Understanding drivers of global urban bird diversity

Abstract

Around 56% of the world's population live in cities, with rapid urbanisation in developing regions. However, most ecological studies focus on developed countries. Here, we conduct a global analysis on bird diversity for 48,180 cities and assess the drivers of avian diversity. Productivity is one of the best indicators of diversity across biomes, but forest-cover only becomes important in biomes with less tree-cover. Important factors also vary based on city-size, though access to green-space is uniformly a major driver of diversity worldwide. Conversely, percentage of impermeable surfaces, night-time light and population density are nigh-universally negative drivers. Green space becomes increasingly important in larger cities. Space-management dramatically increases the ability of cities to host high bird diversity, highlighting the need for data-driven approaches to facilitate greener-development.