Boom-bust episodes alter plant species diversity patterns in arid urban landscapes

We often think of cities as designed ecosystems, where biophysical drivers are superseded by human decisions. But what happens during times of economic crisis? Are yards overrun with undesirable plants? Is there a reshuffling from top-down to bottom-up drivers? The recent recession had a severe impact in Phoenix, Arizona, giving us the opportunity to examine what happens when a city undergoes an economic disturbance. In our examination of the Survey 200 – a foundational CAP LTER data set - we have identified changes in plant community composition in pre- and post-recession Phoenix. In 2005 NMDS ordinations revealed three distinct assemblages of regional-level community composition, but in 2010 desert composition is unique while urban and agriculture communities largely overlap and distinct assemblages are more difficult to identify. At the residential-level, between 2005 and 2010 a large shift from mesic (irrigated lawn, high water-use plants) to oasis (mix of high and low water plants, some lawn, some gravel) landscaping occurred, and indicator species analysis showed major shifts in yard vegetation between survey years. We attribute these shifts in urban vegetation to socioeconomic processes of the recent boom-bust episode. Our future work will further investigate the social-ecological phenomena of differences in plant communities and drivers at the micro-level on a site-by-site basis.