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Costa Rican birds of a feather lost together
Evolutionary history is lost when land is converted for farming, and recently evolved species may cope better with changing land use. Frishkoff et al. compared bird diversity over 12 years in three different kinds of landscape in tropical Central America. They mapped their data onto the bird evolutionary tree and found that more evolutionary branches were lost in intensive agricultural landscapes than in mixed landscapes. In turn, mixed landscapes lost more evolutionary branches than forest reserves. This is not just because of species loss; in fact, mixed agricultural landscapes contained similar numbers of species to those in forest reserves. Evolutionary history is lost because the more evolutionarily distinct species—those with fewer extant relatives and a longer evolutionary history—are more likely to become extinct in agricultural land.
Science, this issue p. 1343
Abstract
Habitat conversion is the primary driver of biodiversity loss, yet little is known about how it is restructuring the tree of life by favoring some lineages over others. We combined a complete avian phylogeny with 12 years of Costa Rican bird surveys (118,127 detections across 487 species) sampled in three land uses: forest reserves, diversified agricultural systems, and intensive monocultures. Diversified agricultural systems supported 600 million more years of evolutionary history than intensive monocultures but 300 million fewer years than forests. Compared with species with many extant relatives, evolutionarily distinct species were extirpated at higher rates in both diversified and intensive agricultural systems. Forests are therefore essential for maintaining diversity across the tree of life, but diversified agricultural systems may help buffer against extreme loss of phylogenetic diversity.
