Bevægelsesmønstre og resource selektion hos rensdyr i Vestgrønland:Erhvervs PhD afhandling
Caribou (Rangifer tarandus groenlandicus) in the Akia-Maniitsoq population were found to be partial migrators as ca. 85 % were migrators or mixed-migrators while ca. 10 % were resident. The average distance between summer and winter home ranges depended on individual movement type; migrators and mix...
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| Format: | Book |
| Language: | English |
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2018
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| Online Access: | https://pure.au.dk/portal/da/publications/movement-patterns-and-resource-selection--insights-from-west-greenland-caribou(9d5a0328-67c9-4305-a4ed-c2faabcea2da).html https://pure.au.dk/ws/files/121612592/2018_Raundrup_IndustrialPhDThesis.pdf |
| Summary: | Caribou (Rangifer tarandus groenlandicus) in the Akia-Maniitsoq population were found to be partial migrators as ca. 85 % were migrators or mixed-migrators while ca. 10 % were resident. The average distance between summer and winter home ranges depended on individual movement type; migrators and mixed migrators moved on average 57 km between ranges, whereas resident animals moved only 7 km. Average home range sizes were larger in summer than in winter (96 km2 vs. 35 km2), and were dependent on caribou body length. Furthermore, migrators had larger home ranges than residents. The caribou selected annual home ranges, which were characterized by the presence of the vegetation types heath, copse and grassland. This corresponds to findings at patch scale where caribou preferred copse during summer while grassland and snowbed rich in lichens were preferred during winter. Analyses of the late winter diet showed that lichens made up more than 60 % of the ingested forage, which stresses the importance of vegetation types rich in lichens as winter habitats. This finding occurred despite the simultaneous expansion of shrubs in the area where the distribution of the vegetation types heath and copse increased by ca. 15 % from 1997 to 2008. Although the behavioral plasticity seen in both movement type and home range size variability is likely to favor the long-term survival of the AM caribou, the increasing shrubification of the AM region combined with the declining abundance of this caribou population, suggest that West Greenland caribou in general may become more vulnerable in a warmer climate. If the marked fluctuations in population sizes seen throughout the past 250 years are to be avoided, it is important with a management regime that includes ample areas undisturbed by humans as well as areas comprising the important winter vegetation types. This may not be an easy task as future warming may increase the shrubification even further, and economic interests may pave the way for the establishment of large-scale ... |
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