Functional Diversity and Functional Traits of Tropical Urban Fauna

Abstract

Although urban landscapes are planned and managed primarily for satisfying human needs, a high diversity of other organisms also inhabit the urban ecosystem. Different animal species are responsible for realizing ecological processes necessary for the sustainable functioning of urban ecosystems, such as predation of herbivorous insects and seed dispersal. The urban fauna is composed of species with different sensitivities to the intensity of urbanization, from organisms restricted to preserved habitat patches to exotic and generalist species that dominate the most urbanized regions. This ability of a species to exploit the different conditions of urban landscapes is related to their functional traits—e.g., diet, nesting behaviour, and morphological characteristics—that will also determine their ecosystem functions. In this chapter, we explore the state of the art of the scientific literature regarding the relationships between urbanization and functional attributes of the tropical urban fauna. Over two decades (between 2000 and 2020), only 23 published studies explicitly applied a functional ecology approach to assess animal communities in tropical urban landscapes. The first study was published in 2016. Most of the research was concentrated on Brazil and the Atlantic Forest. Birds and terrestrial arthropods were the main animal groups addressed by researchers (7 studies each), but charismatic animals, such as terrestrial mammals, were not considered among the 23 studies. A high diversity of functional diversity metrics and predictors were applied by researchers. Although demonstrating that urbanization modulates the functional diversity and the functional composition of urban fauna, especially local environmental conditions, the strong geographic and biological biases of the few studies did not allow the extrapolation of global patterns. Consequently, the possibility of defining planning and management initiatives for developing ecologically functional tropical urban landscapes is limited. We urge that more research is needed on about the functional ecology of animals living in cities across the most biodiverse region of the planet.