title: Foraging conditions, tooth wear and herbivore body reserves: a study of female reindeer.
abstract: Several aspects of the life history of reindeer (Rangifer tarandus) are related to the nutritional condition of the animals. Moreover, compensatory growth and fattening in summer decreases with age. The interaction of tooth wear and the standing crop of lichens on age-related variation in body size and tissue reserves was examined to evaluate the proximate causes of density-dependent food limitation on life history parameters in female reindeer. Studies in nine semi-domesticated free-ranging reindeer herds showed that molar height depended on the mean standing crop of terrestrial lichens in winter habitats. The extent of tooth wear had the strongest effect on body reserves among the oldest females (11-14 years). This indicates that severe tooth wear limits the animals´ ability to process food efficiently and, hence, to maintain their body reserves. Both tooth wear and the biomass of lichens influenced body mass in old females, probably because on heavily exploited winter ranges reindeer had to use higher proportions of lower-ranking coarser foods, especially dwarf shrubs.
authors.affiliation: Finnish Game and Fisheries Research Institute, Taivalkoski Game and Fisheries Research, Ohtaoja, FIN-93400 Taivalkoski, Finland, , , , , , FI.
authors.forename: Ilpo
authors.initials: I
authors.lastname: Kojola
authors.affiliation: The Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland, , , , , , FI.
authors.forename: Timo
authors.initials: T
authors.lastname: Helle
authors.affiliation: University of Oulu, Department of Biology, FIN-90570 Oulu, Finland, , , , , , FI.
authors.forename: Esa
authors.initials: E
authors.lastname: Huhta
authors.affiliation: The Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland, , , , , , FI.
authors.forename: Aarno
authors.initials: A
authors.lastname: Niva
keywords: Body reserves; Key words Winter forage; Life history; Reindeer; Tooth wear