Land-Sparing Agriculture Best Protects Avian Phylogenetic Diversity

The conversion of natural habitats to farmland is a major driver of the global extinction crisis [1, 2]. Two strategies are promoted to mitigate the impacts of agricultural expansion on biodiversity: land sharing integrates wildlife-friendly habitats within farmland landscapes, and land sparing intensifies farming to allow the offset of natural reserves [3]. A key question is which strategy would protect the most phylogenetic diversity—the total evolutionary history shared across all species within a community [4]. Conserving phylogenetic diversity decreases the chance of losing unique phenotypic and ecological traits [5] and provides benefits for ecosystem function and stability [6, 7]. Focusing on birds in the threatened Chocó-Andes hotspot of endemism [8], we tested the relative benefits of each strategy for retaining phylogenetic diversity in tropical cloud forest landscapes threatened by cattle pastures. Using landscape simulations, we find that land sharing would protect lower community-level phylogenetic diversity than land sparing and that with increasing distance from forest (from 500 to >1,500 m), land sharing is increasingly inferior to land sparing. Isolation from forest also leads to the loss of more evolutionarily distinct species from communities within land-sharing landscapes, which can be avoided with effective land sparing. Land-sharing policies that promote the integration of small-scale wildlife-friendly habitats might be of limited benefit without the simultaneous protection of larger blocks of natural habitat, which is most likely to be achieved via land-sparing measures. •Forest conversion to farming drives massive losses of avian phylogenetic diversity•Land-sparing farming would save more avian phylogenetic diversity than land sharing•Under land sharing, phylogenetic diversity declines at larger distance from forest•Evolutionarily distinct bird species benefit more from land sparing than sharing Appropriate management of farming is critical to slowing the biodiversity extinction crisis. Edwards et al. show that farming intensively while offsetting large natural reserves will save more phylogenetic diversity and evolutionarily distinct species of bird than low-intensity farming, especially when farmland is isolated from contiguous forests.