Climatic conditions produce contrasting influences on demographic traits in a long distance Arctic migrant
Journal of Animal Ecology
Reason for embargo
1) The manner in which patterns of variation and interactions among demographic rates contribute to population growth rate (λ) are key to understanding how animal populations will respond to changing climatic conditions. 2) Migratory species are likely to be particularly sensitive to climatic conditions as they experience a range of different environments throughout their annual cycle. However, few studies have provided fully integrated demographic analyses of migratory populations in response to changing climatic conditions. 3) Here, we employed integrated population models (IPM) to demonstrate that the environmental conditions experienced during a short, but critical period, play a central role in the demography of a long-distance migrant, the light-bellied Brent goose (Branta bernicla hrota). 4) Female survival was positively associated with June North Atlantic Oscillation (NAO) values, whereas male survival was not. In contrast, breeding productivity was negatively associated with June NAO, suggesting a trade-off between female survival and reproductive success. Both adult female and adult male survival showed low temporal variation, whereas there was high temporal variation in recruitment and breeding productivity. In addition, while annual population growth was positively correlated with annual breeding productivity a sensitivity analysis revealed that population growth was most sensitive to changes in adult survival. 5) Our results demonstrate that the environmental conditions experienced during a relatively short-time window at the start of the breeding season play a critical role in shaping the demography of a long-distant Arctic migrant. Crucially, different demographic rates responded in opposing directions to climatic variation, emphasizing the need for integrated analysis of multiple demographic traits when understanding population dynamics.
We thank the Irish Brent Goose Research Group and the Icelandic Ringing Group for assistance with catching birds and providing observations of marked individuals. We thank Alan Lauder and Alyn Walsh for leading cannon net catches in Ireland during the study. Sean Boyd, Josee Lefebrve, Chantelle Masson and Alyn Walsh assisted with captures of geese in Canada. SB, IRC and TB are all funded by an ERC Consolidator’s grant (310820: STATEMIG) awarded to SB. FV was funded by an Icelandic Research Council Postdoctoral fellowship grant.
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.
Accepted manuscript online: 14 December 2016