In a study of 15 small community parks located in Phoenix neighborhoods with distinct socioeconomic classifications ranging from lower to upper income, Arizona State University ecologists Ann P. Kinzig and Paige Warren measured the abundance and diversity of both birds and trees. The researchers chose parks rather than residential yards because these city-controlled spaces offered comparable environments for the study sites, with a similar landscape (grass, athletic fields, facilities and scattered trees) but significant differences in the surrounding neighborhoods.
"What we are seeing is a pretty strong trend in the data," said Kinzig. "We can't explain bird diversity in the parks by the size of the parks, or the types or sizes of trees in the parks, which is what we might expect. Instead, the characteristics of the neighborhood, including the income of the residents, seem to play a significant role in influencing the number of species that live in the park ."
Trees and other vegetation are considered to be a major factor affecting bird populations. But the study's findings on diversity and abundance of park trees, which are the primary vegetation in the survey sites, do not correspond with the bird data. While bird populations were found to be most diverse in upper income neighborhood parks and progressively less diverse in parks in middle and lower income neighborhoods,
Contact: James Hathaway
Arizona State University