Molecular analysis of DNA left in the environment, known as environmental DNA (eDNA), has proven to be a powerful and cost-effective approach to infer occurrence of species. Nonetheless, relating measurements of eDNA concentration to population abundance remains difficult because detailed knowledge on the processes that govern spatial and temporal distribution of eDNA should be integrated to reconstruct the underlying distribution and abundance of a target species. In this study, we propose a general framework of abundance estimation for aquatic systems on the basis of spatially replicated measurements of eDNA. The proposed method explicitly accounts for production, transport and degradation of eDNA by utilizing numerical hydrodynamic models that can simulate the distribution of eDNA concentrations within an aquatic area. It turns out that, under certain assumptions, population abundance can be estimated via a Bayesian inference of a generalized linear model. Application to a Japanese jack mackerel (Trachurus japonicus) population in Maizuru Bay revealed that the proposed method gives an estimate of population abundance comparable to that of a quantitative echo sounder method. Furthermore, the method successfully identified a source of exogenous input of eDNA (a fish market), which may render a quantitative application of eDNA difficult to interpret unless its effect is taken into account. These findings indicate the ability of eDNA to reliably reflect population abundance of aquatic macroorganisms; when the “ecology of eDNA” is adequately accounted for, population abundance can be quantified on the basis of measurements of eDNA concentration.

中文翻译：

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通过整合环境 DNA 和流体动力学模型的定量数据来估计鱼类种群丰度

对环境中残留的 DNA 进行分子分析，称为环境 DNA (eDNA)，已被证明是一种推断物种出现的强大且具有成本效益的方法。尽管如此，将 eDNA 浓度的测量与种群丰度相关联仍然很困难，因为应整合有关控制 eDNA 空间和时间分布的过程的详细知识，以重建目标物种的潜在分布和丰度。在这项研究中，我们基于 eDNA 的空间复制测量提出了水生系统丰度估计的一般框架。所提出的方法通过利用可以模拟水生区域内 eDNA 浓度分布的数值流体动力学模型，明确说明了 eDNA 的产生、运输和降解。事实证明，在某些假设下，可以通过广义线性模型的贝叶斯推断来估计人口丰度。对日本鲭鱼的应用（舞鹤湾的Trachurus japonicus ) 种群表明，所提出的方法给出了与定量回声测深仪方法相当的种群丰度估计。此外，该方法成功地确定了 eDNA（鱼市）的外源输入来源，这可能会使 eDNA 的定量应用难以解释，除非考虑其影响。这些发现表明 eDNA 能够可靠地反映水生大型生物的种群丰度；当“eDNA 生态学”得到充分考虑时，可以根据 eDNA 浓度的测量来量化种群丰度。