Systems Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT) GmbH, Fahrenheitstraße 6, 28359, Bremen, Germany.
Systems Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT) GmbH, Fahrenheitstraße 6, 28359, Bremen, Germany.
Environ Pollut. 2020 Aug;263(Pt A):114394. doi: 10.1016/j.envpol.2020.114394. Epub 2020 Mar 20.
Evidence is accumulating about the impacts of plastics on marine life. The prevalence of plastics in seabird nests has been used as an indicator of levels of this pollutant in the ocean. However, the lack of a framework for defining sample sizes and errors associated with estimating the prevalence of plastic in nests prevents researchers from optimising time and reducing impacts of fieldwork. We present a method to determine the confidence intervals for the prevalence of debris in seabird nests and provide, for the first time, information on the prevalence of these items in nests of the Hartlaub's gull Larus hartlaubii, the African penguin Spheniscus demersus, the great white pelican Pelecanus onocrotalus, and the white-breasted cormorant Phalacrocorax lucidus in South Africa. The method, based on observations and resampling simulations and tested here for nests of 12 seabird species from 15 locations worldwide, allows for straightforward hypothesis testing. Appropriate sample sizes can be defined by combining this method with a Bayesian approach. We show that precise estimates of prevalence of debris in nests can be obtained by sampling around 250 nests. Smaller sample sizes can be useful for obtaining rough estimates. For the Hartlaub's gull, the African penguin, the great white pelican, and the white-breasted cormorant, debris were present in 0.75%, 3.00%, 6.41%, and 25.62% of the respective nests. Our approach will help researchers to determine errors associated with the prevalence of debris recorded in seabird nests and to optimise time and costs spent collecting data. It can also be applied to estimate confidence intervals and define sample sizes for assessing prevalence of plastic ingestion by any organism.
有关塑料对海洋生物影响的证据正在不断积累。海鸟巢中塑料的存在已被用作海洋中这种污染物水平的指标。然而，由于缺乏定义样本量和估计巢中塑料存在率的误差的框架，研究人员无法优化时间并减少实地工作的影响。我们提出了一种确定海鸟巢中碎片存在率置信区间的方法，并首次提供了在南非哈特劳布鸬鹚（Larus hartlaubii）、非洲企鹅（Spheniscus demersus）、大白鹈鹕（Pelecanus onocrotalus）和白胸翡翠（Phalacrocorax lucidus）巢中这些物品存在率的信息。该方法基于观察和重采样模拟，在此针对来自全球 15 个地点的 12 种海鸟的巢穴进行了测试，允许进行简单的假设检验。通过将这种方法与贝叶斯方法结合使用，可以定义适当的样本量。我们表明，通过对大约 250 个巢穴进行采样，可以获得巢中碎片存在率的精确估计。较小的样本量可用于获得粗略估计。对于哈特劳布鸬鹚、非洲企鹅、大白鹈鹕和白胸翡翠，相应巢穴中存在 0.75%、3.00%、6.41%和 25.62%的碎片。我们的方法将帮助研究人员确定与海鸟巢中记录的碎片存在率相关的误差，并优化收集数据的时间和成本。它还可以用于估计任何生物体摄入塑料的存在率的置信区间和定义样本量。
