Life history plasticity and population regulation in sea otters
Life history plasticity and population regulation in sea otters
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海獭的生活史可塑性和种群调节
DOI：
10.1034/j.1600-0706.2000.900304.x
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发表时间：
2000
期刊：
影响因子：
3.4
通讯作者：
D. Siniff
中科院分区：
文献类型：
--
作者：
D. Monson;J. Estes;J. Bodkin;D. Siniff
随年龄变化(2-3岁出生女性0.37[CI 0.21~0.53]1岁，女性出生0.83[CI 0.69~0.90]4岁)，两个地区相似。相比之下，阿姆奇卡的断奶成功率(幼崽存活到120d)比科迪亚克低近50%，4岁的雌性分别为0.52(CI0.38至0.66)和0.94(CI0.75至0.99)。在安奇卡，62%的断奶前幼崽损失发生在分娩后一个月内，79%发生在两个月内。在阿姆奇卡，断奶后的存活率也很低，因为在母崽分离一年后，只有18%的仪器化幼崽存活下来。阿姆奇卡和科迪亚克的成虫存活率似乎相似。因此，影响早期生存的因素是海獭种群调节的主要人口统计机制。通过在一段时间内保持统一的高繁殖率，并限制对任何特定繁殖活动的投资，海獭可以利用有利于幼崽生存的不可预测的环境变化。这一策略与“押注对冲”的生活史模型的预测是一致的。
varied with age (0.37 [CI0.21 to 0.53] births female 1 yr 1 for 2‐3-yr-olds, and 0.83 [CI0.69 to 0.90] for females ]4 yr old), and were similar at both areas. Weaning success (pups surviving to ]120 d), in contrast, was almost 50% lower at Amchitka than at Kodiak and for females ]4 yr of age was 0.52 (CI0.38 to 0.66) vs 0.94 (CI0.75 to 0.99), respectively. Sixty-two percent of the preweaning pup losses at Amchitka occurred within a month of parturition and 79% within two months. Postweaning survival was also low at Amchitka as only 18% of instrumented pups were known to be alive one year after mother-pup separation. Adult survival rates appeared similar at Amchitka and Kodiak. Factors affecting survival early in life thus are a primary demographic mechanism of population regulation in sea otters. By maintaining uniformly high reproductive rates over time and limiting investment in any particular reproductive event, sea otters can take advantage of unpredictable environmental changes favorable to pup survival. This strategy is consistent with predictions of ‘‘bet-hedging’’ life history models.