Understanding the impact of urbanization on the ecology and diversity of insect pollinators for a better biodiversity management in tropical ecosystems

Déogratias Nduwarugira, Lin Mizero, Didier Mbarushimana, Longin Ndayikeza

Abstract

Across the world, there is an increased urban expansion leading to the disappearance of ecosystems and disruption of ecological balances. Very little is known about the effects of the transformation of rural landscapes in urban areas on fauna of many African ecosystems. The main objective of the study was to assess the impact of urbanization on insects playing an important role in plant pollination. The case of Bujumbura urbanization, the main town of Burundi, was taken as a model. We collected insect pollinators and their host-plants in two sites located in an urban area and a peri-urban area, respectively. Student paired tests were performed to compare the abundance of the pollinators between the two landscapes. The specific richness of insect pollinators was higher in the peri-urban area than in the urban environment. The preference of the peri-urban area by pollinators could, probably, result from its high richness in plants which may provide them food sources, reproductive sites, and a favorable microclimate. Our research also confirmed that urbanization contributes to the restructuration of local assemblages, with emergence of taxa adapted to the new environment. Understanding the ecological adaptation of pollinators in ecosystems subjected to human transformation may serve as a guide to integrating the management of specific taxa and their habitats, especially in urbanization planning.