Desert Ecology Commons^™

Resolving The Paradox Of Polyploidy: Underexplored Facets Of Polyploid Plants, Benjamin Gerstner

Biology ETDs

Polyploidy, or whole genome duplication, is a common phenomenon in plants, but the establishment and persistence of mixed-ploidy populations remains a paradox. This dissertation explores factors that contribute to the persistence and establishment of mixed-ploidy populations in nature. The first chapter investigates the role of unreduced gametes in neopolyploid establishment and finds that variability in their formation rate can have a significant impact on polyploid establishment and persistence. The second chapter searches for evidence of soil microbes exhibiting ploidy-specificity, a pre-condition for microbe-mediated niche differentiation, a possible stabilizing mechanism contributing to ploidy coexistence. Finally, the third chapter tests for microbe-mediated …

Effects Of Solar Arrays On Southwestern Desert Thermal Landscapes: Consequences For Terrestrial Ectotherms, Adrian Slade

All Master's Theses

Solar energy development in the Southwestern United States coincides with habitat for many sensitive and endemic species, including reptiles such as Mojave Fringe-toed Lizards and Mojave Desert Tortoises who are threatened by a warming and drying climate. While utility-scale solar energy reduces carbon emissions and should ultimately benefit climate-sensitive species, it locally destroys fragile desert habitat, displaces wildlife, and has been shown to incur local air and surface temperature changes. Mitigation-based translocation of wildlife species in the face of solar development yields mixed results, and the unprecedented pace of solar expansion in the desert highlights the need for alternative practices …

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

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 …

Monitoring Mammals At Multiple Scales: Case Studies From Carnivore Communities, Kadambari Devarajan

Doctoral Dissertations

Carnivores are distributed widely and threatened by habitat loss, poaching, climate change, and disease. They are considered integral to ecosystem function through their direct and indirect interactions with species at different trophic levels. Given the importance of carnivores, it is of high conservation priority to understand the processes driving carnivore assemblages in different systems. It is thus essential to determine the abiotic and biotic drivers of carnivore community composition at different spatial scales and address the following questions: (i) What factors influence carnivore community composition and diversity? (ii) How do the factors influencing carnivore communities vary across spatial and temporal …

Global Population Divergence Of A Cosmopolian Desert Plant, Victor Ryan Alfaro

Biology ETDs

Genetic and phenotypic variation can have different patterns within a species if it has populations with contrasting histories. Populations can have discrete differences that are shaped by different evolutionary scenarios, but within each population, range, or region, traits and association with fitness can also be affected by both edaphic and landscape variation. For my dissertation, I surveyed and experimentally analyzed variation and adaptive potential in Sahara mustard (Brassica tournefortii), a desert annual that has endemic, invasive, and agricultural populations in Africa, Asia, and the Americas. Although my multi-trait analysis generated complex results, my findings can be applied to …

Data From: Recovery From Discrete Wound Severities In Side-Blotched Lizards (Uta Stansburiana): Implications For Energy Budget, Locomotor Performance, And Oxidative Stress, Susannah S. French, Spencer B. Hudson

Browse all Datasets

Wounding events (predation attempts, competitive combat) result in injuries and/or infections that induce integrated immune responses for the recovery process. Despite the survival benefits of immunity in this context, the costs incurred may require investment to be diverted from traits contributing to immediate and/or future survival, such as locomotor performance and oxidative status. Yet, whether trait constraints manifest likely depends on wound severity and the implications for energy budget. For this study, food intake, body mass, sprint speed, and oxidative indices (reactive oxygen metabolites, antioxidant capacity) were monitored in male side-blotched lizards (Uta stansburiana) healing from cutaneous wounds of discrete …

A Decision Tool To Identify Population Management Strategies For Common Ravens And Other Avian Predators, Andrea F. Currylow, Brenda J. Hanley, Kerry L. Holcomb, Timothy Shields, Stephen Boland, William I. Boarman, Mercy Vaughn

Human–Wildlife Interactions

Some avian species have developed the capacity to leverage resource subsidies associated with human manipulated landscapes to increase population densities in habitats with naturally low carrying capacities. Elevated corvid densities and new territory establishment have led to an unsustainable increase in depredation pressure on sympatric native wildlife prey populations as well as in crop damage. Yet, subsidized predator removal programs aimed at reducing densities are likely most effective longer-term when conducted in tandem with subsidy control, habitat management, and robust assessment monitoring programs. We developed decision support software that leverages stage structured Lefkovitch population matrices to compare and identify treatment …

Inoculum Potential Of Pinus Edulis-Associated Ectomycorrhizal Fungi Across A Forest Extirpation Chronosequence, Annie M. Montes

Biology ETDs

Few studies have examined inoculum potential of ectomycorrhizal fungi (EMF) in the absence of plant hosts, yet persistence of these fungi may be paramount to resilience of Pinus edulis and other mycorrhizal plant species. We conducted a study in which seven sites were selected in northwestern New Mexico with known dates of P. edulis extirpation and a lack of regeneration. Age classes included: two sites extirpated 10-20 years ago, two extirpated 55-65 years ago, two extirpated 500+ years ago, and one extirpated 11,000+ years ago. At each site, two plots were paired: an extirpated plot and the nearest live adult …

Plant Litter Decomposition Differs With Species And Soil Resources In A Chihuahuan Desert Grassland, Andrea Lopez

Biology ETDs

Uncertainties surround the extent to which diversity can mitigate the effects of climate change and anthropogenic activity on ecosystem functions. In desert grasslands, changes to water availability and soil nitrogen, two primary resources that limit ecosystem processes, can have lasting impacts on nutrient cycling. We used grass litter from Bouteloua eriopoda, Bouteloua gracilis, Pleuraphis jamesii, and Sporobolus spp. to assess the effects of soil resources on single- and multi-species decomposition in a Chihuahuan Desert grassland in central New Mexico, USA. Litterbags were deployed in a factorial experiment that manipulated rain pulse size (5- vs. 20-mm) and frequency …

Energy Content Of Seeds Of Common Sunflowers (Helianthus Annuus) In The Diet Of Scaled Quail (Callipepla Squamata) In Southeastern New Mexico, John L. Hunt, Matthew E. Grilliot, Troy L. Best, Dixie Lozano-Lopez, Emily R. Neilson, Isaac C. Castillo

Journal of the Arkansas Academy of Science

We analyzed the energy content of seeds of common sunflowers (Helianthus annuus) obtained from the crops of scaled quail (Callipepla squamata) collected from plains-mesa sand-scrub habitat in Eddy and Lea counties, New Mexico. Seeds were removed from crops and dried for 48 hours at 60°C to remove moisture and to standardize masses. Seeds were then analyzed for gross caloric value (i.e., energy content) in an oxygen bomb calorimeter. Energy content of seeds of common sunflowers from New Mexico was greater than that of many seeds previously reported from the diet of scaled quail and other granivorous …

Responses Of Bouteloua Eriopoda And Soil Stability To Precipitation Extremes In Chihuahuan Desert Grassland, Laura Kay Sadorf

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

No abstract provided.

Seed Predation By Owyhee Harvester Ants And The Potential Of Seed Introductions In Recovery Efforts For Slickspot Peppergrass, Jennifer A. Brown

Boise State University Theses and Dissertations

Slickspot peppergrass (Lepidium papilliferum) is a rare plant endemic to the sagebrush-steppe habitat in southwestern Idaho. Within sagebrush-steppe, the plant is restricted to microsites known as “slick spots”– shallow depressions of soil characterized by distinct clay layers and surface water retention that is higher than that of surrounding areas. Having one of the highest extirpation rates among rare plant taxa in Idaho, and considering its unique habitat requirements, limited range, and declining numbers, land managers and conservationists have voiced concern regarding the species’ long-term viability. While range-wide declines in slickspot peppergrass have been attributed largely to the loss …

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 …

Genomics Based Approaches To Fungal Evolution, Aaron J. Robinson, Donald O. Natvig

Biology ETDs

Advances in DNA sequencing and data analysis make it possible to address questions in population genetics and evolution at the genomic level. Fungi are excellent subjects for such studies, because they are found in diverse environments, have short generation times, can be maintained in culture and have relatively small genomes. My research employed genetic approaches using a variety of sequencing technologies and methods of analysis to explore questions in fungal evolution.

In one study, I explored the genetics behind differences in thermotolerance between isolates of Neurospora discreta from Alaska and New Mexico. Isolates from the two states exhibited differences in …

The Future Of Biodiversity Assessment: Using Environmental Dna And Next-Generation Sequencing To Characterize Biological Communities In The Central Highlands Of Arizona, Courtney Turner-Rathbone

Undergraduate Research Symposium - Prescott

Historically ecological surveys require significant man hours in the field, utilizing methods which can stress species being observed. In using environmental DNA (eDNA) gathered from air, soil, and water, traditional methods may be supplemented or reduced in order to more efficiently utilize funding and reduce or eliminate stress on surveyed species. Water was collected in replicates using aseptic technique from two different sites, 60 miles apart, along the Verde River. Samples were vacuum filtered within 24 hours through 0.45 μm cellulose nitrate (CN) filters to collect eDNA. DNA extraction from the filters was performed. The polymerase chain reaction (PCR) was …

Radical Social Ecology As Deep Pragmatism: A Call To The Abolition Of Systemic Dissonance And The Minimization Of Entropic Chaos, Arielle Brender

Student Theses 2015-Present

This paper aims to shed light on the dissonance caused by the superimposition of Dominant Human Systems on Natural Systems. I highlight the synthetic nature of Dominant Human Systems as egoic and linguistic phenomenon manufactured by a mere portion of the human population, which renders them inherently oppressive unto peoples and landscapes whose wisdom were barred from the design process. In pursuing a radical pragmatic approach to mending the simultaneous oppression and destruction of the human being and the earth, I highlight the necessity of minimizing entropic chaos caused by excess energy expenditure, an essential feature of systems that aim …

Seasonal Shifts In C3 And C4 Resource Use By A Small Mammal Community Under Changing Precipitation Regimes, Alaina D. Pershall

Biology ETDs

In light of climate change and projections of increasing temperatures and aridity in the North American southwest, it is essential to understand how consumer populations will respond to changes in the resource landscape. Rainfall varies in timing and intensity and therefore the timing, proportion, phenology, and abundance of C₃ and C₄ plant resources vary seasonally and annually. Here we examine rodent resource use in the Chihuahuan desert and focus on two distinct precipitation pulses in this system, where spring C₃ plants increase production in response to winter rains and C₄ plants respond to summer monsoons. We …

Examining The Relationship Between Climate And Seasonal Stream Thermal Regimes In A High Desert Ecosystem, Hannah Moore, Melody Feden

Scholars Week

Climate change is negatively affecting ecosystems around the world, and in the coming years, scientists predict that these changes will only intensify and accelerate. In the western mountains of North America, climate change projections predict elevated temperatures, reduced snowpack, and earlier snowmelt. Elevated air temperatures have the propensity to affect water temperatures in sensitive freshwater ecosystems. Temperature increases may cause streams to reach the upper thermal limit for many aquatic organisms, such as aquatic invertebrates and fish, and result in death or dispersal for these organisms. This makes the availability of cold-water refugia in streams that much more important for …

Can Omnivores Mediate The Effects Of Degradation?, Hannah Moore

Scholars Week

Omnivores feed at multiple trophic levels and have large effects on community structuring and stability. The magnitude and direction of such effects, whether omnivores stabilize or destabilize communities, remains unresolved. Shifts in omnivore diet and trophic position may be of particular importance to community stability in degraded habitats, where resources are sparse. For example, omnivores may reduce the severity and duration of community responses to degradationby dampening the effects of any disturbance-mediated trophic cascade. The relatively simple food webs of freshwater systems are ideal for studying trophic ecology, and in the western U.S., streams are heavily degraded by overgrazing, beaver …

The North American Quails, Partridges, And Pheasants, Paul A. Johnsgard

Zea E-Books Collection

This book documents the biology of six species of New World quails that are native to North America north of Mexico (mountain, scaled, Gambel’s, California, and Montezuma quails, and the northern bobwhite), three introduced Old World partridges (chukar, Himalayan snowcock, and gray partridge), and the introduced common (ring-necked) pheasant. Collectively, quails, partridges, and pheasants range throughout all of the continental United States and the Canadian provinces. Two of the species, the northern bobwhite and ring-necked pheasant, are the most economically important of all North American upland game birds. All of the species are hunted extensively for sport and are highly …

The Impact Of Climate And Elevation On The Growth And Mortality Of Piñon Pine, Alice M. Fretz

Biology ETDs

The Southwestern United States is currently experiencing severe drought, resulting in the mortality of many tree species. Piñon-juniper woodlands are an extensive biome in the Southwest, and are highly vulnerable to extended periods of drought that lead to tree mortality. Specifically, Pinus edulis populations are decreasing due to increasingly arid conditions. I used dendrochronology to investigate how tree growth rings of Pinus edulis reflect severe drought in living and dead trees. I also investigated how severe drought affects Pinus edulis along an altitudinal gradient. Tree core samples were taken from currently living and dead trees, as well as from trees …

Divergence In Life History Traits Between Two Populations Of A Seed-Dimorphic Halophyte In Response To Soil Salinity, Fan Yang, Jerry M. Baskin, Carol C. Baskin, Xuejun Yang, Dechang Cao, Zhenying Huang

Biology Faculty Publications

Production of heteromorphic seeds is common in halophytes growing in arid environments with strong spatial and temporal heterogeneity. However, evidence for geographic variation (reflecting local adaptation) is almost nonexistent. Our primary aims were to compare the life history traits of two desert populations of this halophytic summer annual Suaeda corniculata subsp. mongolica and to investigate the phenotypic response of its plant and heteromorphic seeds to different levels of salt stress. Dimorphic seeds (F₁) of the halophyte S. corniculata collected from two distant populations (F₀) that differ in soil salinity were grown in a common environment under …

Precipitation Patterns And Fungal Community Succession In A Seasonally Dry Secondary Tropical Savanna, Sara R. Lopez

Biology ETDs

Life in seasonally dry areas strongly depends on pulses of precipitation during certain portions of the year. This is particularly relevant for Tropical savannas on the Caribbean coast of Colombia that have been converted from Tropical Dry Forests and subjected to permanent agricultural and grazing practices that in turn induce changes in nutrient status in these systems. Several studies have presented evidence for a shift in C and N dynamics following forest conversion, including a decrease in total soil organic carbon and changes in nitrogen status, but the consequences of forest conversion on soil microbial processes are poorly understood. No …

Plant-Microbial Interactions Are Strong Determinants Of Plant Population And Community Dynamics, Y. Anny Chung 9485698

Biology ETDs

Plant-microbial interactions are ubiquitous and yet the consequences of these interactions on plant population and community dynamics are relatively unknown. Here, we used two different classes of plant-microbial interactions to examine their effects on key plant population and community characteristics such as commonness and rarity, competition and coexistence, as well as community stability.

Vertically-transmitted endophytes had stage-dependent effects on the population growth of two grass species Poa sylvestris and Poa alsodes, and generally increased host population growth rates. However, it was the intrinsic demographic advantage of P. sylvestris that allowed its population to grow at a much faster rate …

Effects Of Wildfires On Rattlesnake (Crotalus Oreganus) Growth And Movement In Washington State, Joseph Chase

All Master's Theses

Fire is a dominant force in the Pacific Northwest that shapes ecosystems and influences wildlife, yet little is known of its effects on local predators. Northern Pacific rattlesnakes (Crotalus oreganus) comprise an excellent model to investigate how fire may influence wildlife because they are important predators that contribute to controlling prey populations, but are also unable to readily escape from wildfires. We developed a novel technique to assess growth rates of rattlesnakes by using digital photography to analyze differences in widths of their rattle segments laid down over time. We compared growth rates of rattlesnakes in habitats that …

Phytophagous Insect Oviposition Shifts In Response To Probability Of Flower Abortion Owing To The Presence Of Basal Fruits, Shivani Jadeja, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Phytophagous insects use a wide range of indicators or associated cues to avoid laying eggs in sites where offspring survival is low. For insects that lay eggs in flowers, these unsuitable sites may be created by the host plant’s resource allocation to flowers. In the sequentially flowering host plant, Yucca glauca, late-opening distal flowers are more likely to be aborted in the presence of already-initiated basal fruits because they are strong resource sinks. If flowers are aborted, all eggs of the phytophagous insect, Tegeticula yuccasella, within the flower die. We used the phytophagous insect T. yuccasella that lays …

Plant-Biocrust Interactions Mediated By The Fungal Loop, Eva Dettweiler-Robinson

Biology ETDs

Plant-microbial interactions influence biogeochemical cycles. Plants and biological soil crusts are primary producers in drylands. Biocrusts include cyanobacteria, lichens, mosses, algae, fungi, bacteria, and archaea on the soil surface, some of which fix atmospheric nitrogen. I investigated controls on biocrust carbon fluxes and their contribution to ecosystem fluxes, the incorporation of plant-derived carbon into biocrusts, and the role of soil fungi in promoting performance of plants and biocrusts. Biocrusts responded to temperature and moisture differently by biome. Biocrusts in grasslands/shrublands contributed >25% of total summertime ecosystem respiration, but biocrusts in savannas/woodlands contributed <1%. Biocrusts contributed <2% to GPP in any biome. To augment their native photosynthesis, biocrusts may include 16% plant-derived carbon. Fungal connections improved plant and biocrust performance and reduced differences in the CN ratio between organisms compared to when connections were impeded. Investigation of interactions among biocrusts, plants, and fungi has improved understanding of resource cycling in drylands.

Comparative Population Genomics And Speciation Of Snakes Across The North American Deserts, Edward A. Myers

Dissertations, Theses, and Capstone Projects

Understanding the process of speciation is of central interest to evolutionary biologists. Speciation can be studied using a phylogeographic approach, by identifying regions that promote lineage divergence, addressing whether speciation has occurred with gene flow, and when extended to multiple taxa, addressing if the same patterns of speciation are shared across codistributed groups with different ecologies. Here I examine the comparative phylogeographic histories and population genomics of thirteen snake taxa that are widely distributed and co-occur across the arid southwest of North America. I first quantify the degree to which these species groups have a shared history of population divergence …