Effects of Landscape Features on Wild Bee Assemblages in Agricultural Areas

Agricultural intensification alters landscape functionality by reducing habitat heterogeneity and resource availability for wild bees. Despite extensive research on semi-natural habitats as important features for wild bees in agricultural landscapes, the role of other landscape components remains less commonly and consistently evaluated. We investigated how landscape composition and flowering plant richness relate to bee abundance, diversity, and functional-group composition across three spatial scales (500, 1000, and 1500 m) in an intensively managed agricultural landscape. Unexpectedly, semi-natural habitats showed limited effects, with responses restricted to specific metrics and spatial scales. The presence of rural settlements negatively affected total bee abundance, as well as female and male abundances. However, effects on total and female abundance disappeared after excluding Apis mellifera from analyses, indicating that managed honeybees strongly influenced community-level patterns. At the largest spatial scale, rural settlements positively affected Andrena flavipes. Roads and flowering plant richness influenced particular bee groups rather than showing general community patterns. The presence of water bodies positively affected bee abundance, while positive effects on diversity metrics became evident only after excluding A. mellifera. Our results demonstrate that responses of wild bee assemblages to landscape characteristics are highly context-dependent, varying among functional groups and spatial scales.