Movement patterns and home range of Cape clawless otters (<i>Aonyx capensis</i>), affected by high food density patches

Somers, Michael J.; Nel, J.A.J.

doi:10.1017/s095283690300445x

Cited by 25 publications

(20 citation statements)

References 28 publications

(36 reference statements)

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“…Studies have shown that male European polecats Mustela putorius and American mink use up to 3 times larger home ranges than females (Gerell 1970, Lodé 1996, Zschille et al 2006, and male pine martens Martes martes establish larger home ranges (Schröpfer et al 1997, Zalewski & Jedrzejewski 2006. Similarly, Somers & Nel (2004) reported significant differences in home range size of males and females for the African clawless otter Aonyx capensis. In the present study, male European mink home ranges were twice the size those of females, comparable to the results of Palazón & Ruíz-Olmo (1998) and Macdonald et al (2002) for Mustela lutreola and to results for Mustela nivalis and Mustela erminea, the smaller members of the Mustelid family (King 1975, Erlinge 1977, Macdonald et al 2004).…”

Section: Discussionmentioning

confidence: 99%

Reintroduction of the European mink Mustela lutreola in Saarland, Germany. Preliminary data on the use of space and activity as revealed by radio-tracking and live-trapping

Peters¹,

Brinkmann²,

Krüger³

et al. 2009

Endang. Species. Res.

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As an attempt to help conserve the endangered European mink Mustela lutreola (Linnaeus, 1761), a reintroduction program was started in a nature reserve in Saarland, Germany; the present study is part of this ongoing reintroduction project. Within the first 2 yr period, 48 (16 m, 32 f) founder animals were reintroduced, out of a total of about 75 animals intended for release in the course of the 3 yr project. Prior to reintroduction, the animals were acclimatized using soft-release pens where they were preconditioned with natural prey . A number of individuals (n = 18) were set free in groups of mating partners (ffm, fm) and in mother-offspring groups. Thirty-three European mink (14 m, 19 f) were fitted with intraperitonial transmitters and radio-tracked and surveyed via live-trapping. Animals were monitored from April 2006 to May 2008 to determine the distribution, size and temporal changes in home range. Released animals showed linear home ranges spreading along rivers and brooks. Home range sizes were 7.2 km (88 ha) for 1 adult male, 0.2-5.9 km (1-505 ha) for adult females, around 1.7-5.6 km (17-132 ha) for juvenile males and 9.2 km (778 ha) for 1 juvenile female, respectively. The released adults showed inter-, but only few intra-, sexual home range overlaps. In contrast, juveniles did not show any home range overlaps. In winter, home range size decreased to a minimum of about 1 km. Further, home range size for females decreased around parturition but increased successively at time of weaning. The activity pattern of released animals was highest at night (especially around dusk and dawn).

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Section: Discussionmentioning

confidence: 99%

Reintroduction of the European mink Mustela lutreola in Saarland, Germany. Preliminary data on the use of space and activity as revealed by radio-tracking and live-trapping

Peters¹,

Brinkmann²,

Krüger³

et al. 2009

Endang. Species. Res.

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“…As many tourists are willing to pay R50.00 or more to view otters, a steady income for at least one trained guide at each suitable reserve along the Wild Coast (and perhaps elsewhere) is attainable. This would involve ca three hours of work in the early morning to catch the ca 2.6 hours of otter activity (Somers & Nel 2004). Seeing otters during the nocturnal activity bout is not considered feasible.…”

Section: Discussionmentioning

confidence: 99%

“…In marine habitats they eat mostly fish followed first by crabs, then by octopus or lobster (Van der Zee 1979, 1981Arden-Clarke 1983;Verwoerd 1987;Somers 2000a, b). Cape clawless otters are typically active from dawn for 2.6 h and from sunset for a mean of 2.3 h (Somers & Nel 2004). During the heat of the day they rest in dry places, in holes in the ground, under rocks, in sheltered places in erosion gullies or in dense reed beds adjacent to their habitat (Somers 2001).…”

Section: Introductionmentioning

confidence: 99%

“…The pattern of female home ranges suggests territoriality. Males have overlapping home ranges, both with other males and females (Somers & Nel 2004). In fresh water, total home range length varies from 4.9 to 54.1 km.…”

Section: Introductionmentioning

confidence: 99%

“…In fresh water, total home range length varies from 4.9 to 54.1 km. The total area of water used ranges from 4.9 to 1062.5 ha (Somers & Nel 2004). In a marine habitat home range varies from 5.4 to 19.5 km of coast (Arden-Clarke 1986).…”

Section: Introductionmentioning

confidence: 99%

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Tourists’ willingness to pay to view otters along the Wild Coast, South Africa: a potential for increased ecotourism

Dumalisile

Somers

Walters

et al. 2005

TDSA

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Abstract. This article reports on tourists' willingness to pay to view Cape clawless otters Aonyx capensis along the Eastern Cape Wild Coast, South Africa. We collected data from a survey carried out using a structured, selfadministered questionnaire. We analyzed 67 completed questionnaires, of which 60 respondents (89.5%) indicated that they would be interested in viewing otters and would be prepared to pay an extra fee, over and above the normal entrance fees, for a trained guide to show them otters. The remaining 7 (10.4%) respondents indicated that they would reconsider and pay if this would create jobs for members of the local community. Most (98.4% and 91.8%) of the respondents also indicated that they would still pay even if there was only a 50% or 25% chance of seeing otters. Most of the respondents were willing to pay either less than R50.00 (ca US$8.00) or R50.00-R100.00 to view otters regardless of the chances of seeing them. We conclude from our results that otters do have the potential to increase ecotourism in the area, and also to contribute financially to the poverty stricken local Dwesa community.

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Otter occupancy in the Cape Peninsula: Estimating the probability of river habitat use by Cape clawless otters, Aonyx capensis, across a gradient of human influence

Okes

O’Riain

2017

Aquatic Conservation

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1. The distribution of Cape clawless otters, Aonyx capensis, in South Africa and their habitat requirements in freshwater and marine systems has been well established. There is, however, a lack of information on how otters are adapting to urban development and the transformation of critical freshwater habitat.2. Within the Western Cape, the Cape Peninsula exhibits substantial variation in levels of human impact over a small geographic range, offering an excellent opportunity to explore the hypothesis that otters are adversely affected by habitat transformation.3. A single season occupancy model was used based on otter sign to determine the probability of otter occupancy across a gradient of habitat transformation at both landscape and local scales.4. The probability of otters occupying river habitat in the Cape Peninsula was low (P = 0.29) but increased with proximity to marine protected areas (MPAs) that included estuaries and wetland habitat. Otter presence was not influenced by proximity to urban areas at the landscape scale, but declined in canalized sections of river that were heavily degraded by human activity. 5. Despite being heavily transformed, lowland aquatic ecosystems may still provide critical resources in the form of fresh water and breeding sites, and together with food within the marine habitat may be sustaining the peninsula's otter population.6. In order for otters to persist on the peninsula, conservation authorities must maintain wetland, estuarine and river habitat in close proximity to MPAs. Further research is needed to determine the long-term impacts on otters persisting in degraded ecosystems. 7. Annual single season occupancy surveys provide a rapid, cost-effective method for monitoring changes in otter occupancy which should be incorporated into current monitoring efforts to provide much needed long-term monitoring of a top predator in freshwater ecosystems.

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Movement patterns and home range of Cape clawless otters (Aonyx capensis), affected by high food density patches

Cited by 25 publications

References 28 publications

Reintroduction of the European mink Mustela lutreola in Saarland, Germany. Preliminary data on the use of space and activity as revealed by radio-tracking and live-trapping

Reintroduction of the European mink Mustela lutreola in Saarland, Germany. Preliminary data on the use of space and activity as revealed by radio-tracking and live-trapping

Tourists’ willingness to pay to view otters along the Wild Coast, South Africa: a potential for increased ecotourism

Otter occupancy in the Cape Peninsula: Estimating the probability of river habitat use by Cape clawless otters, Aonyx capensis, across a gradient of human influence

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