Modelling time to population extinction when individual reproduction is autocorrelated

Lee, Aline Magdalena; Sæther, Bernt‐Erik; Markussen, Stine Svalheim; Engen, Steinar

doi:10.1111/ele.12834

Cited by 10 publications

(9 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, Lee et al . () found that time to extinction for a simulated moose population was not greatly affected by positive covariation between survival and fecundity, compared to models that assumed these rates varied independently. We show here that estimates of λ e and λ s under null and positive covariation are closer to each other than to the negative covariation scenario (i.e.…”

Section: Discussionmentioning

confidence: 96%

See 1 more Smart Citation

The diversity of population responses to environmental change

et al. 2018

View full text Add to dashboard Cite

The current extinction and climate change crises pressure us to predict population dynamics with ever‐greater accuracy. Although predictions rest on the well‐advanced theory of age‐structured populations, two key issues remain poorly explored. Specifically, how the age‐dependency in demographic rates and the year‐to‐year interactions between survival and fecundity affect stochastic population growth rates. We use inference, simulations and mathematical derivations to explore how environmental perturbations determine population growth rates for populations with different age‐specific demographic rates and when ages are reduced to stages. We find that stage‐ vs. age‐based models can produce markedly divergent stochastic population growth rates. The differences are most pronounced when there are survival‐fecundity‐trade‐offs, which reduce the variance in the population growth rate. Finally, the expected value and variance of the stochastic growth rates of populations with different age‐specific demographic rates can diverge to the extent that, while some populations may thrive, others will inevitably go extinct.

show abstract

Section: Discussionmentioning

confidence: 96%

“…Commonly, it is assumed that survival and fecundity have either null or positive covariation (Lee et al . ), despite increasing evidence of within‐year trade‐offs between survival and fecundity (i.e. negative covariation) in natural populations (Cox et al .…”

Section: Introductionmentioning

confidence: 99%

The diversity of population responses to environmental change

et al. 2018

View full text Add to dashboard Cite

show abstract

“…In polygynous species, fluctuations in population size are generally driven by variation in the reproductive success and survival of females. However, the persistent differences in reproductive performance seen among female moose on Vega had only a very small effect on the demographic variance in this population (Lee et al 2017). The effect was somewhat larger when the observed covariation between reproduction and survival was also in cluded, because this covariation amplifies the individual differences.…”

Section: Consequences Of Individual Heterogeneity For Demographymentioning

confidence: 80%

“…Females that had twins were not only more likely to produce twins again in the future if they survived, they were also more likely to survive, causing a synergistic effect between these 2 mechanisms. Nonetheless, the combined effect on the expected time to extinction was negligible (Lee et al 2017). Thus, female individual heterogeneity seems to have minor effects on population dynamics in this population.…”

Section: Consequences Of Individual Heterogeneity For Demographymentioning

confidence: 99%

“…This is likely in part because most female moose do eventually start producing twins, causing the differences between individuals to decrease over their lifetimes (Markussen et al 2018). In fact, theoretical analyses indicate that individual differences in reproduction would have to be quite extreme to have a substantial effect on the expected time to extinction (Lee et al 2017).…”

Section: Consequences Of Individual Heterogeneity For Demographymentioning

confidence: 99%

See 1 more Smart Citation

Demographic consequences of harvesting: a case study from a small and isolated moose population

et al. 2022

View full text Add to dashboard Cite

Harvesting can have a substantial impact on population dynamics and individual performance in wild populations. While the direct consequences of harvest on individual survival and population growth rate are often apparent, harvesting can also have indirect and more subtle demographic consequences. Disentangling these consequences, however, requires in-depth knowledge of individual life histories of both females and males in the population. Here, we summarise demographic research on a population where such data exist: the Vega moose population in northern Norway. In this population, vital rates vary considerably among both females and males, and harvesting increases this variation by generating positive covariation between reproductive performance and survival. The skewed age and sex structure, which is typical of many harvested populations, also has demographic consequences: it reduces the ratio of effective to total population size and influences variation in vital rates in males and females. The moose harvest at Vega is structured by age- and sex-specific quotas, but it is not intentionally selective regarding size or other phenotypic characteristics. Still, harvest selection for earlier birth rates and larger calves was apparent, likely due to habitat-performance relationships and habitat-specific harvest mortality. Together, the bulk of research on this population shows that harvesting impacts population demography through many different pathways, with some being more subtle than others. These complex pathways influence the demographic variance and affect stochastic processes such as population growth, genetic drift, and rates of evolutionary change, and they must therefore be acknowledged in management plans to achieve sustainable harvesting.

show abstract

Age‐dependent patterns of spatial autocorrelation in fish populations

Marquez

Sæther

Aanes

et al. 2021

Ecology

Self Cite

View full text Add to dashboard Cite

The degree of spatial autocorrelation in population fluctuations increases with dispersal and geographical covariation in the environment, and decreases with strength of density dependence. Because the effects of these processes can vary throughout an individual’s lifespan, we studied how spatial autocorrelation in abundance changed with age in three marine fish species in the Barents Sea. We found large interspecific differences in age‐dependent patterns of spatial autocorrelation in density. Spatial autocorrelation increased with age in cod, the reverse trend was found in beaked redfish, while it remained constant among age classes in haddock. We also accounted for the average effect of local cohort dynamics, i.e. the expected local density of an age class given last year’s local density of the cohort, with the goal of disentangling spatial autocorrelation patterns acting on an age class from those formed during younger age classes and being carried over. We found that the spatial autocorrelation pattern of older age classes became increasingly determined by the distribution of the cohort during the previous year. Lastly, we found high degrees of autocorrelation over long distances for the three species, suggesting the presence of far‐reaching autocorrelating processes on these populations. We discuss how differences in the species’ life history strategies could cause the observed differences in age‐specific variation in spatial autocorrelation. As spatial autocorrelation can differ among age classes, our study indicates that fluctuations in age structure can influence the spatio‐temporal variation in abundance of marine fish populations.

show abstract

Modelling time to population extinction when individual reproduction is autocorrelated

Cited by 10 publications

References 66 publications

The diversity of population responses to environmental change

The diversity of population responses to environmental change

Demographic consequences of harvesting: a case study from a small and isolated moose population

Age‐dependent patterns of spatial autocorrelation in fish populations

Contact Info

Product

Resources

About