Reindeer ecology in a changing Arctic: Snow, vegetation, and traditional ecological knowledge

Abstract

The cumulative effects of anthropogenic development on reindeer (Rangifer tarandus, L.), and how these impacts interact with a changing climate, remain largely unknown. To fill this knowledge gap, this thesis begins by examining how presence and winter accessibility of reindeer forage is affected by silviculture in boreal forests of northern Sweden, as stands progress from clear-cut to mature forests. Original surveys show that the abundance of various lichen species generally increases with stand age, highlighting the roles of competition, grazing pressure and disturbance in this process. Snow depth is consistently shallower in old stands, and the number of ice layers in the snow column increases throughout winter, affecting the ability of reindeer to dig to ground-lying lichens. Overall, there is upto 61 % lower availability of forage in clear-cut sites compared to old stands, showing that changes in forest structure have notable impacts on reindeer grazing.
Next the effects of multiple forms of land-use, individually and cumulatively, on reindeer are examined. A model is created which considers the impact of silviculture, roads, mines, hydropower stations, settlements and four climate scenarios, on reindeer populations over 50 years. All scenarios saw a loss of 54-100 % of reindeer, and only 25 % resulted in economically sustainable herd sizes for reindeer herders. Climate had the greatest impact on reindeer survival within the model. The results highlight that current and many projected future scenarios of land development create an unsustainable environment for reindeer and herders.
Alongside natural science methodologies, the role of history, politics and economics in the lives of Indigenous Sámi herders are explored, arguing that to gain a fuller understanding of reindeer ecology in a changing system, it is essential to consider both the biological and human context surrounding them. The processes of trying to carry out research using both scientific and traditional ecological knowledges are discussed, providing suggestions for others undertaking interdisciplinary work in this field.