Raising offspring increases ageing: Differences in senescence among three populations of a long‐lived seabird, the Atlantic puffin

Abstract

Actuarial senescence, the decline of survival with age, is well documented in the wild. Rates of senescence vary widely between taxa, to some extent also between sexes, with the fastest life histories showing the highest rates of senescence. Few studies have investigated differences in senescence among populations of the same species, although such variation is expected from population‐level differences in environmental conditions, leading to differences in vital rates and thus life histories. We predict that, within species, populations differing in productivity (suggesting different paces of life) should experience different rates of senescence, but with little or no sexual difference in senescence within populations of monogamous, monomorphic species where the sexes share breeding duties. We compared rates of actuarial senescence among three contrasting populations of the Atlantic puffin Fratercula arctica. The dataset comprised 31 years (1990–2020) of parallel capture–mark–recapture data from three breeding colonies, Isle of May (North Sea), Røst (Norwegian Sea) and Hornøya (Barents Sea), showing contrasting productivities (i.e. annual breeding success) and population trends. We used time elapsed since first capture as a proxy for bird age, and productivity and the winter North Atlantic Oscillation Index (wNAO) as proxies for the environmental conditions experienced by the populations within and outside the breeding season, respectively. In accordance with our predictions, we found that senescence rates differed among the study populations, with no evidence for sexual differences. There was no evidence for an effect of wNAO, but the population with the lowest productivity, Røst, showed the lowest rate of senescence. As a consequence, the negative effect of senescence on the population growth rate (λ) was up to 3–5 times smaller on Røst (Δλ = −0.009) than on the two other colonies. Our findings suggest that environmentally induced differences in senescence rates among populations of a species should be accounted for when predicting effects of climate variation and change on species persistence. There is thus a need for more detailed information on how both actuarial and reproductive senescence influence vital rates of populations of the same species, calling for large‐scale comparative studies.

Stay or go? Changing breeding conditions affect sexual difference in colony attendance strategies of Atlantic puffins Fratercula arctica

“…Interestingly, the putative age of the birds (time since first capture as an adult) also contributed to the best models, suggesting reproductive experience and investment in previous years also contribute to determine the birds' willingness to uphold their current parental efforts. Apparently, this effect was strongest in females, as could be expected if their life‐history trade‐off is more focussed on fecundity than that of males, which could also explain the marginal tendency for lower survival in females than males (Landsem et al., 2023 ).…”

“…As shown by Landsem et al. ( 2023 ), there is a slight tendency for female puffins to have lower survival than males and although they found no evidence of sexual differences in actuarial senescence of adults, a higher rate of senescence in colonies producing well indicate puffins do invest more in parental care when conditions for breeding are favourable.…”

“…Since all but 13 birds were first ringed as adults, their true age was usually unknown. We, therefore, used time elapsed since first captured as an adult as a proxy for their age, an approach proven useful for studies of senescence in both common guillemots (Crespin et al., 2006 ) and puffins (Landsem et al., 2023 ). As the ringing of puffins with metal rings in the study plot started several decades earlier and colour ringing required proofs of breeding, 314 (54%) of the birds had already been captured as an adult in a year prior to when they got the colour ring(s) (on average 7.6 years earlier, range 1–23 years).…”

Consequences of cross‐season demographic correlations for population viability

“…Both possible mechanisms can, therefore, represent a form of demographic buffering, that is, a mechanism by which population size fluctuations are buffered against environmental stochasticity (Hilde et al, 2020 ; Tuljapurkar et al, 2009 ). Similarly, senescence rates for puffins at Røst were also found to be lower than at Isle of May and Hornøya (Landsem et al, 2023 ), potentially providing another buffering mechanism that limits population‐level consequences of low and/or variable productivity, via individual trade‐offs.…”

Born without a Silver Spoon: A Review of the Causes and Consequences of Adversity during Early Life

“…Older parents, meanwhile, close to the end of their lives sometimes have lower levels of reproductive success than middle-aged parents ( Bonamour et al 2020 ). This is at least partly because raising offspring increases parental aging, with Landsem et al (2023 ) showing that Atlantic puffin ( Fratercula arctica ) parents exhibited increased rates of senescence after raising offspring.…”