Department of Biological and Marine Sciences, University of Hull, Hull, UK.
Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
Mol Ecol. 2021 Jul;30(13):3252-3269. doi: 10.1111/mec.15670. Epub 2020 Oct 24.
Fishes stocked for recreation and angling can damage freshwater habitats and negatively impact biodiversity. The pond-associated crucian carp (Carassius carassius) is rare across Europe and is stocked for conservation management in England, but its impacts on pond biota are understudied. Freshwater invertebrates contribute substantially to aquatic biodiversity, encompassing many rare and endemic species, but their small size and high abundance complicate their assessment. Practitioners have employed sweep-netting and kick-sampling with microscopy (morphotaxonomy), but specimen size/quality and experience can bias identification. DNA and environmental DNA (eDNA) metabarcoding offer alternative means of invertebrate assessment. We compared invertebrate diversity in ponds (N = 18) with and without crucian carp using morphotaxonomic identification, DNA metabarcoding and eDNA metabarcoding. Five 2 L water samples and 3 min sweep-net samples were collected at each pond. Inventories produced by morphotaxonomic identification of netted samples, DNA metabarcoding of bulk tissue samples and eDNA metabarcoding of water samples were compared. Alpha diversity was greatest with DNA or eDNA metabarcoding, depending on whether standard or unbiased methods were considered. DNA metabarcoding reflected morphotaxonomic identification, whereas eDNA metabarcoding produced markedly different communities. These complementary tools should be combined for comprehensive invertebrate assessment. Crucian carp presence minimally reduced alpha diversity in ponds, but positively influenced beta diversity through taxon turnover (i.e., ponds with crucian carp contained different invertebrates to fishless ponds). Crucian carp presence contributes to landscape-scale invertebrate diversity, supporting continued conservation management in England. Our results show that molecular tools can enhance freshwater invertebrate assessment and facilitate development of more accurate and ecologically effective pond management strategies.
为娱乐和钓鱼而放养的鱼类会破坏淡水栖息地，并对生物多样性产生负面影响。池塘相关的鲫鱼（Carassius carassius）在整个欧洲都很罕见，在英格兰被放养用于保护管理，但它对池塘生物群的影响尚未得到充分研究。淡水无脊椎动物对水生生物多样性做出了重大贡献，其中包括许多稀有和特有物种，但它们的体型小且数量多，这使得对它们的评估变得复杂。从业者已经采用了捞网和踢踏采样与显微镜（形态分类学），但样本大小/质量和经验可能会影响鉴定的准确性。DNA 和环境 DNA（eDNA）宏条形码提供了评估无脊椎动物的替代方法。我们比较了有和没有鲫鱼的池塘中的无脊椎动物多样性，使用了形态分类学鉴定、DNA 宏条形码和 eDNA 宏条形码。在每个池塘中收集了五个 2 L 的水样和 3 分钟的捞网样本。通过网捕样本的形态分类鉴定、大块组织样本的 DNA 宏条形码和水样的 eDNA 宏条形码生成的目录进行了比较。考虑到标准或无偏方法，α多样性在 DNA 或 eDNA 宏条形码中最大。DNA 宏条形码反映了形态分类学鉴定，而 eDNA 宏条形码产生了截然不同的群落。这些互补工具应结合使用，以进行全面的无脊椎动物评估。鲫鱼的存在最小化了池塘的 α多样性，但通过分类群更替（即有鲫鱼的池塘包含与无鱼池塘不同的无脊椎动物）对 β多样性产生了积极影响。鲫鱼的存在有助于景观尺度的无脊椎动物多样性，支持英格兰继续进行保护管理。我们的研究结果表明，分子工具可以增强淡水无脊椎动物的评估，并有助于制定更准确和生态有效的池塘管理策略。
