Wyniki wyszukiwania

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Lessons from the use of non-invasive genetic sampling as a way to estimate Eurasian otter popolation size and sex ratio

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Bonesi L., Hale M., Macdonald D. W.

Acta Theriologica

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2013

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tom 58

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nr 2

Given the difficulties in establishing population parameters of elusive animals in the wild by traditional methods, such as trapping, much attention has been given in recent years to non-invasive genetic sampling. Our work compared estimates of population size and sex ratio derived from genetic sampling with the known number and sex of animals released during an otter reintroduction and reports on the pitfalls and opportunities that may be encountered in studies of this kind. This study makes use of 121 samples of otter spraints (faeces) collected over 7 months during a reintroduction in the Upper Thames (UK) where a total of 17 otters was released in two consecutive phases. Spraints were processed with a multiple tubes approach and seven microsatellites were used. Of all collected samples, 19 % were complete for at least five loci, the minimum required for discrimination between individuals. Six out of nine of the otters that were released in the first phase were detected, four males and two females, while none of the otters released in the second phase was detected probably due to a combination of sampling pitfalls and otter behaviour. In particular, the specific sex (mostly females) and dominance composition (lower) of the individuals in the second release group may explain our failure to detect individuals in this group. Taken together, our results add further evidence that genetic sampling approaches represent a potentially accurate and non-invasive route to census populations of otters but that the sampling design should take into account factors like the sex ratio and dominance composition of the population in order to maximise detection and minimise error.

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

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Melero Y., Palazon S., Bonesi L., Gosalbez J.

Acta Theriologica

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2008

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tom 53

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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.

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Is the standard Eurasian otter Lutra lutra survey strategy suitable for surveying the American mink Neovision vision?

88%

Melero Y., Palazon S., Gosalbez J., Martelo J., Bonesi L.

Acta Theriologica

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2013

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tom 58

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nr 2

Ograniczanie wyników

3 Acta Theriologica

3 Bonesi L.

2 Gosalbez J.

2 Melero Y.

2 Palazon S.

1 Hale M.

1 Macdonald D. W.

1 Martelo J.

2 2013

1 2008

Lessons from the use of non-invasive genetic sampling as a way to estimate Eurasian otter popolation size and sex ratio

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

Is the standard Eurasian otter Lutra lutra survey strategy suitable for surveying the American mink Neovision vision?