Population dynamics and spatial pattern of small mammals in protected forest and reforested area

Abstract

Small mammal monitoring using live trapping was done along the upper section of river Drava in 2003-2004, using capture-mark-recapture. Our sample areas were located in a strictly protected alder gallery forest (Lankóci-erdő) and in a neighbouring plot under gradual reforestation which had been clear-cut in 2000. A total of 9 small mammal species were recorded in the two sites, each comprising a 1-hectare sampling grid. The small mammal community revealed here had three characteristic rodent species (Apodemus flavicollis, A. agrárius, Clethrionomys glareolus), and two frequent shrew species (Sorex araneus, Crocidura leucodori). With the populations assumed to be closed, population sizes of the three dominant rodents were estimated from daily capture data. The highest estimated values were obtained for the two Apodemus populations (A. agrárius and A. flavicollis). Population sizes of the bank vole could be estimated from the protected area only. A spatial analysis with the nearest neighbour method showed that individuals of the more frequent species aimed at an even distribution, both in 2003 when densities were lower, and in 2004 when densities were higher. The more detailed analysis of the spatial pattern in 2004 suggested that by the end of late autumn, the different species are already organised in a pattern of winter survival strategy. It was shown by spatial distribution data that in this period the area of the closed alder gallery forest was occupied by individuals of yellow-necked wood mouse and bank vole. In the inner, larger part of the 1 ha forest section, it was mostly yellow-necked wood mice that established their home ranges. Striped field mice occupied only the reforested areas. Using extensive areas, the reforested area was inhabited also by bank voles, which fact is a proof for population translocation between the two areas in this species.