Multispecies conservation planning: identifying landscapes for the conservation of viable populations using local and continental species priorities

Faced with unpredictable environmental change, conservation managers face the dual challenges of protecting species throughout their ranges and protecting areas where populations are most likely to persist in the long term. The former can be achieved by protecting locally rare species, to the potential detriment of protecting species where they are least endangered and most likely to survive in the long term. Using British butterflies as a model system, we compared the efficacy of two methods of identifying persistent areas of species' distributions: a single-species approach and a new multispecies prioritization tool called ZONATION. This tool identifies priority areas using population dynamic principles (prioritizing areas that contain concentrations of populations of each species) and the reserve selection principle of complementarity. ZONATION was generally able to identify the best landscapes for target (i.e. conservation priority) species. This ability was improved by assigning higher numerical weights to target species and implementing a clustering procedure to identify coherent biological management units. Weighting British species according to their European rather than UK status substantially increased the protection offered to species at risk throughout Europe. The representation of species that are rare or at risk in the UK, but not in Europe, was not greatly reduced when European weights were used, although some species of UK-only concern were no longer assigned protection inside their best landscapes. The analysis highlights potential consequences of implementing parochial vs. wider-world priorities within a region. Synthesis and applications. Wherever possible, reserve planning should incorporate an understanding of population processes to identify areas that are likely to support persistent populations. While the multispecies prioritization tool ZONATION compared favourably to the selection of 'best' areas for individual species, a user-defined input of species weights was required to produce satisfactory solutions for long-term conservation. Weighting species can allow international conservation priorities to be incorporated into regional action plans but the potential consequences of any putative solution should always be assessed to ensure that no individual species of local concern will be threatened..