Life after death: Hidden diversity of orchids across European cemeteries

Abstract

Habitats sensitive to anthropogenic pressures are growing in conservation importance in the protection and perpetuation of rare animal and plant species. Although natural habitats sensitive to disturbance in urban areas have mostly declined in availability, patches offer conservation opportunities for wildlife that are fundamental to maintaining biodiversity. Human burial sites can contribute to this: they are more numerous and greater in extent in more urbanized areas, but their significance in the maintenance and promotion of biodiversity has not been considered across Europe and other continents. Because of their high sensitivity to even minor disturbance to natural habitats, orchid diversity is a key bioindicator of terrestrial ecosystem function. We evaluated orchid diversity in cemeteries of 13 European countries. Comprehensive field surveys of orchid flora in 2079 locations revealed that they occurred in every country visited and in high variability in both the number of taxa (n = 65) and individual plant counts (n = 44680). We propose that cemeteries are of major importance as refugia in conserving orchids in most of the visited European countries; however, one of the most urgent issues is to identify the many anthropogenic factors determining biodiversity of cemeteries, and to eliminate some newly emerged management practices in cemeteries that undermine biodiversity, including the orchid flora. Human burial grounds are therefore not just important in preserving the history of humankind; they are key in protecting biodiversity in this modern era of unprecedented anthropogenic changes to our terrestrial environments, especially as a result of rapid and unrelenting urbanization.