Desert Ecology Commons^™

Growth Of Pseudocotalpa Giulianii Larvae In Sand From Different Dune Sources, Cosset Hernandez Pena, Mandy Mountain

Undergraduate Research Symposium Posters

Pseudocotalpa giulianii (PSGU) is an endemic species known to inhabit two sand dunes in Nye County, Nevada: Big Dune Recreational Area and Lava Dune. Differences in sand properties between Big Dune and Lava Dune could impact survival and growth of the larvae of P. giulianii. Use of permitted off-road vehicles (ORV) in Big Dune can impact its habitats and cause disturbances to local populations, including the Giuliani Dune Scarab as ORV activity is correlated with changes in dune vegetation. Lava Dune has no permitted ORV activity, however, differences in sand composition, including eroded basalt, have the potential to influence the …

Ectotherm Thermoregulation At Fine Scales: Novel Methods Reveal A Link Between The Spatial Distribution Of Temperature And Habitat Quality, Ian Axsom

Master's Theses

Investigating ecological questions at the scale of individual organisms is necessary to understand and predict the biological consequences of environmental conditions. For small organisms this can be challenging because we need tools with the appropriate accuracy and resolution to record and quantify their ecological interactions. Unfortunately, many of our existing tools are only appropriate for medium to large organisms or those that are wide ranging, inhibiting our ability to investigate the ecology of small organisms at fine scales.

In Chapter 1, I tested a novel workflow for recording animal movements at very fine spatial and temporal scales. The workflow combined …

Extreme, Positive Geomorphic Change In A Historically Degraded Desert River: Implications For Imperiled Fishes, Tansy T. Remiszewski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rivers comprise some of the most unique and biodiverse ecosystems on the planet with their waters supporting both human societies as well as the organisms that make these rivers their home. Large rivers like the Colorado are often highly regulated and diverted in order to support human residence in arid regions like the desert Southwest, and these water diversions often have dramatic, negative impacts on the natural flow regime of the river. These impacts leave large reaches of the river dry, reduce the river’s capacity to transport sediment, cause channel and habitat homogenization, and significantly reduce the amount of suitable …

Life History And Ecology Of The San Emigdio Blue Butterfly (Lepidoptera: Lycaenidae), Gregory R. Ballmer

The Taxonomic Report of the International Lepidoptera Survey

The San Emigdio blue butterfly, Plebulina emigdionis (Grinnell, 1905), occurs in small, scattered colonies in and near the southwestern Mojave Desert of California. Colonies depend on a symbiotic relationship with the ant Formica francoueri (Bolton), and occur only where the ant’s range (primarily in more mesic cis-montane habitats) narrowly overlaps that of the butterfly’s more widely distributed Atriplex larval hosts in more xeric habitats. Colonies of P. emigdionis are often localized around a few host plants and, therefore, sensitive to habitat changes due to anthropocentric causes and environmental stochasticity. The biology, ecology, and status of known colonies of P emigdionis …

An Integral Projection Modeling Approach To Understanding Demographic Effects Of Multispecies Mutualisms, Alexandra Campbell

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Above- And Belowground Responses To Environmental Change In The Northern Chihuahuan Desert, Renée Françoise Brown

Biology ETDs

Drylands cover 45% of the terrestrial surface and are expanding rapidly due to anthropogenic drivers. Altered precipitation regimes, atmospheric nitrogen deposition, and wildfire will likely have significant consequences in these regions where ecological processes are limited by water and nitrogen. In this dissertation, I explored temporal dynamics of net primary production (NPP) and related above- and belowground processes under several environmental change drivers in the Sevilleta National Wildlife Refuge, central New Mexico, USA. Located in the northern Chihuahuan Desert, this region experiences strong seasonal precipitation patterns driven by the North American Monsoon, historically characterized by frequent small rain events hypothesized …

Foraging Habitat Selection Of Shrubland Bird Community In Tropical Dry Forest, Anant Deshwal, Steven L. Stephenson, Pooja Panwar, Brett A. Degregorio, Ragupathy Kannan, John D. Willson

Biological Sciences Faculty Publications and Presentations

Habitat loss due to increasing anthropogenic disturbance is the major driver for bird population declines across the globe. Within the Eastern Ghats of India, shrubland bird communities are threatened by shrinking of suitable habitats due to increased anthropogenic disturbance and climate change. The development of an effective habitat management strategy is hampered by the absence of data for this bird community. To address this knowledge gap, we examined foraging sites for 14 shrubland bird species, including three declining species, in three study areas representing the shrubland type of forest community in the Eastern Ghats. We recorded microhabitat features within an …

Discovering Novel Polyextremotolerant Fungi And Determining Their Ecological Role Within The Biological Soil Crust Consortium, Erin C. Carr

School of Biological Sciences: Dissertations, Theses, and Student Research

The ecological niche of polyextremotolerant fungi within oligotrophic ecosystems such as biological soil crusts has not yet been determined. These fungi persist in locations where nutrients are depleted while simultaneously surrounded by autotrophic microbes such as algae and cyanobacteria. Yet it has not been shown that they are engaging in any exchange of nutrients the way lichens do. However, there is seemingly no other way for these fungi to obtain vital nutrients, such as carbon or nitrogen, other than from these microbes. Here we have isolated polyextremotolerant fungi from cold desert biological soil crusts which are a microbial biofilm that …

Biodiversity And Global Change In Terrestrial Ecosystems, Timothy John Ohlert

Biology ETDs

Terrestrial ecosystems are critical to human and ecological processes but many gaps in our knowledge remain regarding how terrestrial plant communities assemble and respond to global change. I used field experiments distributed around the world, including long-term experiments from the Sevilleta National Wildlife Refuge (SNWR) in New Mexico and deserts of the southwestern U.S., to evaluate the consequences of drought and other abiotic stressors on plant communities. Dominant grasses were particularly important for the productivity and structure of grasslands at SNWR. In general, the structure of desert plant communities had high resistance to extreme drought, though grasses and other perennial …

Keeping Your Cool: Thermoregulatory Performance And Plasticity In Desert Cricetid Rodents, Richard W. Ramirez, Eric A. Riddell, Steven R. Beissinger, Blair O. Wolf

Biology ETDs

Small mammals in hot deserts often avoid heat via nocturnality and fossoriality and are thought to have a limited capacity to dissipate heat using evaporative cooling. Research to date has focused on thermoregulatory responses to air temperatures (T_a) below body temperature (T_b). Consequently, the thermoregulatory performance of small mammals exposed to high air temperatures is poorly understood, particularly responses across geographic and seasonal scales. We quantified the seasonal thermoregulatory performance of four cricetid rodents (Neotoma albigula, N. lepida, Peromyscus eremicus, P. crinitus) exposed to high T_a, at four sites …

3d Library From Body Size From Unconventional Specimens: A 3d Geometric Morphometrics Approach To Fishes From Ancestral Pueblo Contexts, Jonathan Dombrosky, Thomas F. Turner, Alexandra Harris, Emily Lena Jones

Anthropology Faculty & Staff Publications

Animal body size estimation from zooarchaeological specimens often relies on specific, one-dimensional (i.e., conventional) measures from skeletal elements. Here, we introduce an animal body size estimation technique for archaeological fishes that relies on 3D reference scans and the calculation of centroid size, a standard 3D geometric morphometric proxy measure for organism size. Centroid size-based estimations on whole caudal vertebrae are strongly correlated with a widely accepted measure (i.e., centrum width), but the scalability and flexibility of the centroid size-based approach allows for use on a wide variety of fragmented remains. We use zooarchaeological fish remains (subfamily Ictiobinae) from late pre-Hispanic …

Socio-Economic Factors Of Environmental Problems, Manzura Kamalova, D. Shakenov

Karakalpak Scientific Journal

People consciously and intensively rebuild their nature according to their own needs, creating rural and urban areas in which they live. People care about the quality of life in the context of the unity of nature and culture. Social is a relatively new discipline that deals with urban space and environmental issues. One way to imagine what is beneficial to people is to find out what is economically best for the person. The article examines the economic factors that form the attitude towards social ecology in Kazakhstan. The article concludes that society should cooperate to achieve common things, both for …

Not Only Severe Events: Moderate Dry Periods Impact The Hydraulic Functioning And Survival Of Planted Ponderosa Pine Seedlings, Carolyn R. Koehn, Matthew D. Petrie, Robert M. Hubbard

Life Sciences Faculty Research

Juvenile tree survival will increasingly shape the persistence of ponderosa pine forests in the western United States. In contrast to severe pulse disturbances that induce widespread adult and juvenile tree mortality, moderate periods of low rainfall and warm temperatures may reduce forest persistence by killing juvenile trees at the seedling stage. Intensification of these periods in a changing climate could therefore increasingly restrict both natural regeneration and artificial regeneration of planted seedlings. We conducted a controlled field experiment at a single site in the Front Range of Colorado, USA, to determine the responses and survival of 3 Colorado subpopulations of < 1 year old potted ponderosa pines to moderately dry conditions, variation in small rainfall events based on observed patterns, and shaded and unshaded microsite environments. Near surface soil moisture increased slightly following small rainfall events, but declined over the 45-day experimental period. Seedling transpiration and associated canopy cooling declined after ∼13 days, and further declines in transpiration and canopy cooling suggest that the majority of trees in lower rainfall treatments experienced hydraulic dysfunction between days ∼20–30. After 45 days, mortality across all subpopulations and treatments, inferred by relative water loss, exceeded 90–95%. Despite some uncertainty pertaining to the stress tolerance of nursery grown versus naturally germinated conifers, our results show that planted ponderosa pine seedlings < 1 year old are unlikely to survive moderate dry periods of 20+ days relying on small rainfall events. Although microsite conditions and soil moisture availability shaped tree hydraulic functioning early in the experiment (days 1–13), later functioning was shaped predominately by the legacy of rainfall treatments. Our results illustrate the importance of moderate dry events that occur consistently as part of seasonal variation in climate, and show how their intensification may constitute a sustained press that limits opportunities for natural and artificial regeneration.

Dehydration And Mortality Of Feral Horses And Burros: A Systematic Review Of Reported Deaths, John Derek Scasta, Eric Thacker, Jacob D. Hennig, Karl Hoopes

Human–Wildlife Interactions

Water is a requirement for all organisms, including equids. Dehydration-caused mortality of feral horses (Equus ferus caballus) is often cited as a cause of concern and as justification for management of feral horses, yet a paucity of information exists on the matter. We conducted a systematic review from September 1, 2020 through January 15, 2021 of available news reports of feral horse and burro (E. asinus) dehydration mortalities and public interventions to save horses using a public search engine with a priori defined search term combinations and additional snowball sampling. We found 15 uniquely reported mortality …

Wyoming’S Wild Horse Ranch: History And Description Of A Socio-Ecological Experiment, Alex Sas-Jaworsky, John Derek Scasta

Human–Wildlife Interactions

The growing population of free-roaming horses (Equus ferus caballus) on western public rangelands has necessitated that federal agencies, such as the Bureau of Land Management (BLM) and U.S. Forest Service, develop novel approaches to curb growth including reproduction management. However, bureaucracy has hindered effective research and application of horse management on public lands and examples on private lands may present new solutions. Here we present the history and current population management strategy for the Wild Horse Ranch (WHR) located in southeastern Wyoming, USA, as an example of an ongoing private entity managing horses. Prior to 1985, this ~6,000-ha …

Nonnative Ungulate Impacts On Greater Sage-Grouse Late Brood-Rearing Habitat In The Great Basin, Usa, Mikiah R. Mcginn, Steven L. Petersen, Melissa S. Chelak, Randy T. Larsen, Loreen Allphin, Brock R. Mcmillan, Dennis L. Eggett, Terry A. Messmer

Human–Wildlife Interactions

Domestic livestock grazing is the dominant land use on much of the current range inhabited by greater sage-grouse (Centrocercus urophasianus; sage-grouse) in the western United States. Nonnative feral horses (Equus ferus caballus) also inhabit important sage-grouse seasonal habitats. Overabundant feral horse populations and improper grazing by domestic cattle (Bos taurus) can impact the health of sagebrush (Artemisia spp.) and desert shrub rangeland communities and native wildlife. These impacts to sage-grouse can be exacerbated when they affect late brood-rearing habitat, which provide the forbs and arthropods required to fledge broods. Managers require better information …

Stakeholder Knowledge And Perceptions Of Free-Roaming Equids And Their Management At A Western U.S. Land-Grant University, Hollee S. Wood, S. Nicole Frey, Terry A. Messmer

Human–Wildlife Interactions

The horse (Equus ferus caballus), originally native to North America, became extinct on the continent approximately 10,000 years ago. Horses that migrated from North America to Eurasia across the Bering Strait continued to evolve and were domesticated along with burros (E. asinus). Both species were then transported to the Americas where they were intentionally released or escaped into the wild, forming feral herds. The Wild Free-Roaming Horses and Burros Act of 1971 (WFRHBA) provided federal oversight and protection for feral horses and burros (hereafter, free-roaming equids) that inhabited designated areas on public lands in the western …

Healthy Western Lands: A Proposal For Healthy Rangelands, Wildlife, And Free-Roaming Horses And Burros, James S. Sedinger, Rebekah Stetson

Human–Wildlife Interactions

The Coalition for Healthy Nevada Lands, Wildlife and Free-roaming Horses (CHNL) is dedicated to proper management of free-roaming horses (Equus caballus) and burros (E. asinus) so rangelands are healthy, which benefits wildlife and the horses and burros themselves. The CHNL proposes the rapid reduction of horses and burros on designated public lands to achieve appropriate management levels (AML). After these reductions, the use of fertility control, supplemented with some gathers and adoption of gathered horses, should allow the Bureau of Land Management to economically maintain horse and burro populations at AML. The CHNL believes this approach …

A Stillness In The Desert? Engaging The Public Through An Immersive Exploration Of Southwest Soundscapes, Julian Kilker, Thomas Bjelic

Creative Collaborations

The pandemic highlighted the anthropocentric nature of soundscapes, while the recent popularity of electric cars, quadcopters, and “noise cancellation” earbuds demonstrated how consumer products can rapidly change our awareness of sound. While light pollution is already extensively addressed in scholarly research, popular works such as The End of Night, and public engagement such as The International Dark Sky Association, the complex interplay of sound, natural resources, and public engagement is still emerging, particularly in creative fields.

Two UNLV scholars and artists are collaborating on this project: Julian Kilker, who specializes in visual and emerging technology research, and Tom Bjelic, who …

Energy Content Of Seeds Of Switchgrass (Panicum Virgatum) In The Diet Of Mourning Doves (Zenaida Macroura) In Southeastern New Mexico, John L. Hunt, Matthew E. Grilliot, Troy L. Best, Faith A. Johnson, Tyneshia L. Kilgore, Cade M. Wilkerson

Journal of the Arkansas Academy of Science

Switchgrass (Panicum virgatum) is a common forage plant that grows over much of the United States. It has drawn interest as a possible feedstock for biofuels, is used as forage for livestock, is planted for soil conservation, and is a component of the diet of some species of wildlife. We analyzed the energy content of seeds of switchgrass obtained from the crops of mourning doves (Zenaida macroura) collected from plains-mesa sand-scrub in Lea and Eddy counties, New Mexico. Seeds were removed from crops and dried for 48 hours at 60°C to remove moisture and standardize masses. …