Matching Items (229)
Description
Ecology has been an actively studied topic recently, along with the rapid development of human microbiota-based technology. Scientists have made remarkable progress using bioinformatics tools to identify species and analyze composition. However, a thorough understanding of interspecies interactions of microbial ecosystems is still lacking, which has been a significant obstacle in the further development of related technologies. In this work, a genetic circuit design principle with synthetic biology approaches is developed to form two-strain microbial consortia with different inter-strain interactions. The microbial systems are well-defined and inducible. Co-culture experiment results show that our microbial consortia behave consistently with previous ecological knowledge and thus serves as excellent model systems to simulate ecosystems with similar interactions. Colony patterns also emerge when co-culturing multiple species on solid media. With the engineered microbial consortia, image-processing based methods were developed to quantify the shape of co-culture colonies and distinguish microbial consortia with different interactions. Factors that affect the population ratios were identified through induction and variations in the inoculation process. Further time-lapse experiments revealed the basic rules of colony growth, composition variation, patterning, and how spatial factors impact the co-culture colony.
ContributorsChen, Xingwen (Author) / Wang, Xiao (Thesis advisor) / Kuang, Yang (Committee member) / Tian, Xiaojun (Committee member) / Brafman, David (Committee member) / Plaisier, Christopher (Committee member) / Arizona State University (Publisher)
Created2022
Description
The nests of the Curve-billed Thrasher (Toxostoma curvirostre) were studied across the greater Phoenix area from 2020-2022 in order to assess any significant relationships between their composition and the composition of their environment. Nests were collected and measured, and the vegetation was surveyed to 100 m for potential nest material type. In the lab, nests were separated by material type and tallied. The dense cores of the nests received a 100-piece sampling, with the first hundred pieces plucked from the structure, sorted by type, and massed. Ordinary least squares (OLS) and binomial regression analyses were performed on the body tallies and their corresponding site tallies. Core material weights and their corresponding site tallies only received OLS regression analyses. Beta regression analyses were also performed on the mass proportions of core samples and their corresponding environmental tallies. OLS regression yielded a significant relationship between the spiny body material tally and its site tallies at 25 and 100 m. While failing the assumption of normality, the tally of barrel cactus in a nest body yielded significant p-values in OLS and binomial regression, as well as the Spearman’s correlation test, supporting a strong correlation with the 100m site tally. The tally of anthropogenic materials and the distance to the nearest man-made structure failed the test of normality, but yielded significant p-values in binomial regression and the Spearman’s correlation test. OLS regression of log anthropogenic tally and log distance to nearest structure failed normality but yielded a significant p-value as well. In beta regression analyses, only the spiny core mass proportion yielded a significant relationship at the 100 m site tally.
ContributorsMotta, Anthony Joseph (Author) / Taylor, Jay (Thesis advisor) / Makings, Elizabeth (Committee member) / Puente, Raul (Committee member) / Arizona State University (Publisher)
Created2022
Description
The National Wilderness Preservation System (NWPS) is a collection of more than 800 areas designated as wilderness under the Wilderness Act of 1964. The Act defines wilderness as an “area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.” Wilderness lands are supposed to be pristine examples of nature where the overseeing agency has not allowed any post-designation development. The language of the act describes land designated as wilderness as “untrammeled” by people, discounting thousands of years of human influence. It also discounts the potential effect of surrounding lands and visitors on the wilderness. The management of these lands falls to all four federal land management agencies, and they each had – and still have – their own organizational perspectives on the Wilderness Act and their agency’s role in its implementation. Although the Act provided criteria for designating and managing wilderness, concrete guidance is lacking. This ambiguity has allowed a rift to emerge between those who believe that wilderness should be actively managed and those who believe that wilderness should be preserved and left alone as much as possible. The diversity of views and agency approaches have created administrative divides between wilderness lands and other land types. In parallel, the introduction of subsequent environmental laws have placed additional legal boundaries on the land, creating parcels next to and within wilderness that are subject to different uses and requirements. This study, which marshals dozens of expert interviews and explores a series of wilderness cases across the United States, focuses on several unanticipated challenges of stewarding the NWPS in the 21st Century. These include: the impacts of public land parceling due to legal obligations; how statuary ossification affects current interpretations of the various laws bearing on wilderness lands; and ultimately how land managers and agencies – who are looking toward a future of increased anthropogenic impacts on wildlife biodiversity and endangered/threatened species on wilderness lands – approach these challenges.
ContributorsFacemire, Challie Renee (Author) / Minteer, Ben A (Thesis advisor) / Ellison, Karin (Thesis advisor) / Bradshaw, Karen (Committee member) / Hahn, Beth (Committee member) / Budruk, Megha (Committee member) / Arizona State University (Publisher)
Created2022
Description
Integrated water resources management for flood control, water distribution, conservation, and food security require understanding hydrological spatial and temporal trends. Proliferation of monitoring and sensor data has boosted data-driven simulation and evaluation. Developing data-driven models for such physical process-related phenomena, and meaningful interpretability therein, necessitates an inventive methodology. In this dissertation, I developed time series and deep learning model that connected rainfall, runoff, and fish species abundances. I also investigated the underlying explainabilty for hydrological processes and impacts on fish species. First, I created a streamflow simulation model using computer vision and natural language processing as an alternative to physical-based routing. I tested it on seven US river network sections and showed it outperformed time series models, deep learning baselines, and novel variants. In addition, my model explained flow routing without physical parameter input or time-consuming calibration. On the basis of this model, I expanded it from accepting dispersed spatial inputs to adopting comprehensive 2D grid data. I constructed a spatial-temporal deep leaning model for rainfall-runoff simulation. I tested it against a semi-distributed hydrological model and found superior results. Furthermore, I investigated the potential interpretability for rainfall-runoff process in both space and time. To understand impacts of flow variation on fish species, I applied a frequency based model framework for long term time series data simulation. First, I discovered that timing of hydrological anomalies was as crucial as their size. Flooding and drought, when properly timed, were both linked with excellent fishing productivity. To identify responses of various fish trait groups, I used this model to assess mitigated hydrological variation by fish attributes. Longitudinal migratory fish species were more impacted by flow variance, whereas migratory strategy species reacted in the same direction but to various degrees. Finally, I investigated future fish population changes under alternative design flow scenarios and showed that a protracted low flow with a powerful, on-time flood pulse would benefit fish. In my dissertation, I constructed three data-driven models that link the hydrological cycle to the stream environment and give insight into the underlying physical process, which is vital for quantitative, efficient, and integrated water resource management.
ContributorsDeng, Qi (Author) / Sabo, John (Thesis advisor) / Grimm, Nancy (Thesis advisor) / Ganguly, Auroop (Committee member) / Li, Wenwen (Committee member) / Mascaro, Giuseppe (Committee member) / Arizona State University (Publisher)
Created2022
Description
Advanced technology has increased access to Antarctica; consequently, there has been an increase in research and tourism. The production of the new technology and the increased number of individuals visiting can increase the presence of persistent organic pollutants and microplastic within Antarctic soil. Studies have focused primarily on identifying these pollutants in high human impact areas with perhaps an assumption that low human impact areas would have lower concentrations of pollutants. The object of this paper, therefore, was to test the hypothesis that higher concentrations of persistent organic pollutants and microplastic are found in soils collected near research stations and tourist areas, as opposed to sites that are further from stations and have less direct human impact. Soil samples were collected along a 1,500 km transect of the Scotia Arch and Antarctic Peninsula from three high human impact sites and three low human impact sites to compare the concentration of contaminates identified within the soil. The presence and quantities of microplastic were identified using Nile Red and fluorescence microscopy, while gas chromatography-mass spectrometry was used to detect polychlorinated biphenyls, pesticides, polycyclic aromatic hydrocarbons, n-alkane, and phthalates. Although varying contaminate concentration levels were found at all six sights, counter to the hypothesis, there were no clear patterns of increasing pollutants with increasing human activities. These findings could imply that global sources of pollutants can increase local pollutants indicating the best way to solve any pollution problem is through a global lens.
ContributorsCarroll, Kenneth Charles (Author) / Polidoro, Beth (Thesis advisor) / Kinzig, Ann (Thesis advisor) / Ball, Becky (Committee member) / Arizona State University (Publisher)
Created2022
Description
Climate change is making the arid southwestern U.S. (“Southwest”) warmer and drier. Decreases in water availability coupled with increases in episodic heat waves can pose extraordinary challenges for native riparian tree species to persist in their current ranges. However, the morpho-physiological mechanisms that these species deploy to cope with extreme temperature events are not well understood. Specifically, how do these species maintain leaf temperatures within a safe operational threshold in the extreme conditions found across the region? Morpho-physiological mechanisms influencing intraspecific local adaptation to thermal stress were assessed in Populus fremontii using two experimental common gardens. In a common garden located near the mid-point of this species’ thermal distribution, I studied coordinated traits that reflect selection for leaf thermal regulation through the measurement of 28 traits encompassing four different trait spectra: phenology, whole-tree architecture, and the leaf and wood economic spectrum. Also, I assessed how these syndromes resulted in more acquisitive and riskier water-use strategies that explained how warm-adapted populations exhibited lower leaves temperatures than cool-adapted populations. Then, I investigated if different water-use strategies are detectable at inter-annual temporal scales by comparing tree-ring growth, carbon, and oxygen isotopic measurements of cool- versus warm-adapted populations in a common garden located at the extreme hottest edge of P. fremontii’s thermal distribution. I found that P. fremontii’s adaptation to the extreme temperatures is explained by a highly intraspecific specialized trait coordination across multiple trait scales. Furthermore, I found that warmer-adapted populations displayed 39% smaller leaves, 38% higher midday stomatal conductance, reflecting 3.8 °C cooler mean leaf temperature than cool-adapted populations, but with the tradeoff of having 14% lower minimum leaf water potentials. In addition, warm-adapted genotypes at the hot edge of P. fremontii’s distribution had 20% higher radial growth rates, although no differences were detected in either carbon or oxygen isotope ratios indicating that differences in growth may not have reflected seasonal differences in photosynthetic gas exchange. These studies describe the potential effect that extreme climate might have on P. fremontii’s survival, its intraspecific responses to those events, and which traits will be advantageous to cope with those extreme environmental conditions.
ContributorsBlasini, Davis E (Author) / Hultine, Kevin R (Thesis advisor) / Day, Thomas A (Thesis advisor) / Ogle, Kiona (Committee member) / Throop, Heather (Committee member) / Gaxiola, Roberto (Committee member) / Arizona State University (Publisher)
Created2022
Description
More people live in cities or metropolitan areas than ever before, which encompass many types of urbanization. These areas are culturally diverse and densely populated heterogeneous landscapes that are shaped by socio-ecological patterns. Cities support human and wildlife populations that are influenced indirectly and directly by human decisions. This process can result in unequal access to environmental services and accessible green spaces. Additionally, biodiversity distribution is influenced by human decisions. Although neighborhood income can drive biodiversity in metropolitan areas (i.e., the ‘luxury effect’), other socio-cultural factors may also influence the presence and abundance of wildlife beyond simple measures of wealth. To understand how additional social factors shape distributions of wildlife, I ask, are patterns of wildlife distribution associated with neighborhood ethnicity, in addition to income and ecological landscape characteristics within metropolitan areas? Utilizing data from 38 wildlife cameras deployed in neighborhood public parks and non-built spaces in metro Phoenix, AZ (USA), I estimated occupancy and activity patterns of coyotes (Canis latrans), desert cottontail rabbits (Sylvilagus audubonii), and domestic cats (Felis catus) across gradients of median household income and neighborhood ethnicity, estimated by the proportion of Latinx residents. Neighborhood ethnicity appeared in the top models for all species, and neighborhood % of Latinx residents was inversely associated with presence of native Sonoran Desert animals (coyotes and cottontail rabbits). Furthermore, daily activity patterns of coyotes differed in neighborhoods with higher vs. lower proportion of Latinx residents. My results suggest that socio-cultural variables beyond income are associated with wildlife distributions, and that factors associated with neighborhood ethnicity may be an informative correlate of city-wide ecological patterns. In this research, I unraveled predictive social variables and differentiated wildlife distribution across neighborhood gradients of income and ethnic composition, bringing attention to the potentially unequal distribution of mammals in cities.
ContributorsCocroft, Alexandreana (Author) / Hall, Sharon J (Thesis advisor) / Lerman, Susannah B (Committee member) / Lewis, Jesse (Committee member) / Arizona State University (Publisher)
Created2022
Description
Understanding the effects of fire on the Sonoran Desert is of critical importance as rising temperatures and changing weather patterns increase the frequency and size of wildfires. Seed banks are an important component in post-fire landscape recovery as the seeds that remain in the soil are an indicator of a landscape’s future trajectory. The purpose of this study is to determine the lasting impacts of fire on the soil seed bank of the Sonoran Desert and to identify potential concerns affecting post-fire recovery and restoration. The study site was located in the Arizona Upland division of the Sonoran Desert, Arizona, United States. Soil samples were collected from five burned sites with increasing time since fire, and five nearby unburned sites used as a control. A seedling emergence test was conducted to investigate the density and richness of the seed bank of burned and unburned sites. Seed densities and species richness for sites were calculated using germination results. Findings were analyzed using non-parametric analyses comparing changes in burned and unburned sites over time.
Results found that burn status and time since fire had no significant impact on seed density. Graminoid and forb densities were statistically consistent across burn status and time since fire. While species richness was consistent across both plot types, burned samples typically had fewer species than unburned samples. Burned and unburned plots revealed a dominance of annual species with limited presence of woody perennials. While seed densities and species richness are relatively unchanged across burned and unburned sites over time, the lack of woody perennials in the seed bank raises concerns about landscape recovery trajectories in burned sites. These results suggest that restoration efforts focused on maintaining the presence of woody trees and shrubs in the landscape may have the most impact.
ContributorsCountryman, Kristen (Author) / Makings, Elizabeth (Thesis advisor) / Pigg, Kathleen (Thesis advisor) / Lata, Mary (Committee member) / Arizona State University (Publisher)
Created2023
Description
The use of genetic management in conservation has sparked much debate around the ethical and environmental impacts of the plans. A case study on the conservation of leopard frogs in Arizona was analyzed to better understand the benefits and issues surrounding genetic management plans. The first part of the case focuses on the recent management plan for Chiricahua Leopard Frogs implemented by the Arizona Game and Fish Department. The goal of the plan is to better understand the genetic dynamics of the established Chiricahua Leopard Frog populations to develop a more effective management plan. The second part of the case focuses on the Arizona Game and Fish Department’s management of the Northern Leopard Frog. There was little success with the initial breed and release program of the native species, however a nonnative subspecies of Northern Leopard Frog was able to establish a thriving population. This case study exemplifies the many complications with genetic management plans and the importance of careful assessment of options when deciding on a genetic management plan. Despite the complexity of genetic management plans, it is an important method to consider when discussing the conservation of a species.
ContributorsTurpen, Alexa (Author) / Murphree, Julie (Thesis director) / Collins, James (Thesis director) / Owens, Audrey (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / College of Integrative Sciences and Arts (Contributor) / School of Mathematical and Natural Sciences (Contributor)
Created2024-05
Description
An understanding of the formation of spatial heterogeneity is important because spatial heterogeneity leads to functional consequences at the ecosystem scale; however, such an understanding is still limited. Particularly, research simultaneously considering both external variables and internal feedbacks (self-organization) is rare, partly because these two drivers are addressed under different methodological frameworks. In this dissertation, I show the prevalence of internal feedbacks and their interaction with heterogeneity in the preexisting template to form spatial pattern. I use a variety of techniques to account for both the top-down template effect and bottom-up self-organization. Spatial patterns of nutrients in stream surface water are influenced by the self-organized patch configuration originating from the internal feedbacks between nutrient concentration, biological patchiness, and the geomorphic template. Clumps of in-stream macrophyte are shaped by the spatial gradient of water permanence and local self-organization. Additionally, significant biological interactions among plant species also influence macrophyte distribution. The relative contributions of these drivers change in time, responding to the larger external environments or internal processes of ecosystem development. Hydrologic regime alters the effect of geomorphic template and self-organization on in-stream macrophyte distribution. The relative importance of niche vs. neutral processes in shaping biodiversity pattern is a function of hydrology: neutral processes are more important in either very high or very low discharge periods. For the spatial pattern of nutrients, as the ecosystem moves toward late succession and nitrogen becomes more limiting, the effect of self-organization intensifies. Changes in relative importance of different drivers directly affect ecosystem macroscopic properties, such as ecosystem resilience. Stronger internal feedbacks in average to wetter years are shown to increase ecosystem resistance to elevated external stress, and make the backward shifts (vegetation loss) much more gradual. But it causes increases in ecosystem hysteresis effect. Finally, I address the question whether functional consequences of spatial heterogeneity feed back to influence the processes from which spatial heterogeneity emerged through a conceptual review. Such feedbacks are not likely. Self-organized spatial patterning is a result of regular biological processes of organisms. Individual organisms do not benefit from such order. It is order for free, and for nothing.
ContributorsDong, Xiaolin (Author) / Grimm, Nancy (Thesis advisor) / Muneepeerakul, Rachata (Thesis advisor) / Franklin, Janet (Committee member) / Heffernan, James B (Committee member) / Sabo, John (Committee member) / Arizona State University (Publisher)
Created2015