Insecticides and Drought as a Fatal Combination for a Stream Macroinvertebrate Assemblage in a Catchment Area Exploited by Large-Scale Agriculture

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