Abstract
Most existing protected area networks are usually biased to protect charismatic species or showy landscapes. We hypothesized that conservation networks designed including unseen diversity –groups usually species-rich but consisting of inconspicuous taxa, or affected by knowledge gaps– would be more efficient than networks ignoring those groups. To test this hypothesis, we created species distribution models for 3,006 species of arthropods and determined which were represented in three networks of different size and biogeographic origin. We assessed the efficiency of each network using spatial prioritization to measure its completeness –increment needed to achieve conservation targets– and specificity –how much overlap the priority areas based on unseen diversity with existing networks. We find that representativeness of unseen diversity in existing protected areas –extrinsic representativeness– was low, as ~40% of unseen diversity species were unprotected. We also find that existing networks should be expanded by an additional ~26-46% of their current area to complete targets, and that specificity can be as low as 8.8%, meaning that existing networks are not efficient to conserve unseen diversity. We conclude that information on unseen diversity must be included in systematic conservation planning approaches to design more efficient and ecologically representative protected areas.