Aridland ecosystem response to nutrient deposition from the urban atmosphere

measuring plant growthHow does atmospheric pollution alter the ecology of urban and near-urban native ecosystems?  Using both long-term monitoring and  experimental fertilizer additions, we are exploring the ecological consequences of atmospheric nutrient enrichment and ozone pollution across an urban-rural gradient of 15 sites in Sonoran Desert open space preserves within and surrounding the Phoenix metropolitan area. As a long-term experiment within the CAP LTER project, we have been monitoring plant productivity, spring wildflower diversity and composition, and soil properties since 2006.  See a map of our long-term Sonoran Desert open space sites and read more about the project as a Research Highlight of the CAP LTER.


Experimental nutrient enrichment plots in the Sonoran Desert. Spring herbaceous primary production is most responsive to N (nitrogen) and N+P (nitrogen+phosphorus) additions (visible as green squares).

In 2015, we began a partnership with the Central Arizona Conservation Alliance of Central Arizona (CAZCA) to launch a joint CAP LTER-citizen scientist initiative to survey spring wildflower communities across the urban-rural gradient. Read more about the CAP LTER-CAZCA Community Wildflower Survey here.


Dr. Sharon J. Hall, School of Life Sciences, Arizona State University

Dr. Elizabeth Cook, Universidad Austral de Chile

Dr. Nancy Grimm, School of Life Sciences, Arizona State University

Dr. Becky Ball, School of Mathematical and Natural Sciences, Arizona State University
Dr. Scott Collins, University of New Mexico
Quincy Stewart, CAP LTER, Arizona State University

  • M. Christman, S.J. Hall, and B.A. Ball. Nutrient dynamics during early-stage photodegradation of plant litter in an arid, urban ecosystem. In review at Journal of Arid Environment
  • M. Davis, E. Cook, S. Collins, and S.J. Hall. 2015. Top-down vs. bottom-up regulation of herbaceous primary production and composition in an arid, urbanizing ecosystem. Journal of Arid Environments, 116; 103-114. doi:10.1016/j.jaridenv.2015.01.018.
  • Y. Marusenko, F. Garcia-Pichel, and S.J. Hall. 2015. Ammonia-oxidizing archaea respond positively to inorganic N addition in desert soils. FEMS Microbiology Ecology, 91(2):1-11.
  • Sponseller, RA., S.J. Hall, D. Huber, N.B. Grimm, J.P. Kaye, C. Clark, and S. Collins. 2012. Variation in monsoon precipitation drives spatial and temporal patterns of Larrea tridentata growth in the Sonoran Desert. Functional Ecology, DOI 10.1111/j.1365-2435.2012.01979.x.
  • Kaye, J.P., S.E. Eckert, *D.A. Gonzalez, J.O. Allen, S.J. Hall, R.A. Sponseller, and N.B. Grimm. 2011. Decomposition of urban atmospheric carbon in Sonoran Desert soils. Urban Ecosystems, DOI 10.1007/s11252-011-0173-8
  • Hall, S.J., R.A. Sponseller, N.B. Grimm, D. Huber, J.P. Kaye, C. Clark, and S. Collins. 2011. Ecosystem response to nutrient enrichment across an urban airshed in the Sonoran Desert. Ecological Applications, 21(3): 640-660.

NSF-DEB Award #0514382 (Ecosystem responses to the urban atmosphere)
NSF LTER/Central Arizona–Phoenix Long-term Ecological Research Program, BCS-1026865