Bottendorfer Hügel Nature Reserve: A Geological Cuesta Ridge and Protected Steppe Landscape

Human use of the Bottendorfer Hügel reaches back into prehistory. A burial mound on the ridge, preserved as a protected archaeological monument (Bodendenkmal), testifies to the presence of people during the Bronze Age Tumulus culture period. In the High Middle Ages, one prominent knoll was used as an execution site; the field name Galgenberg, still applied to the highest point of the ridge, preserves that function in the landscape.

The hills were also an early site of industrial mining. Kupferschiefer deposits were worked here and smelted at the Bottendorf copper smelter from 1473 until 1781, when the combination of complex geological conditions, highly variable ore grades, and low overall production led to the abandonment of the operation. Relics of this copper-shale era, including shaft collapse hollows (Einsturztrichter) and spoil heaps (Halden), are still visible within the protected area and form an important part of the present-day substrate mosaic.

During the Second World War, the commanding panoramic view from the Galgenberg made it a suitable location for a flak installation, and the remains of this wartime position were later converted into a public viewpoint. In modern times the reserve is used intensively as a teaching and excursion site for universities, and is also visited for recreation, walking, and appreciation of the open steppe-like scenery.

The Bottendorfer Hügel are a compact ridge in the Kyffhäuserkreis of northeastern Thuringia, oriented from the northwest to the southeast. The whole hill chain is around 2.5 kilometers long but only about 1 kilometer wide, with the summit Galgenberg reaching 206.5 meters above sea level. From the valley, the hills rise on average roughly 82 meters above the floor of the Unstrut; for comparison, the Unstrut dam at the western edge of Bottendorf lies near 124 meters.

Structurally, the Bottendorfer Hügel are a Schichtrippe or cuesta-like ridge that has been broken into several faulted blocks. They are built of Zechstein gypsum and Kupferschiefer, Permian rocks deposited in the vast inland sea that once covered central Germany. They sit in a clear geological corridor between two much larger and higher forested highlands: the Ziegelrodaer Buntsandsteinplatte to the north and the Buntsandstein ridge of the Hohe Schrecke to the south. This sandwich position between sandstone highlands gives the Bottendorfer Hügel a visually distinctive profile: low, pale, treeless, and conspicuously exposed against dark woodland.

What makes the Bottendorfer Hügel ecologically outstanding is the combination of unusual substrate and dry microclimate. Soils derived from gypsum and from metal-rich Kupferschiefer are chemically extreme; they are calcium- or sulfate-rich and, on former mining ground, contain elevated levels of heavy metals. Such soils are inhospitable to most plants, which is precisely why they support highly specialized floras that survive almost nowhere else in Germany.

Two dry grassland communities dominate. The first are subcontinental brome swards (Trespenrasen), a steppe-like vegetation type more typical of eastern European drylands than of central Germany. The second are heavy-metal grasslands (Schwermetallrasen), which appear especially where copper-bearing substrate is exposed or has been disturbed by mining. The heavy-metal swards are extremely open and low-growing, and consist almost entirely of spring sandwort (Minuartia verna) together with the locally endemic Bottendorf thrift. Together, the two grassland types give the ridge its open, almost semi-arid appearance, and the near-total absence of woody vegetation further reinforces this steppe character.

The source material is primarily botanical, and detailed faunal information on the Bottendorfer Hügel is limited. The reserve is widely known as a botanical and geobotanical site rather than a major wildlife destination. In such small, dry, near-treeless steppe grasslands in central Germany, the typical fauna would include open-country insects such as grasshoppers and butterflies associated with thermophilic swards, as well as the usual small mammals and birds of dry farmland margins, but the available documentation focuses overwhelmingly on the flora rather than the animals.

The Bottendorfer Hügel has been protected as a Naturschutzgebiet covering 131.6 hectares, a designation that reflects its national-level value for dry grassland and endemic species. The heavy-metal grasslands in particular are treated as a conservation priority because they host the only known population of the Bottendorf thrift in the world; any change to substrate chemistry or land use here would directly affect a globally unique variety.

Since 2008, the reserve has been one of 13 sites included in the EU LIFE project "Conservation and Development of Thuringian Steppe Grasslands" (Erhaltung und Entwicklung der Steppenrasen Thüringens). The focus of this project, and of the reserve's broader management, is the long-term maintenance of the open steppe character: preventing encroachment by shrubs and trees, maintaining the bare and sparsely vegetated heavy-metal swards, and protecting the mineral substrate conditions that the endemic plants depend on.

The Bottendorfer Hügel carry marks of human presence that stretch from the Bronze Age burial mound on the ridge through the High Medieval execution site on the Galgenberg to the early modern copper mining of 1473 to 1781, whose collapse hollows and spoil heaps still shape parts of the protected landscape. As a result, the reserve is not only a botanical site but also a small cultural landscape, where prehistoric funerary monuments, medieval judicial sites, and early industrial mining heritage overlap with present-day scientific and recreational use.

The strongest features of the Bottendorfer Hügel are its globally unique heavy-metal grassland flora, especially the Bottendorf thrift; its regionally rare subcontinental brome steppe vegetation; its compact Zechstein-age gypsum and Kupferschiefer geology; and the working relics of more than three centuries of copper-shale mining. A converted wartime flak site on the Galgenberg now serves as a viewpoint, allowing visitors to see the full extent of the open ridge and its steppe-like swards against the forested Hohe Schrecke behind it.

Open dry grasslands and steppe swards are best appreciated in late spring and early summer, when the characteristic subcontinental grass and herb species are flowering and when the contrast between the pale, near-treeless Bottendorfer Hügel and the surrounding dark forests is sharpest. Heavy-metal grasslands tend to be visually subtle year-round because they are low-growing and sparse, so the broader scenic character of the ridge, rather than a single peak of color, is the main attraction in any season of open weather.