Understorey changes after an extreme drought event are modulated by overstorey tree species mixtures in thermophilous deciduous forests

Understorey vegetation is a key component of plant biodiversity in forests. Events extreme drought are potential major driver change this layer. Although these predicted to increase frequency and duration due climate change, their impacts on understorey communities still unknown. In paper, we re-surveyed set 36 plots mature thermophilous deciduous forests eight months after the end an extremely dry period 2016–2017. The part European network representing gradient overstorey richness from 1- 5-tree species mixtures, with variable composition. We took advantage model system test hypothesis that identity dominant trees may modulate impact cover, diversity spring 2018, ca. 50% reduction cover occurred both mono-specific mixed plots. Species evenness Shannon ?-diversity increased monospecific plots, abundance tree at juvenile stage appearance non-forest specialists did not occur mixtures. Overstorey effects were negligible. Overall compositional changes moderate, though larger those less drought-adapted overstorey. Ellenberg ecological profile community significantly but light values tended contrary Overall, our findings provide circumstantial support higher stability shortly drought, despite variations. More studies monitoring programs needed assess recovery capacity resilience such events long-term.