Population trends and habitat preferences of ground‐nesting bees in arable landscapes from public‐based records

Bees play a crucial role in maintaining ecosystem services that support a healthy environment and agricultural productivity. Understanding of bee distribution and population changes, particularly in arable landscapes, remains limited, let alone how this varies among different bee groups, including solitary bees and social bees such as bumblebees.

This study investigated the distribution and change of ground‐nesting bees in eastern Scotland, an agriculturally extensive region of the UK. Using public‐based bee records from 2010 to 2019, we developed species habitat models that relate occurrence data to relevant environmental variables.

We found that the likelihood of bee recordings submitted by the public per km ² was greater in areas that are easily accessible and have a favourable environment for outdoor activity. After controlling for the biases associated with these opportunistic survey efforts, our analysis revealed an 8.7% decline in the probability of bee occurrence per km ² , decreasing from an average of 28.1% during 2010–2014 to 25.7% during 2015–2019.

Solitary bees experienced a greater decline than bumblebees, with occurrence probabilities decreasing by 18.1% between the two periods, compared with a 4.9% decline for bumblebees. Both bumblebees and solitary ground‐nesting bees were more likely to be found close to hedgerows and in areas without crops, while solitary bees were further associated with moderate to high vegetation cover.

Our findings underscore the necessity of improving habitats, such as hedgerows and vegetation cover, and maintaining natural and semi‐natural habitat fragments, to support ground‐nesting bee populations in arable landscapes.