Topic: Studying the impacts of urbanization using novel behavioral and evolutionary approaches

Background/Question/Methods Urban environments are now accepted as a new category of ecosystem that differ from more natural ones in a number of important ways. Cities have been shown to differ significantly from surrounding ecosystems in a variety of abiotic (e.g., hydrology, ground permeability, climate) and biotic (plant and animal communities, phenologies) components, and in the spatiotemporal dynamics of ecological interactions. Recent research has begun expanding and deepening our understanding of these novel ecosystems by examining them in a broader multidisciplinary framework, as coupled socioecological systems where human socioeconomic variables underlie many ecological processes. The city represents the ultimate expression of human efforts to control our environment: in evolutionary ecological terms, it reflects a strategy to minimize risks of starvation and predation by creating habitats which dampen natural variability in climate and food availability, and provide shelter from predators. Simultaneously, humans provide a surplus of resources, making cities attractive habitats to some nonhuman species, while repelling others. Cities are thus interesting laboratories for studying behavioral ecology and evolution under novel selection pressures. Here I review our state of knowledge about these behavioral and evolutionary impacts of urbanization, and novel theoretical and empirical approaches being developed to study them. Results/Conclusions Recent theoretical work (tested empirically) shows that typical changes in spatiotemporal patterns of food availability and predation accompanying urbanization alter competitive dynamics such that weak competitors survive better in cities. Implications for species able to invade the novel urban habitat include: higher population densities, reduced selection pressures, and therefore, greater vulnerability to sudden environmental changes. New behavioral research finds other fascinating changes: urban noise alters acoustic signals, affecting social/mating communication, producing novel dialects, and perhaps, potential speciation; increased spatial heterogeneity alters ranging behaviors, placing a premium on spatial memory; relative temporal stability in some food supplies confuses life-history patterns due to mismatched cue-recognition systems; phenological studies illuminate global warming impacts. Population genetic studies are beginning to find molecular differences between urban / exurban populations, indicating significant evolutionary impacts of cities. The coupled socioecological framework opens up novel experimental avenues, leveraging deliberate human engineering of habitats/resource flows to test evolutionary ecological hypotheses, while amateur citizen scientists provide extra manpower for these studies, which feeds back to improve ecological knowledge, urban biodiversity management, and conservation. This variety of urban research offers deeper insights into evolutionary ecological processes while helping us invent better ways to sustainably manage our planet's biodiversity.