Neighborhood socioeconomic status is a useful predictor of perennial landscape vegetation in residential neighborhoods and embedded small parks of Phoenix, AZ

Though landscape vegetation in cities is human-mediated and often more diverse than that in surrounding environments, little work has been done to quantify ways that humans shape its composition. Our study identified important sources of variation in perennial vegetation composition within residential neighborhoods of Phoenix, AZ, USA. We hypothesized that neighborhood socioeconomic status (SES) should offer some capacity for predicting landscape vegetation richness and abundance in both residential neighborhoods and embedded small city parks. As predicted, neighborhood vegetation richness increased across a gradient of low to high SES (R²=0.89) with the most variation explained by median family income (R²=0.86). In contrast, neighborhood vegetation abundance decreased across a gradient of increased time since disturbance (R²=0.62) with the most variation explained by median year of neighborhood development (R²=0.56). Median year of neighborhood development was also the dominant factor (R²=0.47) in explaining decreased park vegetation abundance across a gradient of increased time since disturbance. We were least able to predict park vegetation richness and could account for only 29% of variation using a SES gradient model with percent of population having a graduate education as the most dominant factor. In residential neighborhoods, we identified more than 3 times the number of landscape vegetation taxa than an earlier report and also found a higher percentage of native vegetation in parks than in surrounding neighborhoods. We discuss these different compositional patterns of perennial vegetation in neighborhoods and embedded parks in terms of their relationship to socioeconomic and disturbance gradients, and a conceptual framework of "top-down" and "bottom-up" human management influences. Our study intimates that residential vegetation composition in rapidly expanding, arid cities like Phoenix is largely driven by "luxury" and legacy effects and should be most rich in neighborhoods with the highest socioeconomic standing and most abundant in newest neighborhoods.