According to the New York Times Minneapolis and Phoenix have more in common with one another concerning plants than they do with the surrounding landscape. In the article Bloom Town Maggie Koerth-Baker looks at several recent studies by the Cary Institute of Eco System Studies and the University of Minnesota and finds that urban environments tend to be more similar to one another than to the surrounding rural landscape from a plants and ecological perspective. The articles summary of the University of Minnesota findings is below:
Researchers from the University of Minnesota surveyed 137 yards in Minneapolis and St. Paul, looking at the plants that grew there spontaneously, and found that the yards held more exotic species than rural areas outside the city. Plants that came from much warmer climates were able to thrive there because cities, filled with heat-absorbing buildings and hard surfaces, are warmer than rural areas. They also found that the urban plants were more likely to be able to fertilize themselves, which was important in a place where growing spaces were separated by fences, streets and sidewalks. If you can’t find another member of your species, it’s handy to be able to breed with yourself.
As a student who studied Landscape Architecture the University of Minnesota findings were no surprise to me, especially when considering how many invasive species are found throughout urbanized areas. The surprising fact of the story was that places as different as Minneapolis and Phoenix could have such a similar mix of species, irrigation probably being a leading factor of this. What I would really like to see, and as the story points out studies are ongoing, is how these environments impact animals and native plants that do happen to also inhabit these heavily modified urban spaces.