Project Description

Results from Prior Support The Central Arizona Phoenix Project Long Term Ecological Research (CAP LTER) award (DEB 9714833-010) provided seed funds to initiate a long term experiment on trophic dynamics in urban settings in 2001. CAP LTER is one of 24 long-term sites funded by NSF. In the past, LTER sites have focused upon pristine locations, well removed from the myriad effects brought about by extensive human modification and dominance of ecosystems. The CAP LTER project is a multifaceted study aimed at answering the question, ‘How does the pattern of development of the city alter ecological conditions of the city and its surrounding environment, and vice versa?’ Central to answering this question is understanding how societal decisions drive land-use change, how these decisions alter ecological pattern and process, and how changes in ecological conditions further influence human decision making. Of the 24 sites funded under the nationwide LTER program, Phoenix and Baltimore are the only 2 established specifically to study urban ecosystems. Biological, physical, and social scientists from Arizona State University and a wide range of local partners are working together to study the structure and function of the urban ecosystem, assess the effects of urbanization on biological entities in the city and outlying desert, and define how ecological conditions feedback on urbanization. The project has an explicit commitment to engage the broader community in research and public understanding of science. In 2001-02, we established brittlebush (Encelia farinosa) at three study sites to address the question of how urbanization alters trophic dynamics. The three sites included a mesic yard within the urban/suburban matrix (the President’s House), a desert remnant, also within the urban/suburban matrix (The Desert Botanical Gardens), and a ‘natural’, contiguous area of Sonoran desert just outside the metropolitan boundaries (Usery Mountain Park). We will expand this experiment to include 3 replicates of each urban/non-urban habitat type. In addition, we will initiate a second long term experiment that explicitly tests how gradients in water availability alter trophic dynamics. Finally, we will use natural variability in the abundance of the stable isotopes of hydrogen (deuterium, or D) and oxygen (O) to identify water sources in invertebrate herbivores. This analysis will allow us to quantify the degree to which water stress causes trophic dynamics to deviate from predictions from classic top-down and bottom-up models. Because the first experiment was recently established, results are preliminary (see Preliminary Results below), but promising and exciting, and form the basis for this proposal. However, related projects linked to this proposal have resulted in many publications (CAP LTER website: http://caplter.asu.edu/).