866 resultados para Wolf, Naomi
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Although many carnivores are of conservation concern, most are poorly studied. The maned wolf Chrysocyon brachyurus Illiger, 1811 is the largest South American canid with a broad distribution; however, the largest portion of its range is in the Brazilian Cerrado savannah, where due to intensive agricultural expansion, it is threatened by habitat loss. Maned wolf population trends are virtually unknown. We analyzed radio telemetry data from a 13-year study in Emas National Park, central Brazil, with Burnham`s live recapture/dead recovery models in the program MARK to obtain the first analytically sound estimate of the apparent maned wolf survival rate. We constructed 16 candidate models including variation in survival rate and resighting probability associated with an individual`s sex or age and year of study. Apparent adult survival rate throughout the study ranged from 0.28 (se=0.08) to 0.97 (se=0.06). There was no evidence for sex specificity but strong support for time variation. Model weights supported an age effect and the subadult survival rate was 0.63 (se=0.15). Results indicate similar life patterns for male and female maned wolves and similar mortality risks for adults and subadults in the study area. The observed temporal fluctuations of adult survival rate are important for population dynamics as they decrease average population growth rates. Population dynamics are central for conservation planning and our results are an important step towards a better understanding of the maned wolf`s ecology.
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The maned wolf (Chrysocyon brachyurus) inhabits the savannah-like Cerrado of Brazil. Although 80% of this biome has already been affected by human activity, little is known about maned wolf abundance. Using mark-recapture models, we obtained the first density estimate from central Brazil, the core of maned wolf distribution. With 5.19 individuals/100 km(2), even large reserves support only small maned wolf populations. Therefore, long-term conservation of the maned wolf depends on land management outside of reserves. ( JOURNAL OF WILDLIFE MANAGEMENT 73( 1): 68-71; 2009)
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The Desertas Islands (Madeira, Portugal) are the sole home of one of the largest and rarest wolf spiderspecies, Hogna ingens (Blackwall 1857) (Araneae, Lycosidae). Despite its size, it inhabits a single valleyin the North of the Deserta Grande Island, Vale da Castanheira, currently invaded by the herb Phalarisaquatica. This invasive species competes with the native flora and was subject to several eradicationexperiments, namely through fire and chemicals. The objectives of this work were to: (1) estimate thecurrent distribution and abundance of H. ingens and respective trends; (2) evaluate the impact of theinvasive plant and eradication methods on the spider population; (3) suggest future measures for therecovery of the species; and (4) evaluate its conservation status according to the IUCN criteria. The current distribution of H. ingens covers 23 ha, a recent reduction from its original 83 ha, correspond-ing to the entire Vale da Castanheira. A total of 4447 and 4086 adults and 71,832 and 24,635 juvenileswere estimated to live in the valley during 2011 and 2012, respectively. We found a significant negativeimpact of P. aquatica cover on the presence and abundance of H. ingens and that chemical treatmentspecifically directed towards the invasive plant species may be the only way to effectively recover thespider's habitat. We suggest (1) regular monitoring; (2) extend chemical treatments; (3) ex-situ conserva-tion with future reintroduction of adults. Based on the current area of occupancy (AOO) of H. ingens and itsrecent decline in both AOO and number of individuals, it was recently classified as Critically Endangeredby IUCN and we suggest its urgent inclusion in the Habitats Directive species lists.
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Dissertação de Doutoramento em Literatura Comparada
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The first finding of a Capillariid in the urinary tract of a free ranging maned wolf (Chrysocyon brachyurus) is described. The individual was an adult male attacked by dogs in the locality of Cayastacito (Santa Fe, Argentina, 31º05' S, 60º 34' W). Eggs found in urine measured 64.6-66.9µm (mean 65.4µm) x 26.9-31µm (mean 29µm). Further studies are needed to determine whether this finding corresponds to a new Capillariid species, related to C. brachyurus, or it is an already described species that has been introduced by domestic dogs.
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9780226519920
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Donateur : Wogan, Émile Tanneguy de (1850-1906)
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The Iberian wolf (Canis lupus) is the top predator in the Iberian environments in which it lives, feeding on a wide range of species, thus encountering a wide range of disease agents. Therefore, the wolf can serve as sentinel of environmental contamination with pathogens. We investigated the exposure of free-living wolves to 14 serovars of Leptospira interrogans sensu lato. Kidney samples from 49 wolves collected from 2010-2013 in northwestern Spain were analysed by culture, direct immunofluorescence and polymerase chain reaction. Tissue fluids were analysed for antibodies by a microscopic agglutination test. Ten wolves (observed prevalence: 20%, 95% confidence interval = 11-33%) showed evidence of contact with leptospires, eight through direct detection and nine through serology (7 wolves were positive according to both techniques). Titres below the cut-off level were also detected in seven cases. Serovars confirmed were Canicola (n = 4), Icterohaemorrhagiae (n = 3) and Sejroë, Ballum and Grippotyphosa (n = 1 each), indicating that wolves were infected with serovars for which dogs, rodents and ungulates, are the natural hosts and supporting the utility of the wolf and other large predators as environmental sentinels for pathogens.
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Wolves in Italy strongly declined in the past and were confined south of the Alps since the turn of the last century, reduced in the 1970s to approximately 100 individuals surviving in two fragmented subpopulations in the central-southern Apennines. The Italian wolves are presently expanding in the Apennines, and started to recolonize the western Alps in Italy, France and Switzerland about 16 years ago. In this study, we used a population genetic approach to elucidate some aspects of the wolf recolonization process. DNA extracted from 3068 tissue and scat samples collected in the Apennines (the source populations) and in the Alps (the colony), were genotyped at 12 microsatellite loci aiming to assess (i) the strength of the bottleneck and founder effects during the onset of colonization; (ii) the rates of gene flow between source and colony; and (iii) the minimum number of colonizers that are needed to explain the genetic variability observed in the colony. We identified a total of 435 distinct wolf genotypes, which showed that wolves in the Alps: (i) have significantly lower genetic diversity (heterozygosity, allelic richness, number of private alleles) than wolves in the Apennines; (ii) are genetically distinct using pairwise F(ST) values, population assignment test and Bayesian clustering; (iii) are not in genetic equilibrium (significant bottleneck test). Spatial autocorrelations are significant among samples separated up to c. 230 km, roughly correspondent to the apparent gap in permanent wolf presence between the Alps and north Apennines. The estimated number of first-generation migrants indicates that migration has been unidirectional and male-biased, from the Apennines to the Alps, and that wolves in southern Italy did not contribute to the Alpine population. These results suggest that: (i) the Alps were colonized by a few long-range migrating wolves originating in the north Apennine subpopulation; (ii) during the colonization process there has been a moderate bottleneck; and (iii) gene flow between sources and colonies was moderate (corresponding to 1.25-2.50 wolves per generation), despite high potential for dispersal. Bottleneck simulations showed that a total of c. 8-16 effective founders are needed to explain the genetic diversity observed in the Alps. Levels of genetic diversity in the expanding Alpine wolf population, and the permanence of genetic structuring, will depend on the future rates of gene flow among distinct wolf subpopulation fragments.