[Show abstract][Hide abstract] ABSTRACT: Previous genetic studies of the highly mobile gray wolf (Canis lupus) found population structure that coincides with habitat and phenotype differences. We hypothesized that these ecologically distinct populations (ecotypes) should exhibit signatures of selection in genes related to morphology, coat color, and metabolism. To test these predictions, we quantified population structure related to habitat using a genotyping array to assess variation in 42,036 SNPs in 111 North American gray wolves. Using these SNP data and individual-level measurements of 12 environmental variables, we identified six ecotypes: West Forest, Boreal Forest, Arctic, High Arctic, British Columbia, and Atlantic Forest. Next, we explored signals of selection across these wolf ecotypes through the use of three complementary methods to detect selection: FST /haplotype homozygosity bivariate percentile, BayeScan, and environmentally correlated directional selection with Bayenv. Across all methods, we found consistent signals of selection on genes related to morphology, coat coloration, metabolism, as predicted, as well as vision and hearing. In several high-ranking candidate genes, including LEPR, TYR, and SLC14A2, we found variation in allele frequencies that follow environmental changes in temperature and precipitation, a result that is consistent with local adaptation rather than genetic drift. Our findings show that local adaptation can occur despite gene flow in a highly mobile species and can be detected through a moderately dense genomic scan. These patterns of local adaptation revealed by SNP genotyping likely reflect high fidelity to natal habitats of dispersing wolves, strong ecological divergence among habitats, and moderate levels of linkage in the wolf genome. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Shared values, public trust in an agency, and attitudes can influence support for successful conservation initiatives. To understand these relationships, this paper examines the role of social trust as a partial mediator between salient values similarity and attitudes toward wolves in south-western Alberta, Canada. Rural residents in this area face increasing wolf depredation on livestock. Data were obtained from a mail questionnaire (n = 566 respondents, response rate = 70%) sent to rural residents in three municipal districts in south-western Alberta. Attitudes were predicted to directly influence behavioural intention to support or oppose wolf management. Most respondents held slightly similar values as the management agency and minimally trusted the agency to effectively manage wolves. As predicted, social trust in the agency served as a partial mediator between salient value similarity and attitudes toward wolves. Salient value similarity was also a strong predictor of attitudes toward wolves. Attitudes toward wolves predicted behavioural support. Thus, social trust of the management agency can influence attitudes and management preferences concerning a species. When dealing with human-wildlife conflict, social trust should be examined to understand the context of the problem.
[Show abstract][Hide abstract] ABSTRACT: Human-caused harassment and mortality (e.g. hunting) affects many aspects of wildlife population dynamics and social structure. Little is known, however, about the social and physiological effects of hunting, which might provide valuable insights into the mechanisms by which wildlife respond to human-caused mortality.To investigate physiological consequences of hunting, we measured stress and reproductive hormones in hair, which reflect endocrine activity during hair growth. Applying this novel approach, we compared steroid hormone levels in hair of wolves (Canis lupus) living in Canada's tundra–taiga (n = 103) that experience heavy rates of hunting with those in the northern boreal forest (n = 45) where hunting pressure is substantially lower.The hair samples revealed that progesterone was higher in tundra–taiga wolves, possibly reflecting increased reproductive effort and social disruption in response to human-related mortality. Tundra–taiga wolves also had higher testosterone and cortisol levels, which may reflect social instability.To control for habitat differences, we also measured cortisol in an out-group of boreal forest wolves (n = 30) that were killed as part of a control programme. Cortisol was higher in the boreal out-group than in our study population from the northern boreal forest.Overall, our findings support the social and physiological consequences of human-caused mortality. Long-term implications of altered physiological responses should be considered in management and conservations strategies.
[Show abstract][Hide abstract] ABSTRACT: In Southwest Alberta, beef cattle and wild elk (Cervus elaphus) have similar habitat preferences. Understanding their inter-species contact structure is important for assessing the risk of pathogen transmission between them. These spatio-temporal patterns of interactions are shaped, in part, by range management and environmental factors affecting elk distribution. In this study, resource selection modeling was used to identify factors influencing elk presence on cattle pasture and elk selection of foraging patches; furthermore, consequences for inter-species disease transmission were discussed.
Preventive Veterinary Medicine 08/2014; 117(2). DOI:10.1016/j.prevetmed.2014.08.010 · 2.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In southwestern Alberta, interactions between beef cattle and free-ranging elk (Cervus elaphus) may provide opportunities for pathogen transmission. To assess the importance of the transmission route on the potential for interspecies transmission, we conducted a cross-sectional study on four endemic livestock pathogens with three different transmission routes: Bovine Viral Diarrhea Virus and Bovine Herpesvirus 1 (predominantly direct transmission), Mycobacterium avium subsp. paratuberculosis (MAP) (indirect fecal-oral transmission), Neospora caninum (indirect transmission with definitive host). We assessed the occurrence of these pathogens in 28 cow-calf operations exposed or non-exposed to elk, and in 10 elk herds exposed or not to cattle. We characterized the effect of species commingling as a risk factor of pathogen exposure and documented the perceived risk of pathogen transmission at this wildlife-livestock interface in the rural community. Herpesviruses found in elk were elk-specific gamma-herpesviruses unrelated to cattle viruses. Pestivirus exposure in elk could not be ascertained to be of livestock origin. Evidence of MAP circulation was found in both elk and cattle, but there was no statistical effect of the species commingling. Finally, N. caninum was more frequently detected in elk exposed to cattle and this association was still significant after adjustment for herd and sampling year clustering, and individual elk age and sex. Only indirectly transmitted pathogens co-occurred in cattle and elk, indicating the potential importance of the transmission route in assessing the risk of pathogen transmission in multi-species grazing systems.
Veterinary Research 02/2014; 45(1):18. DOI:10.1186/1297-9716-45-18 · 2.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Climate-driven range fluctuations during the Pleistocene have continuously reshaped species distribution leading to populations of contrasting genetic diversity. Contemporary climate change is similarly influencing species distribution and population structure, with important consequences for patterns of genetic diversity and species’ evolutionary potential. Yet few studies assess the impacts of global climatic changes on intraspecific genetic variation. Here, combining analyses of molecular data with time series of predicted species distributions and a model of diffusion through time over the past 21 kyr, we unravel caribou response to past and future climate changes across its entire Holarctic distribution. We found that genetic diversity is geographically structured with two main caribou lineages, one originating from and confined to Northeastern America, the other originating from Euro-Beringia but also currently distributed in western North America. Regions that remained climatically stable over the past 21 kyr maintained a high genetic diversity and are also predicted to experience higher climatic stability under future climate change scenarios. Our interdisciplinary approach, combining genetic data and spatial analyses of climatic stability (applicable to virtually any taxon), represents a significant advance in inferring how climate shapes genetic diversity and impacts genetic structure.
[Show abstract][Hide abstract] ABSTRACT: 1. A central assumption underlying the study of habitat selection is that selected habitats confer enhanced fitness. Unfortunately, this assumption is rarely tested, and in some systems, gradients of predation risk may more accurately characterize spatial variation in vital rates than gradients described by habitat selection studies.
2. Here, we separately measured spatial patterns of both resource selection and predation risk and tested their relationships with a key demographic trait, adult female survival, for a threatened ungulate, woodland caribou (Rangifer tarandus caribou Gmelin). We also evaluated whether exposure to gradients in both predation risk and resource selection value was manifested temporally through instantaneous or seasonal effects on survival outcomes.
3. We used Cox proportional hazards spatial survival modelling to assess the relative support for 5 selection- and risk-based definitions of habitat quality, as quantified by woodland caribou adult female survival. These hypotheses included scenarios in which selection ideally mirrored survival, risk entirely drove survival, non-ideal selection correlated with survival but with additive risk effects, an ecological trap with maladaptive selection and a non-spatial effect of annual variation in weather.
4. Indeed, we found positive relationships between the predicted values of a resource selection function (RSF) and survival, yet subsequently incorporating an additional negative effect of predation risk greatly improved models further. This revealed a positive, but non-ideal relationship between selection and survival. Gradients in these covariates were also shown to affect individual survival probability at multiple temporal scales. Exposure to increased predation risk had a relatively instantaneous effect on survival outcomes, whereas variation in habitat suitability predicted by an RSF had both instantaneous and longer-term seasonal effects on survival.
5. Predation risk was an additive source of hazard beyond that detected through selection alone, and woodland caribou selection thus was shown to be non-ideal. Furthermore, by combining spatial adult female survival models with herd-specific estimates of recruitment in matrix population models, we estimated a spatially explicit landscape of population growth predictions for this endangered species.
[Show abstract][Hide abstract] ABSTRACT: Landscape genetics provides a framework for pinpointing environmental features that determine the important exchange of migrants among populations. These studies usually test the significance of environmental variables on gene flow, yet ignore one fundamental driver of genetic variation in small populations, effective population size, Ne. We combined both approaches in evaluating genetic connectivity of a threatened ungulate, woodland caribou. We used least-cost paths to calculate matrices of resistance distance for landscape variables (preferred habitat, anthropogenic features and predation risk) and population-pairwise harmonic means of Ne, and correlated them with genetic distances, FST and Dc. Results showed that spatial configuration of preferred habitat and Ne were the two best predictors of genetic relationships. Additionally, controlling for the effect of Ne increased the strength of correlations of environmental variables with genetic distance, highlighting the significant underlying effect of Ne in modulating genetic drift and perceived spatial connectivity. We therefore have provided empirical support to emphasize preventing increased habitat loss and promoting population growth to ensure metapopulation viability.
Proceedings of the Royal Society B: Biological Sciences 08/2013; 280(1769):20131756. DOI:10.1098/rspb.2013.1756 · 5.05 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Rural communities are often considered a homogeneous population in resource management. Wolf management is no exception. To understand the diversity of rural attitudes toward wolves and wolf management, data were obtained through a mail questionnaire to rural residents (n = 555; 69% response rate) of southwestern Alberta. Results indicated three distinct clusters differentiated by respondents' attitudes toward: (a) wolves and fear and (b) wolf management. Cluster 1 had negative attitudes toward wolves (n = 85) and was composed of livestock producers and hunters. Cluster 2 was neutral (n = 184), and cluster 3 was positive (n = 276) toward wolves. Cluster 2 and 3 were primarily composed of non-hunters and non-livestock producers. With movement of people into rural areas with varying backgrounds the rural community now has multiple attitudinal groups and wildlife managers will need to tailor their efforts to communicate with different groups.
Human Dimensions of Wildlife 07/2013; 18(4). DOI:10.1080/10871209.2013.792022
[Show abstract][Hide abstract] ABSTRACT: Ongoing debate about whether food webs are primarily regulated by predators or by primary plant productivity, cast as top-down and bottom-up effects, respectively, may becoming superfluous. Given that most of the world's ecosystems are human dominated we broadened this dichotomy by considering human effects in a terrestrial food-web. We studied a multiple human-use landscape in southwest Alberta, Canada, as opposed to protected areas where previous terrestrial food-web studies have been conducted. We used structural equation models (SEMs) to assess the strength and direction of relationships between the density and distribution of: (1) humans, measured using a density index; (2) wolves (Canis lupus), elk (Cervus elpahus) and domestic cattle (Bos taurus), measured using resource selection functions, and; (3) forage quality, quantity and utilization (measured at vegetation sampling plots). Relationships were evaluated by taking advantage of temporal and spatial variation in human density, including day versus night, and two landscapes with the highest and lowest human density in the study area. Here we show that forage-mediated effects of humans had primacy over predator-mediated effects in the food web. In our parsimonious SEM, occurrence of humans was most correlated with occurrence of forage (β = 0.637, p<0.0001). Elk and cattle distribution were correlated with forage (elk day: β = 0.400, p<0.0001; elk night: β = 0.369, p<0.0001; cattle day: β = 0.403, p<0.0001; cattle, night: β = 0.436, p<0.0001), and the distribution of elk or cattle and wolves were positively correlated during daytime (elk: β = 0.293, p <0.0001, cattle: β = 0.303, p<0.0001) and nighttime (elk: β = 0.460, p<0.0001, cattle: β = 0.482, p<0.0001). Our results contrast with research conducted in protected areas that suggested human effects in the food web are primarily predator-mediated. Instead, human influence on vegetation may strengthen bottom-up predominance and weaken top-down trophic cascades in ecosystems. We suggest that human influences on ecosystems may usurp top-down and bottom-up effects.
PLoS ONE 05/2013; 8(5):e64311. DOI:10.1371/journal.pone.0064311 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Anthropogenic disturbances contribute to an animal's perception of and responses to the predation risk of its environment. Because an animal rarely encounters threatening stimuli in isolation, multiple disturbances can act in non-independent ways to shape an animal's landscape of fear, making it challenging to isolate their effects for effective and targeted management. We present extensions to an existing behavioral agent-based model (ABM) to use as an inverse modeling approach to test, in a scenario-sensitivity analysis, whether threatened Alberta boreal caribou (Rangifer tarandus caribou) differentially respond to industrial features (linear features, forest cutblocks, wellsites) and their attributes: presence, density, harvest age, and wellsite activity status. The spatially explicit ABM encapsulates predation risk, heterogeneous resource distribution, and species-specific energetic requirements, and successfully recreates the general behavioral mechanisms driving habitat selection. To create various industry-driven, predation-risk landscape scenarios for the sensitivity analysis, we allowed caribou agents to differentially perceive and respond to industrial features and their attributes. To identify which industry had the greatest relative influence on caribou habitat use and spatial distribution, simulated caribou movement patterns from each of the scenarios were compared with those of actual caribou from the study area, using a pattern-oriented, multi-response optimization approach. Results revealed caribou have incorporated forestry- and oil and gas features into their landscape of fear that distinctly affect their spatial and energetic responses. The presence of roads, pipelines and seismic lines, and, to a minor extent, high-density cutblocks and active wellsites, all contributed to explaining caribou behavioral responses. Our findings also indicated that both industries produced interaction effects, jointly impacting caribou spatial and energetic patterns, as no one feature could adequately explain anti-predator movement responses. We demonstrate that behavior-based ABMs can be applied to understanding, assessing, and isolating non-consumptive anthropogenic impacts, in support of wildlife management.
[Show abstract][Hide abstract] ABSTRACT: Alberta woodland caribou (Rangifer tarandus) are classified as threatened in Canada, and a local population in the west-central region, the Little Smoky herd, is at immediate risk of extirpation due, in part, to anthropogenic activities such as oil, gas, and forestry that have altered the ecosystem dynamics. To investigate these impacts, we have developed a spatially explicit, agent-based model (ABM) to simulate winter habitat selection and use of woodland caribou, and to determine the relative impacts of different industrial features on caribou habitat-selection strategies. The ABM model is composed of cognitive caribou agents possessing memory and decision-making heuristics that act to optimize tradeoffs between energy acquisition and disturbance. A set of environmental data layers was used to develop a virtual grid representing the landscape over which caribou move. This grid contained forage-availability, energy-content, and predation-risk values. The model was calibrated using GPS data from caribou radio collars (n = 13) deployed over six months from 2004 to 2005, representing caribou winter activities. Additional simulations were conducted on caribou habitat-selection strategies by assigning industrial features (i.e., roads, seismic lines, pipelines, well sites, cutblocks and burns) different levels of disturbance depending on their type, age, and density. Differences in disturbance effects between industry features were confirmed by verifying which resultant simulations of caribou movement patterns most closely match actual caribou distributions and other patterns extracted from the GPS data. The results elucidate the degree to which caribou perceive different industry features as disturbance, and the differential energetic costs associated with each, thus offering insight into why caribou are choosing the habitats they use, and consequently, the level and type of industry most likely to affect their bioenergetics and fitness.
[Show abstract][Hide abstract] ABSTRACT: Species recovery is often impeded by inadequate knowledge on mechanisms of community interactions that cause and exacerbate species endangerment. Caribou and wild reindeer Rangifer tarandus are declining in many regions of their circumpolar range likely because of human-induced landscape changes. In general, their niche specialization enables Rangifer to survive in nutrient-poor habitats spatially separated from other ungulates and their shared predators. Research has indicated that shifts in primary prey distribution following human landscape alteration may result in spatial overlap with Rangifer. We studied overlap relationships of woodland caribou R. t. caribou and moose Alces alces, quantified by their differential use of environmental resources, and evaluated the role of human landscape alteration in spatial sepa-ration in south-western Canada. Anthropogenic conversion of old-growth forests to early seral stands is hypothesized to decrease the spatial separation between caribou and moose, the dominant prey for wolves Canis lupus, contributing to increased caribou mortality. Redundancy analysis (RDA) was first used to examine coarse scale resource separation across our study area. Second, at a finer spatial scale, we used logistic regression to compare resource-and spatial separa-tion of sympatric pairs of 17 moose and 17 caribou. Finally, we tested if the frequency of predator-caused caribou mor-talities was higher in regions with higher moose resource use. Although environmental resource separation was strong at the coarser scale, we observed substantial spatial overlap ( 50%) at the finer scale. In summer we reported a signifi-cant positive relationship between spatial overlap of moose and caribou and the degree of human landscape alteration. Most importantly, locations of caribou mortalities corresponded with areas of high resource use by moose in summer. Thus, consistent with the spatial separation hypothesis, our research suggests that early successional forest stages may decrease spatial separation between caribou and moose, resulting in increased mortality risk for threatened caribou. Over the last century humans have significantly impacted the global environment, leading to dramatic changes in species distributions and increased extinction rates well above natural background levels (Chapin et al. 2011). Ecosystem functions and processes are commonly influ-enced by interactions among species and human-induced changes of systems such as competition and trophic inter-actions can have wide-ranging ecosystem effects. Direct (e.g. habitat loss or over-exploitation) and indirect (e.g. changes in community interactions) mechanisms often act concurrently and their combination can drive vulner-able populations towards extinction (Brook et al. 2008). Therefore, conservation biologists need to understand the mechanisms leading to population declines, and complex interactions among those mechanisms to manage and con-serve species. Unfortunately, how human landscape altera-tion can affect spatial overlap of species and their use of resources, and thus competitive interactions, often remains unstudied in many systems. For example, interactions of