Teneur azotée des ressources et choix trophiques du Mulot sylvestre (Apodemus sylvaticus) dans un système oligotrophe

Abstract

The nitrogen content of plant tissue is an essential factor for the growth and survival of many wild phytophagous vertebrates. We tried to analyse the trophic choices of the wood mouse (Apodemus sylvaticus) in relation to the nitrogen content of various plant organs in a heathland, a common ecosystem in Brittany. Patterns of plant resources utilisation observed in this ecosystem show that this rodent species always selects concentrated resources, namely energy- or nitrogen-rich plant tissues. In other respects, the ingestion of animal prey in quantities varying according to the availability of highly nutritious plant resources is another adaptive response to this selection pressure. This strategy of nitrogen allocation based on seed and insect eating is compared with those observed in various other small rodents and correlations with their demographic and space utilization patterns are discussed.