Publications by authors named "Gustaf Samelius"

15 Publications

  • Page 1 of 1

Evidence of Arctic Fox Survival following Exposure to Rabies Virus.

J Wildl Dis 2021 Nov 23. Epub 2021 Nov 23.

US Department of Agriculture, National Wildlife Research Center, 4101 Laporte Avenue, Fort Collins, Colorado 80521, USA.

The arctic fox variant of the rabies virus (RABV) is enzootic in the circumpolar north. Reports of abortive RABV exposures motivated a retrospective analysis of sera from 41 arctic foxes captured at Karrak Lake in Nunavut, Canada, during 2011-2015. Estimated RABV antibody prevalence among foxes was 14% (95% confidence interval, 7-28%).
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http://dx.doi.org/10.7589/JWD-D-21-00071DOI Listing
November 2021

Increasing risks for emerging infectious diseases within a rapidly changing High Asia.

Ambio 2021 Jul 22. Epub 2021 Jul 22.

Snow Leopard Trust, 4649 Sunnyside Avenue North, Seattle, USA.

The cold and arid mountains and plateaus of High Asia, inhabited by a relatively sparse human population, a high density of livestock, and wildlife such as the iconic snow leopard Panthera uncia, are usually considered low risk for disease outbreaks. However, based on current knowledge about drivers of disease emergence, we show that High Asia is rapidly developing conditions that favor increased emergence of infectious diseases and zoonoses. This is because of the existing prevalence of potentially serious pathogens in the system; intensifying environmental degradation; rapid changes in local ecological, socio-ecological, and socio-economic factors; and global risk intensifiers such as climate change and globalization. To better understand and manage the risks posed by diseases to humans, livestock, and wildlife, there is an urgent need for establishing a disease surveillance system and improving human and animal health care. Public health must be integrated with conservation programs, more ecologically sustainable development efforts and long-term disease surveillance.
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http://dx.doi.org/10.1007/s13280-021-01599-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8297435PMC
July 2021

Hopping species and borders: detection of Bartonella spp. in avian nest fleas and arctic foxes from Nunavut, Canada.

Parasit Vectors 2020 Sep 14;13(1):469. Epub 2020 Sep 14.

Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK, S7N 5B4, Canada.

Background: In a warmer and more globally connected Arctic, vector-borne pathogens of zoonotic importance may be increasing in prevalence in native wildlife. Recently, Bartonella henselae, the causative agent of cat scratch fever, was detected in blood collected from arctic foxes (Vulpes lagopus) that were captured and released in the large goose colony at Karrak Lake, Nunavut, Canada. This bacterium is generally associated with cats and cat fleas, which are absent from Arctic ecosystems. Arctic foxes in this region feed extensively on migratory geese, their eggs, and their goslings. Thus, we hypothesized that a nest flea, Ceratophyllus vagabundus vagabundus (Boheman, 1865), may serve as a vector for transmission of Bartonella spp.

Methods: We determined the prevalence of Bartonella spp. in (i) nest fleas collected from 5 arctic fox dens and (ii) 37 surrounding goose nests, (iii) fleas collected from 20 geese harvested during arrival at the nesting grounds and (iv) blood clots from 57 adult live-captured arctic foxes. A subsample of fleas were identified morphologically as C. v. vagabundus. Remaining fleas were pooled for each nest, den, or host. DNA was extracted from flea pools and blood clots and analyzed with conventional and real-time polymerase chain reactions targeting the 16S-23S rRNA intergenic transcribed spacer region.

Results: Bartonella henselae was identified in 43% of pooled flea samples from nests and 40% of pooled flea samples from fox dens. Bartonella vinsonii berkhoffii was identified in 30% of pooled flea samples collected from 20 geese. Both B. vinsonii berkhoffii (n = 2) and B. rochalimae (n = 1) were identified in the blood of foxes.

Conclusions: We confirm that B. henselae, B. vinsonii berkhoffii and B. rochalimae circulate in the Karrak Lake ecosystem and that nest fleas contain B. vinsonii and B. henselae DNA, suggesting that this flea may serve as a potential vector for transmission among Arctic wildlife.
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http://dx.doi.org/10.1186/s13071-020-04344-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7490881PMC
September 2020

Identification errors in camera-trap studies result in systematic population overestimation.

Sci Rep 2020 04 14;10(1):6393. Epub 2020 Apr 14.

Department of Ecology, Swedish University of Agricultural Sciences, SE-75007, Uppsala, Sweden.

Reliable assessments of animal abundance are key for successful conservation of endangered species. For elusive animals with individually-unique markings, camera-trap surveys are a benchmark standard for estimating local and global population abundance. Central to the reliability of resulting abundance estimates is the assumption that individuals are accurately identified from photographic captures. To quantify the risk of individual misidentification and its impact on population abundance estimates we performed an experiment under controlled conditions in which 16 captive snow leopards (Panthera uncia) were camera-trapped on 40 occasions and eight observers independently identified individuals and recaptures. Observers misclassified 12.5% of all capture occasions, resulting in systematically inflated population abundance estimates on average by one third (mean ± SD = 35 ± 21%). Our results show that identifying individually-unique individuals from camera-trap photos may not be as reliable as previously believed, implying that elusive and endangered species could be less abundant than current estimates indicate.
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http://dx.doi.org/10.1038/s41598-020-63367-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7156508PMC
April 2020

Correction to: Documenting lemming population change in the Arctic: Can we detect trends?

Ambio 2020 03;49(3):801-804

A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskij prosp, Moscow, Russia, 119071.

In the original published article, some of the symbols in figure 1A were modified incorrectly during the typesetting and publication process. The correct version of the figure is provided in this correction.
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http://dx.doi.org/10.1007/s13280-019-01262-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6989706PMC
March 2020

Documenting lemming population change in the Arctic: Can we detect trends?

Ambio 2020 Mar 22;49(3):786-800. Epub 2019 Jul 22.

A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskij prosp, Moscow, Russia, 119071.

Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.
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http://dx.doi.org/10.1007/s13280-019-01198-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6989711PMC
March 2020

Diet shift in bank voles induced by competition from grey-sided voles?

Integr Zool 2019 Jul 26;14(4):376-382. Epub 2019 Jun 26.

Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden.

Grey-sided voles (Myodes rufocanus) and bank voles (Myodes glareolus) co-exist in boreal forests in northern Scandinavia. Previous studies suggest that the 2 species interact interspecifically, the grey-sided vole being the dominant species. We tested the hypothesis that bank voles shift their diet due to competition with the dominant grey-sided vole by studying stable isotope ratios in both species. Muscle samples were taken from voles in patches of old forest occupied by only bank voles and patches of old forest occupied by both grey-sided voles and bank voles. We found that: (i) stable isotope ratios of bank voles differed in areas with and without grey-sided voles; and that (ii) the stable isotope ratios of bank voles were more similar to those of grey-sided voles in areas where grey-sided voles were absent. Our data suggests that grey-sided voles forced bank voles to change their diet due to interspecific competition.
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http://dx.doi.org/10.1111/1749-4877.12369DOI Listing
July 2019

TRANSMISSION DYNAMICS OF IN ARCTIC FOXES (): A LONG-TERM MARK-RECAPTURE SEROLOGIC STUDY AT KARRAK LAKE, NUNAVUT, CANADA.

J Wildl Dis 2019 07 28;55(3):619-626. Epub 2018 Nov 28.

1 Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada.

Transmission dynamics of , a parasite of importance for wildlife and human health, are enigmatic in the Arctic tundra, where free-ranging wild and domestic felid definitive hosts are absent and rarely observed, respectively. Through a multiyear mark-recapture study (2011-17), serosurveillance was conducted to investigate transmission of in Arctic foxes () in the Karrak Lake region, Nunavut, Canada. Sera from adult foxes and fox pups were tested for antibodies to by using serologic methods, including the indirect fluorescent antibody test, direct agglutination test, and modified agglutination test. The overall seroprevalence was 39% in adults and 17% in pups. Mature foxes were more likely to be exposed (seroconvert) than young foxes (less than 1 yr old), with the highest level of seroprevalence in midaged foxes (2-4 yr old). Pups in two different litters were seropositive on emergence from the den, around 5 wk old, which could have been due to passive transfer of maternal antibody or vertical transmission of from mother to offspring. The seropositive pups were born of seropositive mothers that were also seropositive the year before they gave birth, suggesting that vertical transmission might not be limited to litters from mothers exposed to for the first time in pregnancy. All recaptured seropositive foxes remained seropositive on subsequent captures, suggesting that antibodies persist or foxes are constantly reexposed or a combination of both. The results of this study provided insights into how foxes were likely exposed to , the dynamics of antibody persistence and immune response, and how the parasite was maintained in a terrestrial Arctic ecosystem in the absence of felid definitive hosts.
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http://dx.doi.org/10.7589/2018-06-144DOI Listing
July 2019

Variation in home range size of red foxes Vulpes vulpes along a gradient of productivity and human landscape alteration.

PLoS One 2017 6;12(4):e0175291. Epub 2017 Apr 6.

Department of Forestry and Wildlife Management, Faculty of Applied Ecology and Agricultural Sciences, Inland Norway University of Applied Sciences, Campus Evenstad, Koppang, Norway.

Home range size is a fundamental concept for understanding animal dispersion and ecological needs, and it is one of the most commonly reported ecological attributes of free-ranging mammals. Previous studies indicate that red foxes Vulpes vulpes display great variability in home range size. Yet, there has been little consensus regarding the reasons why home range sizes of red foxes vary so extensively. In this study, we examine possible causes of variation in red fox home range sizes using data from 52 GPS collared red foxes from four study areas representing a gradient of landscape productivity and human landscape alteration in Norway and Sweden. Using 90% Local Convex Hull home range estimates, we examined how red fox home range size varied in relation to latitude, elevation, vegetation zone, proportion of agricultural land and human settlement within a home range, and sex and age. We found considerable variation in red fox home range sizes, ranging between 0.95 km2 to 44 km2 (LoCoH 90%) and 2.4 km2 to 358 km2 (MCP 100%). Elevation, proportion of agricultural land and sex accounted for 50% of the variation in home range size found amongst foxes, with elevation having the strongest effect. Red foxes residing in more productive landscapes (those in more southern vegetation zones), had home ranges approximately four times smaller than the home ranges of foxes in the northern boreal vegetation zone. Our results indicate that home range size was influenced by a productivity gradient at both the landscape (latitude) and the local (elevation) scale. The influence of the proportion of agriculture land on home range size of foxes illustrates how human landscape alteration can affect the space use and distribution of red foxes. Further, the variation in home range size found in this study demonstrates the plasticity of red foxes to respond to changing human landscape alteration as well as changes in landscape productivity, which may be contributing to red fox population increases and northern range expansions.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0175291PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5383297PMC
September 2017

ESTIMATING TOXOPLASMA GONDII EXPOSURE IN ARCTIC FOXES (VULPES LAGOPUS) WHILE NAVIGATING THE IMPERFECT WORLD OF WILDLIFE SEROLOGY.

J Wildl Dis 2016 Jan;52(1):47-56

1  University of Saskatchewan, Department of Veterinary Microbiology, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada.

Although the protozoan parasite Toxoplasma gondii is ubiquitous in birds and mammals worldwide, the full suite of hosts and transmission routes is not completely understood, especially in the Arctic. Toxoplasma gondii occurrence in humans and wildlife can be high in Arctic regions, despite apparently limited opportunities for transmission of oocysts shed by felid definitive hosts. Arctic foxes (Vulpes lagopus) are under increasing anthropogenic and ecologic pressure, leading to population declines in parts of their range. Our understanding of T. gondii occurrence in arctic foxes is limited to only a few regions, but mortality events caused by this parasite have been reported. We investigated the exposure of arctic foxes to T. gondii in the Karrak Lake goose colony, Queen Maud Gulf Migratory Bird Sanctuary, Nunavut, Canada. Following an occupancy-modeling framework, we performed replicated antibody testing on serum samples by direct agglutination test (DAT), indirect fluorescent antibody test (IFAT), and an indirect enzyme-linked immunosorbent assay (ELISA) that can be used in multiple mammalian host species. As a metric of test performance, we then estimated the probability of detecting T. gondii antibodies for each of the tests. Occupancy estimates for T. gondii antibodies in arctic foxes under this framework were between 0.430 and 0.758. Detection probability was highest for IFAT (0.716) and lower for DAT (0.611) and ELISA (0.464), indicating that the test of choice for antibody detection in arctic foxes might be the IFAT. We document a new geographic record of T. gondii exposure in arctic foxes and demonstrate an emerging application of ecologic modeling techniques to account for imperfect performance of diagnostic tests in wildlife species.
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http://dx.doi.org/10.7589/2015-03-075DOI Listing
January 2016

Endoparasites in the feces of arctic foxes in a terrestrial ecosystem in Canada.

Int J Parasitol Parasites Wildl 2013 Dec 14;2:90-6. Epub 2013 Mar 14.

Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5B4.

The parasites of arctic foxes in the central Canadian Arctic have not been well described. Canada's central Arctic is undergoing dramatic environmental change, which is predicted to cause shifts in parasite and wildlife species distributions, and trophic interactions, requiring that baselines be established to monitor future alterations. This study used conventional, immunological, and molecular fecal analysis techniques to survey the current gastrointestinal endoparasite fauna currently present in arctic foxes in central Nunavut, Canada. Ninety-five arctic fox fecal samples were collected from the terrestrial Karrak Lake ecosystem within the Queen Maud Gulf Migratory Bird Sanctuary. Samples were examined by fecal flotation to detect helminths and protozoa, immunofluorescent assay (IFA) to detect Cryptosporidium and Giardia, and quantitative PCR with melt-curve analysis (qPCR-MCA) to detect coccidia. Positive qPCR-MCA products were sequenced and analyzed phylogenetically. Arctic foxes from Karrak Lake were routinely shedding eggs from Toxascaris leonina (63%). Taeniid (15%), Capillarid (1%), and hookworm eggs (2%), Sarcocystis sp. sporocysts 3%), and Eimeria sp. (6%), and Cystoisospora sp. (5%) oocysts were present at a lower prevalence on fecal flotation. Cryptosporidium sp. (9%) and Giardia sp. (16%) were detected by IFA. PCR analysis detected Sarcocystis (15%), Cystoisospora (5%), Eimeria sp., and either Neospora sp. or Hammondia sp. (1%). Through molecular techniques and phylogenetic analysis, we identified two distinct lineages of Sarcocystis sp. present in arctic foxes, which probably derived from cervid and avian intermediate hosts. Additionally, we detected previously undescribed genotypes of Cystoisospora. Our survey of gastrointestinal endoparasites in arctic foxes from the central Canadian Arctic provides a unique record against which future comparisons can be made.
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http://dx.doi.org/10.1016/j.ijppaw.2013.02.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3862500PMC
December 2013

Habitat selection and risk of predation: re-colonization by lynx had limited impact on habitat selection by roe deer.

PLoS One 2013 19;8(9):e75469. Epub 2013 Sep 19.

Department of Ecology, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden.

Risk of predation is an evolutionary force that affects behaviors of virtually all animals. In this study, we examined how habitat selection by roe deer was affected by risk of predation by Eurasian lynx - the main predator of roe deer in Scandinavia. Specifically, we compared how habitat selection by roe deer varied (1) before and after lynx re-established in the study area and (2) in relation to habitat-specific risk of predation by lynx. All analyses were conducted at the spatial and temporal scales of home ranges and seasons. We did not find any evidence that roe deer avoided habitats in which the risk of predation by lynx was greatest and information-theoretic model selection showed that re-colonization by lynx had limited impact on habitat selection by roe deer despite lynx predation causing 65% of known mortalities after lynx re-colonized the area. Instead we found that habitat selection decreased when habitat availability increased for 2 of 5 habitat types (a pattern referred to as functional response in habitat selection). Limited impact of re-colonization by lynx on habitat selection by roe deer in this study differs from elk in North America altering both daily and seasonal patterns in habitat selection at the spatial scales of habitat patches and home ranges when wolves were reintroduced to Yellowstone National Park. Our study thus provides further evidence of the complexity by which animals respond to risk of predation and suggest that it may vary between ecosystems and predator-prey constellations.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0075469PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3777928PMC
June 2014

Patterns of variation in reproductive parameters in Eurasian lynx (Lynx lynx).

Acta Theriol (Warsz) 2012 Jul 27;57(3):217-223. Epub 2011 Nov 27.

Detailed knowledge of the variation in demographic rates is central for our ability to understand the evolution of life history strategies and population dynamics, and to plan for the conservation of endangered species. We studied variation in reproductive output of 61 radio-collared Eurasian lynx females in four Scandinavian study sites spanning a total of 223 lynx-years. Specifically, we examined how the breeding proportion and litter size varied among study areas and age classes (2-year-old vs. >2-year-old females). In general, the breeding proportion varied between age classes and study sites, whereas we did not detect such variation in litter size. The lack of differences in litter sizes among age classes is at odds with most findings in large mammals, and we argue that this is because the level of prenatal investment is relatively low in felids compared to their substantial levels of postnatal care.
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http://dx.doi.org/10.1007/s13364-011-0066-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374089PMC
July 2012

Where species go, legal protections must follow.

Science 2008 Nov;322(5904):1049-50; author reply 1049-50

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http://dx.doi.org/10.1126/science.322.5904.1049bDOI Listing
November 2008

Prolonging the arctic pulse: long-term exploitation of cached eggs by arctic foxes when lemmings are scarce.

J Anim Ecol 2007 Sep;76(5):873-80

Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.

1. Many ecosystems are characterized by pulses of dramatically higher than normal levels of foods (pulsed resources) to which animals often respond by caching foods for future use. However, the extent to which animals use cached foods and how this varies in relation to fluctuations in other foods is poorly understood in most animals. 2. Arctic foxes Alopex lagopus (L.) cache thousands of eggs annually at large goose colonies where eggs are often superabundant during the nesting period by geese. We estimated the contribution of cached eggs to arctic fox diets in spring and autumn, when geese were not present in the study area, by comparing stable isotope ratios (delta(13)C and delta(15)N) of fox tissues with those of their foods using a multisource mixing model in Program IsoSource. 3. The contribution of cached eggs to arctic fox diets was inversely related to collared lemming Dicrostonyx groenlandicus (Traill) abundance; the contribution of cached eggs to overall fox diets increased from < 28% in years when collared lemmings were abundant to 30-74% in years when collared lemmings were scarce. 4. Further, arctic foxes used cached eggs well into the following spring (almost 1 year after eggs were acquired) - a pattern that differs from that of carnivores generally storing foods for only a few days before consumption. 5. This study showed that long-term use of eggs that were cached when geese were superabundant at the colony in summer varied with fluctuations in collared lemming abundance (a key component in arctic fox diets throughout most of their range) and suggests that cached eggs functioned as a buffer when collared lemmings were scarce.
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http://dx.doi.org/10.1111/j.1365-2656.2007.01278.xDOI Listing
September 2007
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