How to select surrogate species to ensure the consistency of ecological networks across political and biological levels?

Abstract

Ecological networks – that should facilitate the movement of species within a landscape – are key to reconciling biodiversity conservation and land planning. These networks are, however, species-specific and one different network could be identified for each of the numerous species of a territory. To identify these networks concretely and integrate them within a broader conservation strategy, there is thus a need to select a few representative species (surrogates) that reflect the diversity of habitat and connectivity needs of the entire species pool. French political regions have already struggled with this issue when they identified their networks (in the context of the "Green and Blue Belts" policy). Indeed, this species selection had to rely on very limited ecological data, but disregarding this selection by using indirect methods based on land-cover and habitat data makes the validation of networks risky and communication potentially ineffective. This selection question arises again, now that regional networks have to be applied at more local scales (municipality). Here we first introduce the different approaches that exist to identify ecological networks and depict their drawbacks and advantages. Then we suggest ways to facilitate the choice of species that is consistent across different levels of governance, ensures the multiple needs of a diversity of species as well as the spatio-temporal hierarchisation of the levels of organization of living things.