Smaller, more diverse and on the way to the top: Rapid community shifts of montane wild bees within an extraordinary hot decade

Aim Global warming is assumed to restructure mountain insect communities in space and time. Theory observations along climate gradients predict that abundance richness, especially of small-bodied species, will increase with increasing temperature. However, the specific responses single species rising temperatures, such as spatial range shifts, also alter communities, calling for intensive monitoring real-world over Location German Alps pre-alpine forests south-east Germany. Methods We empirically examined temporal change wild bee its drivers two largely well-protected elevational (alpine grassland vs. forest), each sampled twice within last decade. Results detected clear abundance-based upward shifts particularly cold-adapted bumble demonstrating speed which mobile organisms can respond climatic changes. Mean annual temperature was identified main driver richness both regions. Accordingly, large overlap expectations under warming, we an abundance, low- mid-elevations gradient. Community forest gradient were only partly consistent community alpine grasslands. Main Conclusion In temperate regions, bees may initially profit from by getting more abundant diverse. Less severe differences habitat openness forested gradient, however, might moderate responses. Our study further highlights utility standardized data revealing rapid changes one