...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biological Conservation >Cost-effective abundance estimation of rare animals: Testing performance of small-boat surveys for killer whales in British Columbia
【24h】

Cost-effective abundance estimation of rare animals: Testing performance of small-boat surveys for killer whales in British Columbia

机译：具有成本效益的稀有动物丰度估算：不列颠哥伦比亚省的虎鲸小型船检验性能

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Top predators are often rare, subject to anthropogenic mortality, and possess life-history traits that make them inherently vulnerable to extinction. IUCN criteria recognise populations as Critically Endangered when abundance is <250 mature individuals, but estimating abundance of rare species can be more challenging than for common ones. Cost-effective methods are needed to provide robust abundance estimates. In marine environments, small boats are more widely accessible than large ships for researchers conducting sightings surveys with limited funds, but studies are needed into efficacy of small-boat surveys. This study compares line transect and mark-recapture estimates from small-boat surveys in summer 2004 and 2005 for 'northern resident' killer whales in British Columbia to true population size, known from censuses conducted by Fisheries and Oceans Canada. The line transect estimate of 195 animals (95% CI 27-559) used model averaging to incorporate uncertainty in the detection function, while the mark-recapture estimate of 239 animals (CI 154-370) used a simple two-sample Chapman estimator. Both methods produced estimates close to the true population size, which numbered 219 animals in 2004 and 235 in 2006, but both suffered from the small sample sizes and violations of some model assumptions that will vex most pilot studies of rare species. Initial abundance estimates from relatively low-cost surveys can be thought of as hypotheses to be tested as new data are collected. For species of conservation concern, any cost-effective attempt to estimate absolute abundance will assist status assessments, as long as estimates are presented with appropriate caveats.
机译：顶级掠食者通常很少见，会因人为因素而死亡，并且具有生活史特征，使它们天生就容易灭绝。 IUCN标准认为，当丰度小于250个成熟个体时，这些种群就处于极度濒危状态，但是估计稀有物种的丰度比普通物种更具挑战性。需要提供具有成本效益的方法来提供可靠的丰度估算。在海洋环境中，对于使用有限资金进行目击调查的研究人员来说，与大型船只相比，小型船只的使用更为广泛，但是还需要研究小型船只调查的有效性。这项研究将2004年和2005年夏季对不列颠哥伦比亚省的“北居民”虎鲸进行的小船调查和真实捕获的人口规模估计值与加拿大渔业和海洋局进行的普查相比较。 195只动物（95％CI 27-559）的线横断面估计使用模型平均法将不确定性纳入检测功能，而239只动物（CI 154-370）的标记捕获估计使用简单的两样本查普曼估计器。两种方法所产生的估计值均接近真实种群的数量，2004年为219只动物，2006年为235只，但都受到样本量小和违反某些模型假设的困扰，这些假设会困扰大多数稀有物种的初步研究。来自相对低成本调查的初始丰度估计可以认为是在收集新数据时要检验的假设。对于需要保护的物种，只要估算有适当的警告，任何经济有效的估算绝对丰度的尝试都将有助于状态评估。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号