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Ponderosa pine forests are a dominant land cover type in semiarid montane areas. Water supplies in major rivers of the southwestern United States depend on ponderosa pine forests since these ecosystems: (1) receive a significant amount of rainfall and snowfall, (2) intercept precipitation and transpire water, and (3) indirectly influence runoff by impacting the infiltration rate. However, the hydrologic patterns in these ecosystems with strong seasonality are poorly understood. In this study, we used a distributed hydrologic model evaluated against field observations to improve our understandings on spatial controls of hydrologic patterns, appropriate model resolution to simulate ponderosa pine ecosystems and hydrologic responses in the context of contrasting winter to summer transitions. Our modeling effort is focused on the hydrologic responses during the North American Monsoon (NAM), winter and spring periods. In Chapter 2, we utilized a distributed model explore the spatial controls on simulated soil moisture and temporal evolution of these spatial controls as a function of seasonal wetness. Our findings indicate that vegetation and topographic curvature are spatial controls. Vegetation controlled patterns during dry summer period switch to fine-scale terrain curvature controlled patterns during persistently wet NAM period. Thus, a climatic threshold involving rainfall and weather conditions during the NAM is identified when high rainfall amount (such as 146 mm rain in August, 1997) activates lateral flux of soil moisture and frequent cloudy cover (such as 42% cloud cover during daytime of August, 1997) lowers evapotranspiration. In Chapter 3, we investigate the impacts of model coarsening on simulated soil moisture patterns during the NAM. Results indicate that model aggregation quickly eradicates curvature features and its spatial control on hydrologic patterns. A threshold resolution of ~10% of the original terrain is identified through analyses of homogeneity indices, correlation coefficients and spatial errors beyond which the fidelity of simulated soil moisture is no longer reliable. Based on spatial error analyses, we detected that the concave areas (~28% of hillslope) are very sensitive to model coarsening and root mean square error (RMSE) is higher than residual soil moisture content (~0.07 m3/m3 soil moisture) for concave areas. Thus, concave areas need to be sampled for capturing appropriate hillslope response for this hillslope. In Chapter 4, we investigate the impacts of contrasting winter to summer transitions on hillslope hydrologic responses. We use a distributed hydrologic model to generate a consistent set of high-resolution hydrologic estimates. Our model is evaluated against the snow depth, soil moisture and runoff observations over two water years yielding reliable spatial distributions during the winter to summer transitions. We find that a wet winter followed by a dry summer promotes evapotranspiration losses (spatial averaged ~193 mm spring ET and ~ 600 mm summer ET) that dry the soil and disconnect lateral fluxes in the forested hillslope, leading to soil moisture patterns resembling vegetation patches. Conversely, a dry winter prior to a wet summer results in soil moisture increases due to high rainfall and low ET during the spring (spatially averaged 78 mm ET and 232 mm rainfall) and summer period (spatially averaged 147 mm ET and 247 mm rainfall) which promote lateral connectivity and soil moisture patterns with the signature of terrain curvature. An opposing temporal switch between infiltration and saturation excess runoff is also identified. These contrasting responses indicate that the inverse relation has significant consequences on hillslope water availability and its spatial distribution with implications on other ecohydrological processes including vegetation phenology, groundwater recharge and geomorphic development. Results from this work have implications on the design of hillslope experiments, the resolution of hillslope scale models, and the prediction of hydrologic conditions in ponderosa pine ecosystems. In addition, our findings can be used to select future hillslope sites for detailed ecohydrological investigations. Further, the proposed methodology can be useful for predicting responses to climate and land cover changes that are anticipated for the southwestern United States.
ContributorsMahmood, Taufique Hasan (Author) / Vivoni, Enrique R. (Thesis advisor) / Whipple, Kelin X. (Committee member) / Shock, Everett (Committee member) / Heimsath, Arjun M. (Committee member) / Ruddell, Benjamin (Committee member) / Arizona State University (Publisher)
Created2012
Description
As the world’s population exponentially grows, more food production is required. This increasing food production currently has led to the un-sustainable production of chemical fertilizers and resultant overuse. A more sustainable option to enhance food production could be the use of fertilizer derived from food waste. To address this, we investigated the possibility of utilizing a fertilizer derived from food waste to grow hydroponic vegetables. Arugula (Eruca sativa) ‘Slow Bolt’ and lettuce (Lactuca sativa) ‘Cherokee’ and ‘Rex’ were cultivated using indoor deep-flow hydroponic systems at 23 ºC under a photosynthetic photon flux density of 170 µmol∙m−2∙s−1 with an 18-hour photoperiod. Plant nutrient solutions were provided by food waste fertilizer or commercial 15:5:20 NPK fertilizer at the identical electrical conductivity (EC) of 2.3 mS·cm–1. At the EC of 2.3 mS·cm–1, chemical fertilizer contained 150 ppm N, 50 ppm P, and 200 ppm K, while food waste fertilizer had 60 ppm N, 26 ppm P, and 119 ppm K. Four weeks after the nutrient treatments were implemented, compared to plants grown with chemical fertilizer, lettuce ‘Rex’ grown with food waste fertilizer had four less leaves, 27.1% shorter leaves, 68.2% and 23.1% less shoot and root fresh weight, respectively. Lettuce ‘Cherokee’ and arugula grown with food waste fertilizer followed a similar trend with fresh shoot weights that were 80.1% and 95.6% less compared to the chemical fertilizer, respectively. In general, the magnitude of reduction in the plant growth was greatest in arugula. These results suggest that both fertilizers were able to successfully grow lettuce and arugula, although the reduced plant growth with the food waste fertilizer in our study is likely from a lower concentration of nutrients when we considered EC as an indicator of nutrient concentration equivalency of the two fertilizer types.
ContributorsCherry, Hannah Nichole (Author) / Park, Yujin (Thesis director) / Penton, Ryan (Committee member) / Chen, Zhihao (Committee member) / Environmental and Resource Management (Contributor, Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
As threats to Earth's biodiversity continue to evolve, an effective methodology to predict such threats is crucial to ensure the survival of living species. Organizations like the International Union for Conservation of Nature (IUCN) monitor the Earth's environmental networks to preserve the sanctity of terrestrial and marine life. The IUCN Red List of Threatened Species informs the conservation activities of governments as a world standard of species' risks of extinction. However, the IUCN's current methodology is, in some ways, inefficient given the immense volume of Earth's species and the laboriousness of its species' risk classification process. IUCN assessors can take years to classify a species' extinction risk, even as that species continues to decline. Therefore, to supplement the IUCN's classification process and thus bolster conservationist efforts for threatened species, a Random Forest model was constructed, trained on a group of fish species previously classified by the IUCN Red List. This Random Forest model both validates the IUCN Red List's classification method and offers a highly efficient, supplemental classification method for species' extinction risk. In addition, this Random Forest model is applicable to species with deficient data, which the IUCN Red List is otherwise unable to classify, thus engendering conservationist efforts for previously obscure species. Although this Random Forest model is built specifically for the trained fish species (Sparidae), the methodology can and should be extended to additional species.
ContributorsWoodyard, Megan (Author) / Broatch, Jennifer (Thesis director) / Polidoro, Beth (Committee member) / Mancenido, Michelle (Committee member) / School of Humanities, Arts, and Cultural Studies (Contributor) / School of Mathematical and Natural Sciences (Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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
The Salt River wild horses are a historic population of unbranded, unclaimed, wild and free-roaming horses, that were born in the wild and merit protection within our National Forest and protection of the Wild Horse and Burro act of 1970. Terms like undomesticated or feral are thrown around in place of “wild”. The past couple of decades or so, there has been an ongoing debate about the current state of the horses on the range. The horses that are along the Salt River, are considered to be state protected and not federally protected, which has sparked a vast discussion on the social, ethical and moral aspects. There has been an overabundance of horses on the range and are causing potential issues to the environment and other farmland. According to the BLM, wild horse and burro populations have a demonstrated ability to grow at 18-20 percent per year. With the widespread and overabundance that is occurring with the horses and burros, it has been said to have a great ecological cost on the rangeland ecosystem by overgrazing native plants, exacerbating invasive establishment and out-competing other ungulates like cattle. Overabundant free-roaming horse and burro populations have large and growing economic and ecological costs for the American public. Without effective management actions, horse and burro populations will double within the next 4-5 years. In this project, with the help of Dr. Julie Murphree, the Salt River Horse Management group and Arizona’s State Liaison for the Department of Agriculture, I conducted various ride-a-longs and conducted my own literature study to further solidify the knowledge I gained when navigating through the Salt River Wild Horse Management group. I can use their data as well as my own observations in the field to catalog their behaviors and look for any signs that would give reason to why this method of population control may or may not be used. I was able to note the horses in their “natural state” which would give me the opportunity to see any behavior changes in various population groups (or otherwise known as Bands). The main objective of this paper is to understand PZP as a population control tool and the effect it has on the Salt River Horses in Arizona.
ContributorsRendon, Chyna (Author) / Murphree, Julie (Thesis director) / Saul, Steven (Committee member) / Barrett, The Honors College (Contributor) / College of Integrative Sciences and Arts (Contributor)
Created2022-05
Description
Evaluations of chemical energy supplies for redox reactions used by chemotrophs in water-rock hosted ecosystems are often done separately from evaluations of chemotroph diversity. However, given that energy is a fundamental and unifying parameter for life, much can be gained by evaluating chemical energy as an ecological parameter of water-rock hosted ecosystems. Therefore, I developed an approach that combines evaluation of chemical energy supplies with 16S and 18S rRNA gene amplicon sequencing. I used this approach to assess drivers of microbial distribution, diversity and activity in serpentinized fluids of the Samail Ophiolite of Oman and in hot springs in Yellowstone National Park.
Through the application of the approach, microbiological interactions in serpentinized fluids were found to be more complex than anticipated. Serpentinized fluids are hyperalkaline and pH is often considered the driving parameter of microbial diversity, however hydrogenotrophic community composition varies in hyperalkaline fluids with similar pH. The composition of hydrogenotrophic communities in serpentinized fluids were found to correspond to the availability of the electron acceptor for hydrogenotrophic redox reactions. Specifically, hydrogenotrophic community composition transitions from being dominated by the hydrogenotrophic methanogen genus, Methanobacterium, when the concentration of sulfate is less than ~10 μm. Above ~10 μm, sulfate reducers are most abundant. Additionally, Methanobacterium was found to co-occur with the protist genus, Cyclidium, in serpentinized fluids. Species of Cyclidium are anaerobic and known to have methanogen endosymbionts. Therefore, Cyclidium may supply inorganic carbon evolved from fermentation to Methanobacterium, thereby mitigating pH dependent inorganic carbon limitation.
This approach also revealed possible biological mechanisms for methane oxidation in Yellowstone hot springs. Measurable rates of biological methane oxidation in hot spring sediments are likely associated with methanotrophs of the phylum, Verrucomicrobia, and the class, Alphaproteobacteria. Additionally, rates were measurable where known methanotrophs were not detected. At some of these sites, archaeal ammonia oxidizer taxa were detected. Ammonia oxidizers have been shown to be capable of methane oxidation in other systems and may be an alternative mechanism for methanotrophy in Yellowstone hot springs. At the remaining sites, uncharacterized microbial lineages may be capable of carrying out methane oxidation in Yellowstone hot springs.
Through the application of the approach, microbiological interactions in serpentinized fluids were found to be more complex than anticipated. Serpentinized fluids are hyperalkaline and pH is often considered the driving parameter of microbial diversity, however hydrogenotrophic community composition varies in hyperalkaline fluids with similar pH. The composition of hydrogenotrophic communities in serpentinized fluids were found to correspond to the availability of the electron acceptor for hydrogenotrophic redox reactions. Specifically, hydrogenotrophic community composition transitions from being dominated by the hydrogenotrophic methanogen genus, Methanobacterium, when the concentration of sulfate is less than ~10 μm. Above ~10 μm, sulfate reducers are most abundant. Additionally, Methanobacterium was found to co-occur with the protist genus, Cyclidium, in serpentinized fluids. Species of Cyclidium are anaerobic and known to have methanogen endosymbionts. Therefore, Cyclidium may supply inorganic carbon evolved from fermentation to Methanobacterium, thereby mitigating pH dependent inorganic carbon limitation.
This approach also revealed possible biological mechanisms for methane oxidation in Yellowstone hot springs. Measurable rates of biological methane oxidation in hot spring sediments are likely associated with methanotrophs of the phylum, Verrucomicrobia, and the class, Alphaproteobacteria. Additionally, rates were measurable where known methanotrophs were not detected. At some of these sites, archaeal ammonia oxidizer taxa were detected. Ammonia oxidizers have been shown to be capable of methane oxidation in other systems and may be an alternative mechanism for methanotrophy in Yellowstone hot springs. At the remaining sites, uncharacterized microbial lineages may be capable of carrying out methane oxidation in Yellowstone hot springs.
ContributorsHowells, Alta Emily Gessner (Author) / Shock, Everett (Thesis advisor) / Collins, James (Committee member) / Anbar, Ariel (Committee member) / Cadillo-Quiroz, Hinsby (Committee member) / Arizona State University (Publisher)
Created2020