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首页> 外文学位 >Variability in a crabeater seal population and the marine ecosystem near the Antarctic Peninsula.
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Variability in a crabeater seal population and the marine ecosystem near the Antarctic Peninsula.

机译：南极半岛附近海螯虾海豹种群和海洋生态系统的变异性。

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摘要

A population of crabeater seals, Lobodon carcinophagus, inhabiting the sea ice and waters surrounding the Antarctic Peninsula was studied to clarify the nature of variability in the population age structure. Understanding this variability is important for efforts to identify effects of climate change and marine resource exploitation in the Southern Ocean. The fundamental question is first addressed, of whether the variability is a genuine demographic phenomenon or an artifact of sampling or analysis. Then the evidence is examined for support of an interpretation of periodicity. Because age-estimation errors are known to reduce variability in estimates of cohort strength, and because crabeater seal ages are subject to estimation errors, the effects of those errors are evaluated. Features of the crabeater seal natural history were used to generate hypotheses about expected correlations between the cohort strengths and sea ice extent, surface air temperature, the Southern Oscillation, and an index of leopard seal (Hydrurga leptonyx) populations.;The primary data for this study are age estimates from 2,852 crabeater seals collected near the Antarctic Peninsula between 1964 and 1990. Assuming that the seals were collected at random with respect to age, these "catch-at-age" data were analyzed by a maximum likelihood technique, yielding a time series of relative cohort strengths for the 1945-1988 cohorts and a new life table for crabeater seals. Bootstrap and Monte Carlo techniques were used to assess the uncertainty of the estimates and the power of the sampling scheme to detect true fluctuations in cohort strengths. It was found that if the assumptions are correct, the relative cohort strengths are well determined by the data and therefore unlikely to be artifacts of sampling or analysis. Time series modeling of the data, however, indicated that there is little support for interpreting the fluctuations in cohort strength as periodic. Statistical modeling of the age estimation error process yielded a series of cohort strengths with more variability, as expected, but with features that may reflect invalid assumptions about the age estimates for a portion of the sample. Time series of sea ice extent, surface air temperature, a measure of the Southern Oscillation, and numbers of leopard seals sighted annually at Macquarie Island were unable to explain a significant fraction of the crabeater seal cohort variability. (Abstract shortened by UMI.).
机译：研究了居住在南极半岛周围海冰和水域的海螯虾海豹（Lobodon carcinophagus）种群，以阐明种群年龄结构变异的性质。理解这种可变性对于确定气候变化和南大洋海洋资源开发的影响至关重要。首先要解决一个基本问题，即变异性是真正的人口统计学现象还是抽样或分析的产物。然后，检查证据以支持周期性解释。由于已知年龄估计误差会降低队列强度估计的可变性，并且由于海龟的海豹年龄会受到估计误差的影响，因此将评估这些误差的影响。使用甲壳动物海豹自然史的特征来得出有关队列强度与海冰范围，地表气温，南部涛动和豹海豹（Hydrurga leptonyx）种群指数之间的预期相关性的假设。这项研究是根据1964年至1990年在南极半岛附近收集的2,852只海豹海豹的年龄估算得出的。假设海豹是随年龄随机收集的，则这些“年龄捕获”数据通过最大似然技术进行了分析，得出了1945-1988年队列相对队列强度的时间序列，以及海豹捕食者海豹的新生命表。 Bootstrap和蒙特卡洛技术用于评估估计的不确定性，以及抽样方案检测队列强度真正波动的能力。已经发现，如果这些假设是正确的，则相对队列强度由数据很好地确定，因此不可能是抽样或分析的产物。然而，数据的时间序列建模表明，几乎没有支持将队列强度的波动解释为周期性的。对年龄估计误差过程的统计建模产生了一系列的队列强度，如预期的那样，具有更大的可变性，但是其特征可能反映了对一部分样本的年龄估计的无效假设。麦格理岛每年观测到的海冰范围，地表气温，南部涛动的度量以及豹海豹的数量的时间序列无法解释很大一部分海龟的海豹群变异。 （摘要由UMI缩短。）。

著录项

  • 作者

    Boveng, Peter Laurens.;

  • 作者单位

    Montana State University.;

  • 授予单位 Montana State University.;
  • 学科 Ecology.;Ocean engineering.
  • 学位 Ph.D.
  • 年度 1993
  • 页码 122 p.
  • 总页数 122
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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