Hoffmann S., Beierkuhnlein C., Field R., Provenzale A., Chiarucci A. (2018). Scientific Reports, 8, 6445. doi:10.1038/s41598-018-24390-3
The global loss of biodiversity threatens the human well-being, yet still continues in the 21st century. Biodiversity generally stabilizes ecosystem functioning, providing ecosystem goods and services.
One of the most important tools for nature conservation are protected areas. They aim to preserve biodiversity such as threatened species, habitats and ecosystems. Nowadays the survival of some species solely depends on protected areas.
The conservation policy of the European Union is a story of success. The Natura2000 framework consist of the Birds and Habitats Directive that legally oblige member states to protect and report on 1895 characteristic, rare, endemic and threatened species in the EU.
We here investigated to what extent major European protected areas contribute to the preservation of these Natura2000 species, which are priority species for nature conservation in the EU. We focus on National Parks and UNESCO Man and Biosphere Reserves, since they concentrate on biodiversity protection. Out of 1895, 1303 Natura2000 species occur in these protected areas. National Parks and UNESCO Man and Biosphere Reserves are among the largest protected areas in Europe and are characterized by intensive, integrated and effective biodiversity management, in contrast to other protected area designations such as natural parks.
In order to match species range maps with protected areas we developed a new procedure on the basis of former studies. This procedure accounts for the overlap between protected area and species ranges. With the help of conditional probability theory, we could calculate the probability of occurrence for each species inside each protected area. We then computed several diversity indices for each single protected area. Among these indices, four are shown below:
a) Species richness; the sum of probabilities of occurrence; the higher this index is, the more unique is the protected area.
b) Species richness related to area; the size of the protected area affects the number of species inside the protected area; this index shows the number of species inside protected areas that in relation to the number of species expected for this size of the protected area, considering the whole set of protected areas and species; the higher this index the more unique the PA.
c) Species rarity; the species’ rarities, i.e. frequency of occurrence, naturally varies; this index shows the number of species per PA weighted for the species’ rarities in the EU; the higher this index is, the more unique is the PA.
d) Each protected area includes a set of species; this index shows the dissimilarity of the set of species compared to other sets of other protected areas; the higher this index is, the more unique is the PA.
We use these diversity indices to assess the manifold potential of important European protected areas to preserve Europe’s priority species. The diversity indices resolve that protected areas contribute to species conservation in various ways. Some protected areas harbour many common, others few rare species. Again, others hold a set of species that is very different from the rest. The size of protected areas is thereby a bad indicator for species richness.
The results may serve as a resource for future management practice and policy regarding nature conservation in the EU.
However, simple recommendations cannot be given; are protected areas of many but common species more valuable than protected areas with few but rare species? To establish appropriate management programs in future, sustainable conservation policy has not only to consider the various aspects of biodiversity, but also human impact and climate change.