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The sensitivity of breeding songbirds to changes in seasonal timing is linked to population change but cannot be directly attributed to the effects of trophic asynchrony on productivity

Franks, Samantha E.; Pearce-Higgins, James W.; Atkinson, Sian; Bell, James R.; Botham, Marc S.; Brereton, Tom M.; Harrington, Richard; Leech, David I.

Authors

Samantha E. Franks

James W. Pearce-Higgins

Sian Atkinson

Marc S. Botham

Tom M. Brereton

Richard Harrington

David I. Leech



Abstract

A consequence of climate change has been an advance in the timing of seasonal events. Differences in the rate of advance between trophic levels may result in predators becoming mismatched with prey availability, reducing fitness and potentially driving population declines. Such “trophic asynchrony” is hypothesized to have contributed to recent population declines of long-distance migratory birds in particular. Using spatially extensive survey data from 1983 to 2010 to estimate variation in spring phenology from 280 plant and insect species and the egg-laying phenology of 21 British songbird species, we explored the effects of trophic asynchrony on avian population trends and potential underlying demographic mechanisms. Species which advanced their laying dates least over the last three decades, and were therefore at greatest risk of asynchrony, exhibited the most negative population trends. We expressed asynchrony as the annual variation in bird phenology relative to spring phenology, and related asynchrony to annual avian productivity. In warmer springs, birds were more asynchronous, but productivity was only marginally reduced; long-distance migrants, short-distance migrants and resident bird species all exhibited effects of similar magnitude. Long-term population, but not productivity, declines were greatest among those species whose annual productivity was most greatly reduced by asynchrony. This suggests that population change is not mechanistically driven by the negative effects of asynchrony on productivity. The apparent effects of asynchrony on population trends are therefore either more likely to be strongly expressed via other demographic pathways, or alternatively, are a surrogate for species' sensitivity to other environmental pressures which are the ultimate cause of decline.

Citation

Franks, S. E., Pearce-Higgins, J. W., Atkinson, S., Bell, J. R., Botham, M. S., Brereton, T. M., …Leech, D. I. (2018). The sensitivity of breeding songbirds to changes in seasonal timing is linked to population change but cannot be directly attributed to the effects of trophic asynchrony on productivity. Global Change Biology, 24(3), 957-971. https://doi.org/10.1111/gcb.13960

Journal Article Type Article
Online Publication Date Nov 20, 2017
Publication Date 2018-03
Deposit Date Feb 8, 2024
Journal Global Change Biology
Print ISSN 1354-1013
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 24
Issue 3
Pages 957-971
DOI https://doi.org/10.1111/gcb.13960
Publisher URL https://onlinelibrary.wiley.com/doi/10.1111/gcb.13960