Among the four African otter species, the Congo clawless otter (Aonyx congicus) is the least known due to the remoteness of its Central African equatorial rainforest range. The taxonomic status and ...the criteria to differentiate A. congicus from the quite similar Cape clawless otter (Aonyx capensis) are reviewed. The current distribution and status of A. congicus (Gabon, Congo, Democratic Republic of Congo, southern Cameroon and Central African Republic, northern Angola, and probably western Uganda, Rwanda and Burundi) is updated using an information network, surveys in Gabon, Cameroon and the Democratic Republic of Congo, and localities of museum specimens. The species is mainly threatened by deforestation, hunting for bush meat and use for witchcraft materials.
Actinomycosis, presenting as chronic proliferative pyogranulomatous pleuritis associated with sulfur granules, was diagnosed in a mature male river otter (Lontra canadensis) captured near Victoria, ...British Columbia, Canada, in April 2010. The river otter died during sedation for clinical examination and was necropsied immediately. Bacteria of the genus Actinomyces are commensals of the mucous membranes in a wide range of animals and people that act as opportunistic pathogens. This is the first report of actinomycosis in a river otter.
The giant otter Pteronura brasiliensis was hunted almost to extinction in the Peruvian Amazon during a period of professional trade in wild animal skins during 1920–1973. In 1973 the Department of ...Agriculture of Peru (INRENA) prohibited commercial hunting in the Peruvian Amazon, and the giant otter was included in Appendix I of CITES. From 1973 to 2004 giant otter populations experienced a slow recovery in numerous rivers of the Peruvian Amazon. Here, we report the population growth of the giant otter on the Yavarí-Mirín and Yavarí Rivers in north-east Peru. The first evaluations of giant otter populations in these rivers, in which no individuals were sighted, were in 1992–1993. During surveys in 1996 and 1997 two individuals were sighted. In 2001, 19 individuals were sighted and in 2003 and 2004, 41 individuals were observed. This increase demonstrates a slow recovery and shows that the population has not yet reached its carrying capacity. The prohibition of international trade in otter skins by CITES, supported by INRENA, helped the population recover and was important in the conservation of this species.
The cortical branches of the middle cerebral artery in the otter were described using 60 hemispheres. It was demonstrated that the artery is divided into ten permanent branches. Two rhinal arteries ...supply the region of the brain located on the border between the old and the archicortex and the neocortex. The other eight branches are divided into three branches running towards the frontal lobe, two branches – to the region of the parietal lobe and three temporal branches which supply blood to the neocortex only. The frontal, parietal and temporal branches descended independently from the main trunk of the middle cerebral artery or first formed a common trunk. Common trunks for specific groups of bifurcations were described as the middle cerebral artery (anterior, superior and posterior).
The European Commission Habitats Directive requires that changes in the conservation status of designated species are monitored. Nocturnal and elusive species are difficult to count directly and thus ...population trajectories are inferred by variation in the incidence of field signs. Presence/absence techniques are, however, vulnerable to Type II errors (false negatives). The Eurasian otter (Lutra lutra), listed by the IUCN as ‘near threatened’, is monitored throughout Europe using the ‘Standard Otter Survey’ method. We explored the reliability of this approach by analysing species incidence at 1,229 sites throughout Ireland. Naïve species incidence was 72 % 95 % confidence interval (CI), 69–75 % with variation affected significantly by survey team and, at running freshwater sites, the number of bridges present and rainfall during the month, and most notably during the 7 days, prior to survey. Rainfall had no effect on static freshwater sites or the coast. Marginal estimated mean species incidence derived from a GLM assuming the β coefficient of the survey team associated with the highest prevalence, no rainfall in the week prior to survey and sites that had multiple bridges, was 94 % 95 %CI 78–97 %. We demonstrate that bias and error in binary wildlife surveys can have a major impact on a conservation assessment even when conducted on an apparently well-known species in a developed country with good infrastructure and a long history of similar ecological studies. Our results provide empirical evidence for further criticisms of the Standard Otter Survey method calling into question its value in monitoring changes in otter populations throughout Europe.
Abstract
The presence of habitats such as burrows and dense willows along the rivers is very important for the survival of the European otter in terms of structures allowing quiet living conditions ...and possibilities for reproduction. To prevent the extinction of the otter in Luxembourg and nearby areas, an assessment of otter habitats and populations was made in 1994. This first evaluation has demonstrated that only rivers in the north of Luxembourg were suitable for otter populations in terms of quality of habitats and that only a few individuals were still present in this part of the country. In 2007, a new habitat assessment was carried out to define priorities for the management of habitats and to build or rebuild corridors to support otter migration and allow re-establishment of stable otter populations in the Benelux Countries. Two similar methods were used to assess quality of habitats in 1994 and 2007. The results of the habitat assessment are different for the Mid Sûre River and similar for the River Wiltz, the River Wark, the River Our and the Upper Sûre River. This variation is probably due to assessment complexity and observer subjectivity, but also to the difficulty to have a practical methodology for management priorities. From this point of view it would be useful to have a standard methodology at the European level to assess otter habitats.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The Paraguayan economy did not suffer debt crises in the eighties and had significant growth rates in the second half on the seventies, but poverty remained a problem. Understanding the performance ...and spatial distribution of poverty and inequality over a period of more than ten years can shed new light on structural causes behind what seems to be a low growth – high poverty – high inequality trap in Paraguay. How did poverty and inequality change during the 1990s. Did inequality reduce income growth? What were the growth determinants and what are the main forces driving inequality changes? These are the questions being answered in this book.
The aquatic North American river otter (Lontra canadensis), a charismatic nonendangered mustelid, presently occupies a greatly reduced range. The species is common in zoos and has economic value as a ...furbearer. At least 17 states and one Canadian province have undertaken recent reintroduction programs. Nevertheless, little has been published on nonparasitic diseases of river otters, and little is known of the clinical significance of most of their parasitic infections. Records of environmental contaminant-related diseases and traumatic injuries in free-ranging North American river otters are also rare. This paper reviews present knowledge of North American river otter diseases, especially those with the greatest potential for impacting reintroduction programs.
Gulls Simplified Dunne, Pete; Karlson, Kevin T
2018, 2018-11-13
eBook
A simpler and more user-friendly visual approach to gull identification
This unique photographic field guide to North America’s gulls provides a comparative approach to identification that ...concentrates on the size, structure, and basic plumage features of gulls—gone are the often-confusing array of plumage details found in traditional guides.
Featuring hundreds of color photos throughout, Gulls Simplified illustrates the variations of gull plumages for a variety of ages, giving readers strong visual reference points for each species. Extensive captions accompany the photos, which include comparative photo arrays, digitized photo arrays for each age group, and numerous images of each species—a wealth of visual information at your fingertips. This one-of-a-kind guide includes detailed species accounts and a distribution map for each gull.
An essential field companion for North American birders, Gulls Simplified reduces the confusion commonly associated with gull identification, offering a more user-friendly way of observing these marvelous birds.
Provides a simpler approach to gull identification
Features a wealth of color photos for easy comparison among species
Includes detailed captions that explain identification criteria and aging, with direct visual reinforcement above the captions
Combines plumage details with a focus on size, body shape, and structural features for easy identification in the field
Highlights important field marks and physical features for each gull
Over a period of 21 years, 541 otters mostly killed on the roads were investigated. Three species of ticks (Ixodes hexagonus, I. canisuga, I. ricinus) were found to infest the Eurasian otter (Lutra ...lutra) in Germany. The most common tick species on the otters was I. hexagonus. The prevalence (= infestation extensity; proportion of infested animals) was 8.8%. The average infestation intensity (number of ticks per infested animal) was 7.9 ticks per infested otter. Two species of ticks were only found on two otters. The highest infestation intensity of I. hexagonus found on one otter was 72 larvae plus 3 nymphs and 2 females. The average infestation intensity by the stages of I. hexagonus was 2.0 females, 4.9 nymphs and 8.3 larvae per infested otter. In Upper Lusatia, Germany, the otter has been proven to be a frequent host for I. hexagonus. The common wood tick, I. ricinus, parasitized on only one otter.
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