Expansion of the Striped field mouse ( Apodemus agrarius ) in the south-western Slovakia during 2010–2015

Abstract

Population of the Striped field mouse spread out into unoccupied territories leading to the rapid enlargement of their range of distribution is defined as an expansion. In 2010, the presence of the species in south-western Slovakia was recorded for the first time. During monitoring of this expansion (from 2010 to 2015) 59 new localities in south-western Slovakia were recorded, representing confirmation of the presence of A. agrarius in 18 new quadrates of Databank of Slovak fauna. Thus in 2015, marginal points of the distribution area were the Danube River in south-western Slovakia, the Šur National Nature Reserve in the west, the wetland near Tešmak in the east and the Jasová water reservoir in the north. The impact of this expansion on the quantitative composition of the small mammal’s community has been evaluated for three sites (Čiližská mokraď wetland, Okoličianska mokraď wetland, Martovská mokraď wetland) and one larger area (south-western corner of Danubian lowland). In all the observed sites the expansion of A. agrarius was related to rapid increase of its abundance. However its representation in the small mammal’s community was significantly growing only in the site Čiližská mokraď wetland and Martovská mokraď wetland. In general, the rapid increase of the abundance of Apodemus agrarius in the small mammal’s community in the observed sites led to the significant decrease of the abundance of several species of small mammals, mainly Apodemus sylvaticus, Clethrionomys glareolus and Sorex araneus.