Global Variation in Climate, Human Development, and Population Density Has Implications for Urban Ecosystem Services

Abstract

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.

Global Changes in Urban Vegetation Cover

“…Here, we show that urban vegetation covers a considerably greater area than some other ecosystems that have long been the focus of global conservation and monitoring efforts, such as mangrove forests [61]. Urban vegetation differs from natural ecosystem types in its heavy modification by people, high fragmentation [62], and dispersion across climatic zones and bioregions [17,29]. However, these factors have given rise to a novel variety of ecosystems that can support diverse biodiversity [63], and provide valuable services to urban residents [6,39].…”

“…Urban areas are subject to varied climatic, demographic, economic, and cultural pressures around the world [29], leading to a complex diversity of mechanisms that drive the observed trajectories of urban vegetation change. While the causes of change in individual cities require in-depth study, here we suggest some general mechanisms that may be common across urban areas.…”

“…Reductions in urban vegetation cover are likely to reduce the provision of environmental, social, and economic benefits from urban vegetation, resulting in negative impacts such as elevated urban temperatures and flood risk [71,72]. The higher rate of loss of urban vegetation cover in Africa, Asia, and South America is therefore concerning, as these regions are particularly susceptible to environmental risks [73], and many urban residents depend more directly on ecosystem services for their livelihoods [29,74].…”

Coherence of Global Hydroclimate Classification Systems

“…These frameworks classify elements of a system based on common atmospheric or terrestrial characteristics to maximize their within-zone similarity, or coherence, which allows for a transfer of understanding across zones of similar attributes (Lanfredi et al, 2019). This study focuses specifically on climate classification schemes, which have provided a climatic context for a variety of applications, including socioeconomic assessments of human health conditions (Boland et al, 2017;Jagai et al, 2007;Lloyd et al, 2007), economic development (Mellinger et al, 2000;Richards et al, 2019), and evaluating anticipated biophysical and climatic changes (Chen and Chen, 2013;Tapiador et al, 2019).…”

A Review of Urban Ecosystem Services Research in Southeast Asia

“…As cities expand, peri-urban areas experience rapid land use change. However, only 15% of assessments examined peri-urban areas, consistent with Richards [91] and Wangai [75] that highlight peri-urban areas as being understudied globally. We encourage UES research in peri-urban areas, as these areas are where the intensity of development is the greatest and UES are being lost or degraded, and therefore where planning is mostly urgently needed.…”