How are Natura 2000 protected areas covering different components of avian diversity in Spain?

Abstract

Protected areas are a relevant conservation tool at our disposal, especially for developing management strategies of natural habitats. However, explicit tests at large spatial scales about its effectivity protecting different components of biodiversity are still rare. This study explored the spatial matching between the distribution of three components of avian diversity (taxonomic, functional, and phylogenetic metrics) and the network of Natura 2000 protected areas in Spain, the EU country with the most extensive terrestrial coverage. Overall, the spatial distribution of taxonomic, functional, and phylogenetic diversity was slightly spatially congruent, matching with protected areas. However, each avian diversity metric showed differences in the arrangement of spatial clusters, also regarding the environment type. Species richness was higher in forests while it was lower in orchards, mixed environments, and arable lands. Functional dispersion was higher in forest and arable lands, while it was lower in wetlands. In contrast, the highest phylogenetic diversity was associated with wetlands and water bodies, with shrublands showing the lowest levels for this metric. All three avian diversity metrics were overall higher within than outside the Natura 2000 network. The species richness was higher in areas simultaneously protected by the Habitat and Birds Directives. Functional dispersion was higher in protected areas designed under the Birds Directive. Finally, the evolutionary uniqueness was well represented in all protected areas, although areas designed under Birds Directive showed the higher values for this metric. The presence of spatial mismatch among avian diversity components suggests the importance of considering taxonomic, functional, and evolutionary metrics simultaneously for a better spatial prioritisation in conservation planning.