Institute for Environmental Sciences, University Koblenz-Landau, Fortstrasse 7, 76829 Landau in der Pfalz, Germany.
Institute for Environmental Sciences, University Koblenz-Landau, Fortstrasse 7, 76829 Landau in der Pfalz, Germany.
Sci Total Environ. 2022 Aug 25;836:155688. doi: 10.1016/j.scitotenv.2022.155688. Epub 2022 May 4.
In the last decades, several studies have shown that pesticides frequently occur above water quality thresholds in small streams draining arable land and are associated with changes in invertebrate communities. However, we know little about the potential propagation of pesticide effects from agricultural stream sections to least impacted stream sections that can serve as refuge areas. We sampled invertebrates and pesticides along six small streams in south-west Germany. In each stream, the sampling was conducted at an agricultural site, at an upstream forest site (later considered as "refuge"), and at a transition zone between forest and agriculture (later considered as "edge"). Pesticide exposure was higher and the proportion of pesticide-sensitive species (SPEAR) was lower in agricultural sites compared to edge and refuge sites. Notwithstanding, at some edge and refuge sites, which were considered as being least impacted, we estimated unexpected pesticide toxicity (sum toxic units) exceeding thresholds at which field studies suggested adverse effects on freshwater invertebrates. We conclude that organisms in forest sections within a few kilometres upstream of agricultural areas can be exposed to ecologically relevant pesticide levels. In addition, although not statistically significant, the abundance of pesticide-sensitive taxa was slightly lower in edge compared to refuge sites, indicating a potential influence of adjacent agriculture. Future studies should further investigate the influence of spatial relationships, such as the distance between refuge and agriculture, for the propagation of pesticide effects and focus on the underlying mechanisms.
在过去的几十年里，有几项研究表明，在排水耕地的小河流中，农药经常出现在水质阈值之上，并与无脊椎动物群落的变化有关。然而，我们对农业溪流段到可作为避难所的受影响最小的溪流段的农药效应的潜在传播知之甚少。我们在德国西南部的六条小溪中采集了无脊椎动物和农药样本。在每条溪流中，在农业区、上游森林区（后来被认为是“避难所”）和森林与农业之间的过渡区（后来被认为是“边缘”）进行了采样。与边缘和避难所相比，农业区的农药暴露量更高，对农药敏感的物种比例（SPEAR）更低。尽管如此，在一些被认为受影响最小的边缘和避难所地区，我们估计意外的农药毒性（毒性总和单位）超过了田间研究表明对淡水无脊椎动物有不利影响的阈值。我们得出结论，在距离农业区几公里上游的森林区，生物可能会接触到具有生态意义的农药水平。此外，尽管没有统计学意义，但边缘地区对农药敏感的分类群的丰度略低于避难所，表明毗邻农业可能会产生影响。未来的研究应该进一步调查空间关系（如避难所和农业之间的距离）对农药效应传播的影响，并侧重于潜在的机制。
