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Berlin Environmental Atlas

01.12 Soil Functions (Edition 2009)

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01.12.1 Habitat Functions for Rare and Near-Natural Plant Communities

Description

Almost all soils are generally potential growth sites for plants, and hence provide a habitat function for plant communities. Differences in efficacy arise from the evaluation of the vegetation which potentially grows on that specific soil, with rare species or plant communities being evaluated more highly, primarily from the view of conservation.

Changes of the soil by excavation, land-filling and earth-moving, as well as by groundwater lowering and nutrient introduction cause far-reaching equalization of site qualities, which deprives particularly specialized plant species of their already rare habitats. A not atypical special case is that of poor and dry locations, with the comparatively rare dry meadows which take root there, the occurrence of which in the Berlin area is, however, tied to a low degree of anthropogenic influence.

In the present evaluation of the habitat function, a further continuation of the concept developed by Lahmeyer (2000), soil associations with extreme conditions of water balance and rare soil associations are primarily assessed as valuable. Rare and wet locations are identified as so-called special sites. In that way, ecologically particularly valuable locations and potentials for development, such as meadow communities, damp meadows and boglands, can be highlighted.

Extremely dry and low-nutrient dunes and anthropogenically created young soils represent potential sites for valuable dry meadows. These sections receive a medium evaluation as special natural spaces, regardless of their degree of near-naturalness.

Overall, the evaluation represents the potential of the soil to sustain certain vegetation, and is not an evaluation of the existing vegetation.

Methodology

The habitat function for rare and near-natural plant communities is ascertained on the basis of the criteria near-naturalness (cf. Map 01.11.3), regional rareness of the soil association (cf. Map 01.11.1), dampness of the site (cf. Map 01.01 and 01.06.4) and nutrient supply (cf. Map 01.06.9) (cf. Figure 1). Using these criteria, so-called "special sites" are ascertained. Special sites include:

  • Sections on which the site dampness is indicated as "wet"
  • Sections on which the regional rareness of the soil association has been assessed as "very rare to rare"
  • Sections with dry, low-nutrient soils.

As shown in Table 1, the evaluation of the habitat function for near-natural and rare plant communities is carried out according to three classes (low, medium, high), with consideration given to the degree of near-naturalness. The rare and wet classes receive a considerably higher evaluation than the dry locations, which are less sensitive because they regenerate more easily. The latter are assigned exclusively a medium potential for development, regardless of their near-naturalness. "Normal" locations obtain a medium efficacy rating only with very high near-naturalness.

Diagram for the evaluation of the habitat function for rare and near-natural plant communities
Fig. 1: Diagram for the evaluation of the habitat function for rare and near-natural plant communities

Tab. 1: Evaluation of the soil function habitat for rare and near-natural plant communities, from the evaluation of near-naturalness, by special-site class (or non-special)
  Near-Naturalness
Special-site class high medium low very low
very rare, rare high medium low low
wet high medium low low
dry and low-nutrient
(w/o use category "Construction Sites")
medium medium medium medium
Non-special site medium low low low
Tab. 1: Evaluation of the soil function habitat for rare and near-natural plant communities, from the evaluation of near-naturalness, by special-site class (or non-special) (Gerstenberg/Smettan 2005)

Map Description

Areas of great importance as habitats for rare and near-natural plant communities are restricted almost exclusively to the outskirts of Berlin. Very few sections fall into this category. They contain soils characterized by high ground-water levels, such as bogs, flood-plain meadows and gleyic associations in glacial-stream channels, river plains and valley-sand areas. The lime-mud area in Teerofen should also be mentioned, as should the podzoluvisol soils with arenic dystric cambisol on the boulder marl plateaus in Frohnau, under forests. Since major significance for near-natural and rare plant communities can be achieved only with a high degree of near-naturalness, these sections are certified almost exclusively in forests, only very few are in cemeteries (cf. Figure 2).

The near-natural soils of the low-bog, flood-plain-meadow and gleyic-soil associations of the valley sand areas; the dystric cambisol on the ground, end and push moraines, and the gleyic areas of the glacial-stream channels receive a medium evaluation, as do the luvisols with arenic dystric cambisol on the loamy plateaus, and, in the former sewage-farm areas of Gatow, gleyic luvisols with gleyo-arenic dystric cambisol. Dry sites are, as expected, found predominantly in the anthropogenically formed loose lithosols of the glacial spillway.

Most sections are of only minor significance as habitats for near-natural and rare plant communities. These are primarily inner-city sections with anthropogenic aggradations, such as building rubble.

Area share of the habitat function for rare and near-natural plant communities per use class
Fig. 2: Area share of the habitat function for rare and near-natural plant communities per use class
(incl. impervious sections, without streets and water bodies (not all uses are shown)

Excel
[Statistical base of Figure 2 is also available as Excel-File (MS-Excel is required).]

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