Long-term management history affects seasonal diet composition of semi-domesticated reindeer

Late Lunch Talk by Stefaniya Kamenova

 
Image may contain: World, Wood, Road surface, Flooring, Floor.

Abstract

Semi-domesticated reindeer Rangifer tarandus exert a major top-down control on plant biomass and biodiversity dynamics within the Fennoscandian arctic tundra ecosystem. Reindeer herding practices are complex and have been implemented for centuries by indigenous Sámi people. The interplay between historically established seasonal migration patterns and the management of reindeer stocking densities has resulted in considerable differences in pasture productivity, likely altering the nutritional base for reindeer. But surprisingly, how pasture productivity levels impact reindeer feeding preferences has never been investigated before. Comparing two herding districts with contrasting levels of reindeer densities, we aimed  to indirectly assess the effect of pasture productivity on the composition and diversity of the reindeer annual diet in Eastern Finnmark, Norway. Using a state-of-the-art DNA metabarcoding diet analysis, we show that seasonality rather than reindeer densities explained the largest part of the variation in diet composition. Contrary to our expectations, diet diversity did not differ between districts with contrasting densities, except during winter where, surprisingly, reindeer from the high density herding district displayed higher diversity in their plant diet. But the intake of lichen - an essential and limiting winter food resource - did differ, with reindeer from high density areas incorporating a significantly smaller proportion of lichen in their winter diet. Our results suggest that the impact of stocking densities on reindeer feeding preferences is complex, strongly dependent on the season and whether the focus is on the plant or lichen fraction of the diet. In higher densities areas reindeer do have a lesser intake of lichen during winter but also a more diversified plant diet. This adds to the evidence that persisting herbivory by reindeer might induce a vegetation shift towards more diversified and productive tundra plant communities.

Speaker

Stefaniya Kamenova

Published June 8, 2022 8:49 AM - Last modified June 8, 2022 8:49 AM