When the economic engine stalls − A multi-scale comparison of vegetation dynamics in pre- and post-recession Phoenix, Arizona, USA

Often, we think of cities as designed landscapes, where people manage everything from water to weeds. But we do not fully understand what happens to these extensively managed landscapes when there is an abrupt disruption in economic activity. Considering the ability of cities to support plant biodiversity and their importance as human habitat, we studied pre- and post-recession landscapes across a gradient of human influence by asking: How did vegetation change over time from before the housing bubble to after the nadir of the Great Recession? And how did vegetation vary across sites at regional versus residential scales? This investigation used long-term vegetation data to examine diversity trends and responses to a novel economic disturbance in an urban social-ecological system. Overall, we found that plant species diversity increased through time across scales, while species composition homogenized in urban and agricultural areas. Residential yards, however, initially had high compositional heterogeneity which then increased over time. Changes in residential diversity were driven by substantial increases in the role of annual plants. This research improves our understanding of spatiotemporal vegetation dynamics in a coupled human-natural system, and specifically how urban vegetation dynamics are linked to anthropogenic influence. Ultimately, we recommend that city planners and managers consider economic trends when approaching community projects because of the interconnectedness of ecology and socioeconomics in urban landscapes.