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1.
Human–bear interactions near the town of Churchill, Manitoba occur annually because the Western Hudson Bay polar bear population
spends 4–5 months on-land each year when the sea ice melts completely. Significant changes have occurred in the Hudson Bay
ecosystem and in the bear population as a result of climate warming; however, how these changes may have influenced human–bear
interactions near Churchill is unclear. This study examined the temporal and spatial patterns of 1,487 problem bears captured
in the Churchill area from 1970 to 2004. We also examined the relationship between problem bears and environmental variables
as well as the Nunavut harvest. The number of individual problem bears caught near Churchill varied from 10 to 90 individuals
per year and increased over time. Subadult males comprised 39%, subadult females 23%, adult males 18%, females with young
14%, and solitary females 6% of captures. Bears that became problem individuals were in closer proximity to the Churchill
area. Nutritional stress and a northward shift in the distribution of the bears that spend the summer on-land in northeastern
Manitoba may account for the increase in problem bear numbers. The date of sea ice freeze-up, which is getting progressively
later, was the best predictor explaining the annual variation in the occurrence of problem bears. These results provide an
understanding of how a warming climate may directly impact polar bear behaviour. This information may allow wildlife managers
to predict relative levels of human–bear interactions and thereby implement effective management strategies to improve human
safety and the conservation of polar bears. 相似文献
2.
M. DE BARBA L. P. WAITS E. O. GARTON P. GENOVESI E. RANDI A. MUSTONI C. GROFF 《Molecular ecology》2010,19(18):3938-3951
Genetic monitoring has rarely been used for wildlife translocations despite the potential benefits this approach offers, compared to traditional field‐based methods. We applied genetic monitoring to the reintroduced brown bear population in northern Italy. From 2002 to 2008, 2781 hair and faecal samples collected noninvasively plus 12 samples obtained from captured or dead bears were used to follow the demographic and geographical expansion and changes in genetic composition. Individual genotypes were used to reconstruct the wild pedigree and revealed that the population increased rapidly, from nine founders to >27 individuals in 2008 (λ = 1.17–1.19). Spatial mapping of bear samples indicated that most bears were distributed in the region surrounding the translocation site; however, individual bears were found up to 163 km away. Genetic diversity in the population was high, with expected heterozygosity of 0.74–0.79 and allelic richness of 4.55–5.41. However, multi‐year genetic monitoring data showed that mortality rates were elevated, immigration did not occur, one dominant male sired all cubs born from 2002 to 2005, genetic diversity declined, relatedness increased, inbreeding occurred, and the effective population size was extremely small (Ne = 3.03, ecological method). The comprehensive information collected through genetic monitoring is critical for implementing future conservation plans for the brown bear population in the Italian Alps. This study provides a model for other reintroduction programmes by demonstrating how genetic monitoring can be implemented to uncover aspects of the demography, ecology and genetics of small and reintroduced populations that will advance our understanding of the processes influencing their viability, evolution, and successful restoration. 相似文献
3.
Genetic diversity, structure, and size of an endangered brown bear population threatened by highway construction in the Pindos Mountains, Greece 总被引:1,自引:0,他引:1
Alexandros A. Karamanlidis Martin Straka Elena Drosopoulou Miguel de Gabriel Hernando Ivna Kocijan Ladislav Paule Zacharias Scouras 《European Journal of Wildlife Research》2012,58(3):511-522
One of the major negative effects of roads is the creation of barriers to the movement of wildlife, ultimately disconnecting populations and increasing extinction risk. We collected genetic data from a threatened brown bear population in the central part of the Pindos mountain range in northwestern Greece to provide information about this, as yet genetically undescribed, population and to evaluate its status prior to the construction of a major highway. We used noninvasive genetic sampling methods and microsatellite analysis to investigate nuclear genetic diversity, population genetic structure, demographic history, relatedness within the population and estimated effective and total population size. Brown bears in the study area were found to possess a relatively high level of nuclear genetic diversity and low levels of inbreeding; the population did not show any signs of substructuring but seems to have gone through a genetic bottleneck in the recent past. The estimated effective population size was 29, and the total population size estimate obtained by two different methods was 33 and 51 individuals, respectively. Our results indicate a good conservation status of this bear population and provide baseline genetic data for the future evaluation of the effects on bears from the construction of a major highway, for monitoring the genetic status of this and other bear populations in Greece and for assessing gene flow in bear populations in southern Europe. 相似文献
4.
Blanco Juan Carlos Ballesteros Fernando Garca-Serrano Alicia Herrero Juan Nores Carlos Palomero Guillermo 《European Journal of Wildlife Research》2011,57(3):669-673
Although brown bears (Ursus arctos) are known to be major predators of ungulates in North America and Northern Europe, there is little documentation regarding
bear predation on wild ungulates in Southern Europe. We describe search, detection, killing and prey consumption behaviour
by brown bears during seven attacks on <1-month roe deer, red deer and chamois fawns in spring in the Cantabrian Mountains,
north-western Spain. As soon as the bears detected a fawn by their smell or their mother's presence, they switched from routine
foraging on plants and insects to an intensive search for the fawns, mainly using smell to comb a 0.5–1 ha area for 15–45 min.
They killed the fawns either while the latter were resting or after a brief chase. The bears usually took their prey to dense
vegetation, consuming it immediately. In four cases, 5-month-old cubs accompanying the female did not participate in the hunt.
We also document the apparently non-predatory killing of a 40-kg wild boar by a female bear with cubs surprised by a sudden
encounter. They did not eat the boar after the attack. 相似文献
5.
Reliable population and density estimates are the cornerstone of effective conservation and management planning, as conservation priorities often arise in relation to population numbers. Despite increased public interest and costly conservation programs limited information on brown bear (Ursus arctos, Linnaeus, 1758) abundance and density in Greece exists. We carried out systematic non-invasive genetic sampling using hair traps on power poles, as part of a capture-mark-recapture study design in order to rigorously estimate abundance and density of the Pindos bear population in Greece. From 2007–2010 we identified 211 and estimated a mean of 182.3 individuals in four sampling areas; bear densities ranged from 10.0 to 54 bears/1000 km2. These results indicate an important population recovery of this large carnivore in Greece in recent years; a conservative population estimate would place the population size in the entire country >450 individuals. Considering the results of the study and the increased negative interactions between humans and bears recorded currently in Greece, we suggest that systematic genetic monitoring using power poles should continue in order to collect the necessary information that will enable the definition of an effective Action Plan for the long-term conservation of this species. 相似文献
6.
We quantified the amount, spatial distribution, and importance of salmon (Oncorhynchus spp.)-derived nitrogen (N) by brown bears (Ursus arctos) on the Kenai Peninsula, Alaska. We tested and confirmed the hypothesis that the stable isotope signature (δ15N) of N in foliage of white spruce (Picea glauca) was inversely proportional to the distance from salmon-spawning streams (r=–0.99 and P<0.05 in two separate watersheds). Locations of radio-collared brown bears, relative to their distance from a stream, were
highly correlated with δ15N depletion of foliage across the same gradient (r=–0.98 and –0.96 and P<0.05 in the same two separate watersheds). Mean rates of redistribution of salmon-derived N by adult female brown bears were
37.2±2.9 kg/year per bear (range 23.1–56.3), of which 96% (35.7±2.7 kg/year per bear) was excreted in urine, 3% (1.1±0.1 kg/year
per bear) was excreted in feces, and <1% (0.3± 0.1 kg/year per bear) was retained in the body. On an area basis, salmon-N
redistribution rates were as high as 5.1±0.7 mg/m2 per year per bear within 500 m of the stream but dropped off greatly with increasing distance. We estimated that 15.5–17.8%
of the total N in spruce foliage within 500 m of the stream was derived from salmon. Of that, bears had distributed 83–84%.
Thus, brown bears can be an important vector of salmon-derived N into riparian ecosystems, but their effects are highly variable
spatially and a function of bear density.
Received: 11 February 1999 / Accepted: 7 July 1999 相似文献
7.
In this study the distance, at which polar bears detected and actively responded to approaching snowmobiles was measured and
the behavioural response was recorded. The study was performed on Svalbard, an arctic island where human traffic has increased
substantially in recent years. Fieldwork was conduced in April and/or May during the years 2003–2005. Polar bears were observed
on ice with telescopes and binoculars. Undisturbed polar bears were observed continuously and their behaviours recorded, during
the time when two snowmobiles moved toward the bear(s). Distances between the bear, the observer, and the approaching snowmobiles
were measured using GPS positions taken on the track towards the bear. Data on the behavioural response of 20 encounters with
bears were collected. On average, bears were alerted to the snowmobiles at 1,164 m. Mean distance at which the locomotive
response occurred was 843 m, and there was a statistical significant difference in distance between sex and age classes [326 m
(95% CI = 138–496 m) for adult males; 1,534 m (95% CI = 508–2,768 m) for adult females with cubs; 164 m (95% CI = 49–543 m)
for two adult females without cubs; and 1,160 m (95% CI = 375–1,353 m) for single medium sized bears]. The responses of the
polar bears to the snowmobiles were categorized according to intensity and persistence of reactions. Females with cubs and
single medium sized bears tended to show more intense responses than adult males and lone adult females. Wind direction affects
sound and odour transmission, and although an effect on response distance was not found, the response intensity was affected
by wind direction. We conclude that female polar bears with small cubs in particular may have a greater risk to be disturbed,
since they react at greater distances with amplified reactions; thus, users of snowmobiles should take particular care in
areas where females with cubs are present. 相似文献
8.
James A. Cahill Richard E. Green Tara L. Fulton Mathias Stiller Flora Jay Nikita Ovsyanikov Rauf Salamzade John St. John Ian Stirling Montgomery Slatkin Beth Shapiro 《PLoS genetics》2013,9(3)
Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus) and brown bears (U. arctos) remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. At the center of this controversy are the Alaskan ABC Islands brown bears that show evidence of shared ancestry with polar bears. We present an analysis of genome-wide sequence data for seven polar bears, one ABC Islands brown bear, one mainland Alaskan brown bear, and a black bear (U. americanus), plus recently published datasets from other bears. Surprisingly, we find clear evidence for gene flow from polar bears into ABC Islands brown bears but no evidence of gene flow from brown bears into polar bears. Importantly, while polar bears contributed <1% of the autosomal genome of the ABC Islands brown bear, they contributed 6.5% of the X chromosome. The magnitude of sex-biased polar bear ancestry and the clear direction of gene flow suggest a model wherein the enigmatic ABC Island brown bears are the descendants of a polar bear population that was gradually converted into brown bears via male-dominated brown bear admixture. We present a model that reconciles heretofore conflicting genetic observations. We posit that the enigmatic ABC Islands brown bears derive from a population of polar bears likely stranded by the receding ice at the end of the last glacial period. Since then, male brown bear migration onto the island has gradually converted these bears into an admixed population whose phenotype and genotype are principally brown bear, except at mtDNA and X-linked loci. This process of genome erosion and conversion may be a common outcome when climate change or other forces cause a population to become isolated and then overrun by species with which it can hybridize. 相似文献
9.
Karyn D. Rode Elizabeth Peacock Mitchell Taylor Ian Stirling Erik W. Born Kristin L. Laidre Øystein Wiig 《Population Ecology》2012,54(1):3-18
One of the primary mechanisms by which sea ice loss is expected to affect polar bears is via reduced body condition and growth
resulting from reduced access to prey. To date, negative effects of sea ice loss have been documented for two of 19 recognized
populations. Effects of sea ice loss on other polar bear populations that differ in harvest rate, population density, and/or
feeding ecology have been assumed, but empirical support, especially quantitative data on population size, demography, and/or
body condition spanning two or more decades, have been lacking. We examined trends in body condition metrics of captured bears
and relationships with summertime ice concentration between 1977 and 2010 for the Baffin Bay (BB) and Davis Strait (DS) polar
bear populations. Polar bears in these regions occupy areas with annual sea ice that has decreased markedly starting in the
1990s. Despite differences in harvest rate, population density, sea ice concentration, and prey base, polar bears in both
populations exhibited positive relationships between body condition and summertime sea ice cover during the recent period
of sea ice decline. Furthermore, females and cubs exhibited relationships with sea ice that were not apparent during the earlier
period (1977–1990s) when sea ice loss did not occur. We suggest that declining body condition in BB may be a result of recent
declines in sea ice habitat. In DS, high population density and/or sea ice loss, may be responsible for the declines in body
condition. 相似文献
10.
Jeremy D. Dixon Madan K. Oli Michael C. Wooten Thomas H. Eason J. Walter McCown Mark W. Cunningham 《Conservation Genetics》2007,8(2):455-464
Habitat loss and fragmentation can influence the genetic structure of biological populations. We studied the genetic consequences
of habitat fragmentation in Florida black bear (Ursus americanus floridanus) populations. Genetic samples were collected from 339 bears, representing nine populations. Bears were genotyped for 12 microsatellite
loci to estimate genetic variation and to characterize genetic structure. None of the nine study populations deviated from
Hardy–Weinberg equilibrium. Genetic variation, quantified by mean expected heterozygosity (H
E), ranged from 0.27 to 0.71 and was substantially lower in smaller and less connected populations. High levels of genetic
differentiation among populations (global F
ST = 0.224; global R
ST = 0.245) suggest that fragmentation of once contiguous habitat has resulted in genetically distinct populations. There was
no isolation-by-distance relationship among Florida black bear populations, likely because of barriers to gene flow created
by habitat fragmentation and other anthropogenic disturbances. These factors resulted in genetic differentiation among populations,
even those that were geographically close. Population assignment tests indicated that most individuals were genetically assigned
to the population where they were sampled. Habitat fragmentation and anthropogenic barriers to movement appear to have limited
the dispersal capabilities of the Florida black bear, thereby reducing gene flow among populations. Regional corridors or
translocation of bears may be needed to restore historical levels of genetic variation. Our results suggest that management
actions to mitigate genetic consequences of habitat fragmentation are needed to ensure long-term persistence of the Florida
black bear. 相似文献
11.
Tania Lewis Gretchen Roffler Anthony Crupi Ramona Maraj Neil Barten 《Ecology and evolution》2020,10(14):7654-7668
Glacier bears are a rare grey color morph of American black bear (Ursus americanus) found only in northern Southeast Alaska and a small portion of western Canada. We examine contemporary genetic population structure of black bears within the geographic extent of glacier bears and explore how this structure relates to pelage color and landscape features of a recently glaciated and highly fragmented landscape. We used existing radiocollar data to quantify black bear home‐range size within the geographic range of glacier bears. The mean home‐range size of female black bears in the study area was 13 km2 (n = 11), whereas the home range of a single male was 86.9 km2. We genotyped 284 bears using 21 microsatellites extracted from noninvasively collected hair as well as tissue samples from harvested bears. We found ten populations of black bears in the study area, including several new populations not previously identified, divided largely by geographic features such as glaciers and marine fjords. Glacier bears were assigned to four populations found on the north and east side of Lynn Canal and the north and west side of Glacier Bay with a curious absence in the nonglaciated peninsula between. Lack of genetic relatedness and geographic continuity between black bear populations containing glacier bears suggest a possible unsampled population or an association with ice fields. Further investigation is needed to determine the genetic basis and the adaptive and evolutionary significance of the glacier bear color morph to help focus black bear conservation management to maximize and preserve genetic diversity. 相似文献
12.
We assessed the effectiveness of national and international wildlife trade regulations in Asia by surveying four wildlife
markets in Myanmar for bears and bear parts. Bears are protected in Myanmar and neighbouring countries, and are included in
CITES Appendix I, precluding international trade. Three of the four wildlife markets were situated at the border with neighbouring
countries (China and Thailand) whereas the fourth, situated in Myanmar’s interior, also catered to international markets.
During seven checks (1999–2006) we recorded 1,200 bear parts, representing a minimum of 215 individual bears. Most items were
from Asiatic black bears Ursus thibetanus but also sun bear Helarctos malayanus parts were offered for sale. There were significant temporal and spatial differences in what items were offered for sale.
Prices were low (USD 4–40 per item) and the total monetary value of the items for sale was USD 6,500–9,500 (not including
gall bladders). Carcasses, skulls, canines, paws, claws, whole skins, pieces of skin, gall bladders and derivates, were openly
displayed, with vendors being frank about prices, origin, and potential buyers. Only in the interior were prices quoted in
the local currency; at the other three markets currencies of the neighbouring countries were used. Legal (international) trade
in bears or bear parts from Myanmar is virtually non-existent, and the observed trade in bear parts strongly indicates a serious
lack of enforcement effort. International trade in bear parts from Myanmar is significant, and open, and we conclude that
the enforcement of wildlife trade regulations, at least when they concerns bear species, have by and large failed. 相似文献
13.
Integrating sign surveys and telemetry data for estimating brown bear (Ursus arctos) density in the Romanian Carpathians
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Viorel D. Popescu Ruben Iosif Mihai I. Pop Silviu Chiriac George Bouroș Brett J. Furnas 《Ecology and evolution》2017,7(18):7134-7144
Accurate population size estimates are important information for sustainable wildlife management. The Romanian Carpathians harbor the largest brown bear (Ursus arctos) population in Europe, yet current management relies on estimates of density that lack statistical oversight and ignore uncertainty deriving from track surveys. In this study, we investigate an alternative approach to estimate brown bear density using sign surveys along transects within a novel integration of occupancy models and home range methods. We performed repeated surveys along 2‐km segments of forest roads during three distinct seasons: spring 2011, fall‐winter 2011, and spring 2012, within three game management units and a Natura 2000 site. We estimated bears abundances along transects using the number of unique tracks observed per survey occasion via N‐mixture hierarchical models, which account for imperfect detection. To obtain brown bear densities, we combined these abundances with the effective sampling area of the transects, that is, estimated as a function of the median (± bootstrapped SE) of the core home range (5.58 ± 1.08 km2) based on telemetry data from 17 bears tracked for 1‐month periods overlapping our surveys windows. Our analyses yielded average brown bear densities (and 95% confidence intervals) for the three seasons of: 11.5 (7.8–15.3), 11.3 (7.4–15.2), and 12.4 (8.6–16.3) individuals/100 km2. Across game management units, mean densities ranged between 7.5 and 14.8 individuals/100 km2. Our method incorporates multiple sources of uncertainty (e.g., effective sampling area, imperfect detection) to estimate brown bear density, but the inference fundamentally relies on unmarked individuals only. While useful as a temporary approach to monitor brown bears, we urge implementing DNA capture–recapture methods regionally to inform brown bear management and recommend increasing resources for GPS collars to improve estimates of effective sampling area. 相似文献
14.
Alexandros A. Karamanlidis Aleksandar Stojanov Miguel de Gabriel Hernando Gjorge Ivanov Ivna Kocijan Dimche Melovski Tomaž Skrbinšek Andreas Zedrosser 《Acta theriologica》2014,59(1):119-128
Conservation and management of large carnivores is often hampered by the lack of information of basic biological parameters. This is particularly true for brown bears (Ursus arctos) in the Former Yugoslav Republic (FYR) of Macedonia. The bear population in this country is important, as it links bear populations of the central part of the Dinaric–Pindos population and the endangered population to the south in Greece. The aim of this study was to assess bear presence in FYR Macedonia and to provide the first evaluation of the genetic status of the species in this country. Bear presence was assessed through a questionnaire and sign surveys, while the genetic status of the species was evaluated through noninvasive genetic sampling from power poles and microsatellite analysis. The results of the study indicate the continuous and permanent presence of brown bears in FYR Macedonia from the border to Kosovo in the northwest, along the border to Albania and Greece in the south; bear presence around Mount Ko?uf in the south of the country was seasonal. High levels of genetic diversity were recorded, and it appears that this bear population is currently not threatened by low genetic variability. Cross-border movements of bears between FYR Macedonia and Greece were documented, indicating the presence of an interconnected population and outlining the necessity for a coordinated international approach in the monitoring and conservation of the species in southeastern Europe. 相似文献
15.
《Mammalian Biology》2014,79(4):268-276
The Balkans are one of the last large refugia for brown bear (Ursus arctos) populations in Europe, and Bulgaria, in particular, contains relatively large areas of suitable brown bear habitat and a potential population of more than 600 individuals. Despite this, the majority of brown bear research remains focused on bear populations in Central and Western Europe. We provide the first assessment of genetic population structure of brown bears in Bulgaria by analysing tissue samples (n = 16) as well as samples collected with noninvasive genetic methods, including hair and faecal samples (n = 189 and n = 163, respectively). Sequence analysis of a 248 base pair fragment of the mitochondrial control region showed that two highly divergent mitochondrial European brown bear lineages form a contact zone in central Bulgaria. Furthermore, the analysis of 13 polymorphic microsatellite markers identified 136 individuals and found substantial genetic variability (He = 0.74; NA = 8.9). The combination of both genetic markers revealed the presence of weak genetic substructure in the study area with considerable degrees of genetic admixture and the likely presence of migration corridors between the two subpopulation in the Rhodope Mountains and Stara Planina as evidenced from the genetic detection of two male long-distance dispersers. A detailed assessment from densely collected samples in the Rhodope Mountains resulted in a population size estimate of 315 (95% CI = 206–334) individuals, indicating that not all available habitat is presently occupied by bears in this region. Efficient management plans should focus on preserving connectivity of suitable habitats in order to maintain gene flow between the two Bulgarian brown bear subpopulations. 相似文献
16.
Han-Chan Park Tae-Yuen Han Du-Chan Kim Mi-Sook Min Sung-Yong Han Kyung-Seok Kim Hang Lee 《Genes & genomics.》2011,33(6):653-657
The Eurasian otter, Lutra lutra, is a well known endangered species in South Korea that experienced rapid population decreases through poaching and industrialization until the 1980’s. To evaluate the genetic diversity and the existing number of otters recently found in Daegu City, 81 fecal samples collected from the Gumho River and Shincheon stream were subjected to DNA extraction for sex determination and genetic analysis using nuclear genetic markers. Individual identification and relatedness between individuals were detemined by genotypic data using twelve microsatellite loci, and sex identification was also determined based on sequence variation of the zinc finger protein gene on sex chromosomes. Our results showed that at least seven otter individuals were identified and the kinship relationships of seven individual pairs were determined. It was concluded that otters distributed widely in Daegu City have moderate levels of genetic diversity, and close monitoring of the small-sized otter population is necessary to promote successful settlement of the otters in the area. 相似文献
17.
Klemen Jerina Marko Jonozovič Miha Krofel Tomaž Skrbinšek 《European Journal of Wildlife Research》2013,59(4):459-467
Solid understanding of species’ range and local population densities is important for successful wildlife management and research. Specific behavioral and ecological characteristics make brown bear Ursus arctos a difficult species to study. We present a map of range and local population densities of brown bears in Slovenia, made with the use of a new approach similar to voting classifications based on a combination of four datasets: Global Positioning System telemetry data, records of bear removals, systematic and opportunistic direct observations and signs of bear presence, and noninvasive genetic samples. Results indicate that the majority of bears in Slovenia live in Dinaric Mountains in the southern part of the country where local bear population densities exceed 40 bears/100 km2. This is one of the highest population densities reported so far for this species worldwide. Population densities decrease towards the north (Alpine region) and are very low along the border with Italy and Austria where almost no females are present. This explains slow past and present expansion of this transboundary bear population into the Alps and should be considered in future bear re-colonization management strategies. Results also showed that data from observations and removals overestimate bear population densities at low values, while mortality and genetic data overestimate population densities in areas with more people. Nevertheless, all data types appeared useful for describing the general bear distribution patterns. Similar approach could be applied to studies of other charismatic or game species, for which several types of data are often available. 相似文献
18.
Kim YK Hong YJ Min MS Kim KS Kim YJ Voloshina I Myslenkov A Smith GJ Cuong ND Tho HH Han SH Yang DH Kim CB Lee H 《The Journal of heredity》2011,102(2):165-174
The Asiatic black bear is one of the most endangered mammals in South Korea owing to population declines resulting from human exploitation and habitat fragmentation. To restore the black bear population in South Korea, 27 bear cubs from North Korea and Russian Far East (Primorsky Krai) were imported and released into Jirisan National Park, a reservoir of the largest wild population in South Korea, in 2004. To monitor the success of this reintroduction, the genetic diversity and population structure of the reintroduced black bears were measured using both mitochondrial and nuclear DNA markers. Mitochondrial D-loop region DNA sequences (615 bp) of 43 Japanese black bears from previous study and 14 Southeast Asian black bears in this study were employed to obtain phylogenetic inference of the reintroduced black bears. The mitochondrial phylogeny indicated Asiatic black bear populations from Russian Far East and North Korea form a single evolutionary unit distinct from populations from Japan and Southeast Asia. Mean expected heterozygosity (H(E)) across 16 microsatellite loci was 0.648 for Russian and 0.676 for North Korean populations. There was a moderate but significant level of microsatellite differentiation (F(ST) = 0.063) between black bears from the 2 source areas. In addition, genetic evidences revealed that 2 populations are represented as diverging groups, with lingering genetic admixture among individuals of 2 source populations. Relatedness analysis based on genetic markers indicated several discrepancies with the pedigree records. Implication of the phylogenetic and genetic evidences on long-term management of Asiatic black bears in South Korea is discussed. 相似文献
19.
S. V. Puchkovskiy M. S. Buinovskaya D. K. Voronetskaya G. V. Neustroev 《Contemporary Problems of Ecology》2012,5(1):104-109
Original data on the diameter of bear trees and trees in the stand were collected during the years 2002–2009 at the Upper
Pechora and in the Western Sayan. The data were processed using the two-sample Student’s test and correlation analysis. Comparison
was based on the published data on the thickness of bear trees. Brown bears use the trees 2 to 89 cm in diameter for marking.
As a rule bear trees exceed the trees of the stand in the average diameter that proves that bears select trees with larger
diameter for marking. 相似文献
20.
Cassandra M. Kirk Steven Amstrup Rhonda Swor Darce Holcomb Todd M. O’Hara 《EcoHealth》2010,7(3):307-320
Arctic temperatures are increasing in response to greenhouse gas forcing and polar bears have already responded to changing
conditions. Declines in body stature and vital rates have been linked to warming-induced loss of sea-ice. As food webs change
and human activities respond to a milder Arctic, exposure of polar bears and other arctic marine organisms to infectious agents
may increase. Because of the polar bear’s status as arctic ecosystem sentinel, polar bear health could provide an index of
changing pathogen occurrence throughout the Arctic, however, exposure and monitoring protocols have yet to be established.
We examine prevalence of antibodies to Toxoplasma gondii, and four morbilliviruses (canine distemper [CDV], phocine distemper [PDV], dolphin morbillivirus [DMV], porpoise morbillivirus
[PMV]) including risk factors for exposure. We also examine the relationships between antibody levels and hematologic values
established in the previous companion article. Antibodies to Toxoplasma gondii and morbilliviruses were found in both sample years. We found a significant inverse relationship between CDV titer and total
leukocytes, neutrophils, monocytes, and eosinophils, and a significant positive relationship between eosinophils and Toxoplasma gondii antibodies. Morbilliviral prevalence varied significantly among age cohorts, with 1–2 year olds least likely to be seropositive
and bears aged 5–7 most likely. Data suggest that the presence of CDV and Toxoplasma gondii antibodies is associated with polar bear hematologic values. We conclude that exposure to CDV-like antigen is not randomly
distributed among age classes and suggest that differing behaviors among life history stages may drive probability of specific
antibody presence. 相似文献