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Global analysis of cetacean line-transect surveys:detecting trends in cetacean density

机译：鲸类横断面调查的全球分析：发现鲸类密度的趋势

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摘要

Measuring the effect of anthropogenic change on cetacean populations is hampered by our lack of understanding about population status and a lack of power in the available data to detect trends in abundance. Often long-term data from repeated surveys are lacking, and alternative approaches to trend detection must be considered. We utilised an existing database of line-transect survey records to determine whether temporal trends could be detected when survey effort from around the world was combined. We extracted density estimates for 25 species and fitted generalised additive models (GAMs) to investigate whether taxonomic, spatial or methodological differences among systematic line-transect surveys affect estimates of density and whether we can identify temporal trends in the data once these factors are accounted for. The selected GAM consisted of 2 parts: an intercept term that was a complex interaction of taxonomic, spatial and methodological factors and a smooth temporal term with trends varying by family and ocean basin. We discuss the trends found and assess the suitability of published density estimates for detecting temporal trends using retrospective power analysis. In conclusion, increasing sample size through combining survey effort across a global scale does not necessarily result in sufficient power to detect trends because of the extent of variability across surveys, species and oceans. Instead, results from repeated dedicated surveys designed specifically for the species and geographical region of interest should be used to inform conservation and management.
机译：由于缺乏对人口状况的了解，以及现有数据缺乏检测丰度趋势的能力，因此无法衡量人为变化对鲸类种群的影响。通常缺少重复调查的长期数据，必须考虑趋势检测的替代方法。我们利用现有的线样调查记录数据库来确定在组合来自世界各地的调查工作时是否可以检测到时间趋势。我们提取了25个物种的密度估计值，并拟合了广义加性模型（GAM），以调查系统性线样调查之间的分类，空间或方法差异是否会影响密度估计值，并在考虑了这些因素后是否能确定数据的时间趋势。选定的GAM由两部分组成：拦截项是分类，空间和方法学因素的复杂相互作用，平滑的时项是随家庭和海盆变化的趋势。我们讨论了发现的趋势，并评估了使用回顾性功效分析的密度估计值对检测时间趋势的适用性。总而言之，由于跨调查，物种和海洋的可变性程度，通过在全球范围内组合调查工作来增加样本数量并不一定会产生足够的力量来检测趋势。取而代之的是，应使用专门针对感兴趣的物种和地理区域而进行的反复专门调查得出的结果来告知保护和管理。

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  • 来源
    《Marine ecology progress series》 |2012年第7期|p.227-240|共14页
  • 作者

    R. Jewell; L. Thomas; C. M. Harris; K. Kaschner; R. Wiff; P. S. Hammond; N. J. Quick;

  • 作者单位

    SMRU Ltd., New Technology Centre, North Haugh, St. Andrews, Fife, KY16 9SR, Scotland, Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife, KY16 8LB, UK;

    Centre for Research into Ecological and Environmental Modelling, Buchanan Gardens, University of St. Andrews,St. Andrews, Fife, KY16 9LZ, UK;

    Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife, KY16 8LB, UK, Centre for Research into Ecological and Environmental Modelling, Buchanan Gardens, University of St. Andrews,St. Andrews, Fife, KY16 9LZ, UK;

    Evolutionary Biology and Ecology Lab, Institute of Zoology, Albert-Ludwigs-University, 79104 Freiburg, Germany;

    Instituto de Fomento Pesquero (IFOP), Blanco 839, Valparaiso, Chile;

    Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife, KY16 8LB, UK;

    SMRU Ltd., New Technology Centre, North Haugh, St. Andrews, Fife, KY16 9SR, Scotland, School of Biology, University of St. Andrews, St. Andrews, Fife, KY16 9TF, UK;

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  • 正文语种 eng
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  • 关键词

    marine mammal density; population trends; generalised additive modelling; power analysis; monitoring;

    机译：海洋哺乳动物密度人口趋势;广义加性建模;功率分析;监控;

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