Grassland intensification dramatically impacts grasshoppers: Experimental evidence for direct and indirect effects of fertilisation and irrigation

European mountain hay meadows are hosting an exceptionally rich biodiversity. They currently threatened by both land abandonment and farming intensification via aerial irrigation slurry application. The consequences of grassland on arthropods still poorly documented, which is a serious handicap to proposing ecologically-friendly management guidance. Six experimental treatments mimicking gradient intensity (including irrigation, fertilisation various combinations thereof) were initiated in 2010 at twelve montane subalpine Swiss meadow sites. In 2013, we sampled orthopterans assess the influence practice that taxonomic group. parallel, changes vegetation height ambient temperature (at 10 cm above ground level) induced process quantified order better appraise underlying mechanisms. Intensification had negative impact Caelifera (grasshoppers), with decreases densities species richness reaching as much 70% 50%, respectively, most intensively managed treatment plots. furthermore led marked increase mean cooling up 4.2 °C. Such microhabitat microclimate alterations likely affect development, particular thermophilous species. contrast, Ensifera (bushcrickets) showed no significant response our manipulations. Finally, application sprinklers alone limited microclimate. We conclude orthopterans, Caelifera, fairly sensitive intensification: should be avoided focal areas for biodiversity conservation.