BASF SE, Limburgerhof, Germany.
Bayer AG, CropScience Division, Monheim, Germany.
Integr Environ Assess Manag. 2022 Sep;18(5):1423-1433. doi: 10.1002/ieam.4563. Epub 2021 Dec 21.
Intact soil food webs are pivotal to maintaining essential soil functions, such as carbon recycling, sequestering, and biomass production. Although the functional role of micro- (e.g., bacteria and fungi) and macrofauna (e.g., earthworms) is comparatively well established, the importance of the mesofauna community (e.g., abundance and diversity of Acari and Collembola) in maintaining soil functionality is less clear. We investigated this question in a six-month field experiment in arable soil by actively manipulating mesofauna abundance and biodiversity through the application of two legacy insecticides (lindane and methamidophos) at sufficiently high doses to reduce mesofauna abundance (well above previously registered application rates; 2.5 and 7.5 kg a.s./ha for lindane, and 0.6 and 3 kg a.s./ha for methamidophos) and measure the impact on organic matter degradation. Our results demonstrate that both insecticides had reduced Collembola and Acari abundances by up to 80% over the study's six-month duration. In addition, we observed less pronounced and more complex changes in mesofauna biodiversity over time. These included insecticide-dependent temporal fluctuations (both reduction and increase) for different estimates (indices) of local (alpha)-diversity over time and no lasting impact for most estimates after six months. Even at these exceptionally high field rates, Collembola and Acari diversity was observed to generally recover by six months. In contrast, considering organic matter breakdown, we found no evidence of a treatment-related effect. These results suggest that organic matter breakdown in arable soils is likely driven by other trophic levels (e.g., microorganisms or earthworms) with only a limited influence of the mesofauna community. We discuss these findings with regard to their implications for our current understanding of soil food web function and future European soil risk assessments. Integr Environ Assess Manag 2022;18:1423-1433. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
完整的土壤食物网对于维持土壤的基本功能至关重要，例如碳循环、固碳和生物质生产。尽管微（例如细菌和真菌）和大型动物（例如蚯蚓）的功能作用已得到充分证实，但中型动物群落（例如，螨和弹尾目昆虫的丰度和多样性）在维持土壤功能方面的重要性尚不清楚。我们通过在可耕地土壤中进行为期六个月的野外实验来研究这个问题，通过应用两种旧的杀虫剂（林丹和甲胺磷）来主动操纵中型动物的丰度和生物多样性，这些杀虫剂的剂量足够高，可以降低中型动物的丰度（远远超过之前登记的施用量；林丹为 2.5 和 7.5 kg a.s./ha，甲胺磷为 0.6 和 3 kg a.s./ha），并测量对有机物质降解的影响。我们的研究结果表明，在六个月的研究期间，这两种杀虫剂使弹尾目和螨的数量减少了 80%。此外，我们还观察到随着时间的推移，中型动物生物多样性发生了更明显和更复杂的变化。这些变化包括随着时间的推移，不同估计值（指数）的本地（α）多样性出现杀虫剂依赖性的时间波动（减少和增加），并且六个月后大多数估计值没有持久影响。即使在这些异常高的田间浓度下，在六个月后，螨和弹尾目昆虫的多样性也观察到普遍恢复。相比之下，考虑到有机物质的分解，我们没有发现与处理相关的效果。这些结果表明，耕地土壤中的有机物质分解可能由其他营养级（例如微生物或蚯蚓）驱动，中型动物群落的影响有限。我们将这些发现与它们对我们当前对土壤食物网功能的理解和未来欧洲土壤风险评估的影响进行了讨论。
