Positive Effects of Human Action on the Establishment of Native Stingless Bees in an Urban Environment

Abstract

Facilitation is an ecological interaction in which an organism modifies the environment, benefiting other species. In urban areas, tree pruning conducted to prevent contact with electrical networks can create microhabitats, such as cavities and cut branches, that serve as nesting sites for arthropods, especially bees. This study tested the hypothesis that pruning facilitates the establishment of native stingless bees in urban environments. Research was carried out between November 2022 and November 2023 on the Umuarama campus of the Federal University of Uberlândia, Minas Gerais, Brazil. A total of 323 Sibipiruna trees (Caesalpinia pluviosa) distributed across a 160,000 m² area were evaluated. Each tree was tagged and inspected for bee nests; nest location and abundance were recorded, and collected bees were taxonomically identified. Chi- square analyses were used to assess the association between nest occurrence and tree pruning. Results showed that pruning significantly facilitated the establishment of native stingless bees, particularly in cut trunks and branches that became suitable nesting sites during decomposition. Although other nesting substrates were observed, these modified structures were clearly preferred. Native stingless bees play an important role as urban pollinators, contributing to biodiversity maintenance and the reproduction of ornamental and food plants. The findings highlight the importance of conserving urban pollinators through sustainable practices, including expanding green areas and reducing pesticide use. On the Umuarama campus, annual tree pruning functions not only as urban management but also as a facilitator of bee colonization, demonstrating that human activities can produce positive ecological impacts in urban landscapes.