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Introduction
Gabriel Pigeon currently works at UQAT in wildlife ecology and management.
His interest is in how human perturbations lead to changes in selection pressures and cause changes in traits in wild mammal populations and how these changes in traits can influence population dynamics.
To explore these issues, he uses data from long-term monitoring systems (bighorn sheep & reindeer) and modeling.
Current institution
Publications
Publications (40)
Beluga (Delphinapterus leucas) from the St. Lawrence Estuary, Canada, have been declining since the early 2000s, suggesting recruitment issues as a result of low fecundity, abnormal abortion rates or poor calf or juvenile survival. Pregnancy is difficult to observe in cetaceans, making the ground truthing of pregnancy estimates in wild individuals...
Marine 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...
Heat waves are becoming more frequent across the globe and may impose severe thermoregulatory challenges for endotherms. Heat stress can induce both behavioral and physiological responses, which may result in energy deficits with potential fitness consequences. We studied the responses of reindeer (Rangifer tarandus tarandus), a cold-adapted ungula...
Large herbivores typically have consistently high prime‐aged adult survival and lower, more variable, juvenile, and senescent survival. Many kangaroo populations undergo greater fluctuations in density compared with other large herbivores, but age‐ and sex‐specific survival of kangaroos and their response to environmental variation remain poorly es...
Measuring 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...
While capture-mark-recapture studies provide essential individual-level data in ecology, repeated captures and handling may impact animal welfare and cause scientific bias. Evaluating the consequences of invasive methodologies should be an integral part of any study involving capture of live animals. We investigated short-and long-term stress respo...
Uniform harvesting dominating forest habitats within the boreal biome continue to alter the country’s landscape towards unsustainable silvicultural management. Maladaptation of forest approaches has led to impactful outcomes on the biodiversity of subjected forests. With Forest Ecosystem-based Management (FEM) in place, partial harvest can provide...
The cost of reproduction on demographic rates is often assumed to operate through changing body condition. Several studies have found that reproduction depresses body mass more if the current conditions are severe, such as high population densities or adverse weather, than under benign environmental conditions. However, few studies have investigate...
Seasonal energetic challenges may constrain an animal's ability to respond to changing individual and environmental conditions. Here, we investigated variation in heart rate, a well-established proxy for metabolic rate, in Svalbard reindeer ( Rangifer tarandus platyrhynchus ), a species with strong seasonal changes in foraging and metabolic activit...
The rate of senescence may vary among individuals of a species according to individual life histories and environmental conditions. According to the principle of allocation, changes in mortality driven by environmental conditions influence how organisms allocate resources among costly functions. In several vertebrates, environmental conditions duri...
The fasting endurance hypothesis (FEH) predicts strong selection for large body size in mammals living in environments where food supply is interrupted over prolonged periods of time. The Arctic is a highly seasonal and food‐restricted environment, but contrary to predictions from the FEH, empirical evidence shows that Arctic mammals are often smal...
The Arctic is undergoing the most rapid climate warming on Earth. While concerns have been raised that more frequent icing events cause die‐offs, and earlier springs generate a mismatch in phenology, the effects of warming autumns have been largely neglected. We used 25 years of individual‐based data from a growing population of wild Svalbard reind...
Early‐life environmental conditions may generate cohort differences in individual fitness, subsequently affecting population growth rates. Three, nonmutually exclusive hypotheses predict the nature of these fitness differences: (1) silver spoon effects, where individuals born in good conditions perform better across the range of adult environments;...
In animals with long generation times, evolution of physiological and morphological traits may not be fast enough to keep up with rapid climate warming, but thermoregulatory behaviour can possibly serve as an important buffer mitigating warming effects. In this study, we investigated if the cold-adapted Svalbard reindeer (Rangifer tarandus platyrhy...
Climate change can lead to a mismatch between resource availability and key life history events. Without plasticity in reproductive traits, that mismatch can lower fitness and decrease population size. In birds, phenotypic plasticity is frequently reported as the main mechanism to track environmental changes, but evidence for plasticity in large ma...
The costs of reproduction are important in shaping individual life histories, and hence population dynamics, but the mechanistic pathways of such costs are often unknown. Female reindeer have evolved antlers possibly due to interference competition on winter-feeding grounds. Here, we investigate if variation in antler size explains part of the cost...
Environmental variation can generate life‐long similarities among individuals born in the same breeding event, so called cohort effects. Studies of cohort effects have to account for the potentially confounding effects of current conditions (observation year) and age of individuals. However, estimation of such models is hampered by inherent colline...
As an important extrinsic source of mortality, harvest should select for fast reproduction and accelerated life histories. However, if vulnerability to harvest depends upon female reproductive status, patterns of selectivity could diverge and favor alternative reproductive behaviors. Here, using more than 20 years of detailed data on survival and r...
The sixth Wild Animal Models Bi-Annual Meeting was held in July 2017 in Québec, with 42 participants. This report documents the evolution of questions asked and approaches used in evolutionary quantitative genetic studies of wild populations in recent decades, and how these questions and approaches were represented at the recent meeting. We explore...
Cohort effects, when a common environment affects long-term performance, can have a major impact on population dynamics. Very few studies of wild animals have obtained the necessary data to study the mechanisms leading to cohort effects. We exploited 42 years of individual-based data on bighorn sheep to test for causal links between birth density,...
Recent studies of the joint dynamics of ecological and evolutionary processes show that changes in genotype or phenotype distributions can affect population, community and ecosystem processes. Such eco-evolutionary dynamics are likely to occur in modern humans and may influence population dynamics. Here, we study contributions to population growth...
Recent studies suggest that evolutionary changes can occur on a contemporary time scale. Hence, evolution can influence ecology and vice-versa. To understand the importance of eco-evolutionary dynamics in population dynamics, we must quantify the relative contribution of ecological and evolutionary changes to population growth and other ecological...
Cohort effects can be a major source of heterogeneity and play an important role in population dynamics. Silver-spoon effects, when environmental quality at birth improves future performance regardless of the adult environment, can induce strong lagged responses on population growth. Alternatively, the external predictive adaptive response (PAR) hy...
The development of male secondary sexual characters such as antlers or horns has substantial biological and socio-economic importance because in many species these traits affect male fitness positively through sexual selection and negatively through trophy hunting. Both environmental conditions and selective hunting can affect horn growth but their...
The potential for selective harvests to induce rapid evolutionary change is an important question for conservation and evolutionary biology, with numerous biological, social and economic implications. We analyze 39 years of phenotypic data on horn size in bighorn sheep (Ovis canadensis) subject to intense trophy hunting for 23 years, after which ha...
Figure S1. Harvest regulation guideline for bighorn sheep in Alberta, Canada.
Figure S2. Results of the sensitivity analysis showing the posterior mode with 95% Bayesian posterior interval of highest density of heritability for the multivariate animal model of (A) male horn length, (B) female horn length, (C) male horn base and (D) female horn bas...
Description
"Databighorn" is a dataframe with 14 variables: 1) id = male’s identity, 2) year, 3) loggrowth = log-transformed annual horn growth, 4) density = number of adult females aged 2 years and older in June, 5) age = male’s age, 6) temp.spring = average temperature in spring, 7) prec.spring = precipitation in spring, 8) temp.summer = average...
Evolutionary ecologists have long been interested by the link between different immune defenses and fitness. Given the importance of a proper immune defense for survival, it is important to understand how its numerous components are affected by environmental heterogeneity. Previous studies targeting this question have rarely considered more than tw...
Lower immune response usually translates into lower fitness. Environmental quality can play a key role in shaping immune responses in the wild, as it influences both resource availability and costly maintenance functions. The aim of this study is to evaluate the effect of habitat quality on proinflammatory response to phytohemagglutinin (PHA) in Tr...
