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This dissertation research investigates both spatial and temporal aspects of Bronze Age land use and land cover in the Eastern Mediterranean using botanical macrofossils of charcoal and charred seeds as sources of proxy data. Comparisons through time and over space using seed and charcoal densities, seed to charcoal ratios, and

This dissertation research investigates both spatial and temporal aspects of Bronze Age land use and land cover in the Eastern Mediterranean using botanical macrofossils of charcoal and charred seeds as sources of proxy data. Comparisons through time and over space using seed and charcoal densities, seed to charcoal ratios, and seed and charcoal identifications provide a comprehensive view of island vs. mainland vegetative trajectories through the critical 1000 year time period from 2500 BC to 1500 BC of both climatic fluctuation and significant anthropogenic forces. This research focuses particularly on the Mediterranean island of Cyprus during this crucial interface of climatic and human impacts on the landscape. Macrobotanical data often are interpreted locally in reference to a specific site, whereas this research draws spatial comparisons between contemporaneous archaeological sites as well as temporal comparisons between non-contemporaneous sites. This larger perspective is particularly crucial on Cyprus, where field scientists commonly assume that botanical macrofossils are poorly preserved, thus unnecessarily limiting their use as an interpretive proxy. These data reveal very minor anthropogenic landscape changes on the island of Cyprus compared to those associated with contemporaneous mainland sites. These data also reveal that climatic forces influenced land use decisions on the mainland sites, and provides crucial evidence pertaining to the rise of early anthropogenic landscapes and urbanized civilization.
ContributorsKlinge, JoAnna M (Author) / Fall, Patricia L. (Thesis advisor) / Falconer, Steven E. (Committee member) / Brazel, Anthony J. (Committee member) / Pigg, Kathleen B (Committee member) / Arizona State University (Publisher)
Created2013
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Description
This dissertation investigates spatial and temporal changes in land cover and plant species distributions on Cyprus in the past, present and future (1973-2070). Landsat image analysis supports inference of land cover changes following the political division of the island of Cyprus in 1974. Urban growth in Nicosia, Larnaka and Limasol,

This dissertation investigates spatial and temporal changes in land cover and plant species distributions on Cyprus in the past, present and future (1973-2070). Landsat image analysis supports inference of land cover changes following the political division of the island of Cyprus in 1974. Urban growth in Nicosia, Larnaka and Limasol, as well as increased development along the southern coastline, is clearly evident between 1973 and 2011. Forests of the Troodos and Kyrenia Ranges remain relatively stable, with transitions occurring most frequently between agricultural land covers and shrub/herbaceous land covers. Vegetation models were constructed for twenty-two plant species of Cyprus using Maxent to predict potentially suitable areas of occurrence. Modern vegetation models were constructed from presence-only data collected by field surveys conducted between 2008 and 2011. These models provide a baseline for the assessment of potential species distributions under two climate change scenarios (A1b and A2) for the years 2030, 2050, and 2070. Climate change in Cyprus is likely to influence habitat availability, particularly for high elevation species as the relatively low elevation mountain ranges and small latitudinal range prevent species from shifting to areas of suitable environmental conditions. The loss of suitable habitat for some species may allow the introduction of non-native plant species or the expansion of generalists currently excluded from these areas. Results from future projections indicate the loss of suitable areas for most species by the year 2030 under both climate regimes and all four endemic species (Cedrus brevifolia, Helianthemum obtusifolium, Pterocephalus multiflorus, and Quercus alnifolia) are predicted to lose all suitable environments as soon as 2030. As striking exceptions Prunus dulcis (almond), Ficus carica (fig), Punica granatum (pomegranate) and Olea europaea (olive), which occur as both wild varieties and orchard cultigens, will expand under both scenarios. Land cover and species distribution maps are evaluated in concert to create a more detailed interpretation of the Cypriot landscape and to discuss the potential implications of climate change for land cover and plant species distributions.
ContributorsRidder, Elizabeth (Author) / Fall, Patricia L. (Thesis advisor) / Myint, Soe W (Committee member) / Hirt, Paul W (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Microalgae represent a potential sustainable alternative for the enhancement and protection of agricultural crops. The dry biomass and cellular extracts of Scenedesmus dimorphus were applied as a biofertilizer, a foliar spray, and a seed primer to evaluate seed germination, plant growth, and crop yield of Roma tomato plants. The dry

Microalgae represent a potential sustainable alternative for the enhancement and protection of agricultural crops. The dry biomass and cellular extracts of Scenedesmus dimorphus were applied as a biofertilizer, a foliar spray, and a seed primer to evaluate seed germination, plant growth, and crop yield of Roma tomato plants. The dry biomass was applied as a biofertilizer at 50 g and 100 g per plant, to evaluate its effects on plant development and crop yield. Biofertilizer treatments enhanced plant growth and led to greater crop (fruit) production. Timing of biofertilizer application proved to be of importance - earlier 50 g biofertilizer application resulted in greater plant growth. Scenedesmus dimorphus culture, growth medium, and different concentrations (1%, 5%, 10%, 25%, 50%, 75%, 100%) of aqueous cell extracts were used as seed primers to determine effects on germination. Seeds treated with Scenedesmus dimorphus culture and with extract concentrations higher than 50 % (0.75 g ml-1) triggered faster germination - 2 days earlier than the control group. Extract foliar sprays of 50 ml and 100 ml, were obtained and applied to tomato plants at various extract concentrations (10%, 25%, 50%, 75% and 100%). Plant height, flower development and number of branches were significantly enhanced with 50 % (7.5 g ml-1) extracts. Higher concentration sprays led to a decrease in growth. The extracts were further screened to assess potential antimicrobial activity against the bacterium Escherichia coli ATCC 25922, the fungi Candida albicans ATCC 90028 and Aspergillus brasiliensis ATCC 16404. No antimicrobial activity was observed from the microalga extracts on the selected microorganisms.
ContributorsGarcia-Gonzalez, Jesus (Author) / Sommerfeld, Milton (Thesis advisor) / Steele, Kelly (Committee member) / Henderson, Mark (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Baseline community composition data provides a snapshot in time that allows changes in composition to be monitored more effectively and can inform best practices. This study examines Arizona Upland plant community composition of the Sonoran Desert through three different lenses: floristic inventory, and fire and reseeding effects.

A floristic inventory was

Baseline community composition data provides a snapshot in time that allows changes in composition to be monitored more effectively and can inform best practices. This study examines Arizona Upland plant community composition of the Sonoran Desert through three different lenses: floristic inventory, and fire and reseeding effects.

A floristic inventory was conducted at Cave Creek Regional Park (CCRP), Maricopa County, AZ. One hundred fifty-four taxa were documented within Park boundaries, including 148 species and six infraspecific taxa in 43 families. Asteraceae, Boraginaceae, and Fabaceae accounted for 40% of documented species and annuals accounted for 56% of documented diversity.

Fire effects were studied at three locations within McDowell Sonoran Preserve (MSP), Scottsdale, AZ. These fires occurred throughout the 1990s and recovered naturally. Fire and reseeding effects were studied at the site of a 2005 fire within CCRP that was reseeded immediately following the fire.

Two questions underlie the study regarding fire and reseeding effects: 1) How did fire and reseeding affect the cover and diversity of the plant communities? 2) Is there a difference in distribution of cover between treatments for individual species or growth habits? To address these questions, I compared burned and adjacent unburned treatments at each site, with an additional reseeded treatment added at CCRP.

MSP sites revealed overall diversity and cover was similar between treatments, but succulent cover was significantly reduced, and subshrub cover was significantly greater in the burn treatment. Seventeen species showed significant difference in distribution of cover between treatments.

The CCRP reseeded site revealed 11 of 28 species used in the seed mix persist 12 years post-fire. The reseeded treatment showed greater overall diversity than burned and unburned treatments. Succulent and shrub cover were significantly reduced by fire while subshrub cover was significantly greater in the reseeded treatment. Sixteen species showed significant difference in distribution of cover between treatments.

Fire appears to impact plant community composition across Arizona Upland sites. Choosing species to include in seed mixes for post-fire reseeding, based on knowledge of pre-fire species composition and individual species’ fire responses, may be a useful tool to promote post-fire plant community recovery.
ContributorsBarron, Kara Lynn (Author) / Pigg, Kathleen B (Thesis advisor) / Stromberg, Juliet (Thesis advisor) / Makings, Elizabeth (Committee member) / McCue, Kimberlie (Committee member) / Arizona State University (Publisher)
Created2018
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Description
Die-off of screwbean mesquite (Prosopis pubescens), a species native to the American Southwest, has been documented regionally within the last decade. Historical causes for episodic mortality of the more widely distributed velvet mesquite (Prosopis velutina) and honey mesquite (Prosopis glandulosa) include water table declines and flood scour. Causes of the

Die-off of screwbean mesquite (Prosopis pubescens), a species native to the American Southwest, has been documented regionally within the last decade. Historical causes for episodic mortality of the more widely distributed velvet mesquite (Prosopis velutina) and honey mesquite (Prosopis glandulosa) include water table declines and flood scour. Causes of the recent die-offs of P. pubescens have received little study. Numerous riparian restoration projects have been implemented regionally that include screwbean mesquite. Restoration propagules from foreign sources can introduce diseases, and low genetic diversity plantings may allow for disease irruptions. I asked: 1) Are die-offs associated with a particular age class, 2) Is die-off suggestive of a pathogen or related to specific environmental stressors, 3) Are mortality influences and outcomes the same between restoration and local populations, 4) Are particular land uses and management associated with die-off, and 5) Are populations rebounding or keeping pace with mortality?

I documented the screwbean mesquite population status at rivers and wetlands in Arizona with varying levels of restoration. I used logistic regression and Pearson correlation analysis to explore mortality response to site factors and disease related variables. I compared mortality response and disease severity between local and restoration populations.

Biotic damage surfaced as the most important factor in statistical analyses, suggesting that mortality was caused by a pathogen. Mortality was greatest for young size classes (3 to 14 cm), and biotic damage was higher for individuals at infrequently flooded areas. Strong differences were not found between local and restoration populations – however restoration populations were less stressed and had lower biotic damage. Novel urban and restored sites may provide refuge as site conditions at other locations deteriorate. A culmination of past water diversion, development and land use may be surfacing, rendering riparian species vulnerable to diseases and triggering such events as region-wide die-off.
ContributorsMadera, Robert (Author) / Stromberg, Juliet (Thesis advisor) / Stutz, Jean (Committee member) / McCue, Kimberlie (Committee member) / Arizona State University (Publisher)
Created2016
Description
The remarkable conservation of molecular and intra-/inter-cellular pathways underpinning the fundamental aspects of sugar partitioning in two evolutionarily divergent organisms – a non-vascular moss Physcomitrella patens and a vascular cereal crop Oryza sativa (rice) – forms the basis of this manuscript. Much of our current knowledge pertaining to sugar partitioning

The remarkable conservation of molecular and intra-/inter-cellular pathways underpinning the fundamental aspects of sugar partitioning in two evolutionarily divergent organisms – a non-vascular moss Physcomitrella patens and a vascular cereal crop Oryza sativa (rice) – forms the basis of this manuscript. Much of our current knowledge pertaining to sugar partitioning in plants mainly comes from studies in thale cress, Arabidopsis thaliana, but how photosynthetic sugar is loaded into the phloem in a crop as important as rice is still debated. Even less is known about the mechanistic aspects of sugar movement in mosses. In plants, sugar either moves passively via intercellular channels called plasmodesmata, or through the cell wall spaces in an energy-consuming process. As such, I first investigated the structure of plasmodesmata in rice leaf minor vein using electron tomography to create as of yet unreported 3D models of these channels in both simple and branched conformations. Contrary to generally held belief, I report two different 3D morphotypes of simple plasmodesmata in rice. Furthermore, the complementary body of evidence in arabidopsis implicates plasma membrane localized Proton Pyrophosphatase (H+-PPase) in the energy-dependent movement of sugar. Within this wider purview, I studied the in situ ultrastructural localization patterns of H+-PPase orthologs in high-pressure frozen tissues of rice and physcomitrella. Were H+-PPases neo-functionalized in the vascular tissues of higher plants? Or are there evolutionarily conserved roles of this protein that transcend the phylogenetic diversity of land plants? I show that H+-PPases are distinctly expressed in the actively growing regions of both rice and physcomitrella. As expected, H+-PPases were also localized in the vascular tissues of rice. But surprisingly, H+-PPase orthologs were also prominently expressed at the gametophyte-sporophyte junction of physcomitrella. Upon immunogold labeling, H+-PPases were found to be predominantly localized at the plasma membrane of the phloem complexes of rice source leaves, and both the vacuoles and plasma membrane of the transfer cells in the physcomitrella haustorium, linking H+-PPases in active sucrose loading in both plants. As such, these findings suggest that the localization and presumably the function of H+-PPases are conserved throughout the evolutionary history of land plants.
ContributorsRegmi, Kamesh Chandra (Author) / Gaxiola, Roberto A (Thesis advisor) / Wojciechowski, Martin F (Committee member) / Pigg, Kathleen B (Committee member) / Roberson, Robert W. (Committee member) / Arizona State University (Publisher)
Created2016
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In the face of the sixth mass extinction on Earth, with the flowering plant family Cactaceae assessed as the fifth most endangered plant or animal family by the International Union for the Conservation of Nature (IUCN), it is imperative that all available tools be used to understand the biodiversity, habitat

In the face of the sixth mass extinction on Earth, with the flowering plant family Cactaceae assessed as the fifth most endangered plant or animal family by the International Union for the Conservation of Nature (IUCN), it is imperative that all available tools be used to understand the biodiversity, habitat suitability, climate change impacts and population viability of cacti. Within the Cactaceae, Mammillaria Haw and the closely related genus Cochemiea (K. Brandegee) Walton of Baja California, Mexico, are species-rich, with 46 regionally endemic taxa, 12 of which have been assessed as threatened or endangered by the IUCN. This study clarifies the evolutionary relationships in the Mammilloid clade, a complex and species-rich clade in tribe Cacteae, and generic circumscription of the genera Mammillaria Haw. and Cochemiea (K. Brandegee) Walton, estimates divergence times, diversification rates and ancestral ranges and explores habitat suitability and the risk of extinction of a representative species within these genera. The r species, Cochemiea halei (K. Brandegee) Walton, a narrowly distributed island endemic, is assessed using species distribution modeling (SDM) and population viability analysis (PVA). SDM in this study includes projections to two climate change scenarios over the next century, using four representative particle concentration pathways, and the PVA uses habitat-specific deterministic and stochastic models. The results of molecular phylogenetic analyses of the Mammilloid cladde restore the genus Mammillaria to monophyly via new combinations in the genus Cochemiea. The taxa in this study are shown to be of recent origin resulting from rapid diversification and radiation. Geological and climatic forces at multiple scales appear to be responsible for the high degree of biodiversity and endemism of these cacti. SDM shows that C. halei is likely to be stranded in its fragmented island habitat, has a facultative adaptation to ultramafic soils, and faces a 21%–53% contraction of its range on the islands under climate change scenarios. PVA suggests that C. halei is at increased risk of extinction in response to slight decreases in fecundity and persistence. In general, the perspectives in this dissertation fill several gaps in our prior knowledge of the evolution, biogeography, and conservation pressures of an important, species-rich group of cacti, occurring in a region of high biodiversity and endemism.
ContributorsBreslin, Peter (Author) / Wojciechowski, Martin F (Thesis advisor) / Albuquerque, Fabio (Committee member) / Fehlberg, Shannon (Committee member) / Majure, Lucas (Committee member) / Rebman, Jon (Committee member) / Arizona State University (Publisher)
Created2020
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Xylem conduits, a primary feature of most terrestrial plant taxa, deliver water to photosynthetic tissues and play a critical role in plant water relations and drought tolerance. Non-succulent woody taxa generally follow a universal rate of tip-to-base conduit widening such that hydraulic resistance remains constant throughout the plant stem. Giant

Xylem conduits, a primary feature of most terrestrial plant taxa, deliver water to photosynthetic tissues and play a critical role in plant water relations and drought tolerance. Non-succulent woody taxa generally follow a universal rate of tip-to-base conduit widening such that hydraulic resistance remains constant throughout the plant stem. Giant cacti inhabit arid regions throughout the Americas and thrive in water-limited environments by complimenting water-storing succulent tissues with resource-efficient Crassulacean Acid Metabolism. Considering these adaptations, the objectives of this study were threefold: 1) determine whether xylem conduits in columnar cacti follow universal scaling theory as observed in woody taxa; 2) evaluate whether xylem hydraulic diameter is inversely correlated with xylem vessel density; and 3) determine whether xylem double-wall thickness-to-span ratio and other hydraulic architectural traits are convergent among phylogenetically diverse cactus species. This thesis investigates the xylem anatomy of nine cactus species native to the Sonoran Desert of Arizona and Mexico, the tropical dry forests of southern Mexico, and the Alto Plano region of Argentina. Soft xylem tissues closest to the stem apex underwent a modified polyethylene glycol treatment to stabilize for sectioning with a sledge microtome. Across all species: hydraulic diameter followed a basipetal widening rate of 0.21 (p < 0.001), closely matching the universal rate of 0.20 for woody taxa; and xylem vessel density was inversely correlated with both length from stem apex (p < 0.001) and hydraulic diameter (p < 0.001). Double-wall thickness-to-span ratio had little to no significant correlation with either length from stem apex or hydraulic diameter. There was no significant difference in hydraulic architectural trait patterns between phylogenetically diverse species with various stem morphologies, nor was there a significant correlation between conduit widening rates and volume-to-surface-area ratios. This study demonstrates that giant cacti follow similar internal anatomical constraints as non-succulent woody taxa, yet stem succulence and water storage behavior in cacti remain separate from internal hydraulic architecture, allowing cacti to thrive in arid environments. Understanding how cacti cope with severe water limitations provides new insights on evolutionary constraints of stem succulents as they functionally diverged from other life forms.
ContributorsCaspeta, Ivanna (Author) / Hultine, Kevin (Thesis advisor) / Throop, Heather (Thesis advisor) / Hernandez, Tania (Committee member) / Arizona State University (Publisher)
Created2023
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Drylands cover over 40% of the Earth’s surface, account for one third of global carbon cycling, and are hotspots for climate change, with more frequent and severe droughts coupled with deluges of novel magnitude and frequency. Because of their large terrestrial extent, elucidating dryland ecosystem responses to changes in water

Drylands cover over 40% of the Earth’s surface, account for one third of global carbon cycling, and are hotspots for climate change, with more frequent and severe droughts coupled with deluges of novel magnitude and frequency. Because of their large terrestrial extent, elucidating dryland ecosystem responses to changes in water availability is critical for a comprehensive understanding of controls on global aboveground net primary productivity (ANPP), an important ecosystem service. The focus of this dissertation is to investigate cause-effect mechanisms between altered water availability and ecosystem processes in dryland ecosystems. Across a network of experimental rainfall manipulations within a semiarid Chihuahuan Desert grassland, I examined short- and long-term dynamics of multiple ecosystem processes—from plant phenology to nitrogen cycling—in response to directional precipitation extremes. Aboveground, I found herbaceous plant phenology to be more sensitive in greenup timing compared to deep-rooted, woody shrubs, implying that precipitation extremes will disproportionately affect grass-dominated compared to woody ecosystems. Surprisingly, after 14 years of experimentally adding water and N, I observed no effect on ANPP. Belowground, bulk soil N dynamics remained stable with differing precipitation amounts. However, mineral associated organic N (MAOM-N) significantly increased under chronic N inputs, indicating potential for dryland soil N sequestration. Conversely, the difference between low- and high-N soil N content may increase a drawdown of N from all soil N pools under low-N conditions whereas plants source N from fertilizer input under high-N conditions. Finally, I considered ecosystem-level acclimation to climate change. I found that N availability decreased with annual precipitation in space across continents, but it posed initially increasing trends in response to rainfall extremes at the Jornada that decreased after 14 years. Mechanisms for the acclimation process are thus likely associated with differential lags to changes in precipitation between plants and microorganisms. Overall, my dissertation demonstrates that examining linkages between multiple ecosystem processes, from aboveground phenological cycles to belowground N cycling dynamics, can provide a more integrative understanding of dryland response to climate change. Because dryland range is potentially expanding globally, water limited systems provide a unique and critical focus area for future research that revisit and revise current ecological paradigms.
ContributorsCurrier, Courtney (Author) / Sala, Osvaldo (Thesis advisor) / Collins, Scott (Committee member) / Reed, Sasha (Committee member) / Throop, Heather (Committee member) / Arizona State University (Publisher)
Created2023
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Chemical fertilizers are commonly used for controlled environment agriculture because they provide essential plant nutrient efficiently. However, rising fertilizer costs, global phosphorous shortage, and the negative impacts of producing and using chemical fertilizer are concerns for sustainable crop production. As sustainable alternatives to chemical fertilizers, there is a growing interest

Chemical fertilizers are commonly used for controlled environment agriculture because they provide essential plant nutrient efficiently. However, rising fertilizer costs, global phosphorous shortage, and the negative impacts of producing and using chemical fertilizer are concerns for sustainable crop production. As sustainable alternatives to chemical fertilizers, there is a growing interest in using organic fertilizers with beneficial plant growth promoting microorganisms. The objectives of this research were to investigate how the application of plant growth promoting bacteria and arbuscular mycorrhizal fungi influences plant growth of lettuce (Lactuca sativa) and tomato (Solanum lycopersicum) seedlings in soilless media under organic fertilization. In the first study, the effects of Azosprillium brasilense and Rhizophagus intraradices inoculation on lettuce and tomato seedling growth were quantified under two different organic fertilizer types compared to under chemical fertilizer. The results showed that A. brasilense and R. intraradices had little to no effect on any growth parameter measured in either species regardless of fertilizer type. In the second study, an investigation of the co-inoculation of A. brasilense and R. intraradices or increasing the application frequency of A. brasilense or/and R. intraradices increased plant growth promoting effects in lettuce ‘Cherokee’ and ‘Rex’ grown under organic fertilization. An application frequency of every 2-days of the R. intraradices without or with A. brasilense increased shoot fresh weight in both lettuce cultivars by 51-58%, compared to un-inoculated control. In contrast, lettuce seedling growth were similar without or with applying R. intraradices weekly or A. brasilense regardless of frequency. Together, the results suggest that applying R. intraradices with a proper application frequency can enhance plant growth of lettuce under organic fertilization.
ContributorsMcClintic, Nicklas Charles (Author) / Park, Yujin (Thesis advisor) / Penton, Christopher R (Committee member) / Chen, Changbin (Committee member) / Arizona State University (Publisher)
Created2022