A Portrait of Changing Community Composition in Urban Wetlands of the Salt River, Phoenix AZ USA

Human activities in Phoenix, Arizona, have left the Salt River dammed, diverted, restored, and ignored. Urban wetlands are vital for many species, offering insight into how ecological communities and management are co-produced within social-ecological systems. Which organisms are most impacted by urban management choices? We analyzed long-term surveys (2012-2022) of birds, herpetofauna, and plants across three urban wetlands: a recreation area, an unmanaged accidental wetland, and a restored wetland. We assessed species richness, abundance, and diversity. In collaboration with land managers, we removed vegetation from the restored site and harvested biomass from three abundant marsh plants (Arundo donax, Schoenoplectus californicus, and Typha latifolia). Using Hollander beaters, we pulped the biomass to make paper and visualized plant community changes on it, displaying these artworks in community centers to engage local audiences. Our results show herpetofauna declined in abundance and diversity, while bird populations remained stable. Vegetation abundance increased, and despite invasive species removal efforts, urban plant communities became more cosmopolitan. The unmanaged wetland hosted the highest number of both introduced and rare plant species, along with an increase in culturally significant plants for local Indigenous groups. This study shows urban wetlands in arid regions support surprising species diversity, and accidental wetlands can complement costly restoration efforts, which are more effective for birds than herpetofauna. Introduced plants do not always threaten native or culturally important species, so the rationale for removal should be considered before implementing management plans. Practical biomass uses, like paper-making, can also foster community engagement with research and stewardship.