Am Kleewoog von Gräfenhausen Nature Reserve: A Detailed Geographic Atlas of Inland Sand Habitats

The Am Kleewoog reserve originated as a commercial sand and gravel quarrying site. Industrial extraction left behind steep, structurally complex pit walls that subsequently filled with water, creating the Kleewoog lake along with several smaller pits. As these artificial features began to develop their own ecological character, the area attracted attention for its conservation potential rather than its extractive value.

On 14 November 1985, the Hessian authorities formally designated the site as a Naturschutzgebiet under a regulatory ordinance, covering an area of approximately 20.89 hectares. The protection order explicitly recognized the combination of open water, dry biotopes, and surrounding pine-oak forest as a habitat for endangered species and as a resting site for migratory waterbirds. Less than a decade later, on 31 October 1994, the boundaries of the reserve were adjusted in a supplementary decree, refining the protected area without changing its overall intent. Since then, the site has been managed as a habitat and species management area under IUCN Category IV.

Wildlife is one of the principal reasons the reserve was protected. The Kleewoog lake and its surrounding pits function both as a breeding area and as a resting site for numerous waterbird species, including species whose populations are considered threatened in Hesse. Woodpeckers are particularly characteristic of the older pine-oak stands; great spotted, green, and black woodpeckers have all been recorded within the reserve, supporting both nesting and foraging activity in the mature timber.

In addition to birds, the reserve hosts a rich community of insects associated with its dry sandy habitats and warm open ground. Amphibians and reptiles are a key focus of management: because the surrounding roads pose a barrier to seasonal movements, an amphibian protection installation was constructed along the nearby Weiterstädter Strasse to reduce road mortality and connect breeding and overwintering habitats. The quarry walls and shallow puddles appear to provide breeding grounds for several amphibian species whose populations are highly dependent on such secondary habitats in intensively used agricultural landscapes.

From a conservation perspective, Am Kleewoog is significant because it preserves a habitat mosaic that would be difficult to maintain in the surrounding agricultural matrix. The site demonstrates how former industrial land can be repurposed for biodiversity protection, providing refuge for waterbirds, amphibians, reptiles, and specialist insects in a region otherwise dominated by farmland and transport infrastructure.

The reserve is classified as IUCN Category IV, a habitat and species management area, indicating active management aimed at sustaining target species and habitats rather than purely passive protection. Practical conservation activities have included the construction of an amphibian protection facility along an adjacent road to safeguard seasonal migrations. Despite these efforts, the reserve faces ongoing disturbance from operations at Frankfurt Airport's western runway and from a nearby shooting range, both of which affect the tranquility of the area and its suitability for sensitive species.

While Am Kleewoog is primarily valued for its natural character, the reserve reflects the broader cultural history of the Darmstadt sand region, where centuries of agricultural use and 20th-century gravel extraction shaped today's open landscape. The site's location at the northern fringe of the Teufelshölle forest ties it to a long-standing local landscape identity, and its proximity to Darmstadt and Weiterstadt means that it functions as a small nearby nature experience for residents of these communities.

The principal highlight of the reserve is the Kleewoog itself, a roughly 3.3-hectare former gravel pit lake with steep, structurally rich shorelines that now attract waterbirds and amphibians. Equally distinctive is the surrounding mosaic of approximately 100-year-old pine-oak mixed forest, dry biotopes, and reedy smaller pits on acidic inland dune sands, a substrate rarely encountered elsewhere in the Rhine-Main region. The site's amphibian protection scheme along the Weiterstädter Strasse is also a notable conservation feature, illustrating how infrastructure mitigation is applied in this heavily used landscape.

Seasonally, the reserve tends to be most rewarding for visitors interested in waterbirds during autumn and winter, when the open water and surrounding sand flats attract migratory and resting species. Spring is the most active period for amphibians moving to and from breeding pools, and is also when many woodland birds and woodpeckers are most vocal in the pine-oak forest. Summer highlights the dry biotope flora, while the contrast between bare sandy banks and green forest is most pronounced in late summer.