Population decline in the Delta caribou herd with reference to other Alaskan herds
After growing continuously for nearly 15 years, the Delta caribou herd began to decline in 1989. Most other Interior Alaskan herds also began declining. In the Delta herd, and in other herds, the declines were caused primarily by high summer mortality of calves and increased natural mortality of adu...
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| Format: | Article |
| Language: | English |
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Septentrio Academic Publishing
1996-01-01
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| Series: | Rangifer |
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| Online Access: | https://septentrio.uit.no/index.php/rangifer/article/view/1221 |
| _version_ | 1828409917704241152 |
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| author | Patrick Valkenburg et al. |
| author_facet | Patrick Valkenburg et al. |
| author_sort | Patrick Valkenburg et al. |
| collection | DOAJ |
| description | After growing continuously for nearly 15 years, the Delta caribou herd began to decline in 1989. Most other Interior Alaskan herds also began declining. In the Delta herd, and in other herds, the declines were caused primarily by high summer mortality of calves and increased natural mortality of adult females. Other minor causes included increased winter mortality of calves, and reduced parturition rates of 3-year-old and older females. The decline in the Delta herd also coincided with increased wolf (Canis lupus) numbers, winters with deeper than normal snow, and warm summers. Mean body weight of annual samples of 10-month-old female calves was consistently low during the decline. Except in some of the smallest Interior Alaskan herds, we conclude that evidence for population regulation in Alaskan caribou is weak, and that herds are likely to fluctuate within a wide range of densities due to complex interactions of predation and weather. Unless wolf numbers are influenced by man, the size of a caribou herd in a given year is likely to be largely a function of its size during the previous population low and the number of years of favorable weather in the interim. |
| first_indexed | 2024-12-10T12:03:35Z |
| format | Article |
| id | doaj.art-3599bf5695244619af002463e8e7d6a7 |
| institution | Directory Open Access Journal |
| issn | 1890-6729 |
| language | English |
| last_indexed | 2024-12-10T12:03:35Z |
| publishDate | 1996-01-01 |
| publisher | Septentrio Academic Publishing |
| record_format | Article |
| series | Rangifer |
| spelling | doaj.art-3599bf5695244619af002463e8e7d6a72022-12-22T01:49:31ZengSeptentrio Academic PublishingRangifer1890-67291996-01-0116410.7557/2.16.4.12211151Population decline in the Delta caribou herd with reference to other Alaskan herdsPatrick Valkenburg et al.0Alaska Department of Fish and Game, 1300 College Road, Fairbanks, Alaska 99701 U.S.A.After growing continuously for nearly 15 years, the Delta caribou herd began to decline in 1989. Most other Interior Alaskan herds also began declining. In the Delta herd, and in other herds, the declines were caused primarily by high summer mortality of calves and increased natural mortality of adult females. Other minor causes included increased winter mortality of calves, and reduced parturition rates of 3-year-old and older females. The decline in the Delta herd also coincided with increased wolf (Canis lupus) numbers, winters with deeper than normal snow, and warm summers. Mean body weight of annual samples of 10-month-old female calves was consistently low during the decline. Except in some of the smallest Interior Alaskan herds, we conclude that evidence for population regulation in Alaskan caribou is weak, and that herds are likely to fluctuate within a wide range of densities due to complex interactions of predation and weather. Unless wolf numbers are influenced by man, the size of a caribou herd in a given year is likely to be largely a function of its size during the previous population low and the number of years of favorable weather in the interim.https://septentrio.uit.no/index.php/rangifer/article/view/1221caribourainfallRangifersnowtemperatureweather |
| spellingShingle | Patrick Valkenburg et al. Population decline in the Delta caribou herd with reference to other Alaskan herds Rangifer caribou rainfall Rangifer snow temperature weather |
| title | Population decline in the Delta caribou herd with reference to other Alaskan herds |
| title_full | Population decline in the Delta caribou herd with reference to other Alaskan herds |
| title_fullStr | Population decline in the Delta caribou herd with reference to other Alaskan herds |
| title_full_unstemmed | Population decline in the Delta caribou herd with reference to other Alaskan herds |
| title_short | Population decline in the Delta caribou herd with reference to other Alaskan herds |
| title_sort | population decline in the delta caribou herd with reference to other alaskan herds |
| topic | caribou rainfall Rangifer snow temperature weather |
| url | https://septentrio.uit.no/index.php/rangifer/article/view/1221 |
| work_keys_str_mv | AT patrickvalkenburgetal populationdeclineinthedeltacaribouherdwithreferencetootheralaskanherds |