Payo-Payo, A. Sanz-Aguuilar, A. and Oro, D. 2022. Long-lasting effects of harsh early-life conditions on adult survival of a long-lived vertebrate. Oikos e09371, https://doi.org/10.1111/oik.09371
Summary: Early life conditions, especially in long-lived organisms, can have both
immediate and long-lasting effects in vital traits generating
demographic structure across cohorts. Multiple non-exclusive hypotheses
have been proposed to explore this question. For instance, the silver
spoon, the viability selection or the predictive adaptive response
hypothesis, predict that long lasting effects resulting from harsh early
conditions could be negative, positive or vary with current
environmental conditions, respectively. We use an 18-year
capture–mark–recapture dataset on adult Audouin's gulls Ichthyaetus audouinii
to test for these different hypotheses while accounting for age,
breeding experience and large-scale dispersal. Audouin's gull cohorts
experiencing harsh conditions during early life (i.e. nestling period
and first winter) are known to experience lower first year survival.
Here, we show that early life conditions also explained a large
proportion (54%) of adult survival variation among cohorts. However,
adulthood cohorts experiencing poor early life conditions had higher
adult survival, in accordance with the viability selection hypothesis.
Our results also show that apparent inexperienced breeders showed lower
survival than experienced ones. Moreover, adult survival decreased with
age. These results could suggest an increased cost of reproduction for
deferred breeders, individual quality differences or survival senescence
in this population. Overall, our study highlights the importance of
early development, age and breeding experience as potential factors
generating heterogeneity of survival between cohorts. Understanding the
mechanisms driving responses to early life conditions at different life
stages is fundamental to understanding the long-term dynamics of wild
populations.