Resultados del primer Sondeo de Rata de Agua, Arvicola sapidus Miller 1908, en España

Abstract

The results of the first spanish southern water vole (Arvicola sapidus) survey are presented in this paper. The survey was carried out between March 19, 2011 and June 10, 2012 and 310 volunteers participated in it, of which almost half did so as companions. A total of 1,000 UTM grids of 10x10 km were selected a priori, with a uniform distribution throughout peninsular Spain. In each grid the observer chose three sampling points, with the following conditions: presence of favorable habitat, easy access and minimum distance between sampling points of 2,500 m. More than half of the grids were sampled by a single observer and 97% of the positive points were before 25 minutes of sampling. Data was obtained from 995 grids of the 1,000 initially planned. The presence of southern water vole was detected in 542 (54.5%) of grids: 218 with one positive point (40.2% of the positive ones), 174 with two (32.1%) and 150 with three (27.7%). The total number of points sampled was 2,914, of which 1,016 (34.9%) were positive.