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Migratory diversity predicts population declines in birds

2016; Wiley; Volume: 19; Issue: 3 Linguagem: Inglês

10.1111/ele.12569

1461-0248

James J. Gilroy, Jennifer A. Gill, Stuart H. M. Butchart, Victoria R. Jones, Aldina M. A. Franco,

Ecology and Vegetation Dynamics Studies

Abstract Declines in migratory species are a pressing concern worldwide, but the mechanisms underpinning these declines are not fully understood. We hypothesised that species with greater within‐population variability in migratory movements and destinations, here termed ‘migratory diversity’, might be more resilient to environmental change. To test this, we related map‐based metrics of migratory diversity to recent population trends for 340 European breeding birds. Species that occupy larger non‐breeding ranges relative to breeding, a characteristic we term ‘migratory dispersion’, were less likely to be declining than those with more restricted non‐breeding ranges. Species with partial migration strategies (i.e. overlapping breeding and non‐breeding ranges) were also less likely to be declining than full migrants or full residents, an effect that was independent of migration distance. Recent rates of advancement in Europe‐wide spring arrival date were greater for partial migrants than full migrants, suggesting that migratory diversity may also help facilitate species responses to climate change.