Abstract Understanding how landscape composition influences biodiversity distribution across space is essential for predicting species responses within mosaics of native vegetation and agroecosystems. In this study, we analyzed orchid bee (Euglossini: Apidae) assemblages using presence–absence data and trait-based community-weighted metrics along a vegetation density gradient in the Cerrado–Amazon transition zone of Brazil. We sampled nine sites distributed across the Cerrado − Amazon transition and the Cerrado, compiled an inventory of species and their functional traits, and examined how these patterns relate to vegetation cover. Both vegetation cover and spatial distance were important predictors of Euglossini species composition. However, none of the environmental predictors showed a statistically significant relationship with community functional composition. The differences in species composition between Cerrado communities and the Cerrado–Amazon transition appear to reflect the biogeographic history of the group, with a stronger Amazonian influence on the species in the transition zone than in core Cerrado communities. From a conservation perspective, our results highlight the importance of protecting areas strategically positioned to encompass the environmental gradient between core Cerrado formations and the Cerrado–Amazon transition, including the associated variation in vegetation cover types. Because distinct Euglossini assemblages occur along this gradient with limited species overlap, conservation initiatives restricted to a single vegetation type or biome would likely fail to preserve the full regional diversity of orchid bees and their associated pollination services.
Brasil et al. (2026) studied this question.