Where have the bumblebees and other wild bees gone? - preliminary results of rapid evaluation in grassland habitats near agricultural fields in Ihtimanska Sredna Gora Mts (Bulgaria)

Ecosystem services from wild bees are related to food production and medicine. However, the global decline of wild bees (including bumblebees) is a well-documented fact. The main factors for this phenomenon are pesticides, habitat loss, changing climate, pathogen transmission etc. The aim of this pilot study is to document the bees’ flower visitation activity in several grassland habitats in the close vicinity of agricultural fields in Ihtimanska Sredna Gora Mts. Four study sites were identified with similar plant communities, and transects were carried out in them to observe bee activity. In result we found that wild bees and in particular bumblebees had very low flower visitation activity in the study sites in Ihtimanska Sredna Gora Mts during our short study. We could only speculate about the possible explanation of this fact at the moment. Discussed are the presence of apiaries nearby and intensification of the agriculture in the area during the last decade. This preliminary research demonstrates the necessity of permanent monitoring of wild bees flower visitation activity in the agricultural areas and adjacent territories.