The Green Belt as a European Ecological Network strengths and gaps

Schlumprecht, H., Laube, J.
MONITORING BIODIVERSITY OF THE THURINGIAN GREEN BELT
3.3 Shrub cover and threatened species
Missing land use does not lead to loss of rare plant or animal species in the short run.
With on-going succession to dense shrub stands and young forests the populations of rare
species (i.e. plants of the Red List, or protected by law) will decline and get lost. The 39
occurrences of rare plant species we found at unused sites (see table 4) will get lost in the long
run if no land use or land management will be established. The same is true for rare animal
species, where grazed areas (like ID15) showed the highest numbers of threatened species as
well as highest total species numbers.
Regarding plant and animal species, grazed areas show the highest species numbers,
and the amount of rare species is also very high. Unused areas showed low to medium species
numbers (and only very seldom unused areas reached high numbers), and rare species were
found less frequent. We therefore recommend extensive grazing as best land use type,
producing a high species richness and supporting many rare plant and animal species. A low
shrub or canopy cover (about up to 30-40 %) seems not to harm the occurrence of most
threatened plants or animals. Missing land use and increasing shrub and canopy cover above
this extent decreases the conservational value in the long term. Our recommendation is to
enable grazing (or mowing), and to tolerate a low shrub cover level at the Thuringian Green
Belt.
4. CONCLUSION
The conservation of large areas of highly valuable biotopes is a big challenge. In the
case of the property of the Foundation for Nature Conservation Thuringia at the Green Belt
the major difficulty is to substitute the former military use of large areas for low-cost land use
forms and at the same time conserving the valuable biotopes and habitats. Our results show
that an overall of more than 50 % of the monitored area is covered by biotope types of high
conservation value. Out of these valuable biotopes, only 7 % are critically endangered by
abandonment and shrub encroachment, albeit increased shrub cover to a less severe extent is
among the most frequent threats within the monitoring sites. Regarding plant species
inventory, most of the biotopes (76 %) were considered as of exceptional high or good species
richness. The zoological monitoring also showed high numbers of rare bird, butterfly and
grasshopper species.
The surveyors recommended to maintain the current land use (extensively mowing or
grazing) for a majority of sites. In total, large parts of the monitored areas are in good
conditions. Extensive grazing is favourable for threatened plant species as well as for bird,
butterfly and grasshopper species. This land use type should be promoted or newly
established wherever feasible. Shrub and tree covers up to about 30 % seem not to cause
species or biotope loss, hence could be tolerated to a certain extent.
REFERENCES
[1] Schlumprecht, H., Ludwig, F., Geidezis, L., Frobel, K. 2002. E+E Vorhaben
Biotoptypenkartierung Grünes Band Deutschland. Unveröff. Abschlussbericht, im Auftrag
des Projektbüro Grünes Band beim BUND/BN, Nürnberg.
[2] TLUG – Thüringer Landesamt für Umwelt und Geologie. 2001. Kartieranleitung zur
Offenland-Biotopkartierung im Freistaat Thüringen. Jena, 183 S.
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