Bees travelling south: Climate-induced range shifts and suitable habitat losses in south-eastern neotropics

Aim

To provide an assessment of climate change impacts on a set of wild pollinators restricted to one of the regions with the greatest diversity of bees in the world. Also, we aimed to test whether functional groups responded differently to climate projections.

Location

South-eastern South America (SES).

Taxon

Bees (Hymenoptera: Apidae sensu lato).

Methods

We selected 18 species of bees mostly restricted to the SES region, modelled their distributions and assessed the possible impacts of near future (2050) climate change in species richness and shifts in range centroids. Potential impacts related to different functional groups were evaluated through t-tests.

Results

SES species richness was projected to decrease in the northernmost regions and increase southward. Most bee species were predicted to shift their range centroids towards the south-west and south, while suitable stable areas were found in southern Brazil. We also found higher proportional losses in suitable areas for eusocial species compared to solitary ones, while generalists showed slightly lower gains than specialists.

Main Conclusion

SES bees are likely to undergo changes in the near future, with projected losses of species at northern portions and southward increases. The identified stable areas in southern Brazil underscore the importance of conservation efforts in the region, particularly in natural grasslands – an endangered habitat with high bee diversity. Although our results suggest higher vulnerability for functional groups traditionally considered more resilient, it is essential to acknowledge that other factors, including habitat and mutualists availability, behavioural particularities, phenology and range size, must be determinants for the vulnerability of species to ongoing climate change.