ABSTRACT: Many sea turtle studies globally use counts of nesting activities as a proxy for population abundance estimates and as an indicator of trends within the population. Often these populations are sampled temporally and spatially, but few previous studies have examined the impact of different sampling techniques on the accuracy of these estimates. We investigated temporal sampling errors using a multi-species approach, examining 10 populations comprising green, loggerhead and leatherback sea turtles. Sampling errors were investigated from random, regular and continuous sampling regimes spanning 5-80% coverage. A count approach was used rather than an individual-based capture-mark-recapture approach to broaden the scope and application of the research. Modelling showed that even low survey coverage of 5% gave reasonably accurate estimates of annual nesting activity, with estimated errors of ca. 20% (mean + 1 SD equalling 84.1% of surveys). Survey error is low relative to changes in abundance from the inter-annual variations in nesting activity that occur in sea turtle populations. Thus, annual studies are important to estimate sea turtle abundance, even if these studies have low survey coverage. An increase in survey effort may be more cost effective if spent combining estimates of total nesting activity with sampling turtles as part of a capture-mark-recapture study. This approach will provide a second estimate of annual abundance as well as an estimate of demographic parameters including clutch frequencies, remigration intervals, survivorship, immigration and emigration. This estimation of sampling errors may be useful in the design of monitoring programmes and can be used to guide management and policy decisions.

中文翻译：

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采样筑巢海龟：优化调查设计以尽量减少误差

摘要：全球许多海龟研究使用筑巢活动的计数作为种群丰度估计的代理和种群内趋势的指标。通常，这些人口会在时间和空间上进行抽样，但以前的研究很少检查不同抽样技术对这些估计准确性的影响。我们使用多物种方法调查了时间抽样误差，检查了 10 个种群，包括绿海龟、红海龟和棱皮海龟。从覆盖 5-80% 的随机、定期和连续抽样制度中调查抽样误差。使用计数方法而不是基于个体的捕获-标记-重新捕获方法来扩大研究的范围和应用。建模表明，即使是 5% 的低调查覆盖率也对年度筑巢活动给出了合理准确的估计，估计误差约为 20%（平均值 + 1 SD 等于 84.1% 的调查）。相对于海龟种群中发生的筑巢活动的年际变化引起的丰度变化而言，调查误差较低。因此，年度研究对于估计海龟丰度很重要，即使这些研究的调查覆盖率很低。如果将总筑巢活动的估计与抽样海龟作为捕获-标记-重新捕获研究的一部分相结合，那么增加调查工作可能更具成本效益。这种方法将提供对年丰度的第二次估计以及对人口参数的估计，包括离群频率、迁徙间隔、存活率、移民和迁徙。