A BEE indicator for monitoring wild bee diversity in agricultural systems

Given the growing importance of assessing the condition of wild bees in agroecosystems, we focused on developing a BEE indicator that could be easily used by non-expert taxonomists to score bee diversity. Our goal was to create a tool suitable for farm-level use, one that does not require taxonomic expertise nor heavy field work. Since existing literature has emphasized the significance of environmental features surrounding any investigated site, we incorporated this aspect into our design. We began by identifying a user-friendly field tool to differentiate among bee morphogenera, then proceeded by developing a process for data analyses and interpretation. A protocol is also shared. Further on, we run a case-study testing this tool at 13 sites in three countries, differentiating farms based on farming practices (conventional or organic, as proxy of opposite conditions). The results confirmed that (a) a diagnostic table based on morphological similarities is a practical field tool that, in almost all cases, allows for accurate classification of a bee individual into a specific group (morphogenus); (b) the process of analysis, based on number of morphogenera and landscape composition reflects variability among bees and across sites; (c) evaluating environmental features is essential for placing the results of bee variability into the appropriate context.