UA Arid Lands Poster Session Participants

Thank you to everyone who attended and participated in the recent UA Arid Lands Poster Session. You can view a short video of the event and some photos here. Below are names, titles and abstracts for each of the posters.

Michael Kotutwa Johnson: The Anomaly of Hopi Agriculture: Does Climate Change Really Matter?

The Hopi people learned to adapt to climatic changes associated with long periods of drought for well over a thousand years in the semi-arid region of the Little Colorado Plateau. Adaptation has been formalized through generational knowledge and time tested agricultural techniques allowing them to grow Hopi heirloom crop varieties. My research consists of the development of a best practices manual for Hopi agriculture conservation practices including the optimization of soil moisture for crop production in a semi-arid region. Populations of people found in other semi-arid regions may implement Hopi low-impact conservation and agriculture techniques to adapt to climate change.

Rebecca F.A. Bernat: Water Banking in Arizona: a Closer Look at Aquifer Recharge of Effluent

As Arizona’s population grows, the reuse of wastewater –or effluent- is an important part of water resources management. This presentation is designed to explain how (1) the recharge of effluent by basin infiltration in an Underground Storage Facility (USF) might lead to soil pollution, and (2) how the storage of effluent in USFs might lead to groundwater pollution. This presentation will call into question the use of the recovered CAP water at a USF that stores effluent. The aim is to determine whether or not there is indirect potable reuse in Arizona from the point of view of water chemistry.


Halophytes (salt-tolerant plants) are potentially useful in management of wastewater concentrate from inland desalination or as an agricultural production alternative in regions of brackish groundwater by providing a marketable crop to the cattle feed industry. The successful growth of Atriplex canescens (Fourwing Saltbush) and Atriplex lentiformis (Big Saltbush) has been demonstrated in a semi-arid environment (Alamogordo, NM) with high-gypsum soils and irrigation with reverse osmosis waste concentrate (4,000 ppm TDS).  The biomass grown in this pilot project has high protein and fiber content showing potential as a cattle feed-mix additive with managed avoidance of subsurface migration of applied irrigation water.

Justine Schluntz: International Arid Lands Consortium at the University of Arizona

This poster will introduce attendees to the International Arid Lands Consortium and its history at the University of Arizona.

Marilen Pool: Insect Lac in Ancient and Modern Cultures in the American Southwest

Conservators from the Preservation Division of the Arizona State Museum are currently researching the use of insect exudates in its archaeological and ethnographic collections.  The Survey of entire collections assessing materials and technology with focus led to discoveries about the collection, including findings of continuity between ancient and modern cultures.

This poster will focus on the host plants, their distribution and associated lac producing insects found in the deserts of the American Southwest.  Examples of the application of this material by ancient and modern peoples in the manufacture of a variety of artifact types will be described.

Barbara Hutchinson: Check out the Radically Redesigned Global Rangelands Websites: a Web Portal to Scientific and Educational Resources on the World

The Rangelands Partnership has relaunched its websites Global Rangelands (, Rangelands West (, and state sites such as Arizona Rangelands (  Besides improved navigation and mobile-friendly applications, topical content has been added (i.e. wolf reintroduction and sage grouse) as well as expanded “collections” including journal articles, reports, conference proceedings, fact sheets, and videos.  Global Rangelands provides easy access to more than 20,000 worldwide resources serving research, education, and extension.  New collections include the African Journal of Range and Forage Science from the Grassland Society for Southern Africa (GSSA), extensive collections from the Australian Rangelands Society, and full-text from FAO.

Aaron Lien: Ranching, Jaguars, and Large Landscape Conservation

The semi-arid rangelands of southern Arizona and New Mexico provide the northern-most habitat for endangered jaguars. Once thought extirpated from the United States, there have been numerous jaguar sightings in the region since the mid-1990s. In 2014, the United States Fish and Wildlife Service (USFWS) designated “critical habitat” for jaguars in the region. Critical habitat is a legal designation under the Endangered Species Act for habitat critical to the survival and recovery of an endangered species.
We investigate rancher’s attitudes toward endangered species regulations, the critical habitat designation for jaguars, conservation, and incentive-based approaches to overcoming concerns stemming from endangered species regulations.

Sandra Bernal: Relationship between built environment and indoor air quality in arid regions

A preliminary work developed during my independent study is shown in 3 phases: a) case study of a single-family house in Tucson where a comparison between ventilation systems and dust deposition was observed; b) a summary of what have being found as source of indoor pollutants in houses by other authors; and c) factors that make a building a complex problem for air quality. The outcome of this preliminary work is what I call my "dissertation jar" meaning that I got an idea of what concerns may exist in area of indoor air quality for the residential sector in arid regions.

Maria L. Terrazas-Onofre: Reduction of coliforms, E. coli, and enterococcus in graywater by solar disinfection

Arizona has regulations for graywater (GW) reuse in household landscape irrigation. These permits aim to decrease the health risk because raw GW contains fecal contamination indicators. This study shows that solar disinfection (SODIS) reduces the most probable number (MPN) of coliforms, E. coli, and enterococcus to safe levels. A GW-temperature of 55 °C and less than 20 W m-2 passive UV radiation (280 – 400 nm) are required to reach a concentration < 1 MPN/100 ml of the three bacterial indicators. Whereas with more than 20 W m-2 passive UV only 40 °C is required to reach the same lowest detection limit.

Sean Hendryx: Impacts of hydraulic redistribution on plant and soil carbon and water fluxes in a dryland savanna

Hydraulic redistribution is an important ecohydrological process in dryland environments by which plants preferentially move water from wet to dry soil layers. By synthesizing sap flow data with shallow and deep soil moisture data, we show that soil moisture gradients control hydraulic redistribution in mesquite trees. During prolonged inter-rain periods and in response to vapor pressure deficits, mesquites drew upon this stored water to meet biological demands. We measured mesquite and sub-canopy carbon and water exchange to estimate impacts of hydraulic redistribution, and we found that this hydraulic redistribution provides a drought-buffering capacity for the mesquite but not understory grasses.


The goal of this research is to map soil spatial variation in southwestern Arizona using digital soil mapping techniques and high resolution remote sensing products. An iterative principal component analysis (iPCA) was applied to LiDAR and Landsat ETM+ topographic data and principal components were integrated and classified using ISODATA. Classified maps were segmented using a region growing algorithm, yielding maps of soil-landscapes that were compared with maps of soil landforms identified from aerial photographs and field observation. The approach identified all soil landforms and illustrated its applicability for spatial prediction of soil–landscape attributes necessary for ecosystem management and assessment.

Enrique P. Sanchez-Canete: The need for locally determined diffusion coefficient to reliably assess soil effluxes via the gradient method

Continuous soil CO2 efflux (Fsoil) estimates can be obtained by the gradient method (GM), but, the utility of the method is hindered by uncertainties in the application of published ex-situ models of the diffusion coefficient (Ds). Here, we compared two in-situ methods for determining Ds, one based on the GM and another using SF6 as a tracer gas, and we compared these resulting diffusion models with 14 published models. We found that our SF6 model and the published models using the GM underestimated cumulative Fsoil. Instead, our Ds model based on the GM showed precise estimates in the cumulative Fsoil.

Leland Sutter: An important aspect of soil carbon and water fluxes in desert environments

Within dryland environments, precipitation and incoming energy are the primary determinants of carbon and water cycling. We compared north and south-facing slopes to examine the effects of aspect on soil temperature and moisture and the resulting carbon and water flux rates within the low elevation, desert site of the Catalina-Jemez Critical Zone Observatory. In addition to measurements at a single point in time, we also examined the role that aspect plays in diel patterns of soil fluxes and in response to rain events. Ultimately, our work will illustrate the interactive effects of a range of physical factors on soil fluxes.

Yurong Liu (Joy): Understanding collaborative ecological restoration and its effect on livelihoods of smallholders on the Loess Plateau.

In the context of collaborative governance, the study examines ecological restoration projects as a response to implementation of the Sloping Land Conversion Program in the Loess Plateau, China. It examines the decision-making process and climatic factors influencing the initiation and outcomes of a NGO-led and a state-university-led restoration efforts through ongoing ethnographic research with stakeholders since 2013. The study demonstrates differential experiences of land-degradation and collaboration drive differential participation in externally-directed governance within farming communities. Preliminary finding indicates that lack of knowledge exchange among stakeholders resulted in the delay of adaptation practices, and thus increased environmental risk for farmers’ livelihoods.

Jesus Rodriguez: Downscaling MODIS 250m to Landsat 30m resolution in support of field level ET estimation

In arid and semiarid regions, managing agriculture water starts with better irrigation planning and evapotranspiration (ET) estimation. We are proposing to downscale global MODIS 1km ET estimates using geostatistical methods and vegetation indices as covariates. We developed a method to scale daily vegetation indices from 250m to 30m in order to support the downscaling of MODIS ET. The model was developed and tested in an irrigation district in the Lower Colorado River. Results, validated with independent observations of Landsat reflectance, confirm that this approach works and the uncertainty is acceptable (R2= 69-73%).

Jeremy Weiss: DroughtView: Satellite-based Drought Monitoring and Assessment

Remotely sensed data are valuable for monitoring, assessing, and managing impacts to arid lands caused by natural environmental changes and human activities. With this in mind, we redeveloped DroughtView, a web-based decision-support tool that combines satellite-derived measures of surface greenness with additional geospatial data so that users can visualize and evaluate vegetation dynamics across space and over time. Here, we present the functionality of DroughtView, including new capabilities to report drought impacts and share map information. We also provide examples of recent DroughtView use in determining rangeland conditions and timing vegetation surveys.

Khaled Ali Almazam and Omar Humaidan: Gates of Knowledge for Organ Pipe Cactus National Monument

Gates-of-Knowledge is a multidisciplinary research on integrating the Sonora desert ethics into the built environment in an arid-lands setting. It provides vocabulary on desert adaptation strategies for energy and water conservation, passive solar, renewable energy, and Net-zero design. Features such as the integrated cool towers and tensile shading structures create a landmark in the middle of the desert that guides visitors to this architectural development for the visitor center. The research building will become a showcase for sustainability that features educational tools to teach visitors firsthand how buildings adapt to extreme weather conditions to provide thermal comfort for both indoor and outdoor spaces.

Hussein Ali Naser Al salih: Harvesting Rainwater through Passively Designed Roof Integrated Environmental Systems

In the heart of the Sonoran desert, southwest Arizona, the visitor center of the Organ Pipe Cactus National is a landmark for the park. The water consumption is considered an important aspect in the visitor center. All the used water comes from wells that are located in the park. Most of these wells have significantly declined in their water levels at a rate of one foot per year approximately. The proposed design aims to manipulate the roof of the building and the parking lots to create a system for managing and collecting rainwater for reducing the dependence on the wells water.

Ismat Abdulhamid and Ashley Corron: A Journey through shade

For our studio project, we decided to design a net zero visitor center for the Organ Pipe Cactus National Monument. OPCNM is located in extreme southern Arizona, an arid region that shares a border with the Mexican state of Sonora. Our big idea focuses on a design that incorporates different cooling effects, based on shading and natural ventilation techniques, while still allowing for a connection through the site. Our visitor center will offer interactive tools that will engage the visitors and teach them principles of shading, water harvesting/sustainability and other environmental aspects.

Becky Brice: Fall season soil moisture reconstruction from tree rings in the Upper Colorado River basin, U.S.A.

The arid Colorado River basin is one of the most over-allocated river basins in the world.  Year-to-year variability in Colorado River streamflow has far reaching impacts throughout the seven states and Mexico dependent upon its water supply.  Streamflow variability related to runoff is influenced by seasonal contributions of spring temperature, antecedent soil moisture, and winter snowpack.  This study investigates the potential to use tree rings to reconstruct fall season soil moisture.  The relationship of soil moisture to streamflow magnitude in the Colorado River may enhance our understanding of hydroclimatic variability and inform future water resources decision-making.

Patrick Murphy: Studying Topographic Controls on Primary Productivity

Projections of ecosystem response to climate change are rife with uncertainty, and the influence of topography on primary production in forested ecosystems remains understudied. Because north vs. south aspects receive dissimilar energy inputs, we hypothesize that vegetation on these opposing aspects will respond to seasonal variation in temperature and precipitation differently, particularly in drylands. Additionally, response to these environmental drivers will likely vary between species. Initial results indicate divergence in net photosynthesis between species at the same study site. We will continue measurements across seasonal periods to examine spatio-temporal dynamics in response to periods of temperature and moisture stress.