Socio-ecological drivers of vertebrate biodiversity and human-animal interfaces across an urban landscape.

Titus Imboma,James M. Hassell,Francesco Fava,Eric M. Fèvre,Allan Ogendo,Melissa J. Ward,Dishon Muloi,Michael Begon,Judy M. Bettridge,Timothy P. Robinson

doi:10.1111/gcb.15412

Abstract

Urbanization can have profound impacts on the distributional ecology of wildlife and livestock, with implications for biodiversity conservation, ecosystem services and human health. A wealth of studies have assessed biotic responses to urbanization in North America and Europe, but there is little empirical evidence that directly links human activities to urban biodiversity in the tropics. Results from a large‐scale field study conducted in Nairobi, Kenya, are used to explore the impact of human activities on the biodiversity of wildlife and livestock with which humans co‐exist across the city. The structure of sympatric wildlife, livestock and human populations are characterized using unsupervised machine learning, and statistical modelling is used to relate compositional variation in these communities to socio‐ecological drivers occurring across the city. By characterizing landscape‐scale drivers acting on these interfaces, we demonstrate that socioeconomics, elevation and subsequent changes in habitat have measurable impacts upon the diversity, density and species assemblage of wildlife, livestock and humans. Restructuring of wildlife and livestock assemblages (both in terms of species diversity and composition) has important implications for the emergence of novel diseases at urban interfaces, and we therefore use our results to generate a set of testable hypotheses that explore the influence of urban change on microbial communities. These results provide novel insight into the impact of urbanization on biodiversity in the tropics. An understanding of associations between urban processes and the structure of human and animal populations is required to link urban development to conservation efforts and risks posed by disease emergence to human health, ultimately informing sustainable urban development policy.

Highlights

It is generally accepted that urbanization can have widespread effects on biodiversity and health
This observation could be explained by the extreme variation in types of urban development seen in developing cities such as Nairobi—for example, the most densely populated settlements in the city are located along riparian areas, and on the edge of forests harbouring high levels of biodiversity (Bagnis et al, 2020; Furukawa et al, 2011)
The effects of urbanization on public health and biodiversity have been identified as a key knowledge gap (Gibb et al, 2020)

Summary

Introduction

It is generally accepted that urbanization can have widespread effects on biodiversity and health. Cities in low-middle income countries, which are characterized by rapid, unplanned urbanization, are thought to be at risk (Alirol et al, 2011). This is especially true of urban and peri-urban zones in Africa, where growth and migration is expected to result in an increase in the population residing in these areas from 35% in 2007, to 51% by 2030 (United Nations, 2014). When associated with the socioeconomic characteristics of developing urban centres—social disparity (and resulting health inequalities), large-scale migration, poor living conditions and close contact with domestic animals— such ecological changes pose a risk to human health and wellbeing through the emergence and spread of infectious disease, and lost benefits of biodiversity to immunological and mental health (Alirol et al, 2011; Hanski et al, 2012)

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Conclusion