Wetlands: a natural heritage to preserve in Luxembourg
Too often absent from environmental debates and overlooked by the general public, wetlands are nonetheless essential, rich, and precious natural environments. In Luxembourg, these spaces play a key role in maintaining biodiversity and provide numerous ecosystem services that are vital to society.
As the name suggests, a wetland is characterized by the presence of water, either on the surface or in the soil, permanently or temporarily. It is a transitional zone between land and water. Peatlands, flooded meadows, marshes, alluvial forests, or fens—there are many different types of wetlands in Luxembourg. In 2025, the Foundation owns 610.45 hectares, including 260 bodies of water across the country.
Wetlands: a reservoir of biodiversity in Luxembourg
Luxembourg's wetlands, whether natural or artificial, stagnant or flowing, offer unique biotopes that shelter a remarkable diversity of flora and fauna. These environments serve as refuges, breeding and feeding grounds, and host iconic species such as amphibians like the great crested newt (Triturus cristatus) or the European tree frog (Hyla arborea), migratory birds like the sedge warbler (Acrocephalus schoenobaenus) or the barn swallow (Hirundo rustica), insects such as dragonflies—one in six of which is threatened with extinction globally—mammals like the Eurasian beaver (Castor fiber) or the Eurasian otter (Lutra lutra), as well as numerous other species that depend on aquatic ecosystems for their survival.
Sites such as Cornelysmillen in the Woltz alluvial plain, Lērensmillen and the wet meadows of the Trëtterbaach valley, the Schlammwiss and the ponds of Mensder Brill in the Syre alluvial plain, the floodplains of Dumontshaff along the Alzette and the Kiemelbaach, as well as the Grendel Marsh in the Attert Valley, play an essential role in preserving this biodiversity, the protection of which is vital to maintaining the natural balance in Luxembourg.
Why protect Luxembourg's wetlands?
Wetlands act as true natural sponges, absorbing water during heavy rainfall and releasing it gradually during periods of drought. This unique capacity helps reduce flooding while strengthening resilience to climate change.
However, these areas are currently facing numerous threats:
· Rapid urbanization leads to the destruction of precious habitats.
· The intensification of agriculture alters soils and waterways, while land drainage accelerates their degradation. Climate change worsens these problems by disrupting water cycles and further weakening ecosystems.
· The introduction of invasive species disrupts the ecological balance and endangers native flora and fauna.
Faced with these challenges, Fondation Hëllef fir d'Natur plays a central role. It integrates wetlands into its management strategy and carries out concrete actions for their restoration and preservation. Safeguarding wetlands requires collective mobilization. Restoring degraded sites, strengthening protection policies, and multiplying local initiatives are essential steps to reverse their decline. Protecting these ecosystems means not only preserving a precious natural heritage, but also guaranteeing vital services for the environment and future generations.
The Grendel Marsh
In the Attert Valley, isolated within a modern rural landscape, the "Grendel Marsh" nature reserve spans an area of 4.37 hectares. It is part of the European NATURA 2000 network of protected areas and consists of a mosaic of wetland and extensive habitats with spring areas. Straddling the Belgian-Luxembourg border, it symbolizes successful cross-border cooperation through the joint management of an exceptional site.
At its center, the site consists of two fen areas featuring fine stands of common cottongrass (Eriophorum angustifolium), marsh cinquefoil (Comarum palustre), and marsh violet (Viola palustris). The most remarkable biotope is the remnant of alkaline purple moor-grass meadow, an extremely threatened habitat that includes numerous rare and endangered plant species, such as carnation sedge (Carex panicea), creeping willow (Salix repens), and broad-leaved marsh orchid (Dactylorhiza majalis). The eastern part consists of a wooded area composed of birch, alder, and willow, and is home to bogbean (Menyanthes trifoliata) and greater tussock-sedge (Carex paniculata). The reserve supports interesting birdlife, both in terms of migratory and breeding species, such as the marsh warbler (Acrocephalus palustris).
Two of the 287 cast-iron boundary markers placed along the Belgian-Luxembourg border, specifically numbers 135 and 136, are located within the reserve. Inside the marsh, right in the middle of the reed bed, one of the intermediate markers, the limestone marker "LB135a", still exists in its original form.
A primary objective of the foundation is the expansion of this area and the implementation of targeted maintenance measures, notably through regular mowing of the wet meadow vegetation. Furthermore, the preservation of historical and natural heritage remains a central focus.
Let's bring the Grendel Marsh back to life!
The reserve also serves as a place for education and discovery. It is equipped with an information board, an observation platform to admire the border markers, and a discovery trail. However, this trail needs to be renovated due to wear and tear caused by time and visitors.
With a donation of €25, €50, or €100, you directly contribute to the rebuilding of boardwalks, observation paths, and the facilities needed to protect biodiversity and give everyone the opportunity to discover this unique habitat.
Let's act together to preserve this exceptional natural heritage.
