Study highlights critical impact of urbanization on avian communities in the Afrotropics

31 July 2024

Urbanization negatively affects biodiversity worldwide, making associations between urbanization and avian communities an imperative study. The Head IITA of Forest Center, Adewale Awoyemi, recently published his third PhD paper, alongside other authors, reporting how urbanization affects bird taxonomic, functional, and phylogenetic diversity in the Afrotropics.

The authors compared bird populations in urban and non-urban areas from two vegetation zones in Nigeria: rainforest (Auchi, Calabar, Ibadan, and Lagos) and savannah (Birnin Kebbi, Dutse, Gombe, and Jos). They sampled birds and collected landscape attributes (such as pedestrians or green cover) both during the dry (November to January) and wet seasons (August to September), collecting data from 400-point count stations across the country.

They recorded 8,738 birds of 237 species in their study. Of the eight studied cities, Jos recorded the highest number of bird species in the urban habitat during the dry season, while Ibadan registered the highest number of bird species during the wet season. They found that the impacts of urbanization on birds are more severe in rainforests than in savannahs.

They identified the laughing dove (Streptopelia senegalensis) as the most abundant bird species in cities during the dry season, which was present in 41% of all urban point counts studied. In contrast, the common bulbul, green-backed camaroptera, the vinaceous dove, green crombec, and the little greenbul were the most commonly recorded bird species in natural areas. Interestingly, they discovered that 65% of all the species recorded were never encountered in urban areas, indicating a devastating impact of urbanization on birds within the communities of the region.

The reduction in bird species richness was much more intense in the rainforest areas than in the savannahs, highlighting the particular vulnerability of rainforest birds to urbanization and the need for specific conservation measures in those cities. Awoyemi and his colleagues also found contrasting results among the different measured biodiversity indicators, which suggests that urbanization has a multifaceted effect on wildlife.

The authors also identified the importance of trees and bush cover for urban birds, as well as the crucial role of water bodies in cities during the critical dry season. They strongly recommend replicating their study in other Afrotropical areas and providing useful suggestions to help reconcile urban development and bird conservation in this rich biodiversity area.

Link to paper: https://doi.org/10.1016/j.gecco.2024.e03108

IITA Forest Center manages and utilizes forest resources for conservation, research, and education. The 350 hectares of Forest Reserve within the IITA-Ibadan's 1000-hectare land support biodiversity and diverse habitats. IITA Forest is a haven for birds and is designated as an Important Bird Area (IBA) by BirdLife International. IITA Forest Center has recorded remarkable successes in the propagation and conservation of over 100 native tree species in the Tree Heritage Park, about half of which are already Red-Listed by the IUCN. In January 2022, the THP was awarded a Level II Accreditation by The ArbNet Arboretum Accreditation Program and The Morton Arboretum. The IITA Forest supports over 450 plant species, 272 birds, 236 butterflies, 48 mammals, and 28 reptiles.

Contributed by Folake Oduntan

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