Ausstichgelände Röntgental Nature Reserve: A Protected Wetland Landscape in Brandenburg Germany

The history of the Ausstichgelände Röntgental begins not with nature but with infrastructure. The Berlin–Szczecin railway, originally built at ground level between 1841 and 1843, was progressively elevated in the 1890s and early 1900s to address growing traffic conflicts, particularly between Berlin and Bernau. Because transporting fill material was expensive, sand was excavated locally, and the borrow pit at Röntgental, opened between 1892 and 1895, supplied embankment material for many years.

Once excavation ceased, the roughly 28-hectare depression became a focus of scientific interest. From the mid-1890s onward, Karl Osterwald, a teacher at the Berlin Lessing-Gymnasium, documented an unusually rich flora on the freshly exposed mineral soils, recording more than 800 plant species over the following decades, including about 190 mosses and 152 fungi, as well as botanical rarities such as variegated horsetail, fir clubmoss, bell heather, butterworts, sundews, and cotton grasses. In 1940 the Prussian Regierungspräsident in Potsdam placed the site under protection to ensure the undisturbed continuation of these observations.

Over the following decades, vegetation succession changed the character of the reserve. As scrub encroached, the originally open and species-rich flora was overtaken, and in 1972 the protective status was lifted. The wetland character, however, persisted, and by the 1970s and 1980s the open water and reed beds had become a strong amphibian habitat, prompting renewed protection in 1986 by the Council of the Bernau district.

A more difficult chapter began in the same period. A railway police weapons workshop and shooting range had been built on the edge of the site, and a police dog training ground was established nearby. In 1979 the Central Intake Home of the GDR (ZAH) was added on the northeastern edge, hidden behind a high corrugated metal fence. The shooting facilities were repurposed by the Stasi, and a sound-insulated range was built into an earthen mound. After the peaceful revolution of 1989, civic groups secured the site's environmental future: the weapons workshop and range were transferred to conservationists in May 1990, and the Naturenschutzstation Niederbarnim was established, briefly managing the reserve.

The decisive protection order came from the Bezirkstag Frankfurt (Oder) on 14 March 1990, under Decision No. 130, the designation that still applies today. The reserve subsequently became part of the joint Barnim Nature Park in 1998, and the local conservation station was relocated, returning Ausstichgelände Röntgental to a quieter, primarily ecological role.

Despite its modest size, the Ausstichgelände Röntgental contains a surprisingly varied micro-landscape for a site of fully artificial origin. The central organizing feature is the Buchenallee, a beech-lined path that crosses the reserve and divides it into two clearly different ecological halves.

North of the Buchenallee lies the more open terrain: shallow water bodies, reed fringes, and patches of wet willow scrub. This zone is the visual heart of the reserve and the area most strongly shaped by the original sand excavation, since deeper groundwater reaches the surface here.

South of the path the terrain rises slightly and is dominated by alder carr forest, or Erlenbruchwald, a hummocky, waterlogged woodland of black alder that feels distinctly different from the open scenery to the north. Together, these two halves of the reserve produce a compact but legible contrast between open wetland and wet woodland, framed on the broader map by the railway embankment to the south, the Berlin-Buch area to the west, and the reforested Hobrechtsfelde fields to the north.

Ecologically, Ausstichgelände Röntgental is best understood as an amphibian-centered wetland complex embedded in a wider mosaic of post-agricultural and post-industrial sites. The reserve's habitat structure is unusually diverse for such a small area, comprising open water, extensive reed belts, willow-dominated scrub, and alder carr forest.

This habitat mosaic supports a particularly strong amphibian community, which is the formal reason for the reserve's continued designation. The shallow, fish-free spawning waters are well suited to common frogs, moor frogs, and common toads, while crested newts and smooth newts also use the site. Reptiles such as grass snakes and slow worms are present in the wetter margins.

The reserve is also relevant for bats, which are described as numerous, and for a wide community of breeding and visiting birds, many of which depend on the combination of open water, reed, and adjacent woodland. The botanical heritage, once the reserve's primary scientific attraction, has shifted over time from rare pioneer flora to more typical wetland vegetation, but rare elements from the original succession phase are still part of the site's scientific identity.

Amphibians are the headline wildlife group at Ausstichgelände Röntgental, and the reserve's protected status explicitly reflects this. Common frogs and moor frogs are especially abundant, using the shallow, largely fish-free water bodies as spawning habitat, and common toads are also numerous. Both crested newts and smooth newts occur in the reserve's pools, and grass snakes and slow worms inhabit the wetter margins.

The birdlife is similarly noteworthy. Roughly 85 bird species have been recorded in the reserve, of which approximately 50 breed on site. Typical species associated with the woodland mosaic include green woodpecker, black woodpecker, tawny owl, goshawk, hawfinch, golden oriole, and reed bunting, while the growing importance of the northern open water is reflected in increased use by waterbirds.

Bats are also present in significant numbers, although they are mentioned in general terms rather than by species in the source material. Together with the amphibian population, they underline the reserve's continuing role as a small but ecologically dense refuge on the urban edge of Berlin.

Ausstichgelände Röntgental is classified as an IUCN Category IV Habitat and Species Management Area, a designation that frames it as a site where active biodiversity outcomes are pursued through specific protection of habitats and species, in this case primarily amphibians. The conservation goal of the reserve is explicitly the preservation of the wetland conditions that have developed since the 1970s, which make the site a high-quality amphibian habitat.

The reserve is also part of the larger Barnim Nature Park, established jointly by Berlin and Brandenburg in 1998, which connects it functionally with neighboring protected areas such as the Mittelbruch reserve near Berlin-Buch and the renatured former sewage fields at Hobrechtsfelde.

From a conservation-history perspective, the site offers one of the more instructive local case studies in Brandenburg. The early recognition of its scientific value in 1900, the loss of that value under natural succession in the 1970s, and the subsequent redefinition of protection around amphibians show how a single site can be understood and protected differently in different eras. The fact that the current designation from March 1990 has persisted unchanged through reunification, the establishment of the Barnim Nature Park, and a recent administrative reorganization, gives the reserve an unusual degree of legal continuity for an area of just under 25 hectares.

Although it is small and ecologically driven, the Ausstichgelände Röntgental carries a layered cultural and historical imprint that goes well beyond its natural history. The Buchenallee that crosses the reserve still follows the route of the medieval Uckermärkischer Heerweg, locally once known as the Heerweg, connecting Berlin with the Uckermark region through Bernau.

The twentieth century added a more contested layer. The site was used, at various points, by East German state security institutions, including a railway police weapons workshop, an underground shooting range, and the perimeter of the Zentrales Aufnahmeheim Röntgental. After 1989, civic groups used the political opening to redirect these buildings toward environmental and social uses, and the Naturenschutzstation Niederbarnim was founded directly on the reserve.

The Vogelwelt reserve thus stands not only for a small wetland on the Berlin city edge but also for a successful local example of post-1989 civil society transforming a previously restricted security site into a publicly accessible conservation area.

Ausstichgelände Röntgental stands out as a rare example of a man-made depression that matured into a formally protected nature reserve, offering an unusually legible story of ecological succession in a compact urban-fringe setting. Its central contrast between open wetland north of the Buchenallee and alder carr south of it produces an efficient and diverse habitat mosaic for its size.

The reserve is anchored in the regional conservation network by its inclusion in the Barnim Nature Park and pairs naturally with the nearby Berlin-Buch Mittelbruch reserve. Its long scientific history, from Karl Osterwald's late nineteenth-century plant surveys through the 1940 and 1990 protection orders, gives it a documented continuity that few comparable small reserves in Brandenburg can match.

Because the reserve is small and centered on amphibian breeding habitat, the most ecologically interesting season is spring, when frogs, toads, and newts actively use the shallow water bodies for spawning and the reed beds are at their most visible. Early morning visits during this period offer the best chance to hear amphibian choruses and observe breeding activity.

In summer, the reserve is at its most visually lush, with mature reed vegetation, dense alder foliage, and active birdlife, including woodland species along the Buchenallee. Autumn brings muted colors in the alder carr and a quiet atmosphere that suits observational visits. Winter visits are possible but less rewarding for wildlife, as amphibian activity ceases and much of the area is visually subdued.