Later at higher latitudes: large‐scale variability in seabird breeding timing and synchronicity

Zofia M Burr,Børge Moe,Tone Kristin Reiertsen,Claus Bech,Øystein Varpe,Tycho Anker‐Nilssen,Svein‐Håkon Lorentsen,Hallvard Strøm,Robert T Barrett,Kjell Einar Erikstad,Sébastien Descamps,Signe Christensen‐Dalsgaard

doi:10.1002/ecs2.1283

Abstract

AbstractIn seasonal environments, organisms are expected to optimally schedule reproduction within an annual range of environmental conditions. Latitudinal gradients generate a range of seasonality to which we can expect adaptations to have evolved, and can be used to explore drivers of timing strategies across species’ distribution ranges. This study compares the timing of egg hatching in four seabird species (Atlantic puffin Fratercula arctica, black‐legged kittiwake Rissa tridactyla, common guillemot Uria aalge, and Brünnich's guillemot U. lomvia) covering a subarctic to Arctic latitudinal gradient along the Norwegian coast to Svalbard (65–79°N). Hatching was significantly delayed by an estimated 1.7, 2.3, and 1.9 d per latitudinal degree for puffins, kittiwakes, and common guillemots, respectively, but was not delayed for Brünnich's guillemots. Hatching distributions revealed an increase in intra‐annual breeding synchronicity along a latitudinal gradient for kittiwakes only, whereas the two guillemots exhibited high hatching synchronicity at all colonies. We used this large‐scale, multispecies timing data series to discuss constraints, adaptations, and mechanisms affecting breeding timing, a necessary step to recognize risks to populations and predict future ecosystem change.

Highlights

Theory predicts that species living in seasonal systems would evolve to optimally time important life history events, such as reproduction, within a spectrum of yearly conditions (McNamara and Houston 2008)
Brünnich’s and common guillemot hatching timing was more synchronous at all colonies compared to kittiwakes and puffins, and hatching distributions and their timing were similar in absolute timing from Bjørnøya northwards (Table 1)
The main findings of our study are that (1) hatching timing delayed with latitude in three of the four species considered, (2) intra-a nnual v www.esajournals.org breeding synchronicity increased with latitude for kittiwakes but not for guillemots and puffins, and (3) the study species exhibited different levels of inter-annual variability in hatching timing with kittiwakes showing the largest variability

Summary

Introduction

Theory predicts that species living in seasonal systems would evolve to optimally time important life history events, such as reproduction, within a spectrum of yearly conditions (McNamara and Houston 2008). Latitude has often been used as a proxy in avian phenology studies (Baker 1938, Slagsvold 1975, Olsen and Marples 1993, Wanless et al 2008), and we choose to use the same parameter as a proxy for a general gradient of environmental conditions to address large-s cale spatial comparisons and species differences. Studying variability in breeding timing along a gradient from temperate to polar ecosystems, and a gradient of seasonality, offers a unique opportunity to address the links between reproductive timing and seasonality

Methods

Results

Conclusion