Responsibility type Astragalus exscapus and its habitats in Saxony-Anhalt: Threat analysis and conservation concepts

Steppe grasslands are biodiversity hotspots that occur in small areas in extreme locations, especially on steep, south- to west-facing slopes. They feature a large number of attractive plant species that are optimally adapted to summer-dry locations. In Germany, however, steppe grasslands now cover less than 1,000 hectares. Remaining and fragmented areas are currently under serious threat from land use changes. In order to protect these habitats and their species, studies on threats and development scenarios and, ultimately, effective conservation concepts are necessary. This applies in particular to species for which Germany has a special international responsibility, such as the stemless milk vetch (Astragalus exscapus).

Within Germany, the stemless milk vetch is restricted to relict sites in the Central German Dry Region. With occurrences particularly in the Mansfelder Seen area, the Saaletal northwest of Halle, and the Unstruttal, the species has its clear distribution focus in Saxony-Anhalt. However, around 40% of all populations ever known in the Central German Dry Region are already considered extinct. There is an urgent need for action.

Due to the species’ limited dispersal capacity, combined with the increasing threat to its habitats from land use changes, it is unlikely that, based on current occurrences, reintroduction to former habitats or the establishment of new populations in suitable locations will occur. The top priority for the long-term conservation of the species is therefore to monitor and promote the populations that currently still exist and their habitats in the field.

Project priorities

The aim of the project is to develop essential foundations for a sustainable improvement of the population status of A. exscapus and its habitats in Saxony-Anhalt. The project will develop essential building blocks for a state-wide concept for the long-term protection of the species and its habitats in Saxony-Anhalt through a) site and population ecological studies on current occurrences, b) research and site-specific evaluation of the effectiveness of current conservation measures and instruments, and c) their optimization and the design of further measures.

Project region

Saxony-Anhalt

Further project details

• Methodical approach

  The project will run from May 2014 to December 2015 and is divided into the following four stages.

  1. Compilation of available data on the locations and populations of A. exscapus in Saxony-Anhalt, as well as on the utilization and support measures carried out on the areas to date.
  2. Review and recording of the current condition of the land and the inventory situation through site inspections.
  3. Based on the data, a priority list is drawn up which takes into account the urgency of measures (e.g. due to the current threat to populations) on the one hand and reflects the prospects of success (suitability of location, current and potential integration into current and future management and utilization concepts) on the other.
  4. Concrete measures are being developed for selected areas, and initial measures are being implemented on a trial basis.

• First results

  

  The project covers all 56 known occurrences of Astragalus exscapus in Saxony-Anhalt. Thirty-one of these occurrences were visited and studied in 2014 (including studies on population size and vegetation structure and composition). The occurrences examined so far reflect the very different characteristics of A. exscapus sites. In many cases, the growth sites of A. exscapus represent the best-preserved parts of dry grassland complexes within otherwise more severely degraded stages of abandonment. However, the results to date also show that some of the areas where the species occurs are already more ruderalized and/or scrubby due to insufficient maintenance/use. It has been found that areas in poor condition of conservation exclusively have smaller occurrences comprising populations of fewer than 30 individuals. Changes in population sizes compared to previous surveys also generally correspond to the condition of the dry grasslands. Areas with a decline in the number of individuals often show severe deficits, which are due to a variety of use-related threat factors. Overall, studies to date have shown that a lack of or insufficient grazing, in particular, poses a threat to Astragalus exscapus due to the development of dense fallow stages.

  Due to the increasing threat to Astragalus exscapus habitats as a result of land use changes, there is often a great need for action with regard to the development and implementation of management and utilization concepts. Around 30 percent of the occurrences studied to date are classified as highly endangered due to their location. Measures such as the removal of woody plants in the area of the growth sites are necessary as an initial measure, followed by grazing adapted to the site conditions.

  

• What happens next?

  After developing the essential foundations for a sustainable improvement in the population status of Astragalus exscapus in Saxony-Anhalt, a statewide action plan and targeted measures should be implemented with the involvement of key regional stakeholders. In addition, further options beyond the conservation of the currently existing populations should be discussed. This includes concrete concepts, e.g., for measures to strengthen the population, for reintroduction, and for attempts to reintroduce the species within its range. A first further step in this regard would be to obtain basic seed from the remaining populations for the establishment of intermediate propagation.