Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 8

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Eurasian otter
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Eurasian otter (Lutra lutra) density estimate based on radio tracking and other data sources

100%
Quaglietta L., Hajkova P., Mira A., Boitani L.
Acta Theriologica
|
2015
|
tom 60
|
nr 2
Estimating animal population size is a critical task in both wildlife management and conservation biology. Precise and unbiased estimates are nonetheless mostly difficult to obtain, as estimates based on abundance over unit area are frequently inflated due to the “edge effect” bias. This may lead to the implementation of inappropriate management and conservation decisions. In an attempt to obtain an as accurate and conservative as possible picture of Eurasian otter (Lutra lutra) numbers, we combined radio tracking data from a subset of tracked individuals from an extensive project on otter ecology performed in Southern Portugal with information stemming from other data sources, including trapping, carcasses, direct observation of tagged and untagged individuals, relatedness estimates among genotyped individuals, and a minor contribution from non-invasive genetic sampling. In 158 km of water network, which covers a sampling area of 161 km2 and corresponds to the minimum convex polygon constructed around the locations of five radio-tracked females, 21 animals were estimated to exist. They included the five radio-tracked, reproducing females and six adult males. Density estimates varied from one otter per 3.71–7.80 km of river length (one adult otter per 7.09–14.36 km) to one otter per 7.67–7.93 km2 of range, depending on the method and scale of analysis. Possible biases and implications of methods used for estimating density of otters and other organisms living in linear habitats are highlighted, providing recommendations on the issue.
2

New data on the parasites of the Eurasian otter (Lutra lutra)

84%
Rolbiecki L., Izdebska J. N.
Oceanological and Hydrobiological Studies
|
2014
|
tom 43
|
nr 1
3

Fish selection by riverine Eurasian otters in lowland England

84%
Grant K. R., Harrington L. A.
Acta Theriologica
|
2015
|
tom 60
|
nr 3
4

Habitat factors and the presence or absence of otters Lutra lutra in Denmark

84%
Madsen A. B., Prang A.
Acta Theriologica
|
2001
|
tom 46
|
nr 2
The purpose of the present study was to examine the relative influence of different habitat factors on otters Lutra lutra (Linnaeus, 1758) and to develop a predictive model to better understand the distribution of the otter in Denmark. During the National Otter Survey in 1991 data were collected on 19 variables which reflected aspects of habitat structure, composition, organic pollution and human disturbance. Multiple logistic regression analysis was used to estimate probabilities of the presence of otters as a function of one or more explanatory variables. Six variables (county, pH, water depth, presence of trees, bottom substrate and Saprobien-Index) were identified. In Denmark, otter habitat typically consists of water courses with depths > 1 m over a varied bottom, with pH > 7.0, Saprobien-Index on II-III to III (indicating slight organic pollution) with no trees on the banks. Some of these variables reflect highly productive waters. The use of the otter as an indicator of good water quality and/or aquatic habitat should be used with care.
5

Survey of an otter Lutra lutra population in Southern Italy: site occupancy and influence of sampling season on species detection

84%
Fusillo R., Marcelli M., Boitani L.
Acta Theriologica
|
2007
|
tom 52
|
nr 3
In order to assess the current status of the otterLutra lutra Linnaeus, 1758 in Southern Campania (Italy), we surveyed 141 sites for spraints (faeces) in 2001. Fifty-eight sites were surveyed during the winter and in the following summer in order to test, through an estimation-based approach, the influence of sampling season on species detection. Site occupation in the study area was high (69.5%) and possibly underestimated, because the survey was affected by non-detection errors. Our analyses showed that winter surveying markedly underestimated true otter occupancy at the 58 sites (51.7% vs 97.1%), whereas summer surveying was very reliable (91.4%). Rains and floods may have removed spraints during winter, thereby reducing the detection probability to 0.534. These results suggest that otter standard surveys in areas with Mediterranean-type climates should be conducted during summer or periods without prolonged precipitation. Comparing our results with those of the 1985 National survey, we found an occupancy increase from 65.8 to 100%. We could not establish whether this change reflected a population increase or was due to possible non-detection errors that occurred in the 1985 survey. However, the present occupancy substantiates the strategic relevance of the study area for planning the conservation of Italian otters.
6

Hair density in the Eurasian otter Lutra lutra and the Sea otter Enhydra lutris

67%
Kuhn R. A., Ansorge H., Godynicki S., Meyer W.
Acta Theriologica
|
2010
|
tom 55
|
nr 3
211-222
The hair density of adult Eurasian otters Lutra lutra (Linnaeus, 1758) and sea otters Enhydra lutris (Linnaeus, 1758) was analysed using skin samples taken from frozen carcasses. Lutra lutra exhibited a mean hair density of about 70 000 hairs/cm2 (whole body, appendages excepted), the mean individual density ranging from about 60 000 to 80 000 hairs/cm2. The dominant hair type were secondary hairs (wool hairs), the hair coat comprising only 1.26% of primary hairs (PH). Secondary hair (SH) density remained constant over the body (appendages excepted), whereas a few variations in PH density were observed. Neither an influence of the sex, nor a seasonal variation of the hair coat was found, moulting seems to be continuous. Enhydra lutris had a hair density between 120 000 and 140 000 hairs/cm2, the primary hairs representing less than 1% within the hair coat. Hair density remained quite constant over the regions of the trunk but was lower at the head (about 60 000 hairs/cm2 on the cheek). The hair follicles were arranged in specific groups with different bundles of varying size, normally comprising dominant numbers of wool hair (SH) follicles. Invariably there was always a large central primary hair follicle and numerous sebaceous glands between the bundles and principally around the PH follicles. The results are discussed related to possible ecological influences on hair coat density.
7
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

A record of Pseudamphistomum truncatum (Rudolphi, 1819) (Digenea, Opisthorchiidae) in the Eurasian otter (Lutra lutra L.) from Poland

67%
Hildebrand J., Popiolek M., Zalesny G., Pirog A.
Wiadomości Parazytologiczne
|
2011
|
tom 57
|
nr 3
8

Feeding habits of three sympatric mammals in NE Spain: the American mink, the spotted genet, and the Eurasian otter

67%
Melero Y., Palazon S., Bonesi L., Gosalbez J.
Acta Theriologica
|
2008
|
tom 53
|
nr 3
Diet composition, niche measures, and prey consumption of three sympatric species of carnivores, one non-native and introduced, the American minkNeovison vison Schreber, 1777, and two native, the spotted genetGenetta genetta Linnaeus, 1758 and the Eurasian otterLutra lutra Linnaeus, 1758, were studied in a Spanish Mediterranean area. The study was based on the analysis of prey remains in the faeces of the predators. Faeces of mink (n = 444), genet (n = 310), and otter (n = 108) were collected all year round for four years along the Llobregat (21 km) and Gavarresa rivers (12 km). Simultaneously, and in the same area, prey species density and weight were estimated by means of trapping. The diet of mink and genet was dominated by the American crayfishProcambarus clarkii, while the otter fed almost exclusively on fish. Compared to the mink, the genet seemed to specialise more on small mammals while the mink specialised more on aquatic birds, especially in autumn-winter. Niche overlap was higher between mink and genet than between either of them and the otter.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.