Desert Ecology Commons^™

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 …

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

Electronic Theses and Dissertations

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 …

Population Structure Of A Federally Endangered Plant (Astragalus Jaegerianus Munz, Fabaceae) With Limited Range Using Microsatellites, Sueann Neal

Electronic Theses, Projects, and Dissertations

Studies on population genetics examine the relationship and effects of population structure, migration, gene flow and demographic history, and are therefore important in the conservation of endangered species. Astragalus jaegerianus, a critically federally endangered species found in a geographically restricted range is investigated to determine population structure and genetic variation. Previous research on A. jaegerianus focused on DNA sequence data for cpDNA and nrDNA showed no variation. Further research on A. jaegerianus utilizing AFLP’s on the whole genome indicated substantial gene diversity and population structure consistent with geographically widespread species. AFLP research is a cost-effective process to identify levels …

The Birds Of The Nebraska Sandhills, Paul A. Johnsgard, Josef Kren

Zea E-Books Collection

This book provides basic information on all the species of birds that have been reliably reported from the Nebraska Sandhills region as of 2020. They include 46 permanent residents, 125 summer breeders, 125 migrants, and 102 rare or accidental species, totaling 398 species. Information on status, migration, and habitats is provided for all but the very rare and accidental species. There are also descriptions of 46 refuges, preserves, and other public-access natural areas in the region and seven suggested birding routes. The text contains more than 90,000 words and over 250 literature references along with more than 20 drawings, 9 …

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 …

Resilience And Alternative Stable States After Desert Wildfires, Scott R. Abella, Dominic M. Gentilcore, Lindsay P. Chiquoine

Life Sciences Faculty Research

Improving models of community change is a fundamental goal in ecology and has renewed importance during global change and increasing human disturbance of the biosphere. Using the Mojave Desert (southwestern United States) as a model system, invaded by nonnative plants and subject to wildfire disturbances, we examined models of resilience, alternative stable states, and convergent-divergent trajectories for 36 yr of plant community change after 31 wildfires in communities dominated by the native shrubs Larrea tridentata or Coleogyne ramosissima. Perennial species richness on average was fully resilient within 23 yr after disturbance in both community types. Perennial cover was fully resilient …

Post Burn Restoration Response Of Encelia Virginensis Within A Small Wash System In The Mojave Desert, Dale A. Devitt, Fred Landau, Scott R. Abella, Matt D. Petrie, Ann M. Mcluckie, John O. Kellam

Life Sciences Faculty Research

Spatial variation in response to restoration treatments within landscapes can be a significant but poorly understood driver of successful ecological restoration. We conducted a field experiment to assess effectiveness of out-planting restoration techniques for the native shrub Encelia virginensis across a soil hydrological gradient. We planted seedlings at five wash locations separated by varying distances based on elevation and percent slope. At each of these plots we planted seedlings, half on the side wall slopes of the wash system and half adjacent to the central wash. Seedlings received either cages, hydrogel, cages and hydrogel, or no treatments. We assessed survival …

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 …

Sampling The Local Fare: Fishes At The Sam Israel House Pit (45gr76), Soap Lake, Washington, Adam Fruge

All Master's Theses

The Sam Israel site is a precontact archaeological complex with numerous fish bones at the north end of Soap Lake, Washington. Excavated in 1976, the fish remains recovered from there were never fully analyzed prior to this research. Since this inland Columbia Plateau site had thousands of fish bones, it contained untapped potential for our understanding of ancient local fish procurement. As such, I conducted a detailed analysis of 2,862 fish bone specimens from the Sam Israel House Pit locus to: study a larger sample of fish bones in greater detail than was done before; compare the distribution of fishes …

A Tale Of Two Cervids: Habitat Selection And Spatial Ecology Of Roosevelt And Tule Elk In California, Adam S. Mohr

Cal Poly Humboldt theses and projects

California’s Roosevelt (Cervus canadensis rooseveltii) and tule elk (C. c. nannodes) populations have experienced a remarkable recovery after over-hunting and habitat loss nearly extirpated them from the state. Greater clarity of Roosevelt and tule elk habitat selection patterns would help managers continue to effectively support the recovery of these two iconic subspecies. As the manner in which elk populations balance their competing resource needs is unique to each population (Skovlin et al. 2002), I have examined Roosevelt and tule elk habitat selection patterns in separate analyses and present these results in independent chapters. In both cases, …

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 Research

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 Research

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 …

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.

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. …