Wildlife Genetics International

Nelson, Canada

Wildlife Genetics International

Nelson, Canada
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Pongracz J.D.,Natural Resources Canada | Paetkau D.,Wildlife Genetics International | Branigan M.,Natural Resources Canada | Richardson E.,Environment Canada
Arctic | Year: 2017

Grizzly bears have recently become more common on the Arctic Islands in the Inuvialuit Settlement Region, concurrently with a period of environmental change. Over the last decade, grizzly bear-polar bear hybrids have been confirmed within this region, triggering extensive discussion and speculation regarding the impact of hybridization on the parent species. Through harvests, sightings, and captures, we document an increase in the presence of grizzly bears and combine field observations of hybrids with genetic analysis and parentage analysis to identify four first-generation (F1) hybrids and four offspring of F1 hybrids and grizzly bears (backcross-to-grizzly-bear individuals). We trace these eight hybrid individuals to a single female polar bear who mated with two grizzly bears. We sampled one of her mates on the sea ice in the High Arctic and deduced the genotype of the other from his five offspring. The two male grizzly bears are sires of both the F1 generation and the backcross-to-grizzly-bear generation. So what initially appeared to be a sudden spate of hybridization in the western Canadian Arctic originated with the unusual mating between three non-hybrid parents. The breakdown of species barriers may start with atypical mating preferences of select individuals; however, the story we present can be traced to a single female polar bear who, along with three of her known F1 offspring, has been killed. © The Arctic Institute of North America.


Kamath P.L.,U.S. Geological Survey | Haroldson M.A.,U.S. Geological Survey | Luikart G.,University of Montana | Paetkau D.,Wildlife Genetics International | And 2 more authors.
Molecular Ecology | Year: 2015

Effective population size (Ne) is a key parameter for monitoring the genetic health of threatened populations because it reflects a population's evolutionary potential and risk of extinction due to genetic stochasticity. However, its application to wildlife monitoring has been limited because it is difficult to measure in natural populations. The isolated and well-studied population of grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem provides a rare opportunity to examine the usefulness of different Ne estimators for monitoring. We genotyped 729 Yellowstone grizzly bears using 20 microsatellites and applied three single-sample estimators to examine contemporary trends in generation interval (GI), effective number of breeders (Nb) and Ne during 1982-2007. We also used multisample methods to estimate variance (NeV) and inbreeding Ne (NeI). Single-sample estimates revealed positive trajectories, with over a fourfold increase in Ne (≈100 to 450) and near doubling of the GI (≈8 to 14) from the 1980s to 2000s. NeV (240-319) and NeI (256) were comparable with the harmonic mean single-sample Ne (213) over the time period. Reanalysing historical data, we found NeV increased from ≈80 in the 1910s-1960s to ≈280 in the contemporary population. The estimated ratio of effective to total census size (Ne/Nc) was stable and high (0.42-0.66) compared to previous brown bear studies. These results support independent demographic evidence for Yellowstone grizzly bear population growth since the 1980s. They further demonstrate how genetic monitoring of Ne can complement demographic-based monitoring of Nc and vital rates, providing a valuable tool for wildlife managers. © 2015 John Wiley & Sons Ltd.


PubMed | U.S. Geological Survey, University of Montana and Wildlife Genetics International
Type: Journal Article | Journal: Molecular ecology | Year: 2016

Effective population size (N(e)) is a key parameter for monitoring the genetic health of threatened populations because it reflects a populations evolutionary potential and risk of extinction due to genetic stochasticity. However, its application to wildlife monitoring has been limited because it is difficult to measure in natural populations. The isolated and well-studied population of grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem provides a rare opportunity to examine the usefulness of different N(e) estimators for monitoring. We genotyped 729 Yellowstone grizzly bears using 20 microsatellites and applied three single-sample estimators to examine contemporary trends in generation interval (GI), effective number of breeders (N(b)) and N(e) during 1982-2007. We also used multisample methods to estimate variance (N(eV)) and inbreeding N(e) (N(eI)). Single-sample estimates revealed positive trajectories, with over a fourfold increase in N(e) (100 to 450) and near doubling of the GI (8 to 14) from the 1980s to 2000s. N(eV) (240-319) and N(eI) (256) were comparable with the harmonic mean single-sample N(e) (213) over the time period. Reanalysing historical data, we found N(eV) increased from 80 in the 1910s-1960s to 280 in the contemporary population. The estimated ratio of effective to total census size (N(e) /N(c)) was stable and high (0.42-0.66) compared to previous brown bear studies. These results support independent demographic evidence for Yellowstone grizzly bear population growth since the 1980s. They further demonstrate how genetic monitoring of N(e) can complement demographic-based monitoring of N(c) and vital rates, providing a valuable tool for wildlife managers.


News Article | November 2, 2015
Site: www.techtimes.com

The Grizzly bear population in Yellowstone National park is thriving and the genetic diversity remains stable since the 1980s, says a new study by the Interagency Grizzly Bear Study Team. The report says that there is a potential that the bears will continue to thrive in the future. Published in the journal Molecular Ecology, the collaborative study by the U.S. Geological Survey (USGS), Wildlife Genetics International, University of Montana, and Interagency Grizzly Bear Study Team, included 729 bears and it shows that the effective population or the ones passing down genes to the next generation quadrupled over a 25-year period. The report says that the number of Grizzly bears that were passing the genes to their offspring increased from 100 in the 1980s to 450 in the 2000s. The numbers of bears are lesser than the actual population because not all of these animals breed. This means that the Grizzlies in Yellowstone are going towards having the effective size needed for a continuing genetic sustainability and survival.  As of 2014, there are an estimated 674 to 839 Grizzly Bears in Greater Yellowstone.  However, U.S. Geological Survey estimated the total Yellowstone grizzly population at 757. Gene variations help Grizzlies evolve and adapt in order for them to survive alongside changes in the environment. This is very important especially that the environment faces various predicaments including climate change. "The increase in effective size of the Yellowstone grizzly bear population over the past several decades, with no significant change in genetic diversity, supports evidence of population growth based on traditional surveys," said lead author and USGS ecologist, Pauline Kamath. She cited that their finding is a 'key genetic indicator' of the ability of a population to adapt to future changes in the environment that could affect the animals and their habitat. "This is a key genetic indicator of a population's ability to respond to future environmental change," she added. The bear was listed in the Endangered Species Act in 1975 and multiple efforts were made to help the population of Grizzlies to recover and thrive in the long term. The researchers used several newly available techniques to assess Grizzly population since data on wildlife population are limited due to difficulty in measurement and the long period of time needed for measuring individuals in the population. Thus, this study has shed light on how genetic monitoring is needed to complement traditional demographic-based monitoring. This will provide useful tools for population managers in the present and future in order to accurately estimate the survival rate and population of endangered animals.


Serrouya R.,University of Alberta | Paetkau D.,Wildlife Genetics International | McLellan B.N.,British Columbia Ministry of forests | Boutin S.,University of Alberta | And 2 more authors.
Molecular Ecology | Year: 2012

Identifying conservation units below the species level is becoming increasingly important, particularly when limited resources necessitate prioritization for conservation among such units. This problem is exemplified with caribou, a mammal with a circum-Arctic distribution that is exposed to a broad spectrum of ecological conditions, but is also declining in many parts of its range. We used microsatellite markers to evaluate the suitability of existing intra-specific taxonomic designations to act as population units for conservation and contrasted this with landscape features that were independent of taxonomy. We also quantified the relationship between genetic differentiation and subpopulation size, a factor that has been under-represented in landscape genetic research. Our data set included three subspecies and three ecotypes of caribou that varied in population size by five orders of magnitude. Our results indicated that genetic structure did not correspond to existing taxonomic designation, particularly at the level of ecotype. Instead, we found that major valleys and population size were the strongest factors associated with substructure. There was a negative exponential relationship between population size and F ST between pairs of adjacent subpopulations, suggesting that genetic drift was the mechanism causing the structure among the smallest subpopulations. A genetic assignment test revealed that movement among subpopulations was a fraction of the level needed to stabilize smaller subpopulations, indicating little chance for demographic rescue. Such results may be broadly applicable to landscape genetic studies, because population size and corresponding rates of drift have the potential to confound interpretations of landscape effects on population structure. © 2012 Blackwell Publishing Ltd.


Dumond M.,Environment Canada | Boulanger J.,Integrated Ecological Research | Paetkau D.,Wildlife Genetics International
Wildlife Society Bulletin | Year: 2015

Assessing grizzly bears' (Ursus arctos) abundance in the Arctic has been challenging because of the large scale of their movements and the remoteness of field locations. We modified a post sampling method used for wolverines (Gulo gulo) to allow collection of hair samples from grizzly bears in the Canadian tundra. We deployed 1 post/cell in a sampling grid of 393 10 × 10-km cells sampled in 2008 and 2009 for two 14-day sessions in July-August of both years. We then compared density estimates from mark-recapture estimators that used telemetry data from previous years with spatially explicit mark-recapture models that used only genetic detections. Over the 2 years of sampling, we detected 98 female and 81 male grizzly bears. We found that the DNA degradation rate was related to collection interval and the number of days between rainfall events and sample collection. Estimates of density were in the order of 5 bears/1,000 km2. The estimates from the 2 methods were statistically similar, but spatially explicit estimates were more precise than those using radiocollar data. Our results provide the first demonstration of the viability of posts as hair-snagging stations to obtain DNA from grizzly bears, and of spatially explicit mark-recapture methods to estimate population size and density for grizzly bears above the tree line. © 2015 The Wildlife Society. © The Wildlife Society, 2015.


Proctor M.F.,Birchdale Ecological Ltd. | Paetkau D.,Wildlife Genetics International | McLellan B.N.,British Columbia Ministry of forests | Stenhouse G.B.,Foothills Research Institute | And 15 more authors.
Wildlife Monographs | Year: 2012

Population fragmentation compromises population viability, reduces a species ability to respond to climate change, and ultimately may reduce biodiversity. We studied the current state and potential causes of fragmentation in grizzly bears over approximately 1,000,000 km 2 of western Canada, the northern United States (US), and southeast Alaska. We compiled much of our data from projects undertaken with a variety of research objectives including population estimation and trend, landscape fragmentation, habitat selection, vital rates, and response to human development. Our primary analytical techniques stemmed from genetic analysis of 3,134 bears, supplemented with radiotelemetry data from 792 bears. We used 15 locus microsatellite data coupled withmeasures of genetic distance, isolation-by-distance (IBD) analysis, analysis of covariance (ANCOVA), linear multiple regression, multi-factorial correspondence analysis (to identify population divisions or fractures with no a priori assumption of group membership), and population-assignment methods to detect individual migrants between immediately adjacent areas. These data corroborated observations of inter-area movements from our telemetry database. In northern areas, we found a spatial genetic pattern of IBD, although there was evidence of natural fragmentation from the rugged heavily glaciated coast mountains of British Columbia (BC) and the Yukon. These results contrasted with the spatial pattern of fragmentation in more southern parts of their distribution. Near the Canada-US border area, we found extensive fragmentation that corresponded to settled mountain valleys andmajor highways. Genetic distances across developed valleys were elevated relative to those across undeveloped valleys in central and northern BC. In disturbed areas, most inter-area movements detected were made by male bears, with few female migrants identified. North-south movements within mountain ranges (Mts) and across BC Highway 3 were more common than east-west movements across settled mountain valleys separating Mts. Our results suggest that relatively distinct subpopulations exist in this region, including the Cabinet, Selkirk South, and the decadesisolated Yellowstone populations. Current movement rates do not appear sufficient to consider the subpopulations we identify along the Canada-US border as 1 inter-breeding unit. Although we detected enough male movement to mediate gene flow, the current low rate of female movement detected among areas is insufficient to provide a demographic rescue effect between areas in the immediate future (0-15 yr). In Alberta, we found fragmentation corresponded to major east-west highways (Highways 3, 11, 16, and 43) and most inter-area movements were made by males. Gene flow and movement rates between Alberta and BC were highest across the Continental Divide south of Highway 1 and north of Highway 16. In the central region between Highways 1 and 11, we found evidence of natural fragmentation associated with the extensive glaciers and icefields along the Continental Divide. The discontinuities that we identified would form appropriate boundaries formanagement units. We related sex-specific movement rates between adjacent areas to several metrics of human use (highway traffic, settlement, and humancaused mortality) to understand the causes of fragmentation. This analysis used data from 1,508 bears sampled over a 161,500-km 2 area in southeastern BC, western Alberta, northern Idaho, and northern Montana during 1979-2007. This area was bisected by numerous human transportation and settlement corridors of varying intensity and complexity. We used multiple linear regression and ANCOVA to document the responses of female and male bears to disturbance. Males and females both demonstrated reduced movement rates with increasing settlement and traffic. However, females reduced their movement rates dramatically when settlement increased to >20% of the fracture zone. At this same threshold, male movement declined more gradually, in response to increased traffic and further settlement. In highly settled areas (>50%), both sexes had a similar reduction in movements in response to traffic, settlement, and mortality. We documented several small bear populations with male-only immigration, highlighting the importance of investigating sex-specific movements. Without female connectivity, small populations are not viable over the long term. The persistence of this regional female fragmented metapopulation likely will require strategic connectivity management. We therefore recommend enhancing female connectivity among fractured areas by securing linkage-zone habitat appropriate for female dispersal, and ensuring current large source subpopulations remain intact. The fragmentation we documented may also affect other species with similar ecological characteristics: sparse densities, slow reproduction, short male-biased dispersal, and a susceptibility to human-caused mortality and habitat degradation. Therefore, regional inter-jurisdictional efforts to manage broad landscapes for inter-area movement will likely benefit a broad spectrum of species and natural processes, particularly in light of climate change. © 2011 The Wildlife Society.


Poole K.G.,Aurora Wildlife Research | Reynolds D.M.,British Columbia Ministry of forests | Mowat G.,British Columbia Ministry of forests | Paetkau D.,Wildlife Genetics International
Journal of Wildlife Management | Year: 2011

Non-invasive collection of tissue samples to obtain DNA for microsatellite genotyping required to estimate population size has been used for many wildlife species but rarely for ungulates. We estimated mountain goat (Oreamnos americanus) population size on a mountain complex in southwestern British Columbia by identification of individuals using DNA obtained from fecal pellet and hair samples collected during 3 sampling sessions. We identified 55 individuals from 170 samples that were successfully genotyped, and estimated a population of 77 mountain goats (SE = 7.4). Mean capture probability was 0.38 (SE = 0.037) per session. Our technique provides one of the first statistically rigorous estimates of abundance of an ungulate species using DNA derived primarily from fecal pellets. Our technique enables managers to obtain minimum counts or population estimates of ungulates in areas of low sightability that can be used for conservation and management. Copyright © 2011 The Wildlife Society.


Proctor M.,University of Alberta | McLellan B.,British Columbia Ministry of forests | Boulanger J.,Integrated Ecological Research | Apps C.,Aspen Wildlife Research | And 3 more authors.
Ursus | Year: 2010

Grizzly bears (Ursus arctos) occur across British Columbia and in Alberta in mostly forested, mountainous, and boreal ecosystems. These dense forests make sighting bears from aircraft uncommon and aerial census impractical. Since 1995, we have used genetic sampling using DNA from bear hair collected with barbed wire hair traps to explore a suite of ecological questions of grizzly bears in western Canada. During 19952005, we conducted large-scale sampling (1,650 to 9,866 km2 grids) in 26 areas (covering a combined 110,405 km2), where genetic identification of 1,412 grizzly bears was recorded. Abundance estimation was the primary goal of most surveys. We also used DNA from bear hair to examine population trend, distribution, and presence in areas where grizzly bears were rare, as well as population fragmentation in a region with a high human population. Combining spatial variation in detecting bears with that of human, landscape, and ecological features has allowed us to quantify factors that influence grizzly bear distribution, population fragmentation, and competition with black bears (U. americanus), and to map variation in bear densities. We summarize these studies and discuss lessons learned that are relevant to improving sampling efficiency, study designs, and resulting inference. © 2010 International Association for Bear Research and Management.


Morton J.M.,U.S. Fish and Wildlife Service | White G.C.,Colorado State University | Hayward G.D.,U.S. Department of Agriculture | Paetkau D.,Wildlife Genetics International | Bray M.P.,U.S. Department of Agriculture
Journal of Wildlife Management | Year: 2016

The brown bear population on the Kenai Peninsula, Alaska, has not been empirically estimated previously because conventional aerial methods over this heavily forested landscape were infeasible. We applied a rapid field protocol to a DNA-based, mark-recapture approach on a large and tightly bounded sample frame to estimate brown bear abundance. We used lure to attract bears to barbed wire stations deployed in 145 9-km × 9-km cells systematically distributed across 10,200 km2 of available habitat on the Kenai National Wildlife Refuge and Chugach National Forest during 31 consecutive days in early summer 2010. Using 2 helicopters and 4 2-person field crews, we deployed the stations during a 6-day period and subsequently revisited these stations on 5 consecutive 5-day trap sessions. We extracted DNA to identify individual bears and developed capture histories as input to mark-recapture models. Combined with data from radio-telemetered bears, ≥243 brown bears were alive on the Kenai Peninsula in 2010, but we used only 99 females and 104 males in modeling. We used Akaike's Information Criterion selection and model averaging to estimate 428 (95% lognormal CI = 353-539) brown bears (including all age classes) on the study area. Despite low recaptures rates, we achieved reasonable precision by ensuring geographic and demographic population closure through a spatially comprehensive sample frame and very short sampling window. We reduced bias by including information from rub trees and telemetered females (i.e., occasion 0). Extrapolating the density estimate of 42 bears/1,000 km2 of available habitat on the study area to the Kenai Peninsula suggests a peninsula-wide population of 582 brown bears (95% lognormal CI = 469-719). Despite a density estimate that is low compared to other coastal brown bear populations in Alaska and genetic evidence that suggests this peninsular population is insular, harvest management has been liberalized since 2012. We recommend this population estimate serve as the benchmark for future management. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. © Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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