Intake and chemical composition of winter and spring forage plants consumed by semi-domesticated reindeer (Rangifer tarandus tarandus) in Northern Finland

Reindeer diets are highly influenced by seasonal availability of forage plants and their nutritive value. This study investigated the use and chemical composition of winter and spring forage plants consumed by semi-domesticated reindeer (Rangifer tarandus tarandus) grazing on natural pastures in Northern Finland. Reindeer diet composition was determined by microhistological analysis of faeces collected during winter and spring. Terrestrial lichen species (mainly Cladonia sp.) dominated the winter and spring diet of reindeer, as well as various dwarf shrub species. A seasonal shift occurred in the diet, with proportion of lichen which corresponded with an increase in graminoids as spring progressed, reflecting reindeer adaptations to seasonal fluctuations of forage quality and availability. Chemical composition of forage plants showed that terrestrial lichen had high levels of hemicellulose, while arboreal lichen had relatively high nitrogen levels. In contrast, new growth of birch leaf, graminoids and dwarf shrub had high levels of crude protein, ether extract and minerals. The observed diet composition and its chemical content reflect high seasonal variability in the availability and intake of nutrients to which reindeer have adapted.