Influence of weather on movements and migrations of caribou
Dissertation (Ph.D.) University of Alaska Fairbanks, 1991 Caribou (Rangifer tarandus granti) are typified by use of calving grounds and by making twice-annual migrations between summer and winter ranges. This study used satellite technology to examine the influence of weather on calving site selecti...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/9370 2023-05-15T15:40:39+02:00 Influence of weather on movements and migrations of caribou Eastland, Warren George 1991 http://hdl.handle.net/11122/9370 unknown http://hdl.handle.net/11122/9370 Forestry Animal sciences Range management Zoology Dissertation phd 1991 ftunivalaska 2023-02-23T21:37:15Z Dissertation (Ph.D.) University of Alaska Fairbanks, 1991 Caribou (Rangifer tarandus granti) are typified by use of calving grounds and by making twice-annual migrations between summer and winter ranges. This study used satellite technology to examine the influence of weather on calving site selection, autumn and spring movements, and timing and directionality of migrations of the Porcupine Caribou Herd (PCH) that calves in northeast Alaska and northwestern Canada adjacent to the Beaufort Sea. The reigning hypothesis that females select areas that become free of snow early for calving sites was rejected because females selected areas of $>$75% snowcover ($P=0.02$) preferentially for calving. Benefits from use of mottled snow for calving were access to vegetation in its early phenological stages and protection for their calves from predators. Access to nutritious forage and predator avoidance appeared to be the main reasons for calving site selection. Multiple linear regression models were used to examine rate and direction of autumn and spring migrations using weather data from U.S. and Canadian sources. Weather was found to be both an ultimate and an approximate influence on the rate and direction of autumn migration ($P<0.05$). Explanatory power of the equations was low ($R\sb{a}\sp2<0.41$). Proximal causes of movement were best explained by caribou tracking of vegetation phenology. Pre-rut movements in September lacked concurrence between rate and direction whereas rate and direction were related in October. Models of spring migration of parturient females indicated a common timing among years, late April and early May, and movements were significantly affected by weather ($P<0.02$), in particular snow depths and conditions that would affect foraging and traveling conditions. This study suggests that: (1) females preferentially use areas of delayed snow melt for calving, and (2) weather influences both spring and autumn migration of caribou, although the effect of weather may be more indirect ... Doctoral or Postdoctoral Thesis Beaufort Sea caribou Rangifer tarandus Alaska University of Alaska: ScholarWorks@UA Canada Fairbanks |
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Open Polar |
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University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
unknown |
topic |
Forestry Animal sciences Range management Zoology |
spellingShingle |
Forestry Animal sciences Range management Zoology Eastland, Warren George Influence of weather on movements and migrations of caribou |
topic_facet |
Forestry Animal sciences Range management Zoology |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 1991 Caribou (Rangifer tarandus granti) are typified by use of calving grounds and by making twice-annual migrations between summer and winter ranges. This study used satellite technology to examine the influence of weather on calving site selection, autumn and spring movements, and timing and directionality of migrations of the Porcupine Caribou Herd (PCH) that calves in northeast Alaska and northwestern Canada adjacent to the Beaufort Sea. The reigning hypothesis that females select areas that become free of snow early for calving sites was rejected because females selected areas of $>$75% snowcover ($P=0.02$) preferentially for calving. Benefits from use of mottled snow for calving were access to vegetation in its early phenological stages and protection for their calves from predators. Access to nutritious forage and predator avoidance appeared to be the main reasons for calving site selection. Multiple linear regression models were used to examine rate and direction of autumn and spring migrations using weather data from U.S. and Canadian sources. Weather was found to be both an ultimate and an approximate influence on the rate and direction of autumn migration ($P<0.05$). Explanatory power of the equations was low ($R\sb{a}\sp2<0.41$). Proximal causes of movement were best explained by caribou tracking of vegetation phenology. Pre-rut movements in September lacked concurrence between rate and direction whereas rate and direction were related in October. Models of spring migration of parturient females indicated a common timing among years, late April and early May, and movements were significantly affected by weather ($P<0.02$), in particular snow depths and conditions that would affect foraging and traveling conditions. This study suggests that: (1) females preferentially use areas of delayed snow melt for calving, and (2) weather influences both spring and autumn migration of caribou, although the effect of weather may be more indirect ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Eastland, Warren George |
author_facet |
Eastland, Warren George |
author_sort |
Eastland, Warren George |
title |
Influence of weather on movements and migrations of caribou |
title_short |
Influence of weather on movements and migrations of caribou |
title_full |
Influence of weather on movements and migrations of caribou |
title_fullStr |
Influence of weather on movements and migrations of caribou |
title_full_unstemmed |
Influence of weather on movements and migrations of caribou |
title_sort |
influence of weather on movements and migrations of caribou |
publishDate |
1991 |
url |
http://hdl.handle.net/11122/9370 |
geographic |
Canada Fairbanks |
geographic_facet |
Canada Fairbanks |
genre |
Beaufort Sea caribou Rangifer tarandus Alaska |
genre_facet |
Beaufort Sea caribou Rangifer tarandus Alaska |
op_relation |
http://hdl.handle.net/11122/9370 |
_version_ |
1766373431832477696 |