Non-native minnows cause much larger negative effects than trout on littoral macroinvertebrates of high mountain lakes

Despite being naturally fishless, the widespread introduction of trout and minnows is threatening conservation high mountain lakes all over world. Previous studies have reported that amphibians quickly disappear after introduction, followed by many conspicuous invertebrates. Here, we studied effects versus on littoral macroinvertebrate community 54 from Pyrenees, covering a gradient environmental characteristics. The relative importance fish compared to other variables in explaining communities was assessed using distance-based redundancy analysis (dbRDA) multivariate regression tree (MRT) find main thresholds. Both dbRDA MRT approaches revealed minnow density most important variable negatively determining structure, aquatic macrophytes, which increased taxa richness. occurrence abundance relevant analysed relation densities factors binomial gamma generalized linear models (GLM). GLM suggested had an impact distribution swimmer caused declines clinger burrower taxa. Minnows restricted more than affected wide variety body sizes functional groups. Indeed, found were responsible for dramatic biodiversity loss community. fast spread areas great concern lake macroinvertebrates. Urgent measures stop introductions are strongly recommended.