No Difference between the Sexes in Fine-Scale Spatial Genetic Structure of Roe Deer

Background: Data on spatial genetic patterns may provide information about the ecological and behavioural mechanisms underlying population structure. Indeed, social organization and dispersal patterns of species may be reflected by the pattern of genetic structure within a population. [br/] Methodology/Principal Findings: We investigated the fine-scale spatial genetic structure of a roe deer (Capreolus capreolus) population in Trois-Fontaines (France) using 12 microsatellite loci. The roe deer is weakly polygynous and highly sedentary, and can form matrilineal clans. We show that relatedness among individuals was negatively correlated with geographic distance, indicating that spatially proximate individuals are also genetically close. More unusually for a large mammalian herbivore, the link between relatedness and distance did not differ between the sexes, which is consistent with the lack of sex-biased dispersal and the weakly polygynous mating system of roe deer. [br/] Conclusions/Significance: Our results contrast with previous reports on highly polygynous species with male-biased dispersal, such as red deer, where local genetic structure was detected in females only. This divergence between species highlights the importance of socio-spatial organization in determining local genetic structure of vertebrate populations

Back and forth: day–night alternation between cover types reveals complementary use of habitats in a large herbivore

Context The Complementary Habitat Hypothesis posits that animals access resources for different needs by moving between complementary habitats that can be seen as ‘resource composites’. These movements can occur over a range of temporal scales, from diurnal to seasonal, in response to multiple drivers such as access to food, weather constraints, risk avoidance and human disturbance. Within this framework, we hypothesised that large herbivores cope with human-altered landscapes through the alternate use of complementary habitats at both daily and seasonal scales. Objectives We tested the Complementary Habitat Hypothesis in European roe deer (Capreolus capreolus) by classifying 3900 habitat-annotated movement trajectories of 154 GPS-monitored individuals across contrasting landscapes. Methods We considered day-night alternation between open food-rich and closed refuge habitats as a measure of complementary habitat use. We first identified day–night alternation using the Individual Movement - Sequence Analysis Method, then we modelled the proportion of day–night alternation over the year in relation to population and individual characteristics. Results We found that day-night alternation is a widespread behaviour in roe deer, even across markedly different landscapes. Day–night alternation followed seasonal trends in all populations, partly linked to vegetation phenology. Within populations, seasonal patterns of open/closed habitat alternation differed between male and female adults, but not in juveniles. Conclusion Our results support the Complementary Habitat Hypothesis by showing that roe deer adjust their access to the varied resources available in complex landscapes by including different habitats within their home range, and sequentially alternating between them in response to seasonal changes and individual life history.publishedVersio

Back and forth: day–night alternation between cover types reveals complementary use of habitats in a large herbivore

Context The Complementary Habitat Hypothesis posits that animals access resources for different needs by moving between complementary habitats that can be seen as ‘resource composites’. These movements can occur over a range of temporal scales, from diurnal to seasonal, in response to multiple drivers such as access to food, weather constraints, risk avoidance and human disturbance. Within this framework, we hypothesised that large herbivores cope with human-altered landscapes through the alternate use of complementary habitats at both daily and seasonal scales. Objectives We tested the Complementary Habitat Hypothesis in European roe deer (Capreolus capreolus) by classifying 3900 habitat-annotated movement trajectories of 154 GPS-monitored individuals across contrasting landscapes. Methods We considered day-night alternation between open food-rich and closed refuge habitats as a measure of complementary habitat use. We first identified day–night alternation using the Individual Movement - Sequence Analysis Method, then we modelled the proportion of day–night alternation over the year in relation to population and individual characteristics. Results We found that day-night alternation is a widespread behaviour in roe deer, even across markedly different landscapes. Day–night alternation followed seasonal trends in all populations, partly linked to vegetation phenology. Within populations, seasonal patterns of open/closed habitat alternation differed between male and female adults, but not in juveniles. Conclusion Our results support the Complementary Habitat Hypothesis by showing that roe deer adjust their access to the varied resources available in complex landscapes by including different habitats within their home range, and sequentially alternating between them in response to seasonal changes and individual life history

Cohabitation entre homme et faune sauvage : impacts des activités humaines sur la gestion du compromis « risque-acquisition des ressources » chez le chevreuil

Wild populations are increasingly under severe pressure from predation linked to human activities, which are the source of multiple stress factors forwild populations. Because it is nearly impossible for most organisms to satisfy all of their basic activities (food, reproduction, rest, etc.) withoutrun the risk of predation, they often face trade-offs. Especially in the feeding process, animals have to make trade-offs between acquiring resourcesgood qualities and avoidance of the risk of predation or disturbance, because the best resources are generally associated with a higher risk of predation. One of the ways in which animals can resolve this trade-off is by modifying their patterns of use of habitats. In this thesis we are interested in the Deer-Human system for understand how human activities can impact patterns of use and selection of different habitats. The population of roe deer studied evolves in a landscape fragmented and highly anthropized, representative of modern agricultural landscapes. The follow-up since more than 10 years of this population, with more than 300 animals captured and fitted with GPS collars, offers us a unique opportunity to better understand the mechanisms underlying the strategies adopted by individuals within the “risk – acquisition of resources” trade-off.We have thus shown that the "risk-acquisition of resources" trade-off affects habitat selection patterns differently according to spatio-temporal variations in the intensity of the risk and the availability of resources.All of our work has also allowed to highlight the impact of environmental factors, such as the hunting season or the time of day, but also the impact of internal factors, such as the status reproductive or stress sensitivity of individuals (probably related to their personality), on the habitat use strategies. Strategies for the use of habitats therefore result complex interactions between external and internal factors and can potentially have significant consequences on the adaptive value of individuals and, ultimately, on the dynamics populations. Taking into account all of these factors, and in particular the variability inter-individual in strategies for the use of habitats, should make it possible to improve the tools for the management and conservation of wild ungulate populations.Les populations sauvages sont de plus en plus soumises à d’importantes pressions de prédation en lien avec les activités humaines, qui sont la source de multiples facteurs de stress pour les populations sauvages. Parce qu’il est quasiment impossible pour la plupart des organismes desatisfaire l’ensemble de leurs activités fondamentales (alimentation, reproduction, repos,…) sans encourir un risque de prédation, ils sont souvent confrontés à des compromis. Notamment dans le processus d’alimentation, les animaux doivent faire des compromis entre l’acquisition de ressources de bonnes qualités et l’évitement du risque de prédation ou de dérangement, car les meilleurs ressources sont généralement associées à un risque de prédation plus fort. Une des manière dont les animaux peuvent résoudre ce compromis est par la modification de leurs patrons d’utilisation des habitats. Dans cette thèse nous nous sommes intéressés au système Chevreuil-Homme pour comprendre comment les activités humaines peuvent impacter les patrons d’utilisation et de sélection des différents habitats. La population de chevreuils étudiée évolue dans un paysage fragmenté et fortement anthropisé, représentatif des paysages agricoles modernes. Le suivi depuis plus de 10 ans de cette population, avec plus de 300 animaux capturés et équipés de colliers GPS, nous offre une opportunité unique de mieux comprendre les mécanismes qui sous-tendent les stratégies adoptées par les individus au sein du compromis « risque – acquisition des ressources ».Nous avons ainsi montré que le compromis « risque-acquisition des ressources » affecte différemment les patrons de sélection des habitats en fonction des variations spatio-temporelles dans l’intensité du risque et la disponibilité des ressources. L’ensemble de nos travaux a égalementpermis de mettre en évidence l’impact de facteurs environnementaux, tels que la période de chasse ou le moment de la journée, mais également l’impact de facteurs internes, tels que le statut reproducteur ou la sensibilité au stress des individus (probablement liée à leur personnalité), sur lesstratégies d’utilisation des habitats. Les stratégies d’utilisation des habitats résultent donc d’interactions complexes entre les facteurs externes et internes et peuvent avoir potentiellement des conséquences importantes sur la valeur adaptative des individus et, à terme, sur la dynamiquedes populations. La prise en compte de l’ensemble de ces facteurs, et notamment de la variabilité inter-individuelle dans les stratégies d’utilisation des habitats, devrait permettre d’améliorer les outils de gestion et de conservation des populations d’ongulés sauvages

Roe deer at risk: teasing apart habitat selection and landscape constraints in risk exposure at multiple scales

International audienceNon-consumptive effects of predators result from the cost of responses to perceived risk. Prey modulate risk exposure through flexible habitat selection at multiple scales which, in interaction with landscape constraints, determines their use of risky habitats. Identifying the relative contributions of landscape constraints and habitat selection to risk exposure is a critical first step towards a mechanistic understanding of non-consumptive effects. Here, we provide an integrative multi-scale study of roe deer spatial responses to variable hunting pressure along a landscape gradient of open habitats and dispersed refuges. Between low-risk and high-risk periods, we investigated shifts in 1) home-range location, 2) probability of using risky habitats (between-habitat scale) and 3) distance to the nearest refuge (within-habitat scale). For 2) and 3), we disentangled the contributions of landscape constraints and habitat selection to risky habitat use. We found that when risk was high, roe deer did not shift their home-range, but generally decreased their use of risky habitats, and sometimes reduced their distance to cover (particularly older animals). There was a functional response in between-habitat selection, with animals living in more open landscapes responding more than those living in landscapes with more refuges. However, individuals living in more open landscapes avoided open risky habitat less. Finally, we found that among-individual variation in risk exposure was generally, but not always, minimized by habitat selection across gradients of landscape constraints. To our knowledge, this is the first study simultaneously documenting prey responses to risk at the within-habitat, between-habitat and home-range scales. Our results support the view that between-habitat selection acts at a higher hierarchical level than within-habitat selection, and provide a framework for disentangling the contributions of habitat selection and landscape constraints to risk exposure. Selection cannot always compensate for landscape constraints, indicating a need for further investigation of the processes underlying habitat selection

Black-tailed deer (Odocoileus hemionus sitkensis) adjust habitat selection and activity rhythm to the absence of predators

Although individuals must generally trade-off acquisition of high-quality resources against predation risk avoidance, removal of top predators by humans has resulted in many large herbivores experiencing novel conditions where their natural predators are absent. Anti-predator behaviors should be attenuated or lost in such a context of relaxed predation pressure. To test this prediction, we analyzed daily and seasonal habitat selection and activity rhythm (both commonly linked to predation risk) of GPS-collared Sitka black-tailed deer (Odocoileus hemionus sitkensis Merriam, 1898) on predator-free islands (British Columbia, Canada). In marked contrast to the behavioral patterns commonly observed in populations subject to predation risk, we documented a very low day-night contrast in habitat selection. Moreover, we observed higher activity during daytime than nighttime, as expected for non-hunted populations. We also showed that resource selection was primarily driven by seasonal variations in resource availability. These results are consistent with the expected attenuation of anti-predator behaviors in predation-free environments. However, we also observed marked crepuscular activity peaks which are commonly interpreted as an anti-predator response in ungulates. Our study indicates that large herbivores are able to adjust certain anti-predator behaviors under relaxed selection, notably habitat selection and activity rhythm, while others persist despite the long-term absence of predators.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Under cover of the night: context-dependency of anthropogenic disturbance on stress levels of wild roe deer Capreolus capreolus

Wildlife populations are increasingly exposed to human-induced modifications of their habitats. To cope with anthropogenicstressors, animals can adjust their behaviour—for example, by shifting their activity to more sheltered habitats, or becomingmore nocturnal.However, whether use of spatial and temporal adjustments in behaviourmay regulate the endocrine responseis poorly documented. Here, we analyzed faecal cortisol metabolites (FCMs) of wild roe deer (Capreolus capreolus) living in ahuman-dominated agro-ecosystem. Using Global Positioning Systemmonitoring of 116 individuals, we assessed their spatialbehaviour and tested whether proximity to anthropogenic structures (linear distance to built-up areas) and the use of refugehabitats (woodland and hedges) influenced FCM levels. In accordance with our predictions, individuals ranging closer toanthropogenic structures during daytime had higher FCM levels, but this relationship was buffered as use of refuge habitatincreased. In addition, this link between proximity to anthropogenic structures andFCMlevels disappeared whenwe analyzedspatial behaviour at night. Finally, FCM levels were higher when the ambient temperature was lower, and during years of lowresource availability. Our results demonstrate that the stress levels of large mammals may be strongly influenced by theirproximity to anthropogenic activities, but that these effects may be buffered by behavioural adjustments in terms of spaceuse and circadian rhythm.Whereas most studies have focused on the influence of environmental heterogeneity, our analysishighlights the need to also consider the fine-scale spatial response of individuals when studying the hormonal response ofwild animals to human disturbance. We emphasize the potential to mitigate this hormonal stress response, and its potentialnegative consequences on population dynamics, through the preservation or restoration of patches of refuge habitat in closeproximity to human infrastructure

Reproductive tactics, birth timing and the risk-resource trade-off in an income breeder

International audienceIn variable environments, habitats that are rich in resources often carry a higher risk of predation. As a result, natural selection should favour individuals that balance allocation of time to foraging versus avoiding predation through an optimal decision-making process that maximizes fitness. The behavioural trade-off between resource acquisition and risk avoidance is expected to be particularly acute during gestation and lactation, when the energetic demands of reproduction peak. Here, we investigated how reproductive female roe deer adjust their foraging activity and habitat use during the birth period to manage this trade-off compared with non-reproductive juveniles, and how parturition date constrains individual tactics of risk-resource management. Activity of reproductive females more than doubled immediately following parturition, when energy demand is highest. Furthermore, compared with non-reproductive juveniles, they increased their exposure to risk by using open habitat more during daytime and ranging closer to roads. However, these post-partum modifications in behaviour were particularly pronounced in late-parturient females who adopted a more risk-prone tactic, presumably to compensate for the growth handicap of their late-born offspring. In income breeders, individuals that give birth late may be constrained to trade risk avoidance for foraging during peak allocation to reproduction, with probable consequences for individual fitness

Stick or twist: roe deer adjust their flight behaviour to the perceived trade-off between risk and reward

Because avoiding predation is crucial for fitness, foraging animals must trade acquisition of high-quality resources against risk avoidance when the best resources occur in locations with high predation risk. Although optimality models predict the distance at which an animal should initiate vigilance and flight, many studies have shown that animals generally flee soon after detecting an approaching threat, supporting the 'flush early and avoid the risk' (FEAR) hypothesis. Despite this, flight behaviour varies markedly depending on context, suggesting some behavioural plasticity in the response of prey to a given threat. We evaluated the degree of plasticity in the flight responses of roe deer, Capreolus capreolus, a highly flexible species which thrives in human-dominated landscapes. Based on individually identifiable animals and a standardized flight initiation protocol, we measured the distance at which a deer detected an approaching threat, and the distance at which it subsequently initiated flight. Our results provide strong support for the FEAR hypothesis, suggesting that alert and flight responses are strongly coupled in roe deer. However, the perceived level of both risk (in terms of landscape openness and proximity to human infrastructure) and reward (in terms of habitat quality) influenced the time it took for a deer to detect an approaching threat, and the subsequent time for which the threat was tolerated prior to flight. Overall, our findings indicate that although roe deer minimize monitoring costs when assessing risk by fleeing early, they also adjust their monitoring and flight responses to the local risk-resource trade-off

The link between behavioural type and natal dispersal propensity reveals a dispersal syndrome in a large herbivore

International audienceWhen individuals disperse, they modify the physical and social composition of their reproductive environment, potentially impacting their fitness. The choice an individual makes between dispersal and philopatry is thus critical, hence a better understanding of the mechanisms involved in the decision to leave the natal area is crucial. We explored how combinations of behavioural (exploration, mobility, activity and stress response) and morphological (body mass) traits measured prior to dispersal were linked to the subsequent dispersal decision in 77 roe deer Capreolus capreolus fawns. Using an unusually detailed multi-trait approach, we identified two independent behavioural continuums related to dispersal. First, a continuum of energetic expenditure contrasted individuals of low mobility, low variability in head activity and low body temperature with those that displayed opposite traits. Second, a continuum of neophobia contrasted individuals that explored more prior to dispersal and were more tolerant of capture with those that displayed opposite traits. While accounting for possible confounding effects of condition-dependence (body mass), we showed that future dispersers were less neophobic and had higher energetic budgets than future philopatric individuals, providing strong support for a dispersal syndrome in this species