Spatial distribution of the yellow-necked mouse (Apodemus flavicollis) in large forest areas and its relation with seed crop of forest trees

Abstract

The checking of nestboxes put up in a grid system gives a chance to estimate both relative abundance and spatial distribution of yellow-necked mice (Apodemus flavicollis) in large forest areas. This is difficult to achieve using traps due to manpower that would be required. Long term investigations carried out in Lithuania at two study sites with an area of 60 and 85 ha respectively, showed that there was no relation between relative abundance of A. flavicollis in autumn and the pattern of their spatial distribution. When relative abundance of A. flavicollis was the same in different years, spatial distribution of mice could be both random and aggregated, as well as regular. The pattern of spatial distribution shown by A. flavicollis in large forest areas with a high diversity of tree-stands was related to the productivity and spatial distribution of forest trees with heavy seeds (mainly oak and hazel). In separate years mice used to occupy nestboxes at those places where a heavy seed crop was present. When crops of oak and hazel failed completely, spatial distribution patterns of A. flavicollis tended to be regular. The data obtained suggest one practical conclusion: long-term A. flavicollis population studies in small plots of forest, with a high diversity of forest stands, may only reflect the situation in these specific places and not necessarily the state of the entire A. flavicollis population.