Seepage source

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A seepage source , also known as a swamp source, is a source outlet in which the source water seeps through a layer of soil. As a rule, seepage springs are not punctiform, but flat wet spots in which the draining water forms swamp spots and tiny spring rivulets that only unite behind the source area to form the actual source stream. These can be very extensive, often hundreds of square meters, in exceptional cases they can be several square kilometers in size. Due to the special ecological site conditions, seepage sources are sites of special plant communities .

In the limnological terminology, seepage sources are also referred to as Helokrenen , this expression goes back to the limnologist August Thienemann . The spring discharge from seepage springs varies, but can sometimes be very low. Areas that are sprinkled into usable areas and are soaked in a swell without actual fill are sometimes referred to as wet gall in agriculture.

Although seepage sources are often stated as typical for the lowlands, they occur at all altitudes, up to the alpine level.

Source morphology

Sources of seepage are often located in flat areas or valleys, but also occur on more or less steep slopes. Here they are often sunk into the slope profile. The reason for this is assumed to be the sodden, loose, often poorly rooted soil, which easily leads to soil creeping or other erosion processes. Kammeis formation is probably also involved as a cause. Due to the very low flow velocity, seepage sources are characterized by a fine-grained substrate, mostly in connection with organic detritus . However, seepage springs rich in coarse material are less common in the low mountain range.

colonization

fauna

The specialized species of the source region, limnological Krenal called, can in such be distinguished, which can live only here (Krenobionte) and those here have their main distribution (Krenophile). Their share in the invertebrate spring fauna ( macrozoobenthos ) is just as high in seepage springs in Central Europe as in the other spring types. In a study in Schleswig-Holstein, no significant differences were found in the two-winged species , stone flies and caddis flies . On a regional basis, however, species can be specified that are typical for seepage sources. In Schleswig-Holstein, 174 sources were identified as typical for seepage springs in Schleswig-Holstein: freshwater mites of the Hydryphantidae family , the larvae of the caddis flies Beraea maurus , Crunoecia irrorata and the water beetle Elodes minuta ( Scirtidae family ).

Vegetation and flora

In vegetation science, a distinction is made between the source meadows and their own type of vegetation , which is linked in a special way to seepage sources. In the plant sociological system they are taken as the class Montio-Cardaminetea . Among the characteristic species that may be deemed typical types of sources at the same time include about Moose of the genus scapania and Philonotis , the water-blinks Montia fontana or Gegenblättrige Chrysosplenium Chrysosplenium oppositifolium , other typical species are about Bach chickweed Stellaria alsine , marsh Willowherb Epilobium palustre or Angle-Sedge Carex remota .

Spring corridors are often tree-free, even if they are within forests. The frequency of tree growth in the actual spring swamp decreases in Central Europe from west to east. When trees are present, the most common species is the black alder , followed by the ash .

Individual evidence

  1. ↑ Helokrene. In: Wilfried Schönborn, Ute Risse-Buhl: Textbook of Limnology. 2nd Edition. Schweizerbart, Stuttgart 2013, ISBN 978-3-510-65275-4 , p. 47.
  2. ↑ Fabian Wigger, Stefanie von Fumetti: Sources and their communities in the Bernese Alps. In: Communications from the Natural Research Society in Bern. New episode, 70, pp. 117-131.
  3. ↑ Carl Beierkuhnlein, Arno Kleber: For the morphogenesis of flat source corridors. In: C. Beierkuhnlein, T. Gollan (Ed.): Ecology of silicate forest springs in Central Europe. (= Bayreuth Forum Ecology. Volume 71). Self-published by the Bayreuth Institute for Terrestrial Ecosystem Research, 1999, Chapter 4, pp. 27–34.
  4. ↑ State Office for Water Management Rhineland-Palatinate (Ed.): Basics of water development in Rhineland-Palatinate. Book 2: Source Type Atlas. Mainz 2002, ISBN 3-933123-14-3 .
  5. ↑ Bavarian State Office for Water Management (ed.): Bavarian source catalog. Munich 2004, ISBN 3-930253-93-3 .
  6. ↑ Maren Rückert, Peter Martin, Heinz Brendelberger: The classic source types in Schleswig-Holstein - are there differences in the colonization of Rheo-, Helo- and Limnokrenen in the lowlands? German Society for Limnology, Conference Report 2005 (Karlsruhe). Weißensee Verlag, Berlin, pp. 35-39.
  7. ^ Peter Martin, Matthias Brunke: Faunal typology of lowland springs in northern Germany. Freshwater Science 31 (2), 2012, pp. 542-562. doi: 10.1899 / 11-092.1
  8. ↑ Erich Oberdorfer: South German Plant Societies. Part I: Rock and wall communities, alpine corridors, water, silting and moor communities. Gustav Fischer Verlag, Jena 1992, ISBN 3-334-60417-9 .