Extreme climate events and individual heterogeneity shape life‐history traits and population dynamics

Abstract

Abstract. Extreme climatic conditions and their ecological impacts are currently emerging as critical features of climate change. We studied extreme sea ice condition (ESIC) and found it impacts both life-history traits and population dynamics of an Antarctic seabird well beyond ordinary variability.The Southern Fulmar (Fulmarus glacialoides) is an ice-dependent seabird, and individuals forage near the ice edge. During an extreme unfavorable year (when sea ice area is reduced and distance between ice edge and colony is high), observed foraging trips were greater in distance and duration. As a result, adults brought less food to their chicks, which fledged in the poorest body condition. During such unfavorable years, breeding success was extremely low and population growth rate (k) was greatly reduced. The opposite pattern occurred during extreme favorable years.Previous breeding status had a strong influence on life-history traits and population dynamics, and their responses to extreme conditions. Successful breeders had a higher chance of breeding and raising their chick successfully during the following breeding season as compared to other breeding stages, regardless of environmental conditions. Consequently, they coped better with unfavorable ESIC. The effect of change in successful breeder vital rates on k was greater than for other stages' vital rates, except for pre-breeder recruitment probabilities, which most affected k.For environments characterized by ordinary sea ice conditions, interindividual differences were more likely to persist over the life of individuals and randomness in individual pathways was low, suggesting individual heterogeneity in vital rates arising from innate or acquired phenotypic traits. Additionally, unfavorable ESIC tended to exacerbate individual differences in intrinsic quality, expressed through differences in reproductive status.We discuss the strong effects of ESIC on Southern Fulmar life-history traits in an evolutionary context. ESICs strongly affect fitness components and act as potentially important agents of natural selection of life histories related to intrinsic quality and intermittent breeding. In addition, recruitment is a highly plastic trait that, if heritable, could have a critical role in evolution of life histories. Finally, we find that changes in the frequency of extreme events may strongly impact persistence of Southern Fulmar populations.

Two Recent Massive Breeding Failures in an Adélie Penguin Colony Call for the Creation of a Marine Protected Area in D'Urville Sea/Mertz

“…While an MPA is no solution to global environmental changes, it removes some of the additional impacts (e.g., fisheries) that could weigh on populations. Predictive modeling is a powerful conservation tool to anticipate how populations may react to expected changes (e.g., Jenouvrier et al, 2015) but such approaches require data like those presented here to be obtained in a system with no additional pressure. Protecting the waters of East Antarctica would mean the creation of a large-scale MPA in the Southern Ocean, and be the next step in realizing the initial commitment of the members of CCAMLR to establish a network of protected areas around Antarctica.…”

Genetic and life-history consequences of extreme climate events

“…Tests of theory-based predictions on the consequences of extreme events with empirical data are scarce, though necessary and urgent to provide a balanced view of the adaptive potential of species and the overarching risks associated with all aspects of climate change [6][7][8]. However, when dealing with extreme events, finding the right model system, posing and testing tractable hypotheses on their demographic, genetic and life-history consequences, and developing an overarching predictive framework are inevitably challenging [8].…”

Behavioural, ecological and evolutionary responses to extreme climatic events: challenges and directions

“…Because of these commonalities, fire ecology, as an established research field, has supplied several methodological (including statistical) tools that are also proving useful for the biological study of ECEs. For instance, a demographic model originally developed for post-fire disturbance response has been applied to address the effect of extreme years (in terms of weather) on population growth of birds [38,43].…”

“…The effects of ECEs typically differ among individuals according to their behaviour, state, age, habitat or history [20,23,34,43,62]. However, we know little about how individual heterogeneity may buffer the effect of ECEs on population dynamics and whether it enhances future ECE tolerance by driving selective mortality and selecting for higher quality individuals.…”

“…However, we know little about how individual heterogeneity may buffer the effect of ECEs on population dynamics and whether it enhances future ECE tolerance by driving selective mortality and selecting for higher quality individuals. Comprehensive eco-evolutionary studies on how ECEs affect survival, mating success and reproduction as a function of various individual traits may help to improve our understanding of the importance of individual heterogeneity for population ecology [43] and for evolutionary responses to ECEs. The eco-evolutionary feedbacks between individual and population processes are only one example of how we need to improve our understanding of how effects of ECEs cascade across levels of biological organization.…”