Urban ecosystems are expanding around the world as people migrate to cities and the human population continues to grow. What happens to other species as these urban ecosystems expand, and how species live and interact in established urban ecosystems, is the central focus of urban ecology. Over the past two decades, urban ecology has rapidly expanded from simple studies evaluating what types of species are present in urban ecosystems to complex investigations of the characteristics that allow species to thrive in urban environments. In a recent PLOS Collection, curated by PLOS ONE Academic Editor Christopher Lepczyk and PLOS ONE staff editors, we highlight the diversity of recent urban ecology research published in PLOS ONE.
Today, urban ecology covers a vast array of questions and topics that are helping to shape our understanding of both people and human society. For instance, a large area of research focuses on how urbanization affects basic patterns of urban wildlife in time and space In this vein, Hung and colleagues demonstrate how urbanization fragments bee habitat and what that means for bee diversity through the seasons. Because of such fragmentation effects on species, there has been increased attention at whether conservation-conscious urban planning should prioritize expansion or densification of cities, as discussed by Wolff and co-workers. Not only has the focus been on how to grow cities, but how to co-ordinate this growth with a better understanding of future uncertainties (Troupin and Carmel) and in the face of climate change (Scheuer and colleagues).
Another area of exciting research has focused on how urbanization affects basic aspects of species’ biology. For instance, Owens and colleagues describe how artificial light affects fireflies and demonstrate the mechanisms by which they attune their behavior to urban environments. Similarly, Lahr and co-workers found notable differences in the physiology of red maples depending on whether they were of urban or non-urban ancestry, with important repercussions for urban tree management.
Species interactions are likewise affected by urbanization, such as how coyotes (Canis latrans) and red foxes (Vulpes vulpes) coexist in urban areas (Mueller and colleagues). Similarly, how wildlife diseases are operating and changing in and around urban ecosystems is nicely described by Lewis and co-authors in the context of cat species (felids). In fact, the merging of urban and disease ecology is of critical importance to both human and wildlife health.
An important aspect of urban ecology focuses on the negative impacts of urbanization on species. For instance, Sumasgutner and colleagues show how poor diet quality of urban Eurasian kestrels (Falco tinnunculus) negatively affects their reproduction and health. Along similar lines, Dale and Frank show how warming and drought in cities favor invasive species to the detriment of urban trees. Finally, evaluating how to mitigate the negative consequences of urbanization on species is nicely illustrated by Pena and co-workers in their study of how street trees help alleviate pressures on urban birds.
A final area of importance to both urban ecology- and biodiversity research overall- is how people interact with and perceive species in urban areas. For many people, urban wildlife plays a key role in shaping their views of nature as a whole. Hosaka and colleagues demonstrate how early experiences with species affect individuals’ perceptions of native and invasive species in Japan. Likewise, White and co-authors examine how environmental education programs in cities can aid in awareness and knowledge of urban wildlife. Bringing people into urban ecology is not simply about understanding how they interact with nature, but also in actually engaging them as urban ecologists, as exemplified in a study by Scott and colleagues that uses citizen scientists to collect data on urban carnivores.
Collectively, the studies in the urban ecology collection show an exciting range of research and the increasing importance of the field for basic and applied ecological knowledge. Moreover, these studies indicate how important urban ecology is to conservation and management in city environments. While we have greatly increased our understanding of urban ecosystems, they remain an understudied type of system, and urban ecology provides many open avenues for future research.
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