‘Green’ or ‘Gray’? Infrastructure and Bird Ecology in Urban Latin America

Abstract

Urban systems are highly complex and heterogeneous, comprised basically by two types of infrastructure. On the one hand, ‘gray’ infrastructure includes all artificial structures and buildings, often impervious, and their components. On the other hand, ‘green’ infrastructure is conformed by all remaining and planted vegetation within an urban center. In this chapter, we reviewed the global response of birds to these two main types of urban infrastructures, and then focus on urban Latin America. Few studies have focused on urban ‘gray’ infrastructure, with many of them biased toward its close relationships with exotic, invasive, and/or generalist bird species. On the contrary, many studies have been performed focusing on the ‘green’ infrastructure of cities. Due to the amount of knowledge regarding ‘green’ infrastructure, we approached it considering greenspace location, size, heterogeneity, vegetation traits, management, and human activities. Our review shows that there is a pressing need for studies that consider ‘gray’ comparison baselines when assessing the effect of urbanization on birds. Also, studies need to focus on the ‘gray’ matrix in which urban greenspaces are embedded, as we have little to null information regarding it, and it is essential to plan healthier and sustainable cities. Another important gap that needs to be bridged is the role that exotic plants have not only on bird ecology, but also on the ecology of cities. Finally, we suggest to include other conditions that, although are not as representative in all urban centers, are highly important for birds and other wildlife groups. Specifically, we consider it crucial to join efforts on studying water bodies (‘blue’ infrastructure) and wastelands (‘brown’ infrastructure) to increase our understanding of the role that these urban components play on bird conservation in urban Latin America.