Spatial dynamics of wood mouse (Apodemus sylvaticus) in an agricultural landscape under intensive use in the Mont Saint Michel Bay (France)

Over the last decades intensification in agricultural use has lead to chang es in landscape structure and composition. Seasonal fluctuations of the woo d mouse (Apodemus sylvaticus) ate well known in cultivated landscapes, but not well explained. The main question relates to the fate of individuals du ring summer. The hypothesis of a seasonal dispersal of individuals from hed ges to crops was investigated in the polder of the Mont Saint Michel Bay (F rance) at different landscape scales using GIS. Field and landscape scale p arameters were analysed in relation to wood mouse abundance in the crops mo saic. The results tend to demonstrate that dilution of the population due t o dispersal toward crops could be the main factor explaining the population drops in hedges. Hedgerows act as source habitat in spring whereas field c olonisation rare depends on crop quality in summer. The heterogeneity of th e crops matrix for the presence:of wood mouse has been studied. Variations in vegetation cover of the field plot and its surroundings appear to determ ine dispersal of mice during summer. Results may have implications in terms of pest management and/or food webs preservation in cultivated landscapes. (C) 2000 Elsevier Science B.V. All rights reserved.