Land-cover effects on wild bee diversity and community structure in upland oak forest mosaics

Pollinator communities in temperate forest mosaics are influenced by local habitat conditions, but within upland oak forests of the southeast U.S., these relationships remain poorly understood. This study assessed how differing land-cover types influence wild bee diversity and community composition across upland oak forest habitat. We evaluated how four land-cover types – mixed hardwood forest, pine/mixed pine forest, scattered hardwood, and open/agricultural fields – shape wild bee diversity, community composition, and functional structure in privately owned mixed-use forests in northern Mississippi. Using standardized blue vane and colored pan traps, we sampled bees monthly from May to September 2024. After excluding managed Apis mellifera , we recorded 1315 wild individuals representing 67 species and 26 genera. Shannon diversity differed among land-cover types (F(3, 8) = 5.749, p = 0.021), with open/agricultural fields showing higher diversity than mixed hardwood forest, although evenness did not differ. Community composition also varied by land cover (NMDS stress=0.099; PERMANOVA F(3, 8) = 1.964, R² = 0.424, p = 0.004), and seven species were significant indicators, primarily of open/agricultural fields and pine/mixed pine forest. Canopy cover was the strongest environmental correlate of assemblage structure (global p = 0.009). Open/agricultural sites supported the highest richness and diversity, pine/mixed pine forest and scattered hardwood were intermediate and often functioned as ecotones and closed-canopy hardwood forests had the lowest diversity. These results highlight the value of maintaining a heterogeneous land-cover mosaic and promoting canopy openness and ground-nesting resources to conserve wild bee communities in upland oak forests. Our results contribute to understanding how forest management practices such as thinning and selective logging can balance ecological integrity and enhance pollinator diversity in temperate ecosystems.