Depredación de visón americano sobre desmán ibérico en Galicia

Abstract

In some areas of the Iberian Peninsula, including Galicia, Iberian desman has undergone a remarkable decline. One of the possible causes commonly identified to explain this decline is the effect of American mink. In the Asneiro river (Ulla Basin, Galicia) an American mink latrine was located in August 2012. The frequency of appearance of Iberian desman in mink scats was analyzed and the relative age of the remains was estimated by assessing their tooth wear. Remains of Iberian desman were found in 25 of the 94 scats analyzed (26.6%). Such a high proportion is exceptional, considering that in other diet studies conducted with American mink scats and otter spraints, the proportion of Iberian desman does not usually exceed 5%. On the other hand, from a measured sample of 11 mandibles of Iberian desman (including some samples of other areas of Galicia), 7 (64%) had a wearing less than 25%, which correspond to younger individuals. Specimens of this age class are the more common in natural populations, and for that reason could be more frequently captured by mink and otters. However the small sample size does not allow to conclude anything definitive on the subject. Anyway, the results obtained reveal a situation that could be problematic for Iberian desman populations in rivers with presence of American mink.