Desert Ecology Commons^™

Local‐Regional Similarity In Drylands Increases During Multiyear Wet And Dry Periods And In Response To Extreme Events, Matthew D. Petrie, D. P.C. Peters, N. D. Bruss, W. Ji, H. M. Savoy

Life Sciences Faculty Publications

Climate change is predicted to impact ecosystems through altered precipitation (PPT) regimes. In the Chihuahuan Desert, multiyear wet and dry periods and extreme PPT pulses are the most influential climatic events for vegetation. Vegetation responses are most frequently studied locally, and regional responses are often unclear. We present an approach to quantify correlation of PPT and vegetation responses (as Normalized Difference Vegetation Index [NDVI]) at the Jornada ARS‐LTER site (JRN; 550 km2 area) and the surrounding dryland region (from 0 to 500 km distance; 400,000 km2 study area) as a way to understand regional similarity to locally observed patterns. We …

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 …

Persistence And Turnover In Desert Plant Communities During A 37-Yr Period Of Land Use And Climate Change, Scott R. Abella, Ross J. Guida, Chris L. Roberts, Carrie M. Norman, James S. Holland

Life Sciences Faculty Publications

Understanding long‐term changes in ecological communities during global change is a priority for 21st‐century ecology. Deserts, already at climatic extremes, are of unique interest because they are projected to be ecosystems most responsive to global change. Within a 500‐km2 landscape in the Mojave Desert, USA, we measured perennial plant communities at 100 sites three times (1979, 2008, and 2016) during 37 yr to evaluate six hypotheses of community change. These hypotheses encompassed shifts in community measures (e.g., diversity, cover) and species elevational distributions, biotic homogenization, disproportionately large change at the highest elevations, relationships between turnover and species’ responses to disturbance …

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 …

Examining Interactions Between And Among Predictors Of Net Ecosystem Exchange: A Machine Learning Approach In A Semi-Arid Landscape, Qingtao Zhou, Aaron Fellows, Gerald N. Flerchinger, Alejandro N. Flores

Geosciences Faculty Publications and Presentations

Net ecosystem exchange (NEE) is an essential climate indicator of the direction and magnitude of carbon dioxide (CO₂) transfer between land surfaces and the atmosphere. Improved estimates of NEE can serve to better constrain spatiotemporal characteristics of terrestrial carbon fluxes, improve verification of land models, and advance monitoring of Earth’s terrestrial ecosystems. Spatiotemporal NEE information developed by combining ground-based flux tower observations and spatiotemporal remote sensing datasets are of potential value in benchmarking land models. We apply a machine learning approach (Random Forest (RF)) to develop spatiotemporally varying NEE estimates using observations from a flux tower and several …

Drought And Coyotes Mediate The Relationship Between Mesopredators And Human Disturbance In California, Molly K. Parren

Cal Poly Humboldt theses and projects

Mesopredators in California are facing two major changes to their ecosystem: drought and the expansion of human disturbance. As a result, mesopredators are likely shifting their habitat use as well as their interspecies interactions to balance resource needs and risk-taking on the landscape. In response to severe drought, the California Department of Fish and Wildlife deployed 585 camera traps throughout the Mojave Desert and Central Valley documenting mammalian mesopredator presence in a drought year (2016) and a post-drought year (2017). The objectives of this study were to examine spatial patterns of mesopredator occurrence and co-occurrence with a dominant predator, the …

Evaluation Of Range-Wide Occupancy And Survey Methods For The Giant Kangaroo Rat (Dipodomys Ingens), Alyssa E. Semerdjian

Cal Poly Humboldt theses and projects

Though habitat suitability and occupancy are often correlated, they cannot always be inferred from each other. Therefore, a solid understanding of both is essential to effectively manage species. Recent studies have assessed range-wide habitat suitability for the giant kangaroo rat (Dipodomys ingens; GKR), but data regarding occupancy is lacking in parts of its distribution. Satellite and aerial imagery were used to identify GKR burrows across their known range, producing a range-wide occupancy map and non-invasive survey methods including track plates, manned flight, unmanned aerial vehicle, and sign surveys were conducted to determine effective methods for monitoring GKR occupancy. …

Energy Content Of Seeds Of Texas Doveweed (Croton Texensis) From The Diet Of Mourning Doves (Zenaida Macroura) From Southeastern New Mexico, John L. Hunt, Matthew E. Grilliot, Troy L. Best, Collin S. Deen, Dixie Lozano-Lopez, Emily R. Neilson, Taytumn R. Schlegel-Ridgway

Journal of the Arkansas Academy of Science

We analyzed the energy content of seeds of Texas doveweed (Croton texensis) obtained from the crops of mourning doves (Zenaida macroura) 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 Texas doveweed was greater than many seeds previously reported from the diet of mourning doves.

Rainfall Changes Alter Plant Communities In Chihuahuan Desert Grasslands, Timothy Ohlert

Shared Knowledge Conference

Variations in New Mexico’s climate have been detected over the past century and are expected to continue into the future. Some of these climatic changes result in more frequent instances of extreme drought events and alterations of monsoon seasonality, with monsoons being pushed later into the fall. Such changes could make our Chihuahuan Desert plant communities less productive, shift the abundance of the plant species, or have other destabilizing impacts. Our experiment manipulated precipitation in two desert grassland communities at the Sevilleta National Wildlife Refuge near Socorro, NM. Some plots were subjected to an extreme drought event, receiving only 33% …

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 …

The Ecology Of A Tallgrass Treasure: Audubon’S Spring Creek Prairie, Paul A. Johnsgard

Zea E-Books Collection

This book describes the major plant and animal components of Spring Creek Prairie Audubon Center, an 850-acre National Audubon Society tallgrass prairie in Lancaster County, southeastern Nebraska. In addition to providing a species list of the area’s plants (368 species), there are comprehensive annotated lists of its birds (240), mammals (43), reptiles (23), and amphibians (10). There are also variably complete annotated lists of the area’s butterflies (76), sphinx moths (30), silk moths (7), dragonflies (24), damselflies (11), grasshoppers (9), katydids (11), mantids (2), and walkingsticks (2). Brief profiles of life histories and ecologies of 55 animal and 7 plant …

Cougar Dispersal And Natal Homing In A Desert Environment, David M. Choate, Kathleen M. Longshore, Daniel B. Thompson

Life Sciences Faculty Publications

We present a review of cougar dispersal literature and the first evidence of natural (i.e., unmanipulated) homing behavior by a dispersing male cougar (Puma concolor) that sustained severe injuries crossing the northern Mojave Desert. Based on Global Positioning System and ground tracking data, the male traveled a total distance of 981.1 km at 5.03 km/d, including 170.31 km from the Desert National Wildlife Refuge to the northwestern Grand Canyon, where he sustained severe injuries. The interkill interval increased from 7.1 ± 2.7 d while he was in his natal range to 17.5 ± 4.9 d during dispersal. While homing, the …

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 …

From Outside To Online: Unanticipated Directions For Utah Master Naturalist, Mark Larese-Casanova, Jennifer Perkins

Journal on Empowering Teaching Excellence

Utah Master Naturalist is an award-winning Utah State University Extension program that promotes stewardship of Utah’s natural world through place-based, experiential field courses across the state. Although successful in eliciting positive short- and long-term impacts, Utah Master Naturalist’s traditional five-day field courses were unavailable to many students and instructors due to constraints of time and location. This case study examines Utah Master Naturalist’s first hybrid course, Desert Explorations, and describes the positive results from our pilot study, how a hybrid course solves availability issues, and how field-based learning theories can be adapted to online education through careful design.

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 …

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 …

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 …