This case study documents responses in a headwater macroinvertebrate assemblage to insecticide pollution and hydrological drought. In 2014, the Doubravka brook (Czech Republic) was damaged by a large overflow of a mixture of chlorpyrifos (CPS) and cypermethrin (CP). In 2016–2017, this brook was then affected by severe drought that sometimes led to an almost complete absence of surface water. We found significant relationships between the strength of both these disturbances and the deeper taxonomic levels of both the overall macroinvertebrate assemblage (classes) and the arthropod assemblage alone (orders and dipteran families), as well as the functional feeding groups (FFGs). The CPS-CP contamination was mostly negatively correlated to arthropod and non-arthropod taxa and was positively correlated only with FFG collector-gatherers; on the other hand, the drought was negatively correlated to Simuliidae, Ephemeroptera, Trichoptera, and the FFG of grazer-scrapers and passive filterers. Drought conditions correlated most positively with Isopoda, Ostracoda, Heteroptera, adult Coleoptera, and predator and active filterer FFGs. The chosen eco-indicators (SPEAR_pesticides, SPEAR_refuge, BMWP, and EPT) used as support information reveal the poor ecological status of the whole assemblage, including the control site, the cause of which is most likely to be the exploitation of the adjacent catchment area by large-scale agriculture. This type of agricultural exploitation will undoubtedly affect macroinvertebrate assemblages as a result of agrochemical and soil inputs during run-off events and will also exacerbate the effect of droughts when precipitation levels drop.

中文翻译：

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杀虫剂和干旱是大型农业开发集水区溪流大型无脊椎动物组合的致命组合

该案例研究记录了源头大型无脊椎动物集合对杀虫剂污染和水文干旱的响应。2014年，毒死rif（CPS）和氯氰菊酯（CP）的混合物大量溢流损坏了杜布拉夫卡溪（捷克共和国）。在2016–2017年，这条小溪随后遭受严重干旱的影响，有时甚至导致几乎完全没有地表水。我们发现这两种干扰的强度与整体大型无脊椎动物组合（类）和节肢动物组合（有序和双足类）以及功能性进食组（FFG）的较深分类标准之间存在显着关系。CPS-CP污染主要与节肢动物和非节肢动物类群负相关，仅与FFG采集者正相关。另一方面，干旱与Simuliidae，Ephemeroptera，Trichoptera以及grazer-scrapers和被动过滤器的FFG呈负相关。干旱状况与Isopoda，Osracoda，Heteroptera，成年鞘翅目以及捕食者和主动滤器FFGs呈正相关。选择的生态指标（SPEAR_农药，SPEAR_避难所，BMWP和EPT）作为支持信息，揭示了整个种群（包括控制地点）的不良生态状况，其原因很可能是大规模农业对邻近集水区的利用。毫无疑问，在径流期间，由于农用化学品和土壤的投入，这种类型的农业开发将影响大型无脊椎动物的种群，当降水量下降时，也将加剧干旱的影响。