Desert Fertilization Experiment: composition of annual plants in study plots within desert preserves in and around the greater Phoenix metropolitan area, spring 2008

Launched in 2006 with support from the National Science
Foundation (NSF) and leveraged by the CAP LTER, the Carbon and Nitrogen
deposition (CNdep) project sought to answer the fundamental question of
whether elemental cycles in urban ecosystems are qualitatively different
from those in non-urban ecosystems. Ecosystem scientists, atmospheric
chemists, and biogeochemists tested the hypothesis that distinct
biogeochemical pathways result from elevated inorganic nitrogen and
organic carbon deposition from the atmosphere to the land. To test the
hypothesis, scientists examined the responsiveness of Sonoran desert
ecosystems to nutrient enrichment by capitalizing on a gradient of
atmospheric deposition in and around the greater Phoenix metropolitan
area. Fifteen desert study sites were established, with five locations
each west and east of the urban core, and in the urban core in desert
preserves. In addition to the gradient of atmospheric deposition in and
around the urban core, select study plots at each of the fifteen desert
locations receive amendments of nitrogen, phosphorus, or nitrogen +
phosphorus fertilizer. Measured variables include soil properties,
perennial and annual plant growth, and atmospheric deposition of
nitrogen. At the close of the initial grant period, the CAP LTER assumed
responsibility for the project, renamed the Desert Fertilization
Experiment, which provides a remarkable platform to study the long-term
effects of nutrient enrichment on ecosystem properties.

This data set features the composition of annual plants in subplots at
project study sites assessed in spring 2008. These data are published
independently of surveys of annual plants in subsequent years owing to
slightly differnet methods employed in 2008 relative to other years.
Investigators interested in annual plants composition data from other
years, or for other Desert Fertilization Experiment data, should search
the data repository for 'desert fertilization experiment'.