Demographic profiles and environmental drivers of variation relate to individual breeding state in a long-lived trans-oceanic migratory seabird, the Manx shearwater

Matt J Wood,Holly Kirk,Stace M Fairhurst,Dave Boyle,Aurélien Besnard,Coline Canonne,Tim Guilford,Robin M Mccleery,Miriam Liedvogel,Shelly Lachish,Chris M Perrins,Simon Josey,Samantha C Patrick,Ben Dean,Cat Horswill

doi:10.1371/journal.pone.0260812

Abstract

Understanding the points in a species breeding cycle when they are most vulnerable to environmental fluctuations is key to understanding interannual demography and guiding effective conservation and management. Seabirds represent one of the most threatened groups of birds in the world, and climate change and severe weather is a prominent and increasing threat to this group. We used a multi-state capture-recapture model to examine how the demographic rates of a long-lived trans-oceanic migrant seabird, the Manx shearwater Puffinus puffinus, are influenced by environmental conditions experienced at different stages of the annual breeding cycle and whether these relationships vary with an individual’s breeding state in the previous year (i.e., successful breeder, failed breeder and non-breeder). Our results imply that populations of Manx shearwaters are comprised of individuals with different demographic profiles, whereby more successful reproduction is associated with higher rates of survival and breeding propensity. However, we found that all birds experienced the same negative relationship between rates of survival and wind force during the breeding season, indicating a cost of reproduction (or central place constraint for non-breeders) during years with severe weather conditions. We also found that environmental effects differentially influence the breeding propensity of individuals in different breeding states. This suggests individual spatio-temporal variation in habitat use during the annual cycle, such that climate change could alter the frequency that individuals with different demographic profiles breed thereby driving a complex and less predictable population response. More broadly, our study highlights the importance of considering individual-level factors when examining population demography and predicting how species may respond to climate change.

Highlights

As global climate change continues [1, 2], reliably predicting how species and populations are likely to respond becomes a key conservation priority
We examine whether individual differences in breeding state may alter spatiotemporal exposure to local weather conditions and generate heterogeneity in the demography of a trans-Atlantic migrant seabird, the Manx shearwater Puffinus puffinus
We examine whether individual differences in breeding state may alter spatiotemporal exposure to weather conditions and generate heterogeneity in the demography of a trans-Atlantic migrant seabird, the Manx shearwater

Summary

Introduction

As global climate change continues [1, 2], reliably predicting how species and populations are likely to respond becomes a key conservation priority. Many studies investigating associations between environmental variation and seabird demography use large-scale climatic and oceanographic indices, such as the North Atlantic Oscillation (NAO) and El Niño Southern Oscillation (ENSO) (for example see references in [5, 6]). These large-scale climate indices can be advantageous when dealing with wide-ranging species because they capture variation in local weather conditions over large spatial scales [7]. Individuals respond principally to local conditions, and information on local variables is typically needed to understand the direct and indirect mechanisms linking large-scale climate indices to an ecological response, such as demographic change [7]

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Results

Conclusion