Pool of pipes from herrings

Pool of pipes from herrings IUCN Category IV - Habitat / Species Management Area
View over the Werra to the smaller area of ​​the two-part conservation area on the other side of the river. In the background the "Monte Kali", the spoil dump from potash mining.
location	North of Heringen in the Hersfeld-Rotenburg district in Hesse .
surface	76.5 hectares
Identifier	1632002
WDPA ID	82435
Natura 2000 ID	5026-301
Geographical location	50 ° 54 '  N , 10 ° 1'  E Coordinates: 50 ° 54 '5 "  N , 10 ° 1' 1"  E
Sea level	212  m
Setup date	1979
particularities	Special protection as a nature reserve , FFH area and as part of an EU bird sanctuary and a landscape conservation area .

The Rohrlache von Heringen is a floodplain area in the Werra Valley north of Heringen in the north-east Hessian district of Hersfeld-Rotenburg . The wetland located near the state border with Thuringia has the largest inland salt station in Hesse , which was created by some natural and numerous salt water leaks caused by the potash and salt industries. However, it is not so much a question of real salt springs , but rather of extensive moisture penetration.

The flora that has settled at the salty water outlet points is considered of high ecological value. It is home to rich populations of endangered species such as the beach aster and samphire . The Rohrlache also has supra-regional importance as a resting and breeding area for a large number of bird species and as a habitat for several amphibian species, some of which have large populations.

As a rare example of a landscape area worth protecting, in the development of which natural causes interacted with the effects of industrial activity, the Rohrlache was declared a nature reserve in 1979 and, as a flora-fauna-habitat area, has been part of the Europe-wide Natura 2000 network of protected areas since 2008 .

Geographical location

The Rohrlache is located in the districts of Widdershausen , Leimbach and Heringen in the city of Heringen in the Hersfeld-Rotenburg district. The protected area is bounded in the north by the county road from Widdershausen to Leimbach and in the west by the Werra. In the south there is a smaller area on the other side of the Werra. The eastern border forms a larger drainage ditch, which partly also runs through the protected area.

In terms of nature , the pipe pool is assigned to the "Berka basin" in the main unit " Salzunger Werrabergland " of the " East Hessian mountains ".

climate

The Werraue in the Heringer area is considered to be climatically favored because of its location in the rain shadow of the East Hessian mountainous region. This is shown by the low annual precipitation of 600 mm and the relatively high annual average temperature of 8 ° C, with less than 100 frost days per year.

Protection status

The Rohrlache is under special protection as a nature reserve, flora-fauna-habitat area and as part of an EU bird sanctuary and a landscape conservation area .

Nature reserve

With the ordinance of the District Directorate for Forests and Nature Conservation at the regional council in Kassel , around 47 hectares of the pipe pool were registered in the state nature conservation book in July 1979 and thus placed under protection. The purpose of the protection was to sustainably secure and protect the wetland , which “from an ornithological , herpetological and geobotanical point of view ” is particularly valuable “with a species-rich salt flora and great importance as a breeding and resting area for rare endangered bird species as well as a spawning area and habitat for numerous amphibians . ” In October 1988 another designation followed with additional areas in the north and south-west, on which salt plants also grow. The nature reserve now has an area enlarged to 76.5 hectares and has the national identification 1632002 and the WDPA code 82435.

Flora-fauna habitat area

With the same territorial boundaries and conservation objectives, the nature reserve was reported to the EU in 2004 as Flora-Fauna-Habitat Area No. 5026-301 for the transnational network of protected areas Natura 2000. The main objective of the Natura 2000 directive is to preserve biological diversity in Europe and to keep it in a favorable state of conservation in the long term. Its appendices I and II name the habitat types and the wild animal and plant species that are considered to be of general interest and for which special protection areas must be designated. According to the standard data sheet for special protection areas from 2002, the special importance of the pipe pool lies in the occurrence of the priority FFH habitat type 1340 "Inland salt marshes" with its specific halophyte vegetation . With the "Ordinance on Natura 2000 areas in Hesse" in January 2008, the conservation objectives and area boundaries were legally secured at state level.

The river Werra borders directly on the Rohrlache. This section of the river is part of the FFH area No. 5125-350 "Werra between Phillippsthal and Herleshausen". The development goal here is to preserve the Werra as a migration corridor for fish species and to protect the alder, ash and softwood alluvial forests on the shoreline.

Bird sanctuary

The Rohrlache forms the EU bird sanctuary 5026-402 "Rhäden von Obersuhl" with the two neighboring nature conservation and FFH areas to the north, "Rhäden bei Obersuhl and Bosserode" and "Obersuhler Aue", as well as the northeastern FFH area "Werraaue von Herleshausen" Floodplains on the central Werra ”.

The approximately 540 hectare bird sanctuary is an important resting area for water birds, waders and wading birds. In Hesse, it is considered the most important nesting area for Pochard , bittern and Warbler . For the species corncrake , Spotted Crake , Water Rail , Knäk- , spoon and Gadwall , Marsh Harrier , White Stork , Little Bittern and gray heron is one of the five priority areas of Hesse.

Landscape protection area

The pipe pool lies entirely in the "Auenverbund Werra" nature reserve, which was designated in 1992. which with several sub-areas and a total area of ​​around 4000 hectares is located along the Werra in the districts of Hersfeld-Rotenburg and Werra-Meißner . As part of the landscape protection area, near-natural sections of water in the Werra are to be preserved or restored.

Geology and hydrology

The area of ​​the pipe pool is formed from floodplain sediments from the post-ice age . Loam , clay , sand and gravel are the predominant substrates . Below the river valley, at a depth of more than 1,000 meters, under mighty layers of sandstone, lies the salt mountains, with the valuable raw materials potash and rock salt . The formation of the potash deposits goes back to the geological age of the Upper Permian more than 250 million years ago, when the Zechstein Sea , which existed here at that time, evaporated under the strong solar radiation. Since the 1900s, potash salts have been extracted from two levels lying one above the other along the Werra, primarily for agricultural fertilization .

When the salts are processed, large amounts of waste water are produced , the so-called final liquors, which have been discharged into the Werra since the beginning of the 20th century and have led to the river becoming heavily salinated. Since 1929, the final lyes have also been pressed in the Zechstein's plate dolomite in Heringen . Since the specific weight of the final caustic is higher than the weight of the groundwater , the caustic presses salty groundwater to the soil surface. This process takes place particularly on faults and in salt leaching areas and leads to the formation of salt springs and salt seepage water. Sections of the Werra floodplain, such as the pipe pool, are saturated by the raised near-surface groundwater level. In 1953 an earthquake caused the southern part to sink by around two meters. New salt springs were created, which are attributed to the sinking of the final liquor. The backwater of the Werra power plant in Widdershausen is said to have raised the water table further, which made the meadows even more humid.

There are two layers of groundwater in the floodplain. The first, near-surface layer extends from 0.5 to 1.5 m above sea level. NN and is bordered by a one to two meter thick layer of clay and loam. The second groundwater layer lies in the gravel layer of the floodplain at a depth of three to four meters and carries salty groundwater. In the areas where the clay and loam layer is permeable, salt water comes up. At the exit points there is extensive salinization with salt-influenced vegetation. Near the Werra, the groundwater is mainly influenced by river infiltration . The salinization of the soil leads to a decrease in the crumb stability and pore volume and reduces the plasticity of the soil. When it is wet, the salt soils swell up and shrink when they dry out. This leads to soil compaction and waterlogging.

nature

The salt marshes in the middle of the floodplain.

The flora of the Rohrlache is characterized by the presence of salt-dependent species that have settled at the saline water outlet points. The salt flora occurs in three plant communities :

• The " Salzschuppenmieren - Salt swaths society" is the most common vegetation unit. Their population-forming species are the salt swaths, the only a few centimeters large salt chickweed that develops a red-violet carpet of flowers in July, and the samphire. The samphire only immigrated to the protected area in the 1990s and in a very short time has built up dense, low-growing populations in the vegetation-free areas of the salt pans.
• The swaths of salt also occur in the salt lawn stocks dominated by the Platthalm rush , which, due to the increased presence of the species of waterlogged, nutrient-rich locations, transfer fescue , white ostrich and couch grass to the flood grass communities . The society settles in the north and in the middle of the area small, vegetation-poor, waterlogging depressions ("salt pans"), which are well below the level of the surrounding grassland.
• A plant community with the beach trident , the maned barley naturalized from North America and the purple aster blooming between July and September surrounds a completely vegetation-free basin in the northern part of the area like a belt.

These plant communities occupied a much larger area until the 1980s. The salt marshes extended over large parts of the north and south of the reserve. Today there are floodplains, reeds and brackish reeds in their places .

In the areas in which the caterpillar forage plant Great Wiesenknopf grows, the dark blue anthurium occurs. According to Annex II of the Habitats Directive, the species, which is endangered throughout Europe, is considered to be “of community interest, and special protection areas must be designated for their conservation”.

According to the standard data sheet from 2002, the bird world of the Rohrlache is of importance throughout Hesse. This assessment is confirmed by the results of the basic data collection from 2002. The national significance is the presence of Bluethroat , Red-backed Shrike , Marsh Harrier , Corncrake , White Stork , Red Kite , Black Kite , sandpipers and egrets founded. In addition to these strictly protected species, a large number of other bird species have been observed that use the reed pool as breeding birds, foraging and migrants.

The reed pool offers valuable habitats for the grasshopper species . In the wet grassland, the nationwide endangered marsh insect and the short-winged sword insect were found in high density. Six amphibian species have been identified in the protected area, including a significant population of the common frog , the tree frog and the natterjack toad , which are protected by the Habitats Directive across Europe.

Tourist development

At the edge of the wetland, a cycling and hiking trail runs partly on a boarded embankment.

The Werra Valley cycle path and the Nadelöhr hiking path run along the Werra from Heringen to Widdershausen in the western edge of the protected area.

literature

• Lothar and Sieglinde Nitsche, Marcus Schmidt: Nature reserves in Hessen , Volume 3, cognitio Verlag, Niedenstein 2005, ISBN 3-932583-13-2 .
• Neckermann & Achterhold: Basic data collection of the FFH area "Rohrlache von Heringen." Final report, Cölbe, 2002.
• Gerd Teigeler, Rural Areas Service, Bad Hersfeld: Action plan for the FFH area “Rohrlache von Heringen”, which is also part of the VSG “Rhäden von Obersuhl and Auen on the central Werra” . July 2014.

Web links

Commons : Pipe pool of herrings  - Collection of images, videos and audio files

• “Alarm am Monte Kali” from DER SPIEGEL 35/2009 on the SPIEGELonline website.

Individual evidence

1. ^ ^{A b c d} Neckermann & Achterhold: Basic data collection FFH area "Rohrlache von Heringen." Final report, Cölbe, 2002.
2. ↑ ^{a b} "Rohrlache" nature reserve on the website of www.widdershausen.de; accessed on August 8, 2019.
3. ↑ Classification of natural areas according to Otto Klausing in the Hessen Environmental Atlas at atlas.umwelt.hessen.de ; accessed on August 8, 2019.
4. ↑ Quoted from the ordinance on the "Rohrlache von Heringen" nature reserve of July 9, 1979 in the State Gazette for the State of Hesse, edition 31/79 of July 30, 1979, p. 1591 f.
5. ^ Ordinance on the “Rohrlache von Heringen” nature reserve of October 6, 1988 in the State Gazette for the State of Hesse, edition 44/88 of October 31, 1988, p. 2402 f.
6. ^ "Rohrlache von Heringen" in the world database on protected areas; accessed on August 8, 2019.
7. ↑ Profile of the FFH area 5026-3501 "Rohrlache von Heringen" on the website of the Federal Agency for Nature Conservation (BfN); accessed on August 8, 2019.
8. ↑ FFH area "Rohrlache von Heringen" in the world database on protected areas; accessed on August 8, 2019.
9. ^ Ordinance on the Natura 2000 areas in Hesse of January 16, 2008, in the Law and Ordinance Gazette for the State of Hesse, Part I, No. 4, of March 7, 2008.
10. ↑ Profile of the FFH area 5125-350 "Werra between Phillippsthal and Herleshausen" on the website of the Federal Agency for Nature Conservation (BfN); accessed on August 8, 2019.
11. ↑ Profile of the EU bird protection area "Rhäden von Obersuhl and Auen on the central Werra" on the website of the Federal Agency for Nature Conservation (BfN); accessed on August 8, 2019.
12. ↑ “Rhäden von Obersuhl and Auen on the central Werra” in the world database on protected areas; accessed on August 8, 2019.
13. ↑ ^{a b} Lothar and Sieglinde Nitsche, Marcus Schmidt: Nature reserves in Hessen, Volume 3 .
14. ↑ "Auenverbund Werra" in the world database on protected areas; accessed on August 8, 2019.
15. ↑ Ordinance on the landscape protection area "Auenverbund Werra" of August 13, 1992 in the State Gazette for the State of Hesse, 36/1992 of September 7, 1992, p. 2202 f.
16. ↑ Gerd Teigeler: Action plan for the FFH area "Rohrlache von Heringen".
17. ↑ Species of community interest to be protected from the action plan for the FFH area and the bird sanctuary.