Publications by authors named "Ray T Alisauskas"

23 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%).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7589/JWD-D-21-00071DOI Listing
November 2021

Plasticity in timing of avian breeding in response to spring temperature differs between early and late nesting species.

Sci Rep 2021 03 8;11(1):5410. Epub 2021 Mar 8.

Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 2E5, Canada.

Plasticity for breeding dates may influence population vulnerability to climate change via phenological mismatch between an organism's life cycle requirements and resource availability in occupied environments. Some life history traits may constrain plasticity, however there have been remarkably few comparisons of how closely-related species, differing in key traits, respond to common phenology gradients. We compared population- and individual-level plasticity in clutch initiation dates (CID) in response to spring temperature among five duck species with early- to late-season nesting life histories. Plasticity was strongest in females of the earliest breeding species (common goldeneye [Bucephala clangula], mallard [Anas platyrhynchos], and gadwall [Mareca strepera]), whereas late-nesting lesser scaup (Aythya affinis) and white-winged scoter (Melanitta fusca deglandi) did not respond. These results contrast with previous work in other bird families that suggested late-breeders are generally more flexible. Nevertheless, late-breeding species exhibited annual variation in mean CID, suggesting response to other environmental factors unrelated to spring temperature. Goldeneye and gadwall females varied in their strength of individual plasticity ('individual × environment' interactions) and goldeneye and scoter females showed evidence of interannual repeatability of CID. Fitness consequences of CID plasticity in response to spring phenology, including trophic mechanisms and population consequences, warrant investigation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-84160-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7940653PMC
March 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13071-020-04344-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7490881PMC
September 2020

Assessing bias in demographic estimates from joint live and dead encounter models.

PeerJ 2020 23;8:e9382. Epub 2020 Jun 23.

Science and Technology Branch, Prairie and Northern Wildlife Research Centre, Environment and Climate Change Canada, Saskatoon, SK, Canada.

Joint encounter (JE) models estimate demographic rates using live recapture and dead recovery data. The extent to which limited recapture or recovery data can hinder estimation in JE models is not completely understood. Yet limited data are common in ecological research. We designed a series of simulations using Bayesian multistate JE models that spanned a large range of potential recapture probabilities (0.01-0.90) and two reported mortality probabilities (0.10, 0.19). We calculated bias by comparing estimates against known probabilities of survival, fidelity and reported mortality. We explored whether sparse data (i.e., recapture probabilities <0.02) compromised inference about survival by comparing estimates from dead recovery (DR) and JE models using an 18-year data set from a migratory bird, the lesser snow goose (). Our simulations showed that bias in probabilities of survival, fidelity and reported mortality was relatively low across a large range of recapture probabilities, except when recapture and reported mortality probabilities were both lowest. While bias in fidelity probability was similar across all recapture probabilities, the root mean square error declined substantially with increased recapture probabilities for reported mortality probabilities of 0.10 or 0.19, as expected. In our case study, annual survival probabilities for adult female snow geese were similar whether estimated with JE or DR models, but more precise from JE models than those from DR models. Thus, our simulated and empirical data suggest acceptably minimal bias in survival, fidelity or reported mortality probabilities estimated from JE models. Even a small amount of recapture information provided adequate structure for JE models, except when reported mortality probabilities were <0.10. Thus, practitioners with limited recapture data should not be discouraged from use of JE models. We recommend that ecologists incorporate other data types as frequently as analytically possible, since precision of focal parameters is improved, and additional parameters of interest can be estimated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7717/peerj.9382DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7319022PMC
June 2020

Effects of distance on detectability of Arctic waterfowl using double-observer sampling during helicopter surveys.

Ecol Evol 2019 Jan 5;9(2):859-867. Epub 2019 Feb 5.

Marine Mammal Laboratory, Alaska Fisheries Science Center National Marine Fisheries Service, NOAA Seattle Washington.

Aerial survey is an important, widely employed approach for estimating free-ranging wildlife over large or inaccessible study areas. We studied how a distance covariate influenced probability of double-observer detections for birds counted during a helicopter survey in Canada's central Arctic. Two observers, one behind the other but visually obscured from each other, counted birds in an incompletely shared field of view to a distance of 200 m. Each observer assigned detections to one of five 40-m distance bins, guided by semi-transparent marks on aircraft windows. Detections were recorded with distance bin, taxonomic group, wing-flapping behavior, and group size. We compared two general model-based estimation approaches pertinent to sampling wildlife under such situations. One was based on double-observer methods without distance information, that provide sampling analogous to that required for mark-recapture (MR) estimation of detection probability, , and group abundance, , along a fixed-width strip transect. The other method incorporated double-observer MR with a categorical distance covariate (MRD). A priori, we were concerned that estimators from MR models were compromised by heterogeneity in due to un-modeled distance information; that is, more distant birds are less likely to be detected by both observers, with the predicted effect that would be biased high, and biased low. We found that, despite increased complexity, MRD models (ΔAICc range: 0-16) fit data far better than MR models (ΔAICc range: 204-258). However, contrary to expectation, the more naïve MR estimators of were biased low in all cases, but only by 2%-5% in most cases. We suspect that this apparently anomalous finding was the result of specific limitations to, and trade-offs in, visibility by observers on the survey platform used. While MR models provided acceptable point estimates of group abundance, their far higher stranded errors (0%-40%) compared to MRD estimates would compromise ability to detect temporal or spatial differences in abundance. Given improved precision of MRD models relative to MR models, and the possibility of bias when using MR methods from other survey platforms, we recommend avian ecologists use MRD protocols and estimation procedures when surveying Arctic bird populations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ece3.4824DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6362609PMC
January 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7589/2018-06-144DOI Listing
July 2019

Decadal declines in avian herbivore reproduction: density-dependent nutrition and phenological mismatch in the Arctic.

Ecology 2017 Jul;98(7):1869-1883

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

A full understanding of population dynamics depends not only on estimation of mechanistic contributions of recruitment and survival, but also knowledge about the ecological processes that drive each of these vital rates. The process of recruitment in particular may be protracted over several years, and can depend on numerous ecological complexities until sexually mature adulthood is attained. We addressed long-term declines (23 breeding seasons, 1992-2014) in the per capita production of young by both Ross's Geese (Chen rossii) and Lesser Snow Geese (Chen caerulescens caerulescens) nesting at Karrak Lake in Canada's central Arctic. During this period, there was a contemporaneous increase from 0.4 to 1.1 million adults nesting at this colony. We evaluated whether (1) density-dependent nutritional deficiencies of pre-breeding females or (2) phenological mismatch between peak gosling hatch and peak forage quality, inferred from NDVI on the brood-rearing areas, may have been behind decadal declines in the per capita production of goslings. We found that, in years when pre-breeding females arrived to the nesting grounds with diminished nutrient reserves, the proportional composition of young during brood-rearing was reduced for both species. Furthermore, increased mismatch between peak gosling hatch and peak forage quality contributed additively to further declines in gosling production, in addition to declines caused by delayed nesting with associated subsequent negative effects on clutch size and nest success. The degree of mismatch increased over the course of our study because of advanced vegetation phenology without a corresponding advance in Goose nesting phenology. Vegetation phenology was significantly earlier in years with warm surface air temperatures measured in spring (i.e., 25 May-30 June). We suggest that both increased phenological mismatch and reduced nutritional condition of arriving females were behind declines in population-level recruitment, leading to the recent attenuation in population growth of Snow Geese.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ecy.1856DOI Listing
July 2017

Lesser snow goose helminths show recurring and positive parasite infection-diversity relations.

Int J Parasitol Parasites Wildl 2017 Apr 3;6(1):22-28. Epub 2017 Feb 3.

Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S-5B6, Canada.

The patterns and mechanisms by which biological diversity is associated with parasite infection risk are important to study because of their potential implications for wildlife population's conservation and management. Almost all research in this area has focused on host species diversity and has neglected parasite diversity, despite evidence that parasites are important drivers of community structure and ecosystem processes. Here, we assessed whether presence or abundance of each of nine helminth species parasitizing lesser snow geese () was associated with indices of parasite diversity (i.e. species richness and Shannon's Diversity Index). We found repeated instances of focal parasite presence and abundance having significant positive co-variation with diversity measures of other parasites. These results occurred both within individual samples and for combinations of all samples. Whereas host condition and parasite facilitation could be drivers of the patterns we observed, other host- or parasite-level effects, such as age or sex class of host or taxon of parasite, were discounted as explanatory variables. Our findings of recurring and positive associations between focal parasite abundance and diversity underscore the importance of moving beyond pairwise species interactions and contexts, and of including the oft-neglected parasite species diversity in infection-diversity studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijppaw.2017.01.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5312511PMC
April 2017

Multi-scale occupancy approach to estimate Toxoplasma gondii prevalence and detection probability in tissues: an application and guide for field sampling.

Int J Parasitol 2016 08 4;46(9):563-70. Epub 2016 May 4.

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

Increasingly, birds are recognised as important hosts for the ubiquitous parasite Toxoplasma gondii, although little experimental evidence exists to determine which tissues should be tested to maximise the detection probability of T. gondii. Also, Arctic-nesting geese are suspected to be important sources of T. gondii in terrestrial Arctic ecosystems, but the parasite has not previously been reported in the tissues of these geese. Using a domestic goose model, we applied a multi-scale occupancy framework to demonstrate that the probability of detection of T. gondii was highest in the brain (0.689, 95% confidence interval=0.486, 0.839) and the heart (0.809, 95% confidence interval=0.693, 0.888). Inoculated geese had an estimated T. gondii infection probability of 0.849, (95% confidence interval=0.643, 0.946), highlighting uncertainty in the system, even under experimental conditions. Guided by these results, we tested the brains and hearts of wild Ross's Geese (Chen rossii, n=50) and Lesser Snow Geese (Chen caerulescens, n=50) from Karrak Lake, Nunavut, Canada. We detected 51 suspected positive tissue samples from 33 wild geese using real-time PCR with melt-curve analysis. The wild goose prevalence estimates generated by our multi-scale occupancy analysis were higher than the naïve estimates of prevalence, indicating that multiple PCR repetitions on the same organs and testing more than one organ could improve T. gondii detection. Genetic characterisation revealed Type III T. gondii alleles in six wild geese and Sarcocystis spp. in 25 samples. Our study demonstrates that Arctic nesting geese are capable of harbouring T. gondii in their tissues and could transport the parasite from their southern overwintering grounds into the Arctic region. We demonstrate how a multi-scale occupancy framework can be used in a domestic animal model to guide resource-limited sample collection and tissue analysis in wildlife. Secondly, we confirm the value of traditional occupancy in optimising T. gondii detection probability in tissue samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijpara.2016.04.003DOI Listing
August 2016

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7589/2015-03-075DOI Listing
January 2016

Vector-borne pathogens in arctic foxes, Vulpes lagopus, from Canada.

Res Vet Sci 2015 Apr 16;99:58-9. Epub 2014 Dec 16.

Intracellular Pathogens Research Laboratory (IPRL), Center for Comparative Medicine and Translational Research College of Veterinary Medicine, North Carolina State University, NC, USA. Electronic address:

Because of the relatively low biodiversity within arctic ecosystems, arctic foxes, Vulpes lagopus, could serve as sentinels for the study of changes in the ecology of vector-borne zoonotic pathogens. The objective of this study was to determine the molecular prevalence of 5 different genera of vector borne pathogens (Anaplasma, Babesia, Bartonella, Ehrlichia, and Hemotropic Mycoplasma spp.) using blood collected from 28 live-trapped arctic foxes from the region of Karrak Lake, Nunavut, Canada. Bartonella henselae (n = 3), Mycoplasma haemocanis (n = 1), Ehrlichia canis (n = 1), and an Anaplasma sp. (n = 1) DNA were PCR amplified and subsequently identified by sequencing. This study provides preliminary evidence that vector borne pathogens, not typically associated with the arctic ecosystem, exist at low levels in this arctic fox population, and that vector exposure, pathogen transmission dynamics, and changes in the geographic distribution of pathogens over time should be investigated in future studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rvsc.2014.12.011DOI Listing
April 2015

Toxoplasma gondii exposure in arctic-nesting geese: A multi-state occupancy framework and comparison of serological assays.

Int J Parasitol Parasites Wildl 2014 Aug 30;3(2):147-53. Epub 2014 Jun 30.

Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N5B4, Canada.

The zoonotic parasite, Toxoplasma gondii, has a worldwide distribution and a cosmopolitan suite of hosts. In arctic tundra regions, the definitive felid hosts are rare to absent and, while the complete transmission routes in such regions have yet to be fully elucidated, trophic and vertical routes are likely to be important. Wild birds are common intermediate hosts of T. gondii, and in the central Canadian arctic, geese are probable vectors of the parasite from temperate latitudes to the arctic regions. Our objective was to estimate seroprevalence of T. gondii in Ross's and Lesser Snow Geese from the Karrak Lake ecosystem in Nunavut, Canada. After harvesting geese by shotgun, we collected blood on filter paper strips and tested the eluate for T. gondii antibodies by indirect fluorescent antibody test (IFAT) and direct agglutination test (DAT). We estimated seroprevalence using a multi-state occupancy model, which reduced bias by accounting for imperfect detection, and compared these estimates to a naïve estimator. Ross's Geese had a 0.39 probability of seropositivity, while for Lesser Snow Geese the probability of positive for T. gondii antibodies was 0.36. IFAT had a higher antibody detection probability than DAT, but IFAT also had a higher probability of yielding ambiguous or unclassifiable results. The results of this study indicate that Ross's Geese and Lesser Snow Geese migrating to the Karrak Lake region of Nunavut are routinely exposed to T. gondii at some point in their lives and that they are likely intermediate hosts of the parasite. Also, we were able to enhance our estimation of T. gondii seroprevalence by using an occupancy approach that accounted for both false-negative and false-positive detections and by using multiple diagnostic tests in the absence of a gold standard serological assay for wild geese.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijppaw.2014.05.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4142267PMC
August 2014

Lincoln estimates of mallard (Anas platyrhynchos) abundance in North America.

Ecol Evol 2014 Jan 18;4(2):132-43. Epub 2013 Dec 18.

Department of Environment and Resource Sciences, University of Nevada Reno, Nevada, USA.

Estimates of range-wide abundance, harvest, and harvest rate are fundamental for sound inferences about the role of exploitation in the dynamics of free-ranging wildlife populations, but reliability of existing survey methods for abundance estimation is rarely assessed using alternative approaches. North American mallard populations have been surveyed each spring since 1955 using internationally coordinated aerial surveys, but population size can also be estimated with Lincoln's method using banding and harvest data. We estimated late summer population size of adult and juvenile male and female mallards in western, midcontinent, and eastern North America using Lincoln's method of dividing (i) total estimated harvest, [Formula: see text], by estimated harvest rate, [Formula: see text], calculated as (ii) direct band recovery rate, [Formula: see text], divided by the (iii) band reporting rate, [Formula: see text]. Our goal was to compare estimates based on Lincoln's method with traditional estimates based on aerial surveys. Lincoln estimates of adult males and females alive in the period June-September were 4.0 (range: 2.5-5.9), 1.8 (range: 0.6-3.0), and 1.8 (range: 1.3-2.7) times larger than respective aerial survey estimates for the western, midcontinent, and eastern mallard populations, and the two population estimates were only modestly correlated with each other (western: r = 0.70, 1993-2011; midcontinent: r = 0.54, 1961-2011; eastern: r = 0.50, 1993-2011). Higher Lincoln estimates are predictable given that the geographic scope of inference from Lincoln estimates is the entire population range, whereas sampling frames for aerial surveys are incomplete. Although each estimation method has a number of important potential biases, our review suggests that underestimation of total population size by aerial surveys is the most likely explanation. In addition to providing measures of total abundance, Lincoln's method provides estimates of fecundity and population sex ratio and could be used in integrated population models to provide greater insights about population dynamics and management of North American mallards and most other harvested species.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ece3.906DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3925377PMC
January 2014

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijppaw.2013.02.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3862500PMC
December 2013

Associations between body composition and helminths of lesser snow geese during winter and spring migration.

Int J Parasitol 2012 Jul 17;42(8):755-60. Epub 2012 Jun 17.

Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada B4P 2R6.

Costs of parasitism are predicted to be higher with greater parasite intensities and higher inter-parasite competition (diversity). We tested whether greater helminth intensities and diversity were associated with poorer body composition (whole-body fat, protein, mineral and true body mass) in lesser snow geese, Chen caerulescens caerulescens. As part of a larger study on nutritional ecology, 828 wintering or migrating geese were shot between January and May 1983 in 27 different date-locations (samples) during their northward migration through mid-continental North America. A large proportion of overall variation in body composition and parasite communities was among samples, so we analyzed data within each of the 27 samples, controlling for structural body size (the first principal component of 10 body size measurements), sex and the age of geese. There was no compelling evidence that cestodes, trematodes or helminth diversity were associated with variation in body composition but nematodes had several negative associations with fat reserves. However, negative associations between fat reserves and nematodes occurred most often in geese collected between March and May when nematode prevalences and intensities were relatively low. This suggests several possibilities: that the most common nematodes (Heterakis dispar and Trichostrongylus tenuis) were more virulent at this time, that infected individuals had been chronically infected and suffered cumulative nutrient deficits that lasted until late in the spring migration, or that geese became more vulnerable to the effects of parasites at this time of year, possibly because they redirected resources away from immunity toward fat storage in preparation for reproduction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijpara.2012.05.008DOI Listing
July 2012

Description of the larva of Ceratophyllus vagabundus vagabundus (Siphonaptera:Ceratophyllidae) from nests of Ross's and lesser snow geese in Nunavut, Canada.

J Parasitol 2011 Apr 19;97(2):218-20. Epub 2010 Nov 19.

Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada.

Adults of the flea, Ceratophyllus vagabundus vagabundus , were present in the hundreds in nests of Ross's (Chen rossii) and lesser snow (Chen caerulescens caerulescens) geese in the Arctic goose colony at Karrak Lake, Nunavut, Canada. Ceratophyllus v. vagabundus had not been previously recorded in association with Ross's or snow geese. Large numbers of C. v. vagabundus adults and larvae were collected and a description of the larva is provided for the first time. On the basis of external characters, larvae were indistinguishable from those of a number of other Ceratophyllus spp. previously described from North America, i.e., Ceratophyllus idius, Ceratophyllus niger, and Ceratophyllus lari.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1645/GE-2580.1DOI Listing
April 2011

Evidence of weak contaminant-related oxidative stress in glaucous gulls (Larus hyperboreus) from the Canadian Arctic.

J Toxicol Environ Health A 2010 ;73(15):1058-73

Environment Canada, Prairie & Northern Wildlife Research Centre, 115 Perimeter Rd., Saskatoon, SK, S7N 0X4, Canada.

Environmental contaminants are transported over great distances to Arctic ecosystems, where they can accumulate in wildlife. Whether contaminant concentrations in wildlife are sufficient to produce adverse effects remains poorly understood. Exposure to contaminants elevates oxidative stress with possible fitness consequences. The glaucous gull (Larus hyperboreus), an Arctic top predator, was used as a bioindicator for investigating relationships between contaminant levels (organochlorines and polychlorinated biphenyls [OC/PCB], mercury [Hg], and selenium [Se]) and measures of oxidative stress (glutathione [GSH] metabolism and lipid peroxidation) in Canadian Arctic ecosystems. Contaminant levels were low and associations between contaminant exposure and oxidative stress were weak. Nevertheless, glutathione peroxidase activity rose with increasing hepatic Se concentrations, levels of thiols declined as Hg and OC/PCB levels rose, and at one of the two study sites levels of lipid peroxidation were elevated with increasing levels of hepatic Hg. These results suggest the possibility of a deleterious effect of exposure to contaminants on gull physiology even at low contaminant exposures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/15287394.2010.481619DOI Listing
June 2010

Trace element concentrations in blood of nesting king eiders in the canadian arctic.

Arch Environ Contam Toxicol 2008 Nov 21;55(4):683-90. Epub 2008 Feb 21.

Environment Canada, Prairie & Northern Region, 115 Perimeter Rd, S7N 0X4, Saskatoon, SK, Canada.

The king eider (Somateria spectabilis) is a migratory species of sea duck whose North American population is thought to be declining. We determined levels of cadmium, lead, selenium, and mercury in blood from female king eiders nesting in the central Canadian Arctic from 2001 to 2003. Year-to-year repeatability estimates were calculated from birds sampled in 2 or 3 years. Repeatability coefficients were 0.45, 0.35, 0.58, and 0.25 for cadmium, lead, selenium, and mercury, respectively. The first three were significantly different from zero (p < 0.05), whereas the last approached significance (0.05 < p < 0.1). In 2001 and 2002, we also identified probable wintering locations of a subset of the birds. In both years, cadmium levels were higher and selenium levels were lower in birds inferred to have wintered in the eastern part of their range compared to those that had wintered in the west. There was little evidence that timing of breeding, timing of sampling, or body condition were related to levels of these trace elements, although in 1 of 2 years, lead levels were influenced by body condition and nest initiation date (R(2) = 0.24) and cadmium levels were related to incubation day (partial R(2) = 0.04). Year-to-year repeatability of cadmium and selenium levels among individuals in this population of king eiders was likely influenced by where they wintered.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00244-008-9142-5DOI Listing
November 2008

Survival rates and blood metal concentrations in two species of free-ranging North American sea ducks.

Environ Toxicol Chem 2008 Mar;27(3):698-704

Environment Canada, Saskatoon, Saskatchewan, Canada.

Populations of several species of North American sea ducks have declined in the past few decades. Exposure to environmental contaminants, particularly metals, has been proposed as one of many possible factors contributing to these declines. Population dynamics are influenced by survival rates and breeding effort. In the present study, we examined the relationships between blood metal concentrations (Cd, Pb, Se, and Hg) and apparent annual survival and recapture probabilities (the latter as a surrogate for breeding effort) in adult females of two sea duck species, the king eider (Somateria spectabilis) and the white-winged scoter (Melanitta fusca), both of which have experienced declines in continental population during in recent years. No support was found for the hypothesis that exposure of white-winged scoters to these metals or of king eiders to Cd, Se, and Pb adversely affected probabilities of apparent annual survival. We detected a weak negative relationship (beta = -0.833) between Hg and annual survival of king eiders, but the 90% confidence interval of the slope estimate overlapped zero (-2.439 to +0.672). Recapture probabilities were unrelated to concentrations of Cd, Se, and Pb in either species. Evidence indicated that Hg concentrations affected recapture probability in white-winged scoters (beta = -194.77; 90% confidence interval, -203.770 to -185.778). Mercury levels were low in both species, and blood samples may not adequately represent long-term exposure to Hg. Therefore, conclusions regarding Hg effects on these birds should be considered with caution.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1897/07-321.1DOI Listing
March 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1365-2656.2007.01278.xDOI Listing
September 2007

Do geese fully develop brood patches? A histological analysis of lesser snow geese (Chen caerulescens caerulescens) and Ross's geese (C. rossii).

J Comp Physiol B 2006 Jun 24;176(5):453-62. Epub 2006 Jan 24.

School of Renewable Natural Resources, Louisiana State University, Baton Rouge, LA 70803, USA.

Most birds develop brood patches before incubation; epidermis and dermis in the brood patch region thicken, and the dermal connective tissue becomes increasingly vascularized and infiltrated by leukocytes. However, current dogma states that waterfowl incubate without modifications of skin within the brood patch region. The incubation periods of lesser snow geese (Chen caerulescens caerulescens; hereafter called snow geese) and Ross's geese (C. rossii) are 2-6 days shorter than those of other goose species; only females incubate. Thus, we hypothesized that such short incubation periods would require fully developed brood patches for sufficient heat transfer from incubating parents to eggs. We tested this hypothesis by analyzing the skin histology of abdominal regions of snow and Ross's geese collected at Karrak Lake, Nunavut, Canada. For female snow geese, we found that epidermis and dermis had thickened and vascularization of dermis was 14 times greater, on average, than that observed in males (n=5 pairs). Our results for Ross's geese (n=5 pairs) were more variable, wherein only one of five female Ross's geese fully developed a brood patch. Our results are consistent with three hypotheses about brood patch development and its relationship with different energetic cost-benefit relationships, resulting from differences in embryonic development and body size.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00360-006-0066-yDOI Listing
June 2006

Foraging time and dietary intake by breeding Ross's and Lesser Snow Geese.

Oecologia 2001 Mar 1;127(1):78-86. Epub 2001 Mar 1.

Department of Biology, University of Saskatchewan, 112 Science Place, S7 N 5E2, Saskatoon, SK, Canada.

We compared foraging times of female Ross's (Chen rossii) and Lesser Snow Geese (Chen caerulescens caerulescens) breeding at Karrak Lake, NT, Canada and examined variation due to time of day and reproductive stage. We subsequently collected female geese that had foraged for known duration and we estimated mass of foods consumed during foraging bouts. Female Ross's Geese spent more time foraging (mean % ± SE =28.4±1.3%; P=0.0002), on average, than did female Lesser Snow Geese (21.5 ± 1.4%). Foraging time by female geese differed among reproductive stages, but differences were not consistent among time periods (stage-by-time block interaction, P=0.0003). Females spent considerably more time foraging during prelaying and laying than during incubation. Ross's Geese also spent a greater percent of time feeding (83.0±2.8%) during incubation recesses than did Lesser Snow Geese (60.9±3.6%). Consumption of organic matter during foraging bouts was minimal; estimated consumption averaged 9.6±4.0 and 12.4±4.6 g (mean ± SE) dry mass/day before incubation and 5.9±2.0 and 5.7±2.1 g dry mass/day during incubation for Lesser Snow and Ross's Geese, respectively. Diets consisted primarily of mosses (bryophytes), Chickweed (Stellaria spp.) and Sedges (Carex spp.). Before incubation, eggshell consumption was estimated as 4.3±3.2 and 0.4±0.3 g dry mass/day for Lesser Snow and Ross's Geese, respectively; neither species consumed eggshell during incubation. We conclude that eggshell from nests of previous years is likely an important source of dietary calcium used to meet mineral demands of eggshell formation at Karrak Lake. Our findings of wide disparities between foraging time and food intake indicate that results from studies that do not directly measure intake rates remain equivocal. Finally, we propose four hypotheses accounting for foraging effort that evidently yields little nutritional or energetic benefit to geese nesting at Karrak Lake.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s004420000577DOI Listing
March 2001

MATRIARCHAL POPULATION GENETIC STRUCTURE IN AN AVIAN SPECIES WITH FEMALE NATAL PHILOPATRY.

Evolution 1992 Aug;46(4):1084-1096

Department of Zoology, University of Western Ontario, London, Ontario, N6A 5B7, CANADA.

We employ mitochondrial (mt) DNA markers to examine the matrilineal component of population genetic structure in the snow goose Chen caerulescens. From banding returns, it is known that females typically nest at their natal or prior nest site, whereas males pair with females on mixed wintering grounds and mediate considerable nuclear gene flow between geographically separate breeding colonies. Despite site philopatry documented for females, mtDNA markers show no clear distinctions between nesting populations across the species' range from Wrangel Island, USSR to Baffin Island in the eastern Canadian Arctic. Two major mtDNA clades (as well as rare haplotypes) are distributed widely and provide one of the few available examples of a phylogeographic pattern in which phylogenetic discontinuity in a gene tree exists without obvious geographic localization within a species' range. The major mtDNA clades may have differentiated in Pleistocene refugia, and colonized current nesting sites through recent range expansion via pulsed or continual low-level dispersal by females. The contrast between results of banding returns and mtDNA distributions in the snow goose raises general issues regarding population structure: direct contemporary observations on dispersal and gene flow can in some cases convey a misleading impression of phylogeographic population structure, because they fail to access the evolutionary component of population connectedness; conversely, geographic distributions of genetic markers can provide a misleading impression of contemporary dispersal and gene flow because they retain a record of evolutionary events and past demographic parameters that may differ from those of the present. An understanding of population structure requires integration of both evolutionary (genetic) and contemporary (direct observational) perspectives.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1558-5646.1992.tb00621.xDOI Listing
August 1992
-->