Recent advances in the study of otter (Lutra lutra) ecology in Spain
1996
Ruiz-Olmo, J. (Direccio General del Medi Natural, Barcelona (Spain)) | Delibes, M.
At the beginning of this century, the otter was widespread all over the Iberian peninsula. Its decline started in the fifties. At the present day, the otter distribution area in Spain covers about half of the country, 1327 sites (33.5 percent) out of 3966 surveyed sites having been positive, especially in the western regions. The main reasons of the decline are habitat destruction, environmental pollution (mean muscular levels: 21.14 ppm of DDT and 101.38 ppm of PCBs; n = 19), fragmentation and isolation of small otter populations and intensive use of water resources, mainly for irrigation. The state of trophic resources (namely fish) is compared with the otter distribution. A special interest is given to the situation in Andalucia where the impact of the introduction of the American crayfish has been checked. The results obtained on the reproductive activity (all the year round; 1.72 cub/female), the social organisation (mean group size: 1.6 ind.), the feeding behaviour and the home range use (radiotracking) are also presented. Finally, the authors discuss the conservation policy measures taken during the past few years: legal protection, nature reserves, supplementary feeding, water quality improvement, legal restrictions to the use of pesticides.
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