The protected flora of long-established cemeteries in Hungary: Using historical maps in biodiversity conservation

The role of anthropogenically influenced habitats in conserving elements of the original wildlife has increased worldwide simultaneously with the disappearance of natural sites. Burial places are able to conserve original elements of the wildlife, and this fact has been known for at least a century. To this day, little is known about long-time changes and the effect of long-time management methods in cemeteries on the flora they harbor. The utility of historical maps in research focused on natural values, as well as in answering questions related to conservation was recently demonstrated, but the use of digitized historical maps in biodiversity research of the Carpathian Basin is very limited. In the present paper, we aimed to predict the conservation potential of long-established and newly established cemeteries of Hungarian settlements with various population sizes based on the digitized maps of the 2nd Military Survey of the Austrian Empire (1819-1869), by categorizing cemeteries into 3 distinct (anthropogenic habitat, cemetery, or natural habitat) types. To build our models, we used records of the protected flora from Hungarian cemeteries, based on data of thematic botanical surveys of 991 cemeteries. Out of the surveyed cemeteries, 553 (56%) harbored protected plants, totaling 306.617 estimated individuals of 92 protected species, belonging to 28 plant families. These species represent 12% of the entire protected flora of Hungary. Hungarian cemeteries play a key role mainly in preserving steppe and dry grassland plant species. Long-established and large cemeteries harbor more protected plant species than small and newly established ones. Human population size of the settlements correlated negatively with the number of protected species and individuals. Moreover, woodland cover and proportion of grassland also significantly positively affected the number of protected plant species in cemeteries.