The Maujahn or Maujahn Moor (also known colloquially in German as the Maujahnskuhle) is a kettle bog in North Germany which began as a sinkhole. It is located a good two kilometres west of the town of Dannenberg between the villages of Thunpadel and Schmarsau in northeastern Lower Saxony.
The bog is located on the eastern border of the D28 Lüneburg Heath natural region, within the Lower Drawehn, the transition to the D29 Wendland and Altmark natural region. Culturally, the Drawehn is usually associated with the Wendland. The Maujahn Moor is protected from the Atlantic macroclimate of Lower Saxony by the presence of the eastern slopes of the East Hanoverian end moraines (also known as the Göhrde-Drawehn Hills) formed during the Saalian glaciation and the climate is therefore clearly sub-continental. The surface of the moor lies 25 metres above sea level; the geest hillocks surrounding it reach heights of just above 50 metres. The most exposed point in the High Drawehn - is the Hoher Mechtin which climbs to 142 metres above sea level - is 10 kilometres away.
This terrain hollow was formed about 7000 years ago as a result of the collapse of a salt dome that was leached by underground groundwater action - exactly as happened to the Bullenkuhle in the district of Gifhorn. Thanks to stratigraphic research of the bog carried out by Lesemann (1969), we know that, initially, a carr with a covering of peat moss developed on the valley bottom. About 500 years ago there was clearly another collapse which resulted in the creation of two larger sinkholes. These dolines filled with water, the peat moss layer rose and covered the surface of the lake. Today this enclosed, floating layer of grass and peat has a thickness of between 2.5 and 4 metres and is capable of load-bearing. Underneath the eastern sinkhole is a body of water and mud up to 16 metres deep. Even above ground the terrain shows the characteristic relief of a sinkhole: the eastern bog hollow is semi-circular and surrounded by steep walls up to 15 metres high, covered with oak and pine.
The rounded, oval, more or less treeless surface of the bog in the eastern sinkhole covers about 2ha and is classified as a 'living', i.e. growing, mesotrophic transition moor (Zwischenmoor or Übergangsmoor). It has vegetation typical of a raised bog however. In addition to various peat mosses, certain types of cottongrass characterise its appearance, particularly (Hare's-tail and Common Cottongrass); other typical species are the Common cranberry, Bog-rosemary, Cross-leaved heath and Common heather, various sedges, White beak-sedge (Rhynchospora alba) and the rare Rannoch-rush (Scheuchzeria palustris).
On the periphery is a strip of carr which is dominated by Grey Willow and Alder Buckthorn bushes as well as Downy Birch. In places Bog-bean and Bog Arum may also be found in the undergrowth. The western part of this waterlogged terrain is more fen-like (Niedermoor), with reed beds and tall herbaceous vegetation as well as birch and alder trees. Information about the fauna of the region may be found in the book by Timm (1983).
Unlike the normal situation with these transition moors, the raised centre of the moor body, currently only a few decimetres high, is thought to be at its climatic climax. Any further succession into a true raised bog - with its surface bulging noticeably in the middle, from which the groundwater has fully retreated and which is only fed by rainwater, is not expected. This may be put down to its orographic situation, particularly the kettle hole formation, as well as the very low annual precipitation in the area of well under 600 millimetres per year. This makes the region very different from the Atlantic and sub-Atlantic raised bogs of western and central Lower Saxony.
No information is available about the derivation of the name Maujahn, however it may have Slavic roots, like the Drawehn.
Like the majority of the few still remaining raised and transition bogs in North Germany, the Maujahn is threatened by drainage and changes in nutrient levels.
The quality of this valuable biotope is at risk because the surface of the moor dries out from time to time, causing a mineralisation of the peat layer and encouraging the settlement of trees (downy birch, alder, pine, willow). This threatens to oust the highly specialised, moorland flora and fauna that only thrive in isolated spots. The reason for this intermittent loss of water is that there have been some particularly dry years (for example 2003: 435 mm/a in Lüchow) and the fact that drainage of the hollow southwest into Prissersche Bach valley by a ditch has not been fully prevented. Periodic clearance work by nature conservationists has enabled the invading trees to be removed from the surface of the bog.
In addition the diffusion of nutrients from agriculture in the area (Abdrift) and atmospheric pollution (i.e. the deposition and mobilisation of nitrogen), particularly in central Europe, is a problem. This leads to the unnatural fertilisation of the oligotrophic to mesotrophic moor and alters the mix of plant communities.
Due to its regional landscape uniqueness as a biotope and geotope and its importance as a habitat for numerous rare, plants and animals, the Maujahn has been declared a nature reserve (area: 37ha). The area was also designated by the EU Commission in Brüssel as a Special Area of Conservation as part of the European conservation project Natura 2000.
Unsurprisingly, there are also legends about how the Maujahn was formed. These stories have been passed down the generations in various forms. This version was told by Miss Ungewitter, a teacher at Dannenberg Primary School (around 1970).