Caribou, water, and ice - fine-scale movements of a migratory arctic ungulate in the context of climate change

• Published in: Movement Ecology
• Main Authors: Côté, Steeve D., St-Laurent, Martin-Hugues, Leblond, Mathieu
• Format: Other/Unknown Material
• Language: English
• Published: BioMed Central 2016
• Subjects: Behaviour; Climate; Global change; Long-distance migration; Migratory caribou; Movements; Phenology; Rangifer tarandus; Scales; Step selection function; Space use; Caribou des bois > Migration > Facteurs climatiques; Arctic; Canada; Rivière aux Feuilles; Climate change
• Online Access: https://hdl.handle.net/20.500.11794/1061; https://doi.org/10.1186/s40462-016-0079-4

Background: Freshwater lakes and rivers of the Northern Hemisphere have been freezing increasingly later and thawing increasingly earlier during the last century. With reduced temporal periods during which ice conditions are favourable for locomotion, freshwater bodies could become impediments to the inter-patch movements, dispersion, or migration of terrestrial animals that use ice-covered lakes and rivers to move across their range. Studying the fine-scale responses of individuals to broad-scale changes in ice availability and phenology would help to understand how animals react to ongoing climate change, and contribute to the conservation and management of endangered species living in northern environments. Between 2007 and 2014, we equipped 96 migratory caribou Rangifer tarandus caribou from the Rivière-aux-Feuilles herd in northern Québec (Canada) with GPS telemetry collars and studied their space use. We measured contemporary (digital MODIS maps updated every 8 days, 2000–2014) and historical (annual observations, 1947–1985) variations in freshwater-ice availability and evaluated the concurrent responses of caribou to these changes. Results : Ice had a positive influence on caribou movement rates and directionality, and caribou selected ice and avoided water when moving across or in the vicinity of large water bodies. When ice was unavailable, caribou rarely swam across (6 % of crossings) and frequently circumvented water bodies for several km. Although ice phenology did not change significantly during our study, climate projections indicated that ice availability could decrease considerably before the end of the century, generating a ~28 % increase in distance travelled by caribou during the early spring and fall migrations. Conclusions : We demonstrated that ice availability influenced the movements of a migratory arctic ungulate. Warmer air temperatures in the Arctic will undoubtedly modify the phenology of ice forming on freshwater lakes and rivers. If migratory caribou are unable to adjust the timing ...