Individual and population energy budgets of the water vole

Abstract

M. A., 1976: Individual and population energy budgets of the w ater vole. Acta theriol., 21, 34: 499-512 [With 2 Figs.], Energy budges of individuals of the water vole Arvicola terrestris amphibius (Linnaeus, 1758) were computed from records of activity patterns and temperature experience in enclosures in the field and from m easurem ents of the oxygen usage at differing temperatures, seasons and levels of activity in the laboratory. The proportion of the diel period spent outside the nest was constant at 258/o from September to April, then increased to reach a peak of 38#/o in July and subsequently returned to the overwintering level. Strenuous activities occupied 15% of the time spent outside the nest. The ADMR of overwintering in­ dividuals of 180 g averaged 0.23 kcal/g/day. There was a slight net increase of ADMR in summer. Live trapping, microscopical study of faeces and sampling of the vegetation along 400 m of stream provided analyses of population dynamics, diet, and primary productivity within the feeding range. This extended no more than 1 m from the w ater's edge. It is estim ated that energy assimilated was about 2000 Mcal/ha/ year of feeding range and in the order of 20% of its primary pro­ ductivity. Secondary production was about 4®/e of the energy as­ similated. [Univ. Durham, Dept. Zool., South Rd, Durham DH1 3LE, England],