Habitat selection is a fundamental animal behavior that shapes a wide range of ecological processes, including animal movement, nutrient transfer, trophic dynamics and population distribution. ...Although habitat selection has been a focus of ecological studies for decades, technological, conceptual and methodological advances over the last 20 yr have led to a surge in studies addressing this process. Despite the substantial literature focused on quantifying the habitat‐selection patterns of animals, there is a marked lack of guidance on best analytical practices. The conceptual foundations of the most commonly applied modeling frameworks can be confusing even to those well versed in their application. Furthermore, there has yet to be a synthesis of the advances made over the last 20 yr. Therefore, there is a need for both synthesis of the current state of knowledge on habitat selection, and guidance for those seeking to study this process. Here, we provide an approachable overview and synthesis of the literature on habitat‐selection analyses (HSAs) conducted using selection functions, which are by far the most applied modeling framework for understanding the habitat‐selection process. This review is purposefully non‐technical and focused on understanding without heavy mathematical and statistical notation, which can confuse many practitioners. We offer an overview and history of HSAs, describing the tortuous conceptual path to our current understanding. Through this overview, we also aim to address the areas of greatest confusion in the literature. We synthesize the literature outlining the most exciting conceptual advances in the field of habitat‐selection modeling, discussing the substantial ecological and evolutionary inference that can be made using contemporary techniques. We aim for this paper to provide clarity for those navigating the complex literature on HSAs while acting as a reference and best practices guide for practitioners.
Movement provides a link between individual behavioral ecology and the spatial and temporal variation in an individual’s landscape. Individual variation in movement traits is an important axis of ...animal personality, particularly in the context of foraging ecology. We tested whether individual caribou (Rangifer tarandus) displayed plasticity in movement and space-use behavior across a gradient of resource aggregation. We quantified first-passage time and range-use ratio as proxies for movement-related foraging behavior and examined how these traits varied at the individual level across a foraging resource gradient. Our results suggest that individuals adjusted first-passage time but not range-use ratio to maximize access to high-quality foraging resources. First-passage time was repeatable, and intercepts for first-passage time and range-use ratio were negatively correlated. Individuals matched first-passage time but not range-use ratio to the expectations of our patch-use model that maximized access to foraging resources, a result that suggests that individuals acclimated their movement patterns to accommodate both intra- and interannual variation in foraging resources on the landscape. Collectively, we highlight repeatable movement and space-use tactics and provide insight into how individual plasticity in movement interacts with landscape processes to affect the distribution of behavioral phenotypes and potentially fitness and population dynamics.
In seasonal environments, animals should be adapted to match important life‐history traits to when environmental conditions are optimal. Most animal populations therefore reproduce when resource ...abundance is highest to increase annual reproductive success. When facing variable, and changing, environments animals can display behavioural plasticity to acclimate to changing conditions. Behaviours can further be repeatable. For example, timing of behaviours and life history traits such as timing of reproduction may indicate phenotypic variation. Such variation may buffer animal populations against the consequences of variation and change.
Our goal was to quantify plasticity and repeatability in migration and parturition timing in response to timing of snowmelt and green‐up in a migratory herbivore (caribou, Rangifer tarandus, n = 132 ID‐years) and their effect on reproductive success.
We used behavioural reaction norms to quantify repeatability in timing of migration and timing of parturition in caribou and their plasticity to timing of spring events, while also quantifying phenotypic covariance between behavioural and life‐history traits.
Timing of migration for individual caribou was positively correlated with timing of snowmelt. The timing of parturition for individual caribou varied as a function of inter‐annual variation in timing of snowmelt and green‐up. Repeatability for migration timing was moderate, but low for timing of parturition. Plasticity did not affect reproductive success. We also did not detect any evidence of phenotypic covariance among any traits examined—timing of migration was not correlated with timing of parturition, and neither was there a correlation in the plasticity of these traits.
Repeatability in migration timing suggests the possibility that the timing of migration in migratory herbivores could evolve if the repeatability detected in this study has a genetic or otherwise heritable basis, but observed plasticity may obviate the need for an evolutionary response. Our results also suggest that observed shifts in caribou parturition timing are due to plasticity as opposed to an evolutionary response to changing conditions. While this provides some evidence that populations may be buffered from the consequences of climate change via plasticity, a lack of repeatability in parturition timing could impede adaptation as warming increases.
Animals should match their life‐history to the timing of phenological events, which dictate resource abundance. Using behavioural reaction norms, the authors investigated how the timing of migration and parturition in caribou varied as a function of the timing of spring snowmelt and green‐up and their consequences on fitness.
1. Behaviour is the interface between an organism and its environment, and behavioural plasticity is important for organisms to cope with environmental change. Social behaviour is particularly ...important because sociality is a dynamic process, where environmental variation influences group dynamics and social plasticity can mediate resource acquisition. Heterogeneity in the ecological environment can therefore influence the social environment The combination of the ecological and social environments may be interpreted collectively as the "socioecological environment," which could explain variation in fitness. 2. Our objective was to outline a framework through which individual social and spatial phenotypes can be integrated and interpreted as phenotypes that covary as a function of changes in the socioecological environment. We propose the socioecological environment is composed of individual behavioural traits, including sociality and habitat selection, both of which are repeatable, potentially heritable and may reflect animal personality traits. We also highlight how ecological and social niche theory can be applied to the socioecological environment framework, where individuals occupy different socioecological niches. Individual sociality and habitat selection are also density-dependent, and theory predicts that density-dependent traits should affect reproduction, survival, and therefore fitness and population dynamics. 3. We then illustrate the proximate links between sociality, habitat selection and fitness as well as the ultimate, and possibly adaptive, consequences associated with changes in population density. The ecological, evolutionary and applied implications of our proposed socioecological environment framework are broad and changes in density could influence individual fitness and population dynamics. For instance, human-induced environmental changes can influence population density, which can affect the distribution of social and spatial phenotypes within a population. In summary, we outline a conceptual framework that incorporates individual social and spatial behavioural traits with fitness and we highlight a range of ecological and evolutionary processes that are likely associated with the socioecological environment.
Allocare, care for offspring from nonparents, can carry important benefits for offspring. We investigated the potential benefits of allocare to offspring by examining contexts associated with ...allocare among St. Lawrence belugas in Sainte‐Marguerite Bay, a high‐residency area, and the Saguenay Fjord, a transit area. We hypothesized that calves receive similar benefits from mothers and alloparents, namely, protection and energetic benefits, while juveniles associate with alloparents for social purposes. As such, we expected that calves would associate with mothers and alloparents more frequently when exposed to potential dangers, such as adult males and vessel traffic, and in energetically costly contexts, such as the flood tide and during travel, while juveniles would associate with alloparents more frequently during social behavior. We found no trends between allocare and any variables tested. However, we found that calf maternal care in the fjord decreased significantly during socialization, particularly calf‐calf socialization. We also found that juvenile maternal care in the fjord decreased significantly when males were present, possibly because juveniles sought associations with males. These findings emphasize the importance of socialization for beluga offspring of all ages. Both maternal care and allocare persisted across contexts in Sainte‐Marguerite Bay, highlighting its possible importance as an offspring‐rearing ground.
Incorporating host behavioral variation into epidemiological models is important for predicting host-pathogen dynamics. Animals living at high densities or with many strong social connections are ...predicted to have greater risk of acquiring pathogens. Using social network analysis, we tested the hypothesis that variation in the strength of social connections would influence simulated elk (Cervus canadensis) pathogen dynamics. We quantified fine-scale social connections for captive elk at three experimentally manipulated densities and wild elk at two natural densities. We applied susceptible-infected epidemiological models to networks to infer the relationship between fine-scale host sociality and simulated pathogen dynamics. Networks were filtered based on four association thresholds to determine how variation in the strength of social connections influenced pathogen dynamics. Our simulations suggest that social behavior interacts with population density to predict pathogen dynamics, but this effect was sex-specific. For both males and females at higher density, elk had strong social connections, resulting in higher number of infected individuals. We observed differences in social connections across density, and these results translated to our simulations, which predicted density-dependent pathogen dynamics for captive and wild elk networks. Our results highlight host social behavior as a potential mechanism driving variation in the relationship between population density and pathogen dynamics. Elk are reservoir hosts for numerous emerging infectious diseases, and our models suggest that density-dependent host social behavior could influence pathogen dynamics in elk social networks.
Habitat selection is a fundamental behaviour that links individuals to the resources required for survival and reproduction. Although natural selection acts on an individual’s phenotype, research on ...habitat selection often pools inter-individual patterns to provide inferences on the population scale. Here, we expanded a traditional approach of quantifying habitat selection at the individual level to explore the potential for consistent individual differences of habitat selection. We used random coefficients in resource selection functions (RSFs) and repeatability estimates to test for variability in habitat selection. We applied our method to a detailed dataset of GPS relocations of brown bears (Ursus arctos) taken over a period of 6 years, and assessed whether they displayed repeatable individual differences in habitat selection toward two habitat types: bogs and recent timber-harvest cut blocks. In our analyses, we controlled for the availability of habitat, i.e. the functional response in habitat selection. Repeatability estimates of habitat selection toward bogs and cut blocks were 0.304 and 0.420, respectively. Therefore, 30.4 and 42.0 % of the population-scale habitat selection variability for bogs and cut blocks, respectively, was due to differences among individuals, suggesting that consistent individual variation in habitat selection exists in brown bears. Using simulations, we posit that repeatability values of habitat selection are not related to the value and significance of β estimates in RSFs. Although individual differences in habitat selection could be the results of non-exclusive factors, our results illustrate the evolutionary potential of habitat selection.
Predicting future space use by animals requires models that consider both habitat availability and individual differences in habitat selection. The functional response in habitat selection posits ...animals adjust their habitat selection to availability, but population-level responses to availability may differ from individual responses. Generalized functional response (GFR) models account for functional responses by including fixed effect interactions between habitat availability and selection. Population-level resource selection functions instead account for individual selection responses to availability with random effects. We compared predictive performance of both approaches using a functional response in elk (
Cervus canadensis
) selection for mixed forest in response to road proximity, and avoidance of roads in response to mixed forest availability. We also investigated how performance changed when individuals responded differently to availability from the rest of the population. Individual variation in road avoidance decreased performance of both models (random effects:
β
= 0.69, 95% CI 0.47, 0.91; GFR:
β
= 0.38, 95% CI 0.05, 0.71). Changes in individual road and forest availability affected performance of neither model, suggesting individual responses to availability different from the functional response mediated performance. We also found that overall, both models performed similarly for predicting mixed forest selection (
F
1, 58
= 0.14,
p
= 0.71) and road avoidance (
F
1, 58
= 0.28,
p
= 0.60). GFR estimates were slightly better, but its larger number of covariates produced greater variance than the random effects model. Given this bias-variance trade-off, we conclude that neither model performs better for future space use predictions.
Historically, the study of caribou and reindeer (Rangifer tarandus (Linnaeus, 1788)) diet has been specific to herds and few comprehensive circumpolar analyses of Rangifer diet exist. As a result, ...certain diet items may play an outsized role in the caribou diet Zeitgeist, e.g., lichen. We challenge this notion and test the relevant importance of various diet items within the context of prevailing hypotheses. We provide a systematic overview of 30 caribou studies reporting caribou diet and test biologically relevant hypotheses about spatial and temporal dietary variation. Our results indicate that in the winter caribou primarily consume lichen, but in warmer seasons and when primary productivity is lower, caribou primarily consume graminoids and other vascular plants. In more productive environments, where caribou have more competitors and predators, consumption of lichen increase. Overall, our description of caribou diet reveals that it is highly variable, but in circumstances where caribou can consume vascular plants, then they will. As climate change affects Boreal and Arctic ecosystems, the type and volume of food consumed by caribou have become an increasingly important focus for conservation and management of caribou.
In northern climates, spring is a time of rapid environmental change: for migrating terrestrial animals, melting snow facilitates foraging and travel, and newly emergent vegetation provides a ...valuable nutritional resource. These changes result in selection on the timing of important life-history events such as migration and parturition occurring when high-quality resources are most abundant. We examined the timing of female caribou (Rangifer tarandus, n = 94) migration and parturition in five herds across 7 yr in Newfoundland, Canada, as a function of two measures of environmental change—snowmelt and vegetation green-up. We generated resource selection functions to test whether caribou selected for areas associated with snowmelt and green-up during migration and following calving. We found that caribou migrated approximately 1 wk prior to snowmelt, with the flush of emergent vegetation occurring during the weeks following parturition. The results indicate that caribou “jump” the green wave of emergent forage and do so by tracking the receding edge of melting snow, likely reducing movement and foraging costs related to snow cover. Our research further broadens the ecological scope of resource tracking in animals. We demonstrate that resource tracking extends beyond resources directly related to foraging to those related to movement. We also show that snowmelt provides an environmental cue that may provide a buffer against changing environmental conditions.
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