" BES Project Abstracts 2005
Institute of Ecosystem Studies

2005 BES Annual Meeting Presentation and Poster Abstracts


Humans in the urban food web: Emerging insights from Phoenix and Baltimore
 
P. Tarrant, E. Adley, J. M. Grove, E. Shochat, and S. Faeth
 
Abstract: Human activities dramatically change abundances, diversity, and composition of species. Little is known about how the most intense human activity, urbanization, alters food webs and trophic structure in biological communities. Experimental studies at the Central Arizona-Phoenix (CAP) LTER reveal surprising alterations in control of trophic dynamics. Supplemented resources, particularly water, increase and stabilize productivity, setting the stage for altered control of populations. Stan Faeth and colleagues have found that, in contrast to outlying deserts where limiting resources dominate, predation by birds becomes the dominant force controlling arthropods on urban plants. Eyal Shochat and colleagues argue that reduced predation risk on birds elevates elevated abundance and alters foraging behavior such that urban birds exert increased top-down effects on arthropods. However, the nature of human provisioning and alteration of resources and predation varies within cities, according to our research at both CAP and BES LTER. For example, bird feeders appear more common in neighborhoods with moderate income and with more retired people. Perversely, birds show evidence of greater competition for food resources in these same neighborhoods. How do we integrate humans into our models and understanding of urban food webs? The presentation will serve as the start of a conversation on this topic and an invitation for feedback as we develop the next phases of our research.