March 26, 2017 1103 GMT
A new multi-institution study led by the University of Washington that examines 1,600 global instances of phenotypic change — alterations to species' observable traits such as size, development or behavior — shows more clearly than ever that urbanization is affecting the genetic makeup of species that are crucial to ecosystem health and success, phys.org reported.
Their paper was published in the Proceedings of the National Academy of Sciences. Lead author is Marina Alberti, professor of urban design and planning and director of the Urban Ecology Research Lab in the UW College of Built Environments.
"We found a clear urban signal of phenotypic change — and greater phenotypic change in urbanizing systems compared to natural and non-urban anthropogenic, or human-created systems," Alberti said.
She said the findings open new opportunities for advancing our understanding of the role of humans in Earth's evolution: "By explicitly linking urban development to heritable traits that affect ecosystem function, we can begin to map the implications of human-induced trait changes for ecological and human well-being."
Rapid urbanization, the researchers wrote, poses new challenges for species, some of which will adapt or relocate while others go extinct. With this study, they sought to learn whether signs of human-caused change could be detected across species in urban ecosystems worldwide, and to what extent humans and our cities and societies might be speeding up these changes.
They analyzed 1,600 observations of phenotypic change across multiple regions and ecosystems worldwide, in a geo-referenced database, looking to discriminate between such human-caused signals and natural baselines and ‘non-urban drivers’.
They also assessed the relative impact of several human-caused ‘urban disturbances,’ including the acidification and pollution of lake habitats, the relocation of animals, heat and effluent associated with a power plant, long-term harvesting of certain medicinal plants — even the apparent effects of global warming on the reproductive patterns of birds.
They propose that ‘urban-driven contemporary evolution’ will affect sustainability from the level of the urban ecosystem to the planetary scale.
"The significance of these changes is that they affect the functioning of ecosystems," Alberti said. "They may inhibit the ability of seeds to disperse, cause exposure to infectious diseases, or even change the migratory patterns of some species."