Are cities unnatural? Are urban landscapes disturbed or damaged? “There is no right answer. We can think of cities in many ways,” says Dr. Paige S. Warren of the University of Massachusetts. “Cities are sources of novelty, hotpots of resource inputs, and drivers of evolutionary change.”.. And what about the plants? With access to floras from 112 cities including both natural and spontaneous vegetation since 1975, Dr. Myla Aronson of Rutgers University along with the Urban Biodiversity Research Coordination Network (UrBioNet) is asking questions about the ways in which cities influence global, regional, and local patterns in plant diversity.