The North Desert Village Landscaping Experiment
at CAP LTER

1. How do landscape design and irrigation methods affect NPP and neighborhood microclimate, soil nutrient pools and fluxes, insect abundance and diversity, and bird activity?
2. How does landscape design affect direct human-landscape interactions in terms of both perceptions and behaviors?

In 2004 and early 2005 residential landscapes at 24 of about 152 virtually identical housing units in the “North Desert Village” were installed. Houses are arranged around common areas and five “mini neighborhoods” (groups of six houses) were selected and landscaped in one of the following styles (fig 1):

• Mesic: A mixture of exotic high water-use vegetation and shade trees with turf grass maintained by flood irrigation
• Oasis: A mixture of drip-watered, high and low water-use plants on granite substrate, and sprinkler-irrigated turf grass
• Xeric: Individually drip-watered, low water-use exotic and native plants on granite substrate
• Native: Native Sonoran Desert plants on granite substrate and no supplemental water
• Control: Six additional households will be monitored as no-plant, no-water controls.

Pre-treatment and long-term, post-treatment data will be gathered for soil trace gas flux, net primary production, soil microflora and arthropod communities, bird and small mammal diversity and behavior, and microclimate. Social variables include human behavior (i.e., direct measures of water use, recreation, and landscaping behavior), ecological knowledge, social network structure, overall environmental values, and perceptions of landscapes.

A wide variety of approaches have been successfully used to study the feedbacks between humans and their biophysical environment. Historical ecology and social surveys specifically address human responses to their environment, opportunistic use of natural experiments allows simultaneous study of different stages of human–environment feedback loops, and simulations and modeling allow prediction of future events. Here we focus on the experimental/manipulative approaches which are rarely used in studies of human–environment interactions, despite the key role that experimentation usually plays in science. There are both ethical and logistical reasons for this lack of inclusion of in situ human subjects. Combining approaches from both the biophysical and social sciences can yield fundamental new insights into coupled human–environmental systems. However, because the social dynamics of subjects may change unpredictably in response to experimental intervention, the conceptual models and the experiments that they motivate should be capable of adapting to these shifts. This pragmatic approach to research, which CAP LTER has chosen here is called “adaptive experimentation," and is of particular relevance in urban ecosystems. For instance, when renters expressed major concern about having cacti and other spiny plants in the landscape where children are playing, this was taken into consideration for designing the native and xeric treatments.

For more on CAP’s approach to adaptive experimentation please see:

Cook, W. M., D. G. Casagrande, D. Hope, P. M. Groffman and S. L. Collins. 2004. Learning to roll with the punches: Adaptive experimentation in human-dominated systems. Frontiers in Ecology and the Environment 2:467-474. (pdf)

Read about landscape types in the Phoenix metropolitan area:

Martin C. A., K. A. Peterson, and L. B. Stabler. 2003. Residential landscaping in Phoenix, Arizona: Practices, preferences, and covenants codes and restrictions (CC&Rs). Journal of Arboriculture 29: 9–17. (pdf)

Posters about North Desert Village:

Cook, W., D. Casagrande, D. Hope, C. Martin, and J. Stutz. 2004. The North Desert Village 'Suburbosphere': An experiment in urban ecology. (pdf)

Farley Metzger, E., S. Yabiku, P. Gober, D. Casagrande, C. Redman, N. Grimm, and S. Harlan. 2004. North Desert Village landscaping experiment monitoring human-environment interactions. (pdf)

Farley Metzger, E., S. Yabiku, P. Gober, D. Casagrande, C. Redman, N. Grimm, and S. Harlan. 2005. Initial findings of the North Desert Village landscaping experiment: The green, green grass of home. (pdf)

For more pictures of landscape styles visit the CAP LTER tour.

Other Highlights

Highlight 1 Some Early CAP LTER Findings
Highlight 3 From Patterns to Emerging Processes in Mechanistic Urban Ecology
Highlight 4 Agrarian Legacy in Soil Nutrient Pools of Urbanizing Arid Lands
Highlight 5 Social Vulnerability, Environmental Inequity, and Childhood Asthma