Pelletier
Fanie
Pelletier
Fanie
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ArticleThe interplay between hunting rate, hunting selectivity, and reproductive strategies shapes population dynamics of a large carnivore(Wiley Open Access, 2021-05-05) Van de Walle, Joanie ; Pelletier, Fanie ; Zedrosser, Andreas ; Swenson, Jon E. ; Jenouvrier, Stephanie ; Bischof, RichardHarvest, through its intensity and regulation, often results in selection on female reproductive traits. Changes in female traits can have demographic consequences, as they are fundamental in shaping population dynamics. It is thus imperative to understand and quantify the demographic consequences of changes in female reproductive traits to better understand and anticipate population trajectories under different harvest intensities and regulations. Here, using a dynamic, frequency-dependent, population model of the intensively hunted brown bear (Ursus arctos) population in Sweden, we quantify and compare population responses to changes in four reproductive traits susceptible to harvest-induced selection: litter size, weaning age, age at first reproduction, and annual probability to reproduce. We did so for different hunting quotas and under four possible hunting regulations: (i) no individuals are protected, (ii) mothers but not dependent offspring are protected, (iii) mothers and dependent offspring of the year (cubs) are protected, and (iv) entire family groups are protected (i.e., mothers and dependent offspring of any age). We found that population growth rate declines sharply with increasing hunting quotas. Increases in litter size and the probability to reproduce have the greatest potential to affect population growth rate. Population growth rate increases the most when mothers are protected. Adding protection on offspring (of any age), however, reduces the availability of bears for hunting, which feeds back to increase hunting pressure on the nonprotected categories of individuals, leading to reduced population growth. Finally, we found that changes in reproductive traits can dampen population declines at very high hunting quotas, but only when protecting mothers. Our results illustrate that changes in female reproductive traits may have context-dependent consequences for demography. Thus, to predict population consequences of harvest-induced selection in wild populations, it is critical to integrate both hunting intensity and regulation, especially if hunting selectivity targets female reproductive strategies.
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ArticleTemporal correlations among demographic parameters are ubiquitous but highly variable across species.(Wiley, 2022-05-24) Fay, Remi ; Hamel, Sandra ; van de Pol, Martijn ; Gaillard, Jean-Michel ; Yoccoz, Nigel G. ; Acker, Paul ; Authier, Matthieu ; Larue, Benjamin ; Le Coeur, Christie ; Macdonald, Kaitlin R. ; Nicol-Harper, Alex ; Barbraud, Christophe ; Bonenfant, Christophe ; Van Vuren, Dirk H. ; Cam, Emmanuelle ; Delord, Karine ; Gamelon, Marlène ; Moiron, Maria ; Pelletier, Fanie ; Rotella, Jay J. ; Teplitsky, Celine ; Visser, Marcel E. ; Wells, Caitlin P. ; Wheelwright, Nathaniel T. ; Jenouvrier, Stephanie ; Saether, Bernt-ErikTemporal correlations among demographic parameters can strongly influence population dynamics. Our empirical knowledge, however, is very limited regarding the direction and the magnitude of these correlations and how they vary among demographic parameters and species’ life histories. Here, we use long-term demographic data from 15 bird and mammal species with contrasting pace of life to quantify correlation patterns among five key demographic parameters: juvenile and adult survival, reproductive probability, reproductive success and productivity. Correlations among demographic parameters were ubiquitous, more frequently positive than negative, but strongly differed across species. Correlations did not markedly change along the slow-fast continuum of life histories, suggesting that they were more strongly driven by ecological than evolutionary factors. As positive temporal demographic correlations decrease the mean of the long-run population growth rate, the common practice of ignoring temporal correlations in population models could lead to the underestimation of extinction risks in most species.
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ArticleQuantifying fixed individual heterogeneity in demographic parameters: performance of correlated random effects for Bernoulli variables(British Ecological Society, 2021-09-24) Fay, Remi ; Authier, Matthieu ; Hamel, Sandra ; Jenouvrier, Stephanie ; van de Pol, Martijn ; Cam, Emmanuelle ; Gaillard, Jean-Michel ; Yoccoz, Nigel G. ; Acker, Paul ; Allen, Andrew ; Aubry, Lise M. ; Bonenfant, Christophe ; Caswell, Hal ; Coste, Christophe F. D. ; Larue, Benjamin ; Le Coeur, Christie ; Gamelon, Marlène ; Macdonald, Kaitlin R. ; Moiron, Maria ; Nicol-Harper, Alex ; Pelletier, Fanie ; Rotella, Jay J. ; Teplitsky, Celine ; Touzot, Laura ; Wells, Caitlin P. ; Saether, Bernt-Erik1. An increasing number of empirical studies aim to quantify individual variation in demographic parameters because these patterns are key for evolutionary and ecological processes. Advanced approaches to estimate individual heterogeneity are now using a multivariate normal distribution with correlated individual random effects to account for the latent correlations among different demographic parameters occurring within individuals. Despite the frequent use of multivariate mixed models, we lack an assessment of their reliability when applied to Bernoulli variables. 2. Using simulations, we estimated the reliability of multivariate mixed effect models for estimating correlated fixed individual heterogeneity in demographic parameters modelled with a Bernoulli distribution. We evaluated both bias and precision of the estimates across a range of scenarios that investigate the effects of life-history strategy, levels of individual heterogeneity and presence of temporal variation and state dependence. We also compared estimates across different sampling designs to assess the importance of study duration, number of individuals monitored and detection probability. 3. In many simulated scenarios, the estimates for the correlated random effects were biased and imprecise, which highlight the challenge in estimating correlated random effects for Bernoulli variables. The amount of fixed among-individual heterogeneity was frequently overestimated, and the absolute value of the correlation between random effects was almost always underestimated. Simulations also showed contrasting performances of mixed models depending on the scenario considered. Generally, estimation bias decreases and precision increases with slower pace of life, large fixed individual heterogeneity and large sample size. 4. We provide guidelines for the empirical investigation of individual heterogeneity using correlated random effects according to the life-history strategy of the species, as well as, the volume and structure of the data available to the researcher. Caution is warranted when interpreting results regarding correlated individual random effects in demographic parameters modelled with a Bernoulli distribution. Because bias varies with sampling design and life history, comparisons of individual heterogeneity among species is challenging. The issue addressed here is not specific to demography, making this warning relevant for all research areas, including behavioural and evolutionary studies.
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ArticleDifferent proxies, different stories? Imperfect correlations and different determinants of fitness in bighorn sheep(Wiley Open Access, 2022-12-08) Van de Walle, Joanie ; Larue, Benjamin ; Pigeon, Gabriel ; Pelletier, FanieMeasuring individual fitness empirically is required to assess selective pressures and predicts evolutionary changes in nature. There is, however, little consensus on how fitness should be empirically estimated. As fitness proxies vary in their underlying assumptions, their relative sensitivity to individual, environmental, and demographic factors may also vary. Here, using a long-term study, we aimed at identifying the determinants of individual fitness in bighorn sheep (Ovis canadensis) using seven fitness proxies. Specifically, we compared four-lifetime fitness proxies: lifetime breeding success, lifetime reproductive success, individual growth rate, individual contribution to population growth, and three multi-generational proxies: number of granddaughters, individual descendance in the next generation, and relative genetic contribution to the next generation. We found that all proxies were positively correlated, but the magnitude of the correlations varied substantially. Longevity was the main determinant of most fitness proxies. Individual fitness calculated over more than one generation was also affected by population density and growth rate. Because they are affected by contrasting factors, our study suggests that different fitness proxies should not be used interchangeably as they may convey different information about selective pressures and lead to divergent evolutionary predictions. Uncovering the mechanisms underlying variation in individual fitness and improving our ability to predict evolutionary change might require the use of several, rather than one, the proxy of individual fitness.
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ArticleSpatiotemporal variation in pup abundance and preweaning survival of harbour seals (Phoca vitulina) in the St. Lawrence Estuary, Canada(Canadian Science Publishing, 2023-07-12) Renaud, Limoilou-Amelie ; Pigeon, Gabriel ; Van de Walle, Joanie ; Bordeleau, Xavier ; Hammill, Mike O. ; Pelletier, FanieMarine mammal populations worldwide greatly benefitted from conservation measures put in place since the 1970s following overexploitation, and many pinniped populations have recovered. However, threats due to bycatch, interspecific interactions or climate change remain, and detailed knowledge on vital rates, population dynamics, and their responses to environmental changes is essential for efficient management and conservation of wild populations. In this study, we quantified pup abundance and survival of individually marked harbour seal (Phoca vitulina Linnaeus, 1758) pups during the preweaning period at Bic Island and Métis sites in the St. Lawrence Estuary from 1998 to 2019. We used mark-recapture models to evaluate competing hypotheses regarding variation in daily preweaning survival rates and capture probability during the pups’ first 30 days of life. Pup abundance increased from 76 [95% CI: 59, 101] to 323 [95% CI: 233, 338] in the past two decades at Bic Island and from 66 [95% CI: 47, 91] to 285 [95% CI: 204, 318] at Métis. Preweaning survival was generally higher at Bic (0.73 [95% CI: 0.58, 0.82]) than at Métis (0.68 [95% CI: 0.52, 0.79]). We hypothesize that differences between habitats and human disturbance contribute to lower preweaning survival at Métis, but behavioural studies are needed to understand the impacts of disturbance on mother–pup interactions during the nursing period.
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ArticleIndividual life histories: neither slow nor fast, just diverse(The Royal Society, 2023-07-05) Van de Walle, Joanie ; Fay, Remi ; Gaillard, Jean-Michel ; Pelletier, Fanie ; Hamel, Sandra ; Gamelon, Marlene ; Barbraud, Christophe ; Blanchet, F. Guillaume ; Blumstein, Daniel T. ; Charmantier, Anne ; Delord, Karine ; Larue, Benjamin ; Martin, Julien G.A. ; Mills, James A. ; Milot, Emmanuel ; Mayer, Francine M. ; Rotella, Jay ; Saether, Bernt-Erik ; Teplitsky, Celine ; van de Pol, Martijn ; Van Vuren, Dirk H. ; Visser, Marcel E. ; Wells, Caitlin P. ; Yarrall, John ; Jenouvrier, StephanieThe slow–fast continuum is a commonly used framework to describe variation in life-history strategies across species. Individual life histories have also been assumed to follow a similar pattern, especially in the pace-of-life syndrome literature. However, whether a slow–fast continuum commonly explains life-history variation among individuals within a population remains unclear. Here, we formally tested for the presence of a slow–fast continuum of life histories both within populations and across species using detailed long-term individual-based demographic data for 17 bird and mammal species with markedly different life histories. We estimated adult lifespan, age at first reproduction, annual breeding frequency, and annual fecundity, and identified the main axes of life-history variation using principal component analyses. Across species, we retrieved the slow–fast continuum as the main axis of life-history variation. However, within populations, the patterns of individual life-history variation did not align with a slow–fast continuum in any species. Thus, a continuum ranking individuals from slow to fast living is unlikely to shape individual differences in life histories within populations. Rather, individual life-history variation is likely idiosyncratic across species, potentially because of processes such as stochasticity, density dependence, and individual differences in resource acquisition that affect species differently and generate non-generalizable patterns across species.
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ArticleGenetic rescue from protected areas is modulated by migration, hunting rate, and timing of harvest(Wiley Open Access, 2023-05-12) Lassis, Roxane ; Festa‐Bianchet, Marco ; Van de Walle, Joanie ; Pelletier, FanieIn terrestrial and marine ecosystems, migrants from protected areas may buffer the risk of harvest‐induced evolutionary changes in exploited populations that face strong selective harvest pressures. Understanding the mechanisms favoring genetic rescue through migration could help ensure evolutionarily sustainable harvest outside protected areas and conserve genetic diversity inside those areas. We developed a stochastic individual‐based metapopulation model to evaluate the potential for migration from protected areas to mitigate the evolutionary consequences of selective harvest. We parameterized the model with detailed data from individual monitoring of two populations of bighorn sheep subjected to trophy hunting. We tracked horn length through time in a large protected and a trophy‐hunted populations connected through male breeding migrations. We quantified and compared declines in horn length and rescue potential under various combinations of migration rate, hunting rate in hunted areas and temporal overlap in timing of harvest and migrations, which affects the migrants' survival and chances to breed within exploited areas. Our simulations suggest that the effects of size‐selective harvest on male horn length in hunted populations can be dampened or avoided if harvest pressure is low, migration rate is substantial, and migrants leaving protected areas have a low risk of being shot. Intense size‐selective harvest impacts the phenotypic and genetic diversity in horn length, and population structure through changes in proportions of large‐horned males, sex ratio and age structure. When hunting pressure is high and overlaps with male migrations, effects of selective removal also emerge in the protected population, so that instead of a genetic rescue of hunted populations, our model predicts undesirable effects inside protected areas. Our results stress the importance of a landscape approach to management, to promote genetic rescue from protected areas and limit ecological and evolutionary impacts of harvest on both harvested and protected populations.
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ArticleQuebec legislative framework for the protection of wild species in precarious situations: Critical evaluation and recommendations for a major revision(Canadian Science Publishing, 2024-04-30) Pelletier, Fanie ; Dumont, Pierre ; Van de Walle, Joanie ; Jauvin, Daniel ; Rodrigue, DavidIn Quebec, the Act Respecting Threatened or Vulnerable species (ARTV), adopted in 1989, aims to safeguard Quebec's wild genetic diversity by protecting species at risk. However, since its implementation about 30 years ago, it has been repeatedly pointed out that the application of the Quebec legislative framework for the protection of wildlife species at risk was often slow and inadequate. The aim of this article is therefore to make a series of observations on the limits of current legislation and then propose nine urgent recommendations to improve the effectiveness of conservation efforts for species at risk in Quebec. Our recommendations aim to increase the efficiency and transparency of the designation process, reconsider compensation mechanisms for the loss of critical habitat, and harmonize species status between the federal and provincial levels. We hope that our article will pave the way for a constructive discussion leading to an improved protection of wildlife species in precarious situations and their persistence for future generations. The English version of this article is available in the Supplementary material file.