A 150-year-old herbarium exemplifies change of a regional flora

The loss of biodiversity in terms of plant species in a certain region can be shown by a comparison of historical herbarium records with the present-day occurrence of species. This holds especially true for time periods before 1900, when only few floristic data are otherwise available. Such a comparison can also show whether the distribution area or the abundance of plant species have changed, which habitat types were especially affected by extinction or whether species with specific environmental requirements showed higher extinction rates than ubiquists. Corresponding results can guide conservation authorities in defining appropriate management actions.