Gravel pit madness

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Coordinates: 50 ° 51 '56.1 "  N , 7 ° 5' 28.2"  E

Relief map: North Rhine-Westphalia
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Gravel pit madness​
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North Rhine-Westphalia

The Wahn gravel pit is a nature reserve in the Porz district of Cologne . It is part of the Bergische Heideterrasse . In 1888 it was set up on the site of an excavation area for Quaternary sands and gravels . The 5.43 hectare nature reserve was established with the aim of promoting the preservation of the raw soil and the natural development of valuable wet and water habitats on a former excavation area. The nature reserve Kiesgrube Wahn belongs to the biotope network of the gravel pit habitats around Cologne. In 1990 a biotope maintenance plan was drawn up for the site to realize the development goals. In 2015, a modified maintenance and development plan was drawn up for the nature reserve N 16 Kiesgrube Köln-Wahn .

Characteristic

On the sole of the former excavation area, there are two larger water areas in the east and south, with which the groundwater horizon was cut. There is also another body of water on the north side of the former gravel pit . On the sandy-gravelly raw soil of the pit floor, which is regularly maintained and kept clear, a vegetation typical of the site developed . The open land locations are partly alternately humid, partly dry. To the former pit edges has a willow - mixed deciduous forest developed with mostly natural vegetation, lie only on the sun-exposed north and northeast slopes of the former pit walls open.

Fauna and vegetation

Fitis
Great pond clam
Spring cinquefoil

On the occasion of the preparation of the maintenance and development plan, an area monitoring was carried out in 2012/2013 by the NABU station in Cologne / Leverkusen . When mapping the avifauna , it was found that 43 different bird species live in the area of ​​the gravel pit , 29 of which breed here , including twelve bird species that are on the red list or classified as endangered or included in the warning lists. These include fitis , yellow mockers , bullfinches , goldhammer , rattle warbler , nightingale , starling and pond rail , which breed here, and kingfisher , hawk , sparrowhawk and barn swallow , which can be observed as food guests in the former pit.

Due to the high density of insects in the open waters and the presence of cave trees on the edges of the pit, the area is an important hunting ground as well as summer and intermediate quarters for bats and, despite the small size of the area, has a high ecological value for this group of animals. In the area of ​​the nature reserve, seven species were detected during the observation period, of which the fringed bat , the brown or gray long-eared bat, and the large and small bearded bat are on the red list.

In addition, four amphibian species , a non-native water turtle , seven grasshopper species and twelve butterfly species have been identified, of which the blue-winged wasteland insect is a nationally endangered species and the small hay moth and the blood bear are particularly ecological species that are on the red list Are worth. During the area monitoring, 20 different types of dragonflies were mapped, three of which - the blue-winged demoiselle , flat-bellied and black darter - are also on the red list. When examining the waters, the great pond mussel could be detected, which is also listed as an endangered species on the Red List.

During the vegetation mapping, 190 higher fern and flowering plants were identified , 9 of which are on the red list. Of particular importance is the evidence of spring cinquefoil , which occurs only relatively rarely in the gravel pits around Cologne. In addition, the Red List species colorful and hill forget-me-nots , genuine and ornamental centaury , rough carnation , bristle-feather fescue and teat-swamp rush were found in the plants. The ecological value of the small area for the vegetation was classified by the NABU as high overall . In particular, the vegetation in the area of ​​the water bodies is considered to be particularly valuable, especially since the vegetation of the eastern lake is an FFH habitat type and is therefore of particular importance for the nature reserve. The white water lily could be detected on the water surface as part of the mapping .

Proposed conservation measures

Various measures have been proposed as part of the maintenance and development plan to maintain and develop the nature reserve. These include:

  • Relay mowing to keep the pit floor clear with removal of the plant material;
  • Regular de-bushing of the steep slope areas;
  • Weed removal of the smaller pond in the north;
  • Keeping the areas free of non-native trees such as robinia and vinegar trees ;
  • Creation of temporary small bodies of water as breeding grounds for dragonflies;
  • Maintenance and clearing of the open pit walls to promote wild bees and grasshoppers.

Entry regulation

Due to its small size and the associated sensitivity to anthropogenic disturbances to protect vegetation and fauna, the nature reserve may not be entered and is therefore fenced off with a fence. Information boards indicate the access regulations.

See also

Web links

Individual evidence

  1. ↑ a b Nature reserve "Kiesgrube Wahn" in the specialist information system of the State Office for Nature, Environment and Consumer Protection in North Rhine-Westphalia , accessed on February 23, 2017.
  2. ↑ a b c d Maintenance and development plan for the nature reserve Kiesgrube Wahn. In: ratsinformation.stadt-koeln.de. Retrieved August 21, 2016 .
  3. ^ NABU station Leverkusen-Koeln: K Former gravel pits. In: www.nabu-station-lk.de. Retrieved August 21, 2016 .
  4. ↑ a b Nature reserve: idyll between the motorway and the school center. Retrieved August 21, 2016 .
  5. ↑ Open Council Information System. In: politik-bei-uns.de. Retrieved August 21, 2016 .