Desert Ecology Commons^™

Using Triple Oxygen Isotopes To Investigate Water Usage In Desert Ecosystems, Cloe V. Knutson

Earth and Planetary Sciences ETDs

In arid environments, maintaining water balance can be more critical for survival than obtaining food. As droughts intensify, understanding how animals manage body water is essential. Triple oxygen isotope analysis provides a novel way to trace water sources in animals, distinguishing contributions from free water, food-derived oxygen, and atmospheric O₂. We developed an equilibration method using CO₂–H₂O oxygen exchange and measured δ^’18O and Δ^’17O values via tunable infrared laser direct spectroscopy (TILDAS). Validated against traditional fluorination methods, this technique enables streamlined analysis of whole blood and plant samples. Applied to …

Effects Of Fire Temperatures On Mojave Desert Native And Nonnative Seeds, Sophia Lorenzana, Lindsay Chiquoine

Undergraduate Research Symposium Posters

Large-scale wildfires have been historically rare in hot deserts like the Mojave, largely due to the scarcity or uneven distribution of native plant biomass as fuel. Thus, native plants in these regions are ill-adapted to withstand spreading wildfire, resulting in slow post-fire recovery. Here, I test the hypothesis that nonnative grasses respond better to heat cues than native plant species. Seeds from 3 invasive and 13 native plant species were collected from research sites located in the eastern Mojave Desert, near surrounding Clark County Flood Control District weather stations. Seeds were buried in an artificial substrate mimicking field soil conditions …

Precipitation And Greenness In Pastoral Lands Of East Turkana, Kenya, Paul Akpejeluh

School of Natural Resources: Dissertations, Theses, and Student Research

Pastoralism has long supported livelihoods and provided essential ecosystem services in landscapes of East Africa. Vegetation productivity is central to the functioning of pastoral systems but may be affected by changes in climate and landuse. Vegetation monitoring is important for understanding the effects of global change in pastoral lands; however, it can be time and resource intensive. Remote sensing provides opportunities for efficient multi-scale monitoring of vegetation and climatic drivers. In this thesis, I explore the utility of satellite and UAV remote sensing for monitoring vegetation and precipitation trends and relationships in the East of Lake Turkana Region of northern …

Species Distribution Modeling For Arid Adapted Habitat Specialists In Zion National Park, Sam Driver, Daniel R. Unger, David L. Kulhavy, Chris M. Schalk

Student Publications

The Arizona toad (Anaxyrus microscaphus) and Jones’ waxy dogbane (Cycladenia humilis var. jonesii) are habitat specialists with historical ranges in the desert southwest and specifically, Zion National Park (ZION). The machine learning method, MaxEnt, constructed species distribution models (SDMs) in ZION for the two study species at 30 m and 900 m spatial resolutions using climate, topographic, and remotely sensed data. Additionally, 900 m forecasting models were constructed to observe the shifts in suitable habitat for the years 2050 and 2070, based off two representative concentration pathway scenarios. Results indicate promising predictive power for both high …

Effects Of Increased Precipitation On The Life History Of Spring- And Autumn-Germinated Plants Of The Cold Desert Annual Erodium Oxyrhynchum (Geraniaceae), Yanfeng Chen, Xiang Shi, Lingwei Zhang, Jerry M. Baskin, Carol C. Baskin, Huiliang Liu, Daoyuan Zhang

Biology Faculty Publications

Future increased precipitation in cold desert ecosystems may impact annual/ephemeral plant species that germinate in both spring and autumn. Our primary aim was to compare the life history characteristics of plants from spring-germinating (SG) and autumn-germinating (AG) seeds of Erodium oxyrhynchum. Plants in field plots with simulated increases in precipitation of 0, 30 and 50 % in spring and summer were monitored to determine seedling survival, phenology, plant size, seed production and biomass accumulation and allocation. Germination characteristics were determined in the laboratory for seeds produced by plants in all increased precipitation treatments. Increased precipitation in spring significantly improved survival …

Speed And Resolution In The Age Of Technological Reproducibility, Shawn Taylor

Theses and Dissertations

The rate of acceleration of the biologic and synthetic world has for a while now, been in the process of exponentially speeding up, maxing out servers and landfills, merging with each other, destroying each other. The last prehistoric relics on Earth are absorbing the same oxygen, carbon dioxide and electronic waves in our biosphere as us. A degraded .jpeg enlarged to full screen on a Samsung 4K UHD HU8550 Series Smart TV - 85” Class (84.5” diag.). Within this composite ecology, the ancient limestone of the grand canyon competes with the iMax movie of itself, the production of Mac pros, …

Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca

UNLV Theses, Dissertations, Professional Papers, and Capstones

An assessment of the growth response of key vegetative species to climatic variability is vital to identifying possible local impacts on ecosystems faced with imminent climate change. With current climate projections in Nevada predicting a shift to an even more arid climate with greater year-to-year variability, the imperative exists to identify the effects of specific climatic controls on plant growth and to research methods to assess large-scale vegetative changes, especially in more remote areas where readily available data sets may be lacking. This study utilized annual growth ring indices constructed from big sagebrush (Artemisia tridentatassp.tridentata) stems collected in Spring Valley, …

Soil Moisture Recognition And The Spatial Distribution Of Storm Activity In The Mojave Desert Using High-Resolution Aster And Modis Imagery For Thermophysical Mapping, Russell J. Skuse

UNLV Theses, Dissertations, Professional Papers, and Capstones

Climate models suggest that the Mojave Desert ecoregion is vulnerable to becoming drier in the future, and as the human population grows and development increases, environmental stresses will likely increase. Determining the spatial distribution and variation of soil moisture on a regional scale is an essential component to climate change, hydrologic, and habitat analyses. Soil permeability and sediment stability are characteristics that have been shown to be measurable from remote sensing observations. The primary objective of this project is to map the mechanical composition of the surface materials in the Mojave Desert ecoregion with implications for soil permeability, sediment stability, …

Integrating, Developing, And Testing Methods To Generate More Cohesive Approaches To Biogeographic Inference, Mallory Elizabeth Eckstut

UNLV Theses, Dissertations, Professional Papers, and Capstones

As a fundamental component of the developing discipline of conservation biogeography, broadscale analyses of biotic assembly and disassembly across multiple temporal and spatial scales provide an enhanced understanding of how geologic transformations and climate oscillations have shaped extant patterns of biodiversity. As with any scientific field, there are limitations in the case of biogeographic historical reconstructions. Historical reconstructions are only as robust as the theoretical underpinnings of the methods of reconstruction (including data collection, quality, analysis, and interpretation). Nevertheless, historical reconstructions of species distributions can help inform our understanding of how species respond to environmental change.

My dissertation takes a …

Understanding Effects Of Changes In Land Use, Environmental Parameters, Habitat Characteristics On The Great Basin Aquatic Invertebrates Using Ecological Stoichiometric Theory, Knut Mehler

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many freshwater ecosystems in the Great Basin have undergone dramatic alteration over the past decades due to groundwater withdrawal, water diversion and changes in land use. These changes have affected benthic food web dynamics by altering the availability of chemical key elements for primary and secondary producers, by loss of biodiversity and extinction of endemic species. However, only few studies are available that addresses the link between changes in land use, habitat characteristics and its effects on benthic macroinvertebrates (BMI) communities comprehensively and little attention has been given to integrating physiochemical aspects to link ecosystem functions.

This dissertation analyzes the …

The Evaluation Of Water Storage In Death Valley Using Grace Satellite Data, Maile Sweigart

UNLV Theses, Dissertations, Professional Papers, and Capstones

As drought conditions spread across the United States, concerns over water supplies, water use, and water management policies are growing and possible contributing environmental factors are continually being scrutinized. This thesis examines Death Valley as an analog for Southern Nevada and utilizes NASA EOS data, combined with ancillary climate data, to assess the effect of decadal climate variability on groundwater storage in the Death Valley area. Historical climate data, combined with satellite imagery observations, were compiled and calculated for analyses. Conclusions derived from statistical analyses infer trends between GRACE (Gravity Recovery and Climate Experiment) satellite data and fluctuating levels of …

Moving Forward: Preventing Water Shortage For Nevada, Sandra Blandon, Brianna Lyon

Anthropology 100: Feast and Famine In a Global World Poster Assignment

Southern Nevada is located in the arid Mojave Desert, which averages about 4 inches of rain each year. Southern Nevada gets about 90% of its water supply from the Colorado River. Seven western states and Mexico share the river. This means that The Colorado River provides water to 25 million people.

Impact Of Vegetation On Land-Atmosphere Coupling Strength And Its Implication For Desertification Mitigation Over East Asia, Boksoon Myoung, Yong-Sang Choi, Suk-Jin Choi, Seon Ki Park

Mathematics, Physics, and Computer Science Faculty Articles and Research

Desertification of the East Asian drylands and the consequent dust transport have been serious concerns for adjacent Asian countries as well as the western United States. Tree planting has been considered one applicable strategy to mitigate the desertification. However, the desired effect of the tree planting would not be brought to fruition unless the newly planted trees change the coupling characteristics between the land and the atmosphere. Based on this perception, we attempt to clarify the effects of vegetation on the coupling strength between the atmosphere and land surface, and we suggest the most efficient areas of tree planting for …

A Landscape Approach To Late Prehistoric Settlement And Subsistence Patterns In The Mojave Sink, Tiffany Ann Thomas

UNLV Theses, Dissertations, Professional Papers, and Capstones

The environment of the Late Prehistoric period (1200 A.D. to Historic Contact) Mojave Sink was wetter than modern conditions. The settlement and subsistence patterns of the occupants of the region during this period were driven by the availability of water, subsistence resources, raw material sources, and tradition. These people utilized the regional landscape based upon the seasonal availability of these resources. Supplemental agricultural production has been proposed for the Mojave River Delta due to the more favorable environmental conditions of this period. If agriculture was being practiced it would have affected the regional land-use patterns. For this thesis I propose …

Effects Of Climate Change On Spring Ecosystem Hydroecology As A Guide To Developing Alternative Water Policies, Scott Mensing, Saxon E. Sharpe, Scott Bassett, Don Sada, Jim Thomas

Climate Change Seminar Series (NNE)

Hydroecology: the interface of ecological systems and water which combines the scientific disciplines of hydrology and ecology

Goal: evaluate the hydrologic and climate history using pollen, loss on ignition, total inorganic carbon, and invertebrates from spring sediments in Spring Valley, Eastern Nevada and Snake Valley, Western Utah

Climate And Vegetation Change In The Newberry Mountains, Southern Clark County, Nevada, Ross Joseph Guida

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ecological studies have shown worldwide that vegetation is being affected by climate change. Species are shifting to new elevations and physiographic positions to adapt to changes in their environment. More specifically, paleoecology studies in the Mojave Desert have shown shifting vegetation patterns in response to past warming and precipitation changes. Recent studies have shown mortality among desert plants related to extended drought and warming. However, few studies have shown how the geographic distribution of Mojave Desert species has changed during this most recent period of warming. This study addresses this gap in the literature by focusing on several plant species …

Similarity Of Climate Change Data For Antarctica And Nevada, Corbin Benally, Shahram Latifi, Karletta Chief

Undergraduate Research Opportunities Program (UROP)

The correlation between temperature and carbon dioxide concentration in the past one hundred years is studied. Separate graphs containing data from Vostok, Antarctica and the Mojave desert/mountain west (Nevada region) are presented. Using data obtained from these graphs, an attempt is made to explain the results and investigate the similarity of these results for Antarctica and Nevada. The importance of this study lies in the fact that if data show the same trend in the two regions, many findings for climate change in Antarctica may readily be validated and employed for Nevada.

Water Source Partitioning For Shrubland Transpiration Using Innovative Field Methods, Dale A. Devitt, Michael Young, Matthew S. Lachniet, Jeremy Koonce, Amanda Wagner, Brian M. Bird, J. Healey

2010 Annual Nevada NSF EPSCoR Climate Change Conference

37 PowerPoint slides Convener: Franco Biondi, UNR & Michael Young, DRI Session 4: Ecological Change and Water Resources Abstract: -Climate change models predict a decline in precipitation over the next few decades throughout much of the southwest. -Such change has the potential to shift water uptake dynamics of phreatophytes -If groundwater pumping also occurs, the impact of climate change could be exacerbated. -A better understanding of the forces that drive the coupling and decoupling of phreatophytes to groundwater is needed.

Design And Status Of The Elevationl Transect And Monitoring Systems For Nevada’S Nsf Epscor Climate Change Research Program, Brian M. Bird, Scotty Strachan, David B. Simeral, Richard L. Jasoni

2010 Annual Nevada NSF EPSCoR Climate Change Conference

15 PowerPoint slides Convener: Franco Biondi, UNR & Michael Young, DRI Session 4: Ecological Change and Water Resources Abstract: -Current status of Transects -Sheep Range Transect (5 sites) fully permitted through Fish and Wildlife Service. -Site access agreement acquired from the Long Now Foundation for Snake Range (sites 1, 2 and 3). -Snake Range site 4 access granted through the Nevada Land Conservatory. -Waiting for site permit approval on sites 8,9 and 6,7 from BLM and GBNP respectively. -Tower installed at North Las Vegas UWCC for testing of sensors and communications. -Installation of towers will begin winter 2010 at lower …

Biotic Responses To Climate Change In The Great Basin And Mojave Desert: Vegetation, David Charlet, Patrick Leary

2010 Annual Nevada NSF EPSCoR Climate Change Conference

84 PowerPoint slides Convener: Franco Biondi, UNR & Michael Young, DRI Session 4: Ecological Change and Water Resources Abstract: -The Problem -To detect changes in vegetation as it responds to changes in climate, we must first know where the vegetation is now -GAP (Geographic Approach to Protection of Biodiversity) map --National project to map land cover throughout the US. --Nevada map (Edwards et al. 1996) -Southwest ReGAP map --Land cover map for southwestern US (Prior-Magee et al. 2007) to correct problems identified in GAP map

Research Poster: Climate Change Science For Northern Nevada Educators, Melissa Slayden, Jacque Ewing-Taylor, Kelly Cannon

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Research Poster: Climate Change Impacts To Groundwater, Springs Hydrology And Aquatic Communities Amargosa Desert And Death Valley National Park, Nevada And California, Terry Fisk, Greg Pohll, Don Sada, Mark Stone

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Research Poster: Vegetation Change In The Newberry Mountains Of Southern Nevada, Ross Guida, William J. Smith Jr., Scott R. Abella

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Research Poster: Tree Population Dynamics At Ash Meadows National Wildlife Refuge: Influences Of Environmental Stress And Disturbance, Sarah L. Karam, Peter J. Weisberg, Stephanie O. Sunderman

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Research Poster: Water Source Partitioning For Shrubland Transpiration Using Innovative Field Methods, Amanda Wagner, Dale A. Devitt, Michael Young, Matthew S. Lachniet, Jeremy Koonce, Brian M. Bird

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Research Poster: Biotic Responses To Climate Change In The Mojave Desert: Floristics, Patrick Leary, David Charlet

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Research Poster: Clark County School District Involvement In The Nsf Epscor Program, Education Component, Aubrey M. Shirk, Larry Rudd, Paul Buck

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Climate Change Education For Nevada, David M. Hassenzahl, Michael Collopy, John W. Farley, Paul Buck, Jacque Ewing-Taylor, Shama Perveen

2010 Annual Nevada NSF EPSCoR Climate Change Conference

42 PowerPoint slides Session 1: Education Convener: David Hassenzahl, UNLV Abstract: -Five Year Strategic Plan -Goal 6 - Create a scholarly environment to promote research skills and intellectual development for Nevada educators and students (K-12, undergraduate undergraduate, and graduate) -Primary Strategy - Develop educational infrastructure to train students at all levels and provide public outreach in climate change issues

Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Quarterly Report, Period Ending September 30, 2009, Margaret N. Rees

Limnological Studies

Project 1: Two advisory team meetings were attended this year; technical input was provided as appropriate; and summaries were prepared and delivered to Kent Turner. The SCOP Selenium Management Plan has been reviewed with two reports provided.

Project 2: Whitepapers on the carp die-off due to Koi Herpes Virus (KHV) and on lead-base paint use on launch ramps were finalized and delivered to Mr. Turner.

Project 3: The Interagency Monitoring Action Plan (I-MAP) for Quagga Mussels has been approved for implementation.

Project 5: Seven articles based on presentations at the Lake Mead Science Symposium have been approved by the technical …

Baseline Microbial Characterizations Of An Imperiled Aquatic Diversity Hotspot: Ash Meadows National Wildlife Refuge, Jessica Newburn, Jim Bruckner, Jenny C. Fisher, Duane P. Moser

Undergraduate Research Opportunities Program (UROP)

Located in the discharge zone of the Death Valley Flow System, Ash Meadows National Wildlife Refuge is a spring-fed desert oasis and biodiversity hotspot about 90 miles northwest of Las Vegas. These critical wetlands are potentially threatened by groundwater pumping, exotic species invasions, and climate change. Although a major component of the lower food web, very little is known about the microbial makeup of this ecosystem. As a first step towards understanding the microbial and biogeochemical aspects of this system, a detailed molecular-based characterization of microbial communities, baseline chemistry, and physical characteristics of various springs of Ash Meadows will be …