repair hall, are still visible.

Conservation efforts began in the mid-1990s under the leadership of NABU Berlin, which has since carried out ongoing management work, including grazing with sheep and goats in five paddocks, to keep the dry grassland open and prevent it from being overgrown by shrubs. As early as 2000, conservationists recommended protecting the green corridor between the Biesdorf interchange in the north and the Wuhlheide in the south as a landscape protection area, and the Lichtenberger dry-grassland sections were specifically proposed as a nature reserve. Almost two decades later, on 18 March 2021, Biesenhorster Sand officially became a Naturschutzgebiet, formalizing the protection that years of voluntary management had already built up on the ground.

The landscape of Biesenhorster Sand is dominated by a flat, sandy outwash plain of glacial origin. The site sits in the Warsaw-Berlin Urstromtal, where ice-age meltwater once deposited thick layers of sand that today reach up to ten meters deep in some places. This geological foundation gives the reserve its defining character: broad, open, well-drained sandy soils that naturally resist forest colonization.

The most visually distinctive feature is a wide belt of dry grassland (Trockenrasen), in places up to 450 meters across, interspersed with areas of completely bare sand. Within this open matrix, scattered tree groups, tall herb patches, and individual shrubs break up the otherwise exposed sandy ground. The result is a mosaic of open sand, dry grassland, and sparse woody cover, an unusual sight in the densely built-up eastern districts of Berlin.

The sand surfaces reach extreme temperatures in summer, heating up to around 65 degrees Celsius under direct sun. These conditions create a near-steppe microclimate that is rare so far north and is central to the site's ecological identity. The fragmented relicts of industrial and military infrastructure still on the land, including the ruin of a former repair hall, are part of the visible landscape and are slowly being absorbed into the recovering habitat.

Biesenhorster Sand is ecologically defined by its dry grassland and open sand habitat complex, a habitat type that has become very rare in Berlin. The reserve's ecosystem is built on shallow, nutrient-poor, sandy soils that hold little water and favor light-demanding, drought-adapted species rather than woodland.

The vegetation mosaic combines extensive dry grassland, completely open sand patches, scattered trees, tall herb fringes, and solitary shrubs. This habitat diversity is unusually high for such a compact site and is the foundation of its biological richness. Botanists have documented 382 fern and flowering plant species in the reserve, a remarkable density that reflects the wide range of small-scale habitat conditions present across the open sand plain.

The combination of open sand and dry grassland supports a wide range of ecological niches, from warm, exposed sand surfaces for ground-nesting insects and reptiles, to grassy tussocks for grasshoppers and moths, to scattered shrubs and small trees for nesting birds. Conservation management actively seeks to maintain this openness: grazing with sheep and goats and other maintenance work keeps encroaching woody growth in check, ensuring the open character that makes the site valuable.

The wildlife of Biesenhorster Sand is dominated by invertebrates and open-land bird and reptile species tied to dry sandy habitats. Entomological surveys have recorded 1,324 insect species on the site, including 388 macro-moth species, of which 111 are classified as threatened on regional Red Lists. Twelve of these insect species had previously been regarded as extinct in Berlin, and at least one of the weevils found there had not been recorded in Berlin and Brandenburg for over a century. One wild bee species had not been seen in the region since 1912. The reserve also supports 25 grasshopper species, including the Italian locust (Calliptamus italicus) and the largest Berlin population of the blue-winged sand grasshopper (Sphingonotus caerulans).

Beetles are also exceptionally well represented, with 778 documented beetle species, roughly 20 percent of all species known from Berlin and Brandenburg. Around 8 percent of these beetles are on Berlin's Red List.

The hot, exposed sand surfaces are important habitat for reptiles, especially the strictly protected sand lizard (Lacerta agilis), which finds ideal basking and nesting conditions on the dry grassland and open sand. The reserve is also recognized as a breeding area for 33 bird species, with a clear emphasis on open-land and ground-nesting birds. Notable breeding species include the tawny pipit, crested lark, woodlark, northern wheatear, red-backed shrike, and common linnet, all of which are Red List species in Germany.

Biesenhorster Sand is a conservation priority because it safeguards one of the last and most species-rich dry grassland and open sand ecosystems in Berlin, a habitat type that has been almost entirely lost from the surrounding cityscape. Its official designation as a Naturschutzgebiet (nature reserve) on 18 March 2021 confirmed decades of informal protection and gave the site a formal legal status. The reserve is managed to maintain its open character through ongoing grazing and mowing.

The site's conservation value lies primarily in its biodiversity density. Despite covering only about 42.9 hectares and being fully enclosed by railways, urban infrastructure, and allotments, it hosts 382 plant species, 1,324 insect species, 778 beetle species, and 33 breeding bird species, including multiple Red List and nationally protected species and several rediscoveries of species previously thought extinct in the region. The reserve thus serves as a critical refuge for species that depend on habitats that Berlin has otherwise lost to urbanization.

Conservation management is led by NABU Berlin, which has worked on the site since the mid-1990s through a formal Pflege- und Entwicklungsplan (management and development plan). Management tools include grazing with sheep and goats across five paddocks, along with manual interventions, all aimed at keeping the dry grassland open and preventing shrub encroachment. The reserve also functions as a local recreational area, with a network of paths that allow visitors to experience the habitat without compromising its conservation goals.

The cultural history of Biesenhorster Sand is shaped by layers of 20th-century industrial and military use, followed by a deliberate return to nature. The site was cleared of its original woodland in the 19th century, used as farmland, then converted into airship and aviation infrastructure by Siemens and the German military in the early 20th century. After the Second World War and during the GDR period, it lay within a large Soviet military and railway complex that included the Wuhlheide marshalling yard and a Soviet barracks with its own loading facility.

The departure of Soviet troops in 1994 and the closure of the marshalling yard in the same year created an abrupt end to nearly a century of intensive land use and opened the door to a new ecological identity for the area. Current cultural relevance is strongly tied to nature conservation: NABU Berlin has framed the site as both a local nature experience area (Naherholung) and an example of successful urban-industrial land recovery, with walking paths, information boards at entrances, and guided visits connecting the reserve to broader public engagement with biodiversity in the city.

Biesenhorster Sand stands out as a compact but ecologically dense urban nature reserve, where a glacial sand plain supports dry grassland, open sand, scattered trees, and tall herb vegetation in the middle of eastern Berlin. It is notable for rediscoveries of plant and insect species long thought extinct in Berlin, including a plant previously considered lost from the city and at least one insect species unseen in the region for over a century.

Equally distinctive is its conservation story: decades of work by NABU Berlin, supported by sheep and goat grazing, transformed a former military and railway site into a formal nature reserve in 2021. The result is a small but biologically rich protected area combining geological heritage, threatened species recovery, and active habitat management within an intensively used urban landscape.

Spring and early summer are generally the most rewarding seasons to experience Biesenhorster Sand, when dry grassland plants are in bloom, many insects are active, and breeding birds are present, including species like the tawny pipit, woodlark, and northern wheatear that depend on the open sandy habitat. Visits in late spring also tend to feature milder temperatures compared with the deep summer, when exposed sand surfaces can heat to extreme levels.

Late summer and early autumn remain interesting for insect and grasshopper sightings, though the heat of open sand areas is at its peak and reptiles such as sand lizards are most easily observed in warmer conditions. In winter, the open character of the site is most visible; vegetation dies back and the structure of the glacial sand plain, dry grassland strips, and scattered trees becomes the dominant visual impression.