Impacts of future climate on the distribution of 4 bumblebee species in the Qinghai-Tibet Plateau.

Climate warming threatens dozens of bumblebee species across the world, including alpine areas. In plateaus with vast and continuous high-altitude areas, bumblebees' response to climate warming may be relatively optimistic. To study the species' responses to future climate in the Qinghai-Tibet Plateau, we quantified the suitable areas for 4 local bumblebee indicator species under current and future climate scenarios (Shared Socio-economic Pathway 126, 245, 370, and 585 in 2,100) using MaxEnt models. Suitable areas of indicator species were stacked to obtain the species richness layer. According to the acreage and connectivity of suitable areas and the acreage of the high richness area, a warmed climate will be more suitable for bumblebees' distribution compared to the current climate. The SSP 126 and SSP 245 scenario will be the 2 most suitable. Meanwhile, with climate warming, suitable areas and the high richness areas will move to high altitudes and their altitude range will decrease. The greater suitability in warmed climates may be caused by the topography of plateaus, which provides an opportunity for bumblebees to migrate to cooler areas. However, mitigation of warming is still necessary because an excessively warm climate will decrease bumblebees' habitat suitability. In plateaus, species in lower altitudes will migrate to higher altitudes, conservation in high altitudes should pay attention to not only original species, but also immigrated species. In lower altitudes, many species will migrate to higher altitudes, then local bumblebee diversity will decrease. Local conservation should be focused on these lower altitude areas.