Climate change effects on multi-taxa pollinator diversity and distribution along the elevation gradient of Mount Olympus, Greece

Abstract

Climate change is predicted to dramatically affect mountain biodiversity and especially mountain pollination systems due to the mutual dependence between plants and pollinators. In this work, we investigate climate change effects on pollinator distribution and diversity along the altitudinal gradient of Mt. Olympus, a biodiversity hotspot.We used a species distribution modelling framework and predicted species richness hotspots, potential distribution and altitude change for 114 pollinator species, comprising bees, butterflies, and hoverflies along the altitudinal gradient (327–2596 m a.s.l.).We projected potential loss of suitable habitat and upward shift for most pollinator groups, with the exception of bumblebees and hoverflies which were predicted to descend. Pollinator extinctions were not forecasted; instead, we observed a pronounced species-specific response to climate change. Species richness hotspots will be relocated to higher altitudes and to the north-eastern mountain side.Projections for substantial but not detrimental climate change effects on pollinator fauna may be due to species differential resilience to climate change along with the existence of microrefugia on Mt. Olympus. Divergent response to global warming by bumblebees and hoverflies is probably due to species distribution modelling limitations, resulting in exclusion of the rarest species. We conclude that the predicted climate change impact stresses for the need of urgent conservation measures, including the expansion of the protection status over the whole mountain.