title: Climate, icing, and wild arctic reindeer: past relationships and future prospects.
abstract: Across the Arctic, heavy rain-on-snow (ROS) is an "extreme" climatic event that is expected to become increasingly frequent with global warming. This has potentially large ecosystem implications through changes in snowpack properties and ground-icing, which can block the access to herbivores' winter food and thereby suppress their population growth rates. However, the supporting empirical evidence for this is still limited. We monitored late winter snowpack properties to examine the causes and consequences of ground-icing in a Svalbard reindeer (Rangifer tarandus platyrhynchus) metapopulation. In this high-arctic area, heavy ROS occurred annually, and ground-ice covered from 25% to 96% of low-altitude habitat in the sampling period (2000-2010). The extent of ground-icing increased with the annual number of days with heavy ROS (> or = 10 mm) and had a strong negative effect on reindeer population growth rates. Our results have important implications as a downscaled climate projection (2021-2050) suggests a substantial future increase in ROS and icing. The present study is the first to demonstrate empirically that warmer and wetter winter climate influences large herbivore population dynamics by generating ice-locked pastures. This may serve as an early warning of the importance of changes in winter climate and extreme weather events in arctic ecosystems.
authors.affiliation: Centre for Conservation Biology (CCB), Department of Biology, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway. brage.hansen@bio.ntnu.no
authors.forename: Brage Bremset
authors.initials: BB
authors.lastname: Hansen
authors.forename: Ronny
authors.initials: R
authors.lastname: Aanes
authors.forename: Ivar
authors.initials: I
authors.lastname: Herfindal
authors.forename: Jack
authors.initials: J
authors.lastname: Kohler
authors.forename: Bernt-Erik
authors.initials: BE
authors.lastname: Saether
mesh_terms: D000818:Animals; D057231:Climate Change; D005247:Feeding Behavior / Q000502:physiology*; D007053:Ice; D009664:Norway; D063245:Plant Development; D011891:Rain; D012053:Reindeer / Q000502:physiology*; D012621:Seasons; D012914:Snow
chemical_list: D007053:Ice