Environmental DNA, good or bad proxy for macroinvertebrate abundance? Allometric scaling and trait category do benefits

Macroinvertebrates play a crucial role as bioindicators of freshwater ecosystem health due to their sensitivity to pollution and human activities. Environmental DNA (eDNA) metabarcoding is a promising tool for monitoring biodiversity but faces challenges in accurately quantifying species abundance. In this study, we tested the effectiveness of eDNA methods in controlled laboratory conditions with ten macroinvertebrate species of varying sizes and body structures. We found that eDNA read abundance was strongly correlated with species abundance but not with biomass. Body structure and size significantly influenced eDNA detection, with smaller species even producing higher read counts. Using allometric scaling models, we improved the prediction of species abundance from eDNA data. These findings support the use of eDNA metabarcoding as a reliable approach for assessing macroinvertebrate diversity and abundance, with potential applications in ecological monitoring and conservation.

大型无脊椎动物（macroinvertebrates）对污染与人类活动具有较高敏感性，因此作为淡水生态系统健康的核心生物指示物发挥着关键作用。环境DNA（eDNA）元条形码技术是监测生物多样性的极具潜力的手段，但在精准量化物种丰度层面仍存在挑战。本研究在受控实验室条件下，针对10种体型、体构各异的大型无脊椎动物，验证了eDNA方法的应用效能。研究结果显示，eDNA读段丰度与物种丰度呈显著正相关，但与生物量无明显关联；体结构与体型对eDNA检测具有显著影响，体型更小的物种甚至可获得更高的读段计数。本研究借助异速生长模型，优化了基于eDNA数据的物种丰度预测效果。上述发现证实，eDNA元条形码技术可作为评估大型无脊椎动物多样性与丰度的可靠途径，在生态监测与生物保护领域具备潜在应用价值。