Land-use changes in a neotropical biodiversity hotspot and its effects on Euglossini bees

Abstract

Natural landscapes are facing rapid transformation in many parts of the world, but the consequences of such changes for insects are poorly known. We evaluated how the conversion of the savannas and forests from Brazil´s Cerrado into lands devoted to intensive agriculture, livestock, or plantation forestry affects euglossine bees. We determined the effects of land-use change on the species richness of euglossines, and functional traits related to the body size and wing fluctuating asymmetry (FA) of a habitat generalist species. Few species were recorded in the anthropogenic land uses and most presented lower abundances in the converted than in the native habitats. The exception was Eulaema nigrita, whose average abundance in cattle pastures and in soy fields did not differ from that observed in the native habitats. However, El. nigrita males collected in pastures or in soy fields were significantly smaller than those from savannas and forests, whereas those from eucalypt tree plantations were smaller than those from savanna. Furthermore, El. nigrita males from the tree plantations had higher levels of FA in wing shape than those from native forests.

Implications for conservation

Our results showed that land-use change in the Cerrado biodiversity hotspot causes the impoverishment and homogenization of the Euglossini fauna. Furthermore, we found evidence that the converted habitats present more stressful conditions for the larval development of some species. This indicates that the conservation of euglossine populations in human- modified Cerrado landscapes depends largely on the presence of protected areas, including those within rural private land as required by Brazil´s Native Vegetation Protection Law.