Partitioning the Effects of Urbanization on Biodiversity: Beyond Wildlife Behavioural Responses to a Multilevel Assessment of Community Changes in Taxonomic, Functional and Phylogenetic Diversity

In the Anthropocene era, urbanization is increasing across the Globe, and urban areas constitute one of the fastest growing land-use types. Indeed, since 2008 more than 50% of the global human population and almost 80% of the population in developed countries has lived in cities, and predictions for the near future suggest an increase to 85% by 2050. While the effects of urbanization on abundance have been documented, the consequences for biodiversity and its component parts are poorly known despite the fact that they are important for conservation. Urbanization alters both biotic and abiotic ecosystem properties, thereby leading to biodiversity loss around the world. However, for a more adequate understanding, the biodiversity need to be studied through a partitioning in many levels and/or components. The most frequently used diversity metric is taxonomic diversity, measured simply as the number of species in a given assemblage. Functional diversity, instead, links species assembly with ecosystem functioning and environmental constraints. Functional diversity can reveal species coexistence processes, the variety of roles that different organisms play in the ecosystem and assembly rules driven by functional traits. In contrast, phylogenetic diversity, which mirrors the total evolutionary history of all species in a community, is increasingly considered in community ecology and macro-ecology disciplines. It recognizes the value of evolutionary diversity in communities, being another important component for nature conservation.

Cities and other urban environments, with their deep and convergent anthropogenic transformation worldwide, are nodes of intense species exchange and for this reason hotspot of accelerated biotic homogenization for various organisms. However, the wide focus of this topic calls for a multidisciplinary approach assessing the response of different taxa to the stress caused by the expansion of urban areas. For example, plant, bird and mammal responses to a gradient of urbanization could be different. In this regard, the exploration of taxonomic diversity, functional diversity and phylogenetic diversity or evolutionary uniqueness of animal and plant assemblages could be an interesting strategy, able to provide more comprehensive answers on direct and indirect effects of urbanization processes on natural environments, necessary for setting accurate conservation planning.

This Research Topic has the following aim: to collect a robust set of original scientific evidence (papers), in order to assess the impact of specific elements of urbanization and/or pollution on different and complementary biodiversity metrics. With this aim, authors will be requested original contributions by combining field data, geospatial analysis and modelling procedures, in order to provide new insights on identification of problems and pitfalls related to the interactions between humans, plants and animals in human dominated environments.

We encourage the following sub-themes: direct/indirect effects of urban features on plant / animal species and assemblages; explicit tests of different effects in a multi-level approach of diversity or community metrics (taxonomic, functional and phylogenetic diversity); associations between urban areas and incidence of alien species; effects of light and noise pollution on plant and animals of urban areas; potential use of plant and animal species as bioindicators of environmental quality in cities; and human perception of biodiversity in urban areas. The topic could be open to receive also new suggested sub-themes falling within the broad topic of the proposal.