Humans challenge the phenotypic, genetic, and cultural makeup of species by affecting the fitness landscapes on which they evolve. Recent studies show that cities might play a major role in contemporary evolution by accelerating phenotypic changes in wildlife, including animals, plants, fungi, and other organisms. Many studies of ecoevolutionary change have focused on anthropogenic drivers, but none of these studies has specifically examined the role that urbanization plays in ecoevolution or explicitly examined its mechanisms. This paper presents evidence on the mechanisms linking urban development patterns to rapid evolutionary changes for species that play important functional roles in communities and ecosystems. Through a metaanalysis of experimental and observational studies reporting more than 1,600 phenotypic changes in species across multiple regions, we ask whether we can discriminate an urban signature of phenotypic change beyond the established natural baselines and other anthropogenic signals. We then assess the relative impact of five types of urban disturbances including habitat modifications, biotic interactions, habitat heterogeneity, novel disturbances, and social interactions. Our study shows a clear urban signal; rates of phenotypic change are greater in urbanizing systems compared with natural and nonurban anthropogenic systems. By explicitly linking urban development to traits that affect ecosystem function, we can map potential ecoevolutionary implications of emerging patterns of urban agglomerations and uncover insights for maintaining key ecosystem functions upon which the sustainability of human wellbeing depends.ecoevolution | urbanization | ecosystem function | sustainability | anthropocene E merging evidence of phenotypic change on contemporary timescales challenges the assumption that evolution only occurs over hundreds or thousands of years. Anthropogenic changes in ecological conditions can drive evolutionary change in species traits that can alter ecosystem function (1-3). However, the reciprocal and simultaneous outcomes of such interactions have only begun to emerge (4). Despite increasing evidence that humans are major drivers of microevolution, the role of human activities in such dynamics is still unclear. Might human-driven evolution lead to ecosystem change with consequences for human well-being within contemporary timescales (5, 6)?To address this question, human-driven phenotypic change must be considered in the context of global rapid urbanization. In 1950, 30% of the world's population lived in urban settlements (7). By 2014, that figure had risen to 54%, and by 2050 it is expected to reach 66% (7). By 2030, urban land cover is forecast to increase by 1.2 million km 2 , almost tripling the global urban land area of 2000 (8). Urbanization drives systemic changes to socioecological systems by accelerating rates of interactions among people, multiplying connections among distant places, and expanding the spatial scales and ecological consequences of human activities to glo...

Human-induced trait change has been documented in freshwater, marine, and terrestrial ecosystems worldwide. These trait changes are driven by phenotypic plasticity and contemporary evolution. While efforts to manage human-induced trait change are beginning to receive some attention, managing its ecological consequences has received virtually none. Recent work suggests that contemporary trait change can have important effects on the dynamics of populations, communities, and ecosystems. Therefore, trait changes caused by human activity may be shaping ecological dynamics on a global scale. We present evidence for important ecological effects associated with human-induced trait change in a variety of study systems. These effects can occur over large spatial scales and impact system-wide processes such as trophic cascades. Importantly, the magnitude of these effects can be on par with those of traditional ecological drivers such as species presence. However, phenotypic change is not always an agent of ecological change; it can also buffer ecosystems against change. Determining the conditions under which phenotypic change may promote vs prevent ecological change should be a top research priority.

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We document the invasion of Chinook salmon (Oncorhynchus tshawytscha) to southern South America providing historical, current and future perspectives. We conducted field sampling, angler surveys, and analyzed all written records, and found evidence of reproductive populations in more than ten Andean (and many more coastal) watersheds draining mainly to the Pacific Ocean in Chile (39°-53°S), but also to the Atlantic Ocean in Argentina (50°S). Invasion begun *25 years ago apparently from a few point sources of introduction by ocean ranching operations using spring-run Chinook salmon originated from tributaries of the lower Columbia River, USA. The rapid spread suggests that Chinook salmon were pre-adapted to their novel marine and freshwater environments because of similarities to equivalent North Pacific habitats, and invasion may have been facilitated by low ecological resistance. Preliminary data suggest that populations express a latitudinal gradient in juvenile migration life histories equivalent to that in their native range. Parallels to the only other establishment of anadromous Chinook salmon outside their native range, New Zealand, suggests a predictable invasion rate. In South America, the invasion is ongoing in southern areas, yet we deem unlikely colonization of rivers north of the range reached thus far. This is the first anadromous salmon species to have invaded such a large range in South America, and it raises many evolutionary, ecological, environmental and socioeconomic issues, with several discussed here.