Recherche

Dryad Translation missing: fr.blacklight.search.logo
Data from: The eastern migratory caribou: the role of genetic introgression in ecotype evolution
Klutsch, Cornelya F. C.; Manseau, Micheline; Trim, Vicki; Polfus, Jean; Wilson, Paul J. — 2016-01-11 Understanding the evolutionary history of contemporary animal groups is essential for conservation and management of endangered species like caribou (Rangifer tarandus). In central Canada, the ranges of two caribou subspecies (barren-ground/woodland caribou) and two woodland caribou ecotypes (boreal/eastern migratory) overlap. Our objectives were to reconstruct the evolutionary history of the eastern migratory ecotype and to assess the potential role of introgression in ecotype evolution. STRUCTURE analyses identified five higher order groups (i.e. three boreal caribou populations, eastern migratory ecotype and barren-ground). The evolutionary history of the eastern migratory ecotype was best explained by an early genetic introgression from barren-ground into a woodland caribou lineage during the Late Pleistocene and subsequent divergence of the eastern migratory ecotype during the Holocene. These results are consistent with the retreat of the Laurentide ice sheet and the colonization of the Hudson Bay coastal areas subsequent to the establishment of forest tundra vegetation approximately 7000 years ago. This historical reconstruction of the eastern migratory ecotype further supports its current classification as a conservation unit, specifically a Designatable Unit, under Canada’s Species at Risk Act. These findings have implications for other sub-specific contact zones for caribou and other North American species in conservation unit delineation.
Dryad Translation missing: fr.blacklight.search.logo
Data from: An assessment of sampling designs using SCR analyses to estimate abundance of boreal caribou
McFarlane, Samantha; Manseau, Micheline; Steenweg, Robin; Hervieux, Dave; Hegel, Troy; Slater, Simon; Wilson, Paul — 2021-08-16 <p class="List1" style="text-indent:0cm;margin-top:2px;margin-bottom:2px;"><span>Accurately estimating abundance is a critical component of monitoring and recovery of rare and elusive species. Spatial capture-recapture (SCR) models are an increasingly popular method for robust estimation of ecological parameters. We provide an analytical framework to assess results from empirical studies to inform SCR sampling design, using both simulated and empirical data from non-invasive genetic sampling of seven boreal caribou populations (<i>Rangifer tarandus caribou</i>) which varied in range size and estimated population density. We use simulated population data with varying levels of clustered distributions to quantify the impact of non-independence of detections on density estimates, and empirical datasets to explore the influence of varied sampling intensity on the relative bias and precision of density estimates.  Simulations revealed that clustered distributions of detections did not significantly impact relative bias or precision of density estimates. The genotyping success rate of our empirical dataset (n = 7,210 samples) was 95.1%, and 1,755 unique individuals were identified. Analysis of the empirical data indicated that reduced sampling intensity had a greater impact on density estimates in smaller ranges. The number of captures and spatial recaptures were strongly correlated with precision, but not absolute relative bias. The best sampling designs did not differ with estimated population density but differed between large and small ranges. We provide an efficient framework implemented in R to estimate the detection parameters required when designing SCR studies. The framework can be used when designing a monitoring program to minimize effort and cost while maximizing effectiveness, which is critical for informing wildlife management and conservation.</span></p> https://creativecommons.org/publicdomain/zero/1.0/
Dryad Translation missing: fr.blacklight.search.logo
Data from: Partitioning drivers of spatial genetic variation for a continuously-distributed population of boreal caribou: implications for management unit delineation
Dryad
Priadka, Pauline; Manseau, Micheline; Trottier, Tim; Hervieux, Dave; Galpern, Paul; McLoughlin, Philip D.; Wilson, Paul J. — 2018-12-18 Isolation-by-distance (IBD) is a natural pattern not readily incorporated into theoretical models nor traditional metrics for differentiating populations, although clinal genetic differentiation can be characteristic of many wildlife species. Landscape features can also drive population structure additive to baseline IBD resulting in differentiation through isolation-by-resistance (IBR). We assessed the population genetic structure of boreal caribou across western Canada using non-spatial (STRUCTURE) and spatial (MEMGENE) clustering methods and investigated the relative contribution of IBD and IBR on genetic variation of 1221 boreal caribou multilocus genotypes across western Canada. We further introduced a novel approach to compare the partitioning of individuals into management units (MU) and assessed levels of genetic connectivity under different MU scenarios. STRUCTURE delineated five genetic clusters while MEMGENE identified finer-scale differentiation across the study area. IBD was significant and did not differ for males and females both across and among detected genetic clusters. MEMGENE landscape analysis further quantified the proportion of genetic variation contributed by IBD and IBR patterns, allowing for the relative importance of spatial drivers, including roads, water bodies and wildfires, to be assessed and incorporated into the characterization of population structure for the delineation of MUs. Local population units, as currently delineated in the boreal caribou recovery strategy, do not capture the genetic variation and connectivity of the ecotype across the study area. Here, we provide the tools to assess fine-scale spatial patterns of genetic variation, partition drivers of genetic variation and evaluate the best management options for maintaining genetic connectivity. Our approach is highly relevant to vagile wildlife species that are of management and conservation concern and demonstrate varying degrees of IBD and IBR with clinal spatial genetic structure that challenges the delineation of discrete population boundaries.
Dryad Translation missing: fr.blacklight.search.logo
Data from: Evolutionary reconstruction supports the presence of a Pleistocene Arctic refugium for a large mammal species
Dryad
Klütsch, Cornelya F. C.; Manseau, Micheline; Anderson, Morgan; Sinkins, Peter; Wilson, Paul J. — 2017-09-20 Aim: The presence of refugia in the Canadian High Arctic has been subject to debate for decades. We investigated the potential existence of Arctic refugia during the Pleistocene for a large mammal species in the Canadian Archipelago because if these refugia were present, reconsideration of the evolutionary histories of North American fauna and flora beyond the major refugia of Beringia and south of the Laurentide and Cordilleran Ice Sheets would be required. Peary caribou (Rangifer tarandus pearyi), identified as a subspecies based on morphological characteristics, inhabits the Canadian Arctic Islands and Boothia Peninsula. Previous studies demonstrated incomplete lineage sorting of mitochondrial DNA interpreted as a Beringian origin but were based on small sample sizes. Location: Canadian Arctic. Major taxa studied: Mammals: caribou (Rangifer tarandus). Methods: We used two molecular markers (microsatellites and mitochondrial DNA) and approximate Bayesian computations (ABC) testing the hypotheses of colonization out of Beringia into the Arctic Islands following the Last Glacial Maximum (LGM) or a divergence from Beringia significantly before the end of the LGM within a different refugium. Results: The coalescent-based analyses rejected a recent Beringian origin with subsequent colonization, instead supporting a divergence of Peary caribou from Beringia ~100,000 years ago linking it to the last interglacial/early Wisconsin Glacial Stage (125,000–75,000 years ago). Admixture on Banks Island with Beringian-derived barren-ground caribou is indicative of post-Pleistocene secondary contact; further supporting a divergent history of Peary caribou within a separated Arctic refugium. Main conclusions: Our results offer support for the existence of an Arctic refugium for large mammal species and add to the increasing evidence of such refugia in North America. This has significant implications on understanding the evolution and conservation of Arctic species, particularly in light of sensitivities and adaptive potential to a rapidly changing climate.
Dryad Translation missing: fr.blacklight.search.logo
Data from: Spatial familial networks to infer demographic structure of wild populations
Dryad
McFarlane, Samantha; Manseau, Micheline; Wilson, Paul J. — 2022-01-30 <p class="List1" style="margin-bottom:13px;">In social species, reproductive success and rates of dispersal vary among individuals resulting in spatially structured populations. Network analyses of familial relationships may provide insights on how these parameters influence population-level demographic patterns. These methods have however rarely been applied to genetically-derived pedigree data from wild populations.</p> <p class="List1" style="margin-bottom:13px;">Here we use parent-offspring relationships to construct familial networks from polygamous boreal woodland caribou (<i>Rangifer tarandus caribou</i>) in Saskatchewan, Canada, to inform recovery efforts. We collected samples from 933 individuals at 15 variable microsatellite loci along with caribou-specific primers for sex identification. Using network measures, we assess the contribution of individual caribou to the population with several centrality measures and then determine which measures are best suited to inform on the population demographic structure. We investigate the centrality of individuals from eighteen different local areas, along with the entire population.</p> <p class="List1" style="margin-bottom:13px;">We found substantial differences in centrality of individuals in different local areas, that in turn contributed differently to the full network, highlighting the importance of analyzing networks at different scales. The full network revealed that boreal caribou in Saskatchewan form a complex, interconnected familial network, as the removal of edges with high betweenness did not result in distinct subgroups. Alpha, betweenness, and eccentricity centrality were the most informative measures to characterize the population demographic structure and for spatially identifying areas of highest fitness levels and family cohesion across the range. We found varied levels of dispersal, fitness and cohesion in family groups.</p> <p class="List1" style="margin-bottom:13px;"><i>Synthesis and applications</i>: Our results demonstrate the value of different network measures in assessing genetically-derived familial networks. The spatial application of the familial networks identified individuals presenting different fitness levels, short and long-distance dispersing ability across the range in support of population monitoring and recovery efforts.</p>
Dryad Translation missing: fr.blacklight.search.logo
Data from: The effect of terrain and female density on survival of neonatal white-tailed deer and mule deer fawns
Dryad
Bonar, Maegwin; Manseau, Micheline; Geisheimer, Justin; Bannatyne, Travis; Lingle, Susan — 2017-04-18 Juvenile survival is a highly variable life-history trait that is critical to population growth. Antipredator tactics, including an animal's use of its physical and social environment, are critical to juvenile survival. Here, we tested the hypothesis that habitat and social characteristics influence coyote (Canis latrans) predation on white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) fawns in similar ways during the neonatal period. This would contrast to winter when the habitat and social characteristics that provide the most safety for each species differ. We monitored seven cohorts of white-tailed deer and mule deer fawns at a grassland study site in Alberta, Canada. We used logistic regression and a model selection procedure to determine how habitat characteristics, climatic conditions, and female density influenced fawn survival during the first 8 weeks of life. Fawn survival improved after springs with productive vegetation (high integrated Normalized Difference Vegetation Index values). Fawns that used steeper terrain were more likely to survive. Fawns of both species had improved survival in years with higher densities of mule deer females, but not with higher densities of white-tailed deer females, as predicted if they benefit from protection by mule deer. Our results suggest that topographical variation is a critical resource for neonates of many ungulate species, even species like white-tailed deer that use more gentle terrain when older. Further, our results raise the possibility that neonatal white-tailed fawns may benefit from associating with mule deer females, which may contribute to the expansion of white-tailed deer into areas occupied by mule deer.
Dryad Translation missing: fr.blacklight.search.logo
Data from: Sex-specific graphs: Relating group-specific topology to demographic and landscape data
Dryad
Bertrand, Philip; Bowman, Jeff; Dyer, Rodney; Manseau, Micheline; Wilson, Paul J.; Dyer, Rodney J. — 2017-05-05 Sex-specific genetic structure is a commonly observed pattern among vertebrate species. Facing differential selective pressures, individuals may adopt sex-specific life history traits that ultimately shape genetic variation among populations. Although differential dispersal dynamics are commonly detected in the literature, few studies have used genetic structure to investigate sex-specific functional connectivity. The recent use of graph theoretic approaches in landscape genetics has demonstrated network capacities to describe complex system behaviours where network topology represents genetic interaction among subunits. Here, we partition the overall genetic structure into sex-specific graphs, revealing different male and female dispersal dynamics of a fisher (Pekania [Martes] pennanti) metapopulation in southern Ontario. Our analyses based on network topologies supported the hypothesis of male-biased dispersal. Furthermore, we demonstrated that the effect of the landscape, identified at the population level, could be partitioned among sex-specific strata. We found that female connectivity was negatively correlated with snow depth, whereas connectivity among males was not. Our findings underscore the potential of conducting sex-specific analysis by identifying landscape elements or configuration that differentially promotes or impedes functional connectivity between sexes, revealing processes that may otherwise remain cryptic. We propose that the sex-specific graph approach would be applicable to other vagile species where differential sex-specific processes are expected to occur.
Dryad Translation missing: fr.blacklight.search.logo
DNA metabarcoding sequence data for diet analysis of caribou
Dryad
Mitchell, Greniqueca; Wilson, Paul; Redquest, Bridget; Patterson, Brent; Manseau, Micheline; Rutledge, Linda — 2022-06-11 <p>Woodland caribou (<em>Rangifer tarandus caribou</em>) are threatened in Canada due to the drastic decline in population size caused primarily by human-induced landscape changes that decrease habitat and increase predation risk. Conservation efforts have largely focused on reducing predators and protecting critical habitat, whereas research on dietary niches and the role of potential food constraints in lichen-poor environments is limited. To improve our understanding of dietary niche variability, we used a next-generation sequencing approach with metabarcoding of DNA extracted from faecal pellets of woodland caribou located on Lake Superior in lichen-rich (mainland) and lichen-poor (island) environments. Amplicon sequencing of fungal ITS2 region revealed lichen-associated fungi as predominant in samples from both populations, but amplification at the chloroplast <em>trnL </em>region, which was only successful on island samples, revealed primary consumption of yew based on relative read abundance (<em>Taxus spp.</em>; 83.68%) with dogwood (<em>Cornus spp</em>.; 9.67%) and maple (<em>Acer spp.</em>; 4.10%) also prevalent. These results suggest that conservation efforts for caribou need to consider the availability of food resources beyond lichen to ensure successful outcomes.  More broadly, we provide a reliable methodology for assessing ungulate diet from archived faecal pellets that could reveal important dietary shifts over time in response to climate change.</p>

Instructions pour la recherche cartographique

1.Activez le filtre cartographique en cliquant sur le bouton « Limiter à la zone sur la carte ».
2.Déplacez la carte pour afficher la zone qui vous intéresse. Maintenez la touche Maj enfoncée et cliquez pour encadrer une zone spécifique à agrandir sur la carte. Les résultats de la recherche changeront à mesure que vous déplacerez la carte.
3.Pour voir les détails d’un emplacement, vous pouvez cliquer soit sur un élément dans les résultats de recherche, soit sur l’épingle d’un emplacement sur la carte et sur le lien associé au titre.
Remarque : Les groupes servent à donner un aperçu visuel de l’emplacement des données. Puisqu’un maximum de 50 emplacements peut s’afficher sur la carte, il est possible que vous n’obteniez pas un portrait exact du nombre total de résultats de recherche.

(auteur : Manseau, Micheline)

Limiter par :

Effacer tout

au