The impact of agricultural colonization and deforestation on orchid bees (Apidae: Euglossini) in the Brazilian Amazon

Researchers have studied orchid bees for decades to determine the impact of tropical deforestation on biodiversity. Our objective was to determine impacts on orchid bees at scales other than forest patches/fragments, as called for in the broader literature on the impacts of habitat fragmentation on biodiversity. We examine an orchid bee survey, which employed chemical baits and live netting in rapid assessments, across the entire state of Rondônia in the Brazilian Amazon. We analyze the relationships between age of agricultural settlement of collection zones and the immediate land cover (closed vs. open canopy of land use/land cover) of collection sites on orchid bee abundance, richness, and composition. The survey reveals a highly diverse community (2497 individuals, represented by 5 genera and 48 species across 12 collection zones and 130 sample locations). Species richness declined significantly between conservation units and older settlement zones, but richness in newer settlement zones remained at an intermediate, insignificantly different level. Significantly greater abundance was found within conservation units, less in newer settlement zones, and even less in older settlement zones. Species composition was significantly different when comparing the conservation unit and older settlement categories of collection zone. Closed canopy species richness and abundance were significantly higher than that found in open canopy. Composition also differed significantly between open and closed canopy land cover canopy types. Eulaema nigrita and several Euglossa species are identified as particularly strong indicators of degraded and preserved environments, respectively.