WEGE: A new metric for ranking locations for biodiversity conservation

Aim Effective policy making for biological conservation requires the
identification and ranking of the most important areas for protection or
management. One of the most frequently used systems for selecting priority
areas is Key Biodiversity Areas (hereafter KBAs), developed by the
International Union for Conservation of Nature (IUCN). However, KBAs
cannot be used to rank areas, potentially limiting their use when limited
funding is available. To tackle this shortcoming and facilitate spatial
prioritization, here we develop and validate the “WEGE index” (Weighted
Endemism including Global Endangerment index), consisting of an adaptation
of the EDGE score (Evolutionarily Distinct and Globally Endangered). WEGE
allows the ranking of any set of locations according to the KBA guidelines
and on a continuous scale. Location Global. Methods We calculated the EDGE
score, Weighted Endemism, Evolutionary distinctiveness, Extinction risk
and our newly developed WEGE index for all terrestrial species of
amphibians, mammals and birds accessed by IUCN. We then compared the
performance of each of those five indices at prioritizing areas according
to the KBA guidelines. Results We found that for all taxa surveyed, WEGE
was consistently better at identifying areas that trigger KBA status. Main
conclusions In our analyses, WEGE outperformed all other methods and
metrics designed for similar purposes. It can therefore serve as a robust
evidence-based methodology to prioritize among otherwise equally qualified
sites according to the KBA categories. WEGE can therefore support
transparent, evidence-based and biologically meaningful decision-making
for conservation priorities.