A small increase in the size of the world’s protected areas could have a large, positive influence on global biodiversity, a Nature paper reveals. The study, which focuses on less commonly studied metrics of biodiversity, will be of use to those involved in conservation planning and policy.

Biodiversity is commonly measured by counting the number of species present in a particular area, but other facets of biodiversity are equally important. Laura Pollock and colleagues broadened the focus by evaluating phylogenetic diversity (a measure of evolutionary relatedness) and functional diversity (a measure of traits that are linked to trophic interactions and resource acquisition) as well as number of species. Concentrating on birds and mammals, they find that if the world’s protected areas were expanded by just 5% it could more than triple the protected range of species, phylogenetic diversity or functional diversity.

Protected areas safeguard the world’s biodiversity. There is now widespread evidence that a globally coordinated increase in protected areas is necessary to achieve biodiversity targets, and policies are in place to achieve this goal. When determining which areas to expand, however, it is important to consider the specific conservation objective. The authors point out that although many priority regions are well-known biodiversity hot spots, such as eastern Madagascar and southeast Asia, using diversity hot spots to assign conservation priorities vastly under-represents what could be achieved with conservation planning. For example, over 1,500 more bird species or 8,236 million years more evolutionary diversity could be represented in protection if a 5% protected area expansion is done with optimized spatial conservation algorithms rather than simply prioritizing the most diverse areas.