Wild reindeer foraging‐niche organization

• Published in: Ecography
• Main Author: Skogland, Terje
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1984
• Subjects: Prudhoe Bay; Svalbard
• Online Access: http://dx.doi.org/10.1111/j.1600-0587.1984.tb01138.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0587.1984.tb01138.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0587.1984.tb01138.x

Part 1: Diet selection was studied on free‐ranging reindeer fitted with an esophageal fistula (EF) and by analysis of rumen samples from reindeer shot in the field. Plant density was assessed from quadrats on field plots. Three measures of palatability were used, the nitrogen, fiber, and total non structural carbohydrate (TNC) contents of samples from clipped vegetation. As lichen density decreased the EK reindeer included progressively more vascular litter and pieces of winter dormant species in their diet. Diets with highest TNC and N/F and the lowest fiber, providing the most readily digestible diets, were selected. The combined density‐quality criterion gave the best prediction of their diets. In summer, forbs, and to some extent grasses and dwarf shrubs, were selected. Plants of highest density and in an early growth phase gave the best prediction of summer diets. In winter the variety of vascular plants utilized increased with increasing herd size and decreasing density of lichens in the vegetation. The width of diets was a function of diversity of available plants. It is suggested that dietary selection by reindeer has been a three stage process: evolution of a gastro‐intestinal system capable of digesting lichens containing secondary compounds, behavioural tracking of the plant production pulse, and diet width scaling according to density‐quality of all potential foods. Part 2: Wild reindeer closely followed the wave of vascular plant production in spring and summer with a significant correlation being found between the daily foraging time per habitat type and the highest concentration of green phytomass. Snow‐bed meadows were the most consistently selected vegetation type by the four herds studied, viz. Hardangervidda, Snøhetta, Prudhoe Bay, and Svalbard, during the summer. Habitat niche‐breadths were narrow during the winter, largely due to the limitation of access to the food supply by the snow‐cover, broadened as the landscape became clear of snow, narrowed again with the initiation of plant growth ...