• Changes in riparian vegetation following release of reclaimed effluent water into the Santa Cruz River: As a corollary, the effects of channelization on vegetation in the Santa Cruz River

      Livingston, Margaret M.; Gormally, Joshua (The University of Arizona., 2002)
      Recharge has been conducted very efficiently for twenty-five years near Roger and Ina roads along the Santa Cruz River using reclaimed water. This project seeks to determine the composition of river vegetation due to the release of the reclaimed water, and as a corollary, to examine the effects of channelization on the vegetation of the Santa Cruz River. Using belt and line transects the vegetation along the Santa Cruz River was surveyed. Treatment with effluent was found to increase plant density, diversity, richness, cover, and incidence of exotic plants. Channelization was found to increase only plant richness and incidence of exotic plants. Furthermore, effluent encouraged the growth of tree plant types while channelization discouraged such growth. Recommendations were made regarding future release of effluent into the Santa Cruz River and future attempts to restore the once prolific, willow-cottonwood forests and mesquite forests.
    • Relationship between remnant size and plant species richness in the Tucson urban matrix

      Livingston, Margaret; Duncan, Allison B. (The University of Arizona., 2002)
      The Sonoran Desert surrounding Tucson, Arizona is the dominant matrix in a region undergoing a transition from desert matrix to urban matrix with little emphasis placed on preserving this native ecosystem intact. Instead, patches of desert, remnants, are cut off the desert matrix and surrounded by a variety of land uses including residential, transit, and commercial. 31 sites within the City of Tucson were surveyed and the site's plant species richness, woody cover, herbaceous cover, and disturbance percentage measured. The plants found on-site were classified into native or exotic, annual or perennial, and woody or herbaceous, and further broken down into growth form. Results indicated a significant correlation between a site's area and its percent disturbance, as well as correlations between its native vegetation and area.