More than 75% of European bumblebee species may be threatened in the next 40-60 years according to worst-case-scenario projections of bumblebee populations, according to a paper published in Nature. Degradation of habitats and alterations of climate due to human activity are identified as key drivers of these estimated population declines. The findings underscore the importance of climate change mitigation policies to protect bumblebees.

“Our results underline the critical role of global change mitigation policies as effective levers to protect bumblebees from manmade transformation of the biosphere,” the authors write.

Around 90% of all wild plants and most crop plants benefit from pollination by animals. The bumblebee (Bombus) is a genus of bees considered to be especially important for the pollination of crops in the cold and temperate regions of the northern hemisphere. Human-generated transformations of natural habitats and increases in temperature are implicated as key drivers of wildlife collapse; understanding the trajectory of insect populations is important for devising conservation efforts.

Guillaume Ghisbain from Université Libre de Bruxelles, Brussels, Belgium and others quantify past, present and future ecological suitability of Europe for bumblebees. Observational data cover the periods 1901-1970 (past) and 2000-2014 (‘present day’), and projections are made up to 2080. Around 38-76% of European bumblebee species currently considered as non-threatened are projected to see their ecologically suitable territory shrink by at least 30% by 2061-2080. In particular, species from Arctic and alpine environments may be at the verge of extinction in Europe, with an expected loss of at least 90% of their territory in the same period. The authors report that parts of Scandinavia may potentially become refuges for displaced or threatened species, although it remains unclear whether these regions may be affected by human activity-driven changes.

Further work is needed to understand the effects of finer-scale variation in climate and habitat changes, the authors note. However, the current results highlight the need for conservation measures and policies that mitigate the human impact on important ecosystems.