Global variation in climate, human development, and population density has implications for urban ecosystem services

Humans rely upon ecosystem services to regulate their environment and to provide resources and cultural benefits. As the world's urban population grows, it becomes increasingly important to find ways of improving the provision of ecosystem services in urban areas. However, the kinds of ecosystem services that are most needed or demanded by urban populations, and the opportunities to provide these, vary widely in cities around the world. Here we explore variation in climate, Human Development Index (HDI), and population density, and discuss their implications for providing and managing urban ecosystem services. Using 221 published studies of urban ecosystem services, we analyse the extent to which existing research adequately covers global variation in climatic and social conditions. Our results reveal an under-representation of studies from tropical cities and from lower HDI countries, with implications for how we conceptualize and quantify urban ecosystem services, and how we transfer benefits across case studies. Future work should be aimed at correcting these deficits and determining the extent to which conclusions about urban ecosystem services are transferable from one city to another.