IUCN/SSC Otter Specialist Group Bulletin
© IUCN/SCC Otter Specialist Group
Volume 28 Issue 2 Pages 62 - 118 (October 2011)
Abstracts
Biology and Ecology of Asian Small-Clawed Otter Aonyx cinereus (Illiger, 1815): A Review
Pages 63 - 75 (Review)
Syed Ainul Hussain, Sandeep Kumar Gupta and Padma Kumari de Silva
The Asian small-clawed otter is the smallest among the 13 extant species of otters. It has a large distribution range extending from India in South Asia through Southeast Asia up to Taiwan and Philippines in the east and Southern China in the north. It is considered ‘Vulnerable’ due to habitat loss and degradation, depletion of prey species and exploitation. Being adapted to live in shallow streams and water bodies, they are more vulnerable to modification of these habitats by anthropogenic as well as climate change impacts. This paper summarizes the state of knowledge on the biology and ecology of this little known species. Over the years, the IUCN SSC Otter Specialist Group has developed a cadre of biologist across Asia to conduct field surveys and has popularized otter conservation by promoting otter as the ambassador of wetlands. However, concerted effort is needed for its long-term survival. Policy based action, research on factors affecting survival, habitat-based actions on creation and where required expansion of protected areas and communication and awareness building among local communities are suggested.
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Investigation into the Dietary Habits of the Eurasian Otter (Lutra lutra) in the County of Essex
Pages 76 - 83 (Article)
Leslie Cousins, D. Tansley and L. Hepburn
Monitoring throughout the county of Essex has shown annual widening of otter distribution. There is, however, room for expansion and some areas remain un-colonised. This paper reports a snapshot study of spraints collected from within the areas of known distribution, providing additional insight on a growing population. Prey remains were identified to family level and data used to calculate trophic breadths over the range of stream orders. Investigative comparisons were used to detect changes in diet with stream order. Further consideration was given to the importance of crayfish predation (e.g. the signal crayfish Pacifastacus leniusculus).Within the sample (n= 54) from four stream orders (Strahler 2-5), fish occurred most frequently (67%). Other groups included; invertebrates 20%, birds 7% and mammals 6%. Crayfish comprised 4% of the sample. There were no significant differences between Trophic Niche Breadth and stream order (H*=2.73, P>0.05), a finding strengthened by subsequent statistical analysis of the data. Dietary composition was consistent within the range and period studied. Extended research could determine seasonal variation and the extent to which available prey assemblage limits distribution against wider environmental and biological variables.
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A Study on Eurasian Otter (Lutra lutra) in Amirkelayeh Wildlife Refuge and International Wetland in Guilan Province, Northern Iran
Pages 84 - 98 (Article)
Ehsan Hadipour, Mahmud Karami, Asghar Abdoli, Riazi Borhan and Reza Goljani
This is the first study on otters in the wetlands of Iran. We worked in Amirkelayeh Wildlife Refuge and International Wetland (Amirkelayeh W.R&I.W). In this investigation, we surveyed the quality of Eurasian otter (Lutra lutra) sign distribution as a species presence index on the coast of Amirkelayeh (W.R&I.W). During a nine month period of monthly surveys, 673 signs were identified of which the majority were spraints. The number of spraints during different months differed significantly (χ2 =408.732, P<0.05). The results indicated a close negative correlation between frequency of fish and frequency of spraints (r = -1, P<0.01). Shorelines of the wetland showed significant differences in the mean value of spraint number (K=19.628, P<0.05). There were two hot spots with values greater than 66% “Spraint Presence Intensity” (SPI) during the nine month period. The number of spraints and SPI were correlated significantly (r=0.793, P<0.01). In addition, significant differences among “Types Of Sprainting Places” (χ2=130.723, P<0.05) and also in “Height of Sprainting places” (χ2= 459.408, P< 0.05) were observed. More than 89% of spraints were within 200 cm of the nearest cover. Association between presences of spraints and canals (χ2= 21.547, P<0.05 and λ=0.086), and also “chars” (access routes through reed beds between land and open water) (χ2= 63.691, P<0.05 and λ=0.210) were shown. “Reed Bed Breadth” in places with and without spraints differed significantly (U=495, P<0.05).
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Eurasian Otter (Lutra lutra) in the Central Part of the Slovak-Hungarian Border Area
Pages 99 - 112 (Article)
Peter Urban, Csaba Balázs, István Lantos, Sebastián Gáspár, Miklós Joó and Krisztián Harmos
The mapping of the Eurasian otter (Lutra lutra) distribution in the central part of the Slovak-Hungarian border was undertaken in winter 2010/2011 by searching for signs of presence of the otter. Authors checked 351 chosen survey sites (50-m transects, 242 points in Hungary and 109 in Slovakia). At every site, all signs of otter presence were surveyed. Preferably, survey sites were located under bridges (299). Sites were considered as either “positive” or “negative”. In total, 155 sites (44.1%, 105 in Hungary and 50 in Slovakia) were positive and 196 (55.8%, 137 in Hungary and 59 in Slovakia) were negative. Otters deposited spraints usually on specific substrate, mostly on blocks (201; 27.3%), concrete (189, 25.7%), and stone concrete (125, 17.0%). Altogether, 185 (61.9%) bridges and culverts were passable and 114 (38.1%) were not passable for the otters during mapping. The otters were regularly observed in optimal habitats (e.g. Ipeľ and Zagyva rivers and its larger tributaries) but also in suboptimal and marginal habitats such as regulated and narrow brooks and channels. The otter population in the central part of the Slovak-Hungarian border area was considered stable and otters occurred throughout this area.
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