A roadmap for urban evolutionary ecology

Abstract

Urban ecosystems are rapidly expanding throughout the world, but how urban growth affects the evolutionary ecology of species living in urban areas remains largely unknown. Urban ecology has advanced our understanding of how the development of cities and towns change environmental conditions and alter ecological processes and patterns. However, despite decades of research in urban ecology, the extent to which urbanization influences evolutionary and eco‐evolutionary change has received little attention. The nascent field of urban evolutionary ecology seeks to understand how urbanization affects the evolution of populations, and how those evolutionary changes in turn influence the ecological dynamics of populations, communities, and ecosystems. Following a brief history of this emerging field, this Perspective article provides a research agenda and roadmap for future research aimed at advancing our understanding of the interplay between ecology and evolution of urban‐dwelling organisms. We identify six key questions that, if addressed, would significantly increase our understanding of how urbanization influences evolutionary processes. These questions consider how urbanization affects nonadaptive evolution, natural selection, and convergent evolution, in addition to the role of urban environmental heterogeneity on species evolution, and the roles of phenotypic plasticity versus adaptation on species’ abundance in cities. Our final question examines the impact of urbanization on evolutionary diversification. For each of these six questions, we suggest avenues for future research that will help advance the field of urban evolutionary ecology. Lastly, we highlight the importance of integrating urban evolutionary ecology into urban planning, conservation practice, pest management, and public engagement.

Urbanization reduces genetic connectivity in bobcats (Lynx rufus) at both intra– and interpopulation spatial scales

“…Understanding how landscape features influence connectivity within and among populations, and hence at varying spatial scales, is important for identifying factors that maintain connectivity and to elucidate the impacts of habitat degradation on genetic variation (Johnson & Munshi–South, ; Miles et al, ; Rivkin et al, ). In most of our studied populations, a proportion of the variation in genetic distances among individuals was attributable to one or more of our landscape resistance hypotheses.…”

“…Isolated populations are susceptible to inbreeding depression and genetic drift that reduce overall fitness and adaptive potential in the face of current and future threats, such as climate change and novel pathogens (Hoffmann, Sgrò, & Kristensen, ; Keyghobadi, ), and suffer reduced potential for demographic rescue (Brown & Kodric–Brown, ). However, the consequences of fragmentation may vary among populations and species due to variation in factors such as patch size, the distribution and intensity of urban development, landscape characteristics such as topography and vegetation, as well as intrinsic factors such as species vagility or generality of habitat requirements (Johnson & Munshi–South, ; Rivkin et al, ). In addition, the impacts of habitat fragmentation and landscape drivers of connectivity may vary across spatial scales (Cushman & Landguth, ; Vandergast, Bohonak, Hathaway, Boys, & Fisher, ; Vandergast, Bohonak, Weissman, & Fisher, ), particularly in urban environments (Miles, Dyer, & Verrelli, ).…”

Gene flow and genetic drift in urban environments

“…To be as exhaustive as possible, we examined the literature cited within these research articles to identify and include studies that may have been omitted using our initial search terms. We further considered all studies listed in several recent prominent reviews (Alberti, ; Alberti et al, ; Johnson & Munshi‐South, ; Rivkin et al, ). From these literature surveys, we identified 167 empirical research articles (Table ) that met these criteria, which represents the most comprehensive data set of population genetic responses to urbanization ever assembled.…”

“…The variation in both the ecoregions and the level of urbanization of the cities sampled likely play a large role in what drives variance in gene flow among populations (Miles, Dyer, et al, ). In addition, new initiatives like the Global Urban Evolution Project (GLUE; http://www.globalurbanevolution.comcom), which has representation from cities across six continents, may help resolve global patterns in urban evolution (Rivkin et al, ).…”

“…Repeated and consistent environmental modification has the capacity to influence evolutionary patterns and processes in our cities (Hendry, Gotanda, & Svensson, ; Johnson & Munshi‐South, ). Increasingly, urbanization has been identified as a force that alters the strength and form of natural selection, increases mutation rates due to pollution and influences genetic drift and gene flow among populations (Box ; Rivkin et al, ). Consequently, we seek to characterize how urbanization consistently and potentially shapes patterns of evolution through a review of the literature.…”