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Biotic and Abiotic Factors Influencing Population Dynamics of Yellowstone Cutthroat Trout and Utah Chubs in Henrys Lake, Idaho
No full textNegative interactions with nonnative species are a concern for many species including Yellowstone Cutthroat Trout (YCT) Oncorhynchus clarkii bouvieri. In many YCT fisheries, managers are tasked with balancing angler satisfaction and fish conservation. Trying to balance these needs is typified at Henrys Lake, Idaho. Recent surveys have revealed increase in the abundance of nonnative Utah Chubs (UTC) Gila atraria in Henrys Lake. The effect of nonnative UTC on native YCT in Henrys Lake is unknown, but UTC have negatively affected salmonids in other systems. A comprehensive analysis of historical data was conducted to assess long-term trends and identify factors influencing population dynamics of YCT in Henrys Lake. To better understand YCT and UTC interactions, YCT and UTC were radio-tagged in spring 2019 and 2020 to describe their movement and habitat use in Henrys Lake. This research provides insight into possible interactions between YCT and UTC, and provides a comprehensive understanding of factors influencing population dynamics of YCT that can be used to guide management actions.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2021-0
Evaluation of Natural and Hatchery-Produced Kokanee in Flaming Gorge Reservoir, Wyoming-Utah
No full textKokanee Oncorhynchus nerka were first stocked in Flaming Gorge Reservoir (FGR), Wyoming-Utah, in 1963. In a system that uses supplemental stocking to enhance a popular sport fishery, an understanding of the contributions from natural and hatchery-produced fish is critically important so that hatchery resources can be appropriately allocated. The goal of this research was to identify the natal origin (i.e., natural, hatchery) of kokanee in FGR using otolith microchemistry. Return to the creel, composition of spawning aggregates, and growth of kokanee in Flaming Gorge Reservoir were evaluated with a focus on differences associated with natal origin. Kokanee otoliths collected from hatcheries (n = 60) and FGR (n = 1,003) were analyzed for the strontium isotope ratio, 87Sr/86Sr, using laser ablation and a multi-collector inductively coupled plasma mass spectrometer. Kruskal-Wallis tests were conducted to compare the Sr isotope ratios from the otolith edge of kokanee sampled from hatcheries and FGR. Strontium isotope ratios differed for eleven out of twelve hatcheries (Pmasters, M.S., Environmental Science -- University of Idaho - College of Graduate Studies, 2021-1
An Examination of Satellite-Based Cropland Canopy Water Content Maps for Yield Ratio Prediction
No full textWhile difficult to characterize, drought has been defined as a period of water shortage compared to normal conditions. Soil water availability has a larger impact on agricultural productivity than any other abiotic factor. It is critical to develop research which tracks the spatial and temporal patterns of drought as droughts become more frequent and severe, particularly in regions of high agricultural productivity. Traditional drought monitoring indices are based on point measurements of weather conditions from weather station instruments, which increase in uncertainty when extrapolating the measurements to spatially delineate the drought event, especially in data sparse regions. Satellite-based measurements, such as rainfall, evapotranspiration (ET), soil moisture, or vegetation health have increased in use to gap-fill the uncertainty from point-based measurements and increase the scale of drought monitoring. The spatial and temporal requirements for farm-level agricultural monitoring, however, create challenges when implementing remote sensing technology for drought and yield monitoring. The research in this dissertation proposes a transferable method for using moderate resolution satellite imagery in physical-based radiative transfer model (RTM) inversion methods for retrieving cropland canopy water content (CCWC) as a direct indicator of crop water status for predicting yield. The method aims to alleviate the “ill-posed” nature of inversion problem solving by using phenology and crop species a priori information to dynamically constrain the inversion of the RTM, PRO4SAIL, for estimating CCWC at the 30-m pixel level. The 30-m CCWC product is integrated into a framework for predicting drought stress and yield loss by combining a previously published relationship between leaf water content (LWC) and available soil water content (ASWC) with the crop water use definitions outlined in Food and Agriculture Organization (FAO) Irrigation and Drainage paper 56 . The leaf structure parameter (Ns) accounts for a large proportion of uncertainty in PRO4SAIL inversion problems as it is the only biophysical parameter that is not physically measurable. Chapter 1 examined whether there is statistically significant variation in Ns as a function of phenology, crop species type, and water status with the purpose of generating reference values of Ns to be used as a priori information in subsequent research. A total of 230 spectral measurements were taken from three monocotyledon species (hard red wheat, soft white wheat, and upland rice) and one dicotyledon species (soy) over two full growth seasons at the University of Idaho Pitkin’s Nursery. The spectral measurements were used to characterize Ns over phenology, crop species type, and water status. The study demonstrated that a significant relationship exists between phenology and Ns as well as a significant relationship between crop species type and Ns. No significant relationship was found between the water treatments of the study and Ns , providing evidence that water status and Ns are independent.In chapter 2, a novel PRO4SAIL inversion approach was proposed and tested using the Harmonized Landsat-Sentinel (HLS) surface reflectance product to estimate CCWC in wheat, barley, and garbanzo fields outside of Genesee, Idaho over three growing seasons. The inversion strategy used information about phenology and crop species to generate a set of Look-up Tables (LUTs) for each overpass date. A set of 225 leaf measurements were used to train the LUTs, and 102 independent field measurements were used to validate the inversion. The novel crop and time dependent strategy had the best performance when compared to a phenology specific LUT strategy, and single nominal range LUT inversion strategy. The results showed the potential of an operational HLS-based CCWC product which may serve as the basis for further improvement. Chapter 3 presents a study which examines the feasibility of using a satellite derived time series of CCWC to predict the yield ratio in maize, defined as the ratio between actual harvested yield and maximum potential yield. The paper establishes the relationships between CCWC, drought stress, and yield ratio by combining a logistic relationship between LWC and ASWC with FAO-56 definitions of water balance, drought, and yield. Using these definitions, and known relationships between PRO4SAIL biophysical parameters, CCWC, NDVI, and yield ratio were modeled for different treatments of an independent irrigation experiment which created late drought conditions in Inner Mongolia, China. Coincident Landsat-8 Operational Land Imager (OLI) scenes were used to create the PRO4SAIL estimated CCWC and observed NDVI time series. The results demonstrated the first steps towards s farm-level yield ratio prediction using physical-based estimation of CCWC with FAO-56 soil water balance methods. The implications of the study highlight a potential for using CCWC in yield ratio prediction and justify future field-level irrigation treatment research with ground measured yield for testing the CCWC-yield relationship.doctoral, Ph.D., Natural Resources -- University of Idaho - College of Graduate Studies, 2021-1
Particle Density, Particle Size, and Nutrient Distribution of Flushed Dairy Manure
No full textThe handling of large volumes of liquid manure produced by hydraulic flushing systems can be challenging for dairy farmers. The high solid content in flushed dairy manure causes numerous challenges during manure handling, and the high nutrient content limits the amount of manure that can be applied onto cropland. The knowledge of particle density, particle size, and nutrient distribution of flushed dairy manure would allow dairy farmers to select appropriate manure treatment technologies and make better manure nutrient management on their farms. The major goal of this study was to understand the particle density, particle size, and total nitrogen (TN) and total phosphorous (TP) distributions of flushed dairy manure by using four commercial dairies in Southern Idaho as case studies. The study also aimed to examine the statistical significance of using different pore-sized inclined screen separators for solids and nutrients removal from flushed dairy manures of the four dairies. The particle densities of flushed dairy manure solids were determined by the pycnometer method using a methanol medium. A new technique—wet sieving combined with the hydrometer-pipette method—was used to determine the particle size and nutrient distributions of the flushed dairy manures. Nutrient analyses were carried out using the Hach methods: TNT 880 for TN and TNT 845 for TP. The flushed dairy manures of the four dairies differed in the initial total solid as well as nutrient contents with total solids (TS) ranging from 2.23% to 7.69%, TN ranging from 0.08% to 0.19%, and TP ranging from 0.04% to 0.13%. The particle densities of flushed dairy manure solids were found to vary with particle size, and the average particle densities of dried solids in flushed manures of dairies, #1, #2, #3, and #4 were found to be 1.48, 1.39, 1.37, and 1.30 g/cm3, respectively, much lower than the commonly used particle density of soils of 2.65 g/cm3. The distributions of solids and nutrients in flushed dairy manures also varied between the four dairies and were found to be site-specific. However, regardless of the dairy, the majority of TS, TN, and TP in flushed manures were observed at diameters smaller than 0.5 mm. Dairies, #1, #2, #3, and #4 had 63.85%, 58.17%, 57.94%, and 51.50% of TS smaller than 0.5 mm in diameter. Similarly, the percentages of TN and TP observed at diameters smaller than 0.5 mm for dairies, #1, #2, #3, and #4 were 72.00%, 75.14%, 75.76%, and 61.92% and 85.64%, 70.58%, 69.28%, and 61.35%, respectively. The statistical differences between the solid and nutrient removal capacities of different pore-sized inclined screen separators were found to be dairy-specific. From this study, it was estimated that 0.5-mm pore-sized inclined screen separators would remove between 25.41% and 37.40% of TS, 24.24% and 38.08% of TN, and 14.36% and 38.65% of TP from flushed dairy manures with initial TS ranging from 2.23% to 7.69%. This suggests that the inclined screen separators with pore size larger than 0.5 mm would remove only a fraction of total solids, total nitrogen, and total phosphorus from flushed dairy manures, and most of the TS, TN, and TP would remain in the liquid fraction after solid-liquid separation. Therefore, commercial dairies that rely on inclined screen separators with pore sizes larger than 0.5 mm for solid-liquid separation might need to look beyond the 0.5-mm pore-sized screen separators to remove higher quantities of solids and nutrients from their flushed dairy manures.masters, M.S., Water Resources -- University of Idaho - College of Graduate Studies, 2021-0
Genetic Association of Beef Cattle with Fertility and Rangeland Behavior
No full textSelecting for efficient replacement females is a crucial decision for cattle producers. Replacement females need to be reproductively efficient and if the producer pasture grazes their animals, they also need to have efficient rangeland behavior. Genetic associations with important traits can help understand the biology behind the traits and be used to make selection decisions. One study identified genetic associations with cattle fertility traits, antral follicle counts and reproductive tract scores in crossbred heifers. The second study examines cattle rangeland behavior traits, grazing minutes, walking minutes, and maximum slope use while experiencing mild heat stress. In addition, a significant association was identified with the amount of time cows spent on slopes greater than 15 degrees regardless of experiencing heat stress. Identifying the genetic associations can deepen the understanding of the biology behind significant traits as well as enable producers to select for replacement females that will benefit their management strategies.masters, M.S., Animal and Veterinary Science -- University of Idaho - College of Graduate Studies, 2021-0
Neuromodulation Strategies for Controlling Brain Network Plasticity Dynamics
No full textNeuromodulation refers to a broad term for perturbing the brain states using either external electrical stimulation, optical stimulation, a drug, or a combination of all. In recent years, neurostimulation, a paradigm for perturbing the brain states electrically or optically, has emerged as a promising approach for investigating basic neuroscience questions and developing therapies for various brain disorders such as Parkinson’s disease, epilepsy, major depressive disorders, and Alzheimer’s disease. However, most of the existing neurostimulation-based therapies for brain disorders focus on suppressing symptoms and ignore the dynamical aspects of the underlying network that create the pathological symptoms. As a result, the symptoms of specific disorders reemerge once the external stimulation turns off. Based on the evidence of the plastic nature of brain circuits in many areas of the brain, this dissertation investigates novel neuromodulation strategies to achieve long-term changes in the brain states by harnessing brain network’s plasticity. In the first part of this dissertation, a unified multi-timescale computational modeling framework is developed to investigate drug-based neuromodulation strategies for modulating synaptic plasticity dynamics in the hippocampus and basal ganglia circuits for potential applications in developing therapies for stress-mediated brain disorders and Parkinson’s disease. The second part of the dissertation focuses on developing electrical stimulation strategies for controlling synchronization of neuronal activity in large-scale brain networks by harnessing synaptic plasticity for potential applications in suppressing epileptic seizures and pathological synchronization in Parkinson’s disease.doctoral, Ph.D., Chemical and Materials Science Engineering -- University of Idaho - College of Graduate Studies, 2021-0
Production of Wild Bonneville Cutthroat Trout in Bear Lake: Evaluation of a Harvest Fishery
No full textBonneville Cutthroat Trout (BCT) Oncorhynchus clarkii utah is one of fourteen subspecies of Cutthroat Trout Oncorhynchus clarkii and is a species of high ecological and social importance. Bonneville Cutthroat Trout is a species of conservation concern in the states of Idaho and Utah. Bonneville Cutthroat Trout was historically widespread in lentic and lotic systems in the Bonneville basin of Idaho, Nevada, Wyoming, and Utah. During the 1900s, European settlement began in the Bonneville basin and BCT were overexploited in many systems (Behnke and Zarn 1976; Behnke 1992; Lentsch et al. 2000). Additionally, anthropogenic disturbances resulted in an overall loss of suitable habitat for BCT (Lentsch et al. 2000; Teuscher and Capurso 2007; Williams et al. 2009). Overexploitation and loss of habitat for BCT was particularly evident in Bear Lake and its tributaries. Bear Lake is a large, natural, oligotrophic lake located in southeastern Idaho and northern Utah. Four endemic fishes occur in Bear Lake and BCT is the only trout species native to the system. Bonneville Cutthroat Trout in Bear Lake is the only population to follow an adfluvial life history strategy in Idaho (Wurtsbaugh and Hawkins 1990; Behnke 1992; Teuscher and Capurso 2007). Three main spawning tributaries flow into the lake: St. Charles and Fish Haven creeks in Idaho, and Swan Creek in Utah. Nonnative fishes were introduced into the Bear Lake system in the mid 1900s (i.e., Lake Trout Salvelinus namaycush, Brook Trout S. fontinalis, Rainbow Trout Oncorhynchus mykiss) and have likely contributed to the decline in abundance and distribution of BCT. The population of BCT in Bear Lake was considered extirpated by the 1950s (Kershner 1995; Lentsch et al. 2000). In response to the population decline, Utah Division of Wildlife Resources (UDWR) began stocking hatchery BCT in 1973. Additionally, harvest of wild BCT was closed in 1998 and current regulations allow for the daily harvest of two hatchery fish. In the last decade, efforts to improve the population of wild BCT focused on habitat restoration for adfluvial fish in tributaries to Bear Lake. Habitat restoration projects have been largely successful and the proportion of wild BCT in Bear Lake has increased from 5% in 2002 to 70% in 2017. In recent years, a change in harvest regulations to allow for the harvest of wild BCT has been proposed. However, gaining a more comprehensive understanding of the population dynamics and ecology of BCT in Bear Lake and its tributaries is necessary before changes are made to the management of the fishery. Additionally, this research will provide insight on continued habitat restoration efforts and conservation actions. The objectives of my research were to: (1) evaluate ecology and early life history characteristics of BCT in St. Charles, Fish Haven, and Swan creeks; and (2) describe the population dynamics of wild and hatchery BCT in Bear Lake, and evaluate different management options.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2021-0
