scholarly journals The hidden side of the Allee effect: correlated demographic traits and extinction risk in experimental populations

2021 ◽  
Vol 1 ◽  
pp. 1-None
Author(s):  
Elodie Vercken ◽  
Géraldine Groussier ◽  
Laurent Lamy ◽  
Ludovic Mailleret
Keyword(s):  
Allee Effect ◽  
Extinction Risk ◽  
Demographic Traits ◽  
Experimental Populations

scholarly journals Genetic Allee effects and their interaction with ecological Allee effects

2016 ◽  
Author(s):  
Meike J. Wittmann ◽  
Hanna Stuis ◽  
Dirk Metzler
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Survival Probability ◽  
Allee Effect ◽  
Extinction Risk ◽  
List Type ◽  
Small Populations ◽  
Allee Effects ◽  
Deleterious Mutations ◽  
Lethal Equivalents

SummaryIt is now widely accepted that genetic processes such as inbreeding depression and loss of genetic variation can increase the extinction risk of small populations. However, it is generally unclear whether extinction risk from genetic causes gradually increases with decreasing population size or whether there is a sharp transition around a specific threshold population size. In the ecological literature, such threshold phenomena are called “strong Allee effects” and they can arise for example from mate limitation in small populations.In this study, we aim to a) develop a meaningful notion of a “strong genetic Allee effect”, b) explore whether and under what conditions such an effect can arise from inbreeding depression due to recessive deleterious mutations, and c) quantify the interaction of potential genetic Allee effects with the well-known mate-finding Allee effect.We define a strong genetic Allee effect as a genetic process that causes a population’s survival probability to be a sigmoid function of its initial size. The inflection point of this function defines the critical population size. To characterize survival-probability curves, we develop and analyze simple stochastic models for the ecology and genetics of small populations.Our results indicate that inbreeding depression can indeed cause a strong genetic Allee effect, but only if individuals carry sufficiently many deleterious mutations (lethal equivalents) on average and if these mutations are spread across sufficiently many loci. Populations suffering from a genetic Allee effect often first grow, then decline as inbreeding depression sets in, and then potentially recover as deleterious mutations are purged. Critical population sizes of ecological and genetic Allee effects appear to be often additive, but even superadditive interactions are possible.Many published estimates for the number of lethal equivalents in birds and mammals fall in the parameter range where strong genetic Allee effects are expected. Unfortunately, extinction risk due to genetic Allee effects can easily be underestimated as populations with genetic problems often grow initially, but then crash later. Also interactions between ecological and genetic Allee effects can be strong and should not be neglected when assessing the viability of endangered or introduced populations.

Neglecting uncertainty behind Allee effect estimation may generate false predictions of population extinction risk

Oikos ◽  
2012 ◽  
Vol 122 (6) ◽  
pp. 845-856 ◽  
Author(s):  
Luděk Berec ◽  
Tomáš Mrkvička
Keyword(s):  
Allee Effect ◽  
Extinction Risk ◽  
Population Extinction ◽  
Effect Estimation

scholarly journals Dynamic Complexities in 2-Dimensional Discrete-Time Predator-Prey Systems with Allee Effect in the Prey

2016 ◽  
Vol 2016 ◽  
pp. 1-14
Author(s):  
Jie Yan ◽  
Chunli Li ◽  
Xueli Chen ◽  
Lishun Ren
Keyword(s):  
Bifurcation Theory ◽  
Allee Effect ◽  
Center Manifold ◽  
Prey Species ◽  
Extinction Risk ◽  
Flip Bifurcation ◽  
Crowding Effect ◽  
Predator Prey ◽  
Center Manifold Theorem ◽  
Predator Prey Model

The Allee effect is incorporated into a predator-prey model with linear functional response. Compared with the predator-prey which only takes the crowding effect and predator partially dependent on prey into consideration, it is found that the Allee effect of the prey species would increase the extinction risk of both the prey and predator. Moreover, by using a center manifold theorem and bifurcation theory, it is shown that the model with Allee effect undergoes the flip bifurcation and Hopf bifurcation in the interior ofR+2with different Allee effect values. In the two bifurcations, we can come to the conclusion that different Allee effect will have different bifurcation value and the increasing of the Allee effect will increase the value of bifurcation, respectively.

scholarly journals Time-lag in extinction dynamics in experimental populations: evidence for a genetic Allee effect?

2013 ◽  
Vol 82 (3) ◽  
pp. 621-631 ◽  
Author(s):  
Elodie Vercken ◽  
Flora Vincent ◽  
Ludovic Mailleret ◽  
Nicolas Ris ◽  
Elisabeth Tabone ◽  
...  
Keyword(s):  
Allee Effect ◽  
Time Lag ◽  
Experimental Populations

scholarly journals Contrasting effects of ecological and evolutionary processes on range expansions and shifts

2021 ◽  
Author(s):  
Christopher Weiss-Lehman ◽  
Allison Shaw
Keyword(s):  
Allee Effect ◽  
Extinction Risk ◽  
Range Shifts ◽  
Evolutionary Processes ◽  
Ecological Processes ◽  
Mate Finding ◽  
Factors Influencing ◽  
Spatial Sorting ◽  
And Shifts ◽  
Dispersal Evolution

Research has conclusively demonstrated the potential for dispersal evolution in range expansions and shifts through a process termed spatial sorting. However, the degree of dispersal evolution observed has varied substantially among organisms. Further, it is unknown how the factors influencing dispersal evolution might impact other ecological processes at play. We use an individual-based model to investigate the effects of the underlying genetics of dispersal and mode of reproduction in range expansions and shifts. Spatial sorting behaves similarly to natural selection in that dispersal evolution increases with sexual selection and loci number. Contrary to our predictions, however, increased dispersal does not always improve a population’s ability to track changing conditions. The mate finding Allee effect inherent to sexual reproduction increases extinction risk during range shifts, counteracting the beneficial effect of increased dispersal evolution. Our results demonstrate the importance of considering both ecological and evolutionary processes for understanding range expansions and shifts.

scholarly journals Malthusian Catastrophe: Species Extinction Caused by Oversized Population

2017 ◽  
Author(s):  
Xubin Pan
Keyword(s):  
Lower Limit ◽  
Growth Model ◽  
Logistic Model ◽  
Allee Effect ◽  
Extinction Risk ◽  
Logistic Growth ◽  
Extinction Debt ◽  
Species Extinction ◽  
Upper Limit ◽  
Logistic Growth Model

AbstractThere is one pseudo-extinction debt and four occurring conditions for real extinction debt. Since small and oversized populations have a high extinction risk, Pan threshold (upper limit) was calculated for Verhulst-Pear “logistic” growth model and logistic model with the Allee effect, an important parameter corresponding to Allee threshold (lower limit).

Genetic Mapping in Experimental Populations

2013 ◽  
Author(s):  
J. W. Van Ooijen ◽  
J. Jansen
Keyword(s):  
Genetic Mapping ◽  
Experimental Populations

Inter-individual differences in the foraging behavior of breeding Adélie penguins are driven by individual quality and sex

2020 ◽  
Vol 636 ◽  
pp. 189-205
Author(s):  
A Lescroël ◽  
PO’B Lyver ◽  
D Jongsomjit ◽  
S Veloz ◽  
KM Dugger ◽  
...  
Keyword(s):  
Individual Differences ◽  
Foraging Behavior ◽  
Ross Sea ◽  
Individual Quality ◽  
High Quality ◽  
Breeding Experience ◽  
Age Related ◽  
Demographic Traits ◽  
Iteroparous Species ◽  
Adélie Penguins

Inter-individual differences in demographic traits of iteroparous species can arise through learning and maturation, as well as from permanent differences in individual ‘quality’ and sex-specific constraints. As the ability to acquire energy determines the resources an individual can allocate to reproduction and self-maintenance, foraging behavior is a key trait to study to better understand the mechanisms underlying these differences. So far, most seabird studies have focused on the effect of maturation and learning processes on foraging performance, while only a few have included measures of individual quality. Here, we investigated the effects of age, breeding experience, sex, and individual breeding quality on the foraging behavior and location of 83 known-age Adélie penguins at Cape Bird, Ross Sea, Antarctica. Over a 2 yr period, we showed that (1) high-quality birds dived deeper than lower quality ones, apparently catching a higher number of prey per dive and targeting different foraging locations; (2) females performed longer foraging trips and a higher number of dives compared to males; (3) there were no significant age-related differences in foraging behavior; and (4) breeding experience had a weak influence on foraging behavior. We suggest that high-quality individuals have higher physiological ability, enabling them to dive deeper and forage more effectively. Further inquiry should focus on determining the physiological differences among penguins of different quality.

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