Selecting surrogate species for connectivity conservation

Abstract : Habitat loss and fragmentation impede the movement of animals across landscapes causing biodiversity change. One strategy to counter these effects is to protect and restore habitat quality and connectivity for a diversity of species. How should surrogate species be selected to represent a diversity of needs from a larger species pool? Using a recent method to prioritize multispecies habitat networks, we tested how the selection of surrogate species affects prioritization outcomes. We ran prioritization schemes using subsets of N (N = 0, 1, 3, 5, 7, 9) species selected from a 14-species reference set. Selection was based on different concepts of surrogate species: umbrella, taxonomy, habitat diversity, movement diversity, movement and habitat diversity. Prioritization outputs were compared to the 14-species set for their effectiveness and comprehensiveness at retaining habitat quality and connectivity criteria, and for their spatial congruence. We show that species-based surrogates perform better than habitat-based surrogates and that a moderate number of species (5-7) might be sufficient to capture the needs of a broader species pool for one habitat type (forest). However, how species are selected matters as much as how many. The best performing approach is to select species representing a diversity of habitat and/or movement needs. Umbrella or taxonomy-based selections were less effective and comprehensive. Our results can guide the selection of surrogate species when designing a prioritization plan for regional connectivity conservation. We recommend favoring systematic trait-based species selection over single-species, umbrella or taxonomy-based selections. When a proper species-based surrogate approach cannot be done, a habitat-based surrogate approach might still be a useful alternative.