Abstract
Thanks to the EU FP7 project STEP (Potts et al. 2011), over one million bumblebee records from all over Europe have been collated. Based on data from 1970 to 2000 we modelled the current climatic niche for almost all European species (56 out of 69) and projected future climatically suitable conditions based on three climate change scenarios (SEDG, BAMBU and GRAS) for the years 2050 and 2100.
Due to limited knowledge of actual bumblebee dispersal, we made two extreme assumptions: (i) the species has full dispersal abilities (meaning that the species is able to spread all over its suitable area) or (ii) the species is unable to disperse at all (i.e. that changes in climatic conditions can only lead to projected range retractions). However, to aid the assessment as to which of these two extreme assumptions are more likely to meet reality, we also provide a rough indication of the species' potential dispersal ability based on the ecology of the different bumblebees.
Since bumblebees are mainly adapted to colder conditions, they appear as highly vulnerable to climate change. In 2100, depending on the scenario of climate change, up to 36% of the European bumblebees are projected to be at an high climatic risk (i.e. losing more than 80% of their current range), 41% will be at risk (loss between 50% and 80%).
Non-modelled species are all very rare and localised and their ranges are most likely to be shrinking considerably under all of the scenarios. Only a few species are projected to benefit from climate change and can potentially enlarge their current distributions in Europe, such as B. argillaceus and B. haematurus.
The book inform the broader public about the potential risks of climate change for the future fate of European bumblebees. It aim to aid biodiversity conservation managers and policy makers.
It also provide background knowledge for critical discussions about the sustainable provision of pollination services in the light of food security.