Heterogeneous agroecosystems support high diversity and abundance of trap nesting bees and wasps amongst tropical crops

Land-use intensification for agricultural purposes modifies the structure
of natural environments in various ways and at different spatial scales.
These modifications can affect ecological processes and the community
structure of multi-environment users such as solitary bees and wasps.
Understanding the role of distinct habitat descriptors in promoting such
changes is one of the major challenges of empirical studies. In this
study, we use a multi-scale approach to evaluate how landscape
compositional and configurational heterogeneity, vegetation structural
complexity, and the proportion of agricultural landscape composition
affect communities of bees and wasps that nest in pre-existing cavities in
remnants of native vegetation bordering agroecosystems. We selected 25
sampling points along a gradient of amount of surrounding agriculture and
landscape diversity within natural physiognomies located in Chapada
Diamantina, Bahia, Brazil. Through model selection using Akaike's
information criterion, we verified the complementary roles of landscape
heterogeneity and local vegetation in structuring these hymenopteran
communities. Abundance in the groups showed different tendencies depending
on the descriptors employed, pointing to the importance of evaluating
within-group specificity. Furthermore, bees and wasps presented
differential responses to landscape composition, but they did not differ
in relation to configurational complexity. In more heterogeneous
landscapes or sites with more complex local vegetation, the proportion of
agriculture had a positive influence on the response evaluated. Efficient
management of agricultural landscapes therefore requires increased
landscape heterogeneity and conservation or restoration of native
vegetation remnants at the local scale.