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- Creator:
- Yoder, Sean C.
- Description:
- The genus Mycobacterium is commonly associated with diseases such as leprosy, tuberculosis and other pulmonary infections. Mycobacterium avium is increasingly identified as a cause of disseminated disease in AIDS patients. A need for a better understanding of possible sources and routes of transmission of this organism is necessary. This study firc
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Biology
- Creator:
- Traugh, Courtney
- Description:
- California chaparral shrubs have developed different life history types that are categorized by response to fire disturbance and that include sprouting (S) and non-sprouting (NS) species. Plants that resprout after fire (S) use carbon stored in roots and a specialized root structure termed a lignotuber to produce shoots. In contrast, non-sprouting plants (NS) are killed by fire and establish in the post-fire environment through the recruitment of seedlings from a fire-cued seed bank. Previous studies have found that NS have greater cavitation resistance than S, presumably because they must survive the hot dry summers characteristic of the Mediterranean-type climate of California at the seedling stage of development in an open-canopy environment when rooting depth is limited. The focus of this study was to examine tradeoffs between root and stem water stress resistance, carbohydrate storage capacity, and biomechanics of six evergreen NS and S species of shrubs. I predicted that S would have increased storage at the cost of reduced biomechanics and stress tolerance and that NS would have traits associated with increased water stress resistance and biomechanics at the cost of decreased storage. Carbohydrate storage was estimated by the percentage of starch during the fall and the percentages of total non-structural carbohydrates which includes starch, sucrose and glucose. Mechanical strength was estimated using xylem density and water stress resistance was estimated using cavitation resistance. Tradeoffs between traits were analyzed as correlations between traits. There were no differences in storage, xylem density, or cavitation resistance between NS and S. Among all species, there were no trade-offs between water stress resistance and biomechanics or between carbohydrate storage and biomechanics; however, there was a trade-off between carbohydrate storage and resistance to cavitation. The results suggest that allocation differences between NS and S are not strong determinants of stem and root xylem function. Other tradeoffs may be more important such as differences in growth or reproductive investment.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Metz, Mark A.
- Description:
- Two syrphine flies (Diptera: Syrphidae) were studied to measure the possible difference in the abdominal color pattern variation of sternites 2-5. Toxomerus marginatus, a non-mimetic syrphine, shows much more variation in its abdominal color pattern than Ch,ysotoxum derivatum, a high fidelity syrphine mimic of vespid wasps. Chrysotoxum derimtum also showed stability of its abdominal color pattern with little heterogeneity of abdominal color pattern types. It is assumed that organisms under strong selection pressure for a phenotypic character will show a narrow range of phenotypes for that character in a population. This study demonstrates that the homogeneity of the mimetic abdominal color pattern of Chrysotoxum derivatum is probably due to discriminatory visual predation.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Biology
- Creator:
- McFaddin, Joe
- Description:
- The position of the United States as a global leader in science and technology is being undermined, not by out-competing nations, but by the waning development of domestic science talent (NSB 2002; NSB 2003). Even though demand for professionals in science fields will outpace many other career fields (Dohm and Schniper 2007; NSB 2010), there is a projected shortfall of educated professionals resulting from low enrollment in science-based college programs (NSB 2002) and the problem is further compounded by large numbers of science and engineering retirees in the coming decade (NSB 2002). Also, United States students have not exhibited the best performance in core science subjects when compared internationally (Gonzales et al. 2008; Baldi et al. 2007) and domestic programs have not produced consistent improvements in science proficiency (Rampey et al. 2009). Science Technology Engineering and Math (STEM) initiatives are increasingly becoming perceived as a remedy for promoting early development in STEM-fields and increasing student preparation for entrance into STEM-related degree programs. Upon receiving a large amount of federal and corporate sponsorship, the Taft College STEM Program was initiated in 2009 and began outreach and associated program development within the Taft College campus as well as at K12 schools in the College’s service area. The Mobile Science Center (MSC) was conceived as an innovative tool that would house a Mobile Mission Command Center for the Goldstone Apple Valley Radio Telescope (GAVRT). While physics-based curriculum was prepared for engaging students in the use of the GAVRT, additional curriculum was developed for promoting learning in other STEM-subjects. Two modules, Forensic Science and Alternative Energy, were developed for implementation in local K-12 programs. This paper highlights the development and implementation of STEM curriculum for the MSC and includes an assessment of the effectiveness of STEM curriculum implementation in two test groups from Lincoln Junior High School and Taft College. In general, initial results do not support an improvement in student performance as determined by pre-post test analysis (Taft College p=0.19; Lincoln Junior High School p=0.053); however, there were indicators that future implementation has a high potential to yield positive measurable outcomes. 1
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Hernandez, Trang Manny
- Description:
- There is a possibility to eradicate infectious diseases with antibiotics. However, new infectious diseases are continually being identified and some known pathogens are again becoming a threat because of antibiotic resistance. Amphibians mostly live in a moist environment which is the best condition for the growth of bacteria and fungi as well. Antimicrobial peptides produced by serous glands in the amphibian skin play a key role in limiting microbial growth and preventing infections with pathogenic microorganisms. In addition to the antimicrobial peptides produced by serous glands, microbial symbionts on the bullfrog skin are also a source of antimicrobial peptides that can protect the amphibian against diseases. In this research, we investigated whether cutaneous bacterial species isolated from Rana catesbeiana (North American Bullfrog), an amphibian species that is resistant to chytridiomycosis, produce secondary metabolites that could be used to inhibit the growth of three species of dermatophytes (Microsporum gypseum, Epidermotphyton floccosum, Trichophyton mentagrophytes) which are known to cause skin infections in humans. The isolated bacterial species from R. catesbeiana may be useful as producers of antifungal metabolites that kill, or inhibit the growth of, dermatophytes known to cause topical or subdermal skin infections in humans.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Lewis, Ryan D.
- Description:
- Purpose of the Study: The endangered Sonoma County population of the California tiger salamander, Ambystoma californiense, undergoes migrations between breeding pools and upland dry-season refugia. Orientation in this species during breeding migrations has been addressed minimally in previous studies, and literature is particularly sparse concerning newly metamorphosed juveniles. Previous works have not addressed the ability of metamorphs to orient or the way in which they search for upland refugia. The purpose of this study is to evaluate if California tiger salamander metamorphs can re-orient during initial migration and if search movements constitute a Correlated Random Walk. Procedure: We evaluated fine scale movements of newly metamorphosed California tiger salamanders as they moved away from breeding pools, by capturing salamanders with a drift fence. Metamorphs received different orientation treatments, and subsequent movement was tracked with fluorescent powder. We measured turning angles and step lengths at each segment of the tracks, and compared the effect of different treatments. Findings: Here we show that newly metamorphosed juveniles can re-orient to their upland migration path after being interrupted and disoriented. Further, we demonstrate that while searching for burrow refugia, metamorph movement is a correlated random walk. Conclusions: The initial migration from natal pools to uplands following metamorphosis has been identified as a crucial life history juncture for the persistence of this species. Our findings show that these migrations are directed by some orientation, and that these movements are not random. The presence of a Correlated Random Walk is consistent with search patterns in many vertebrates.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Grimes, Adam John
- Description:
- The blunt-nosed leopard lizard (Gambelia sila) is a federally and state-listed endangered species, endemic to the San Joaquin Valley, Carrizo and Elkhorn Plains, and Cuyama Valley of central California. Habitat degradation has had a profound impact on the historic distribution and population size of G. sila. Although recognition of G. sila as a distinct species has been questioned by some authors (e.g., Cope 1900, Smith 1946), it is currently recognized as a full species separate from the wide-ranging long-nosed leopard lizard (G. wislizenii); however, genetic support for the specific status of G. sila is lacking. Furthermore, the genetic identity of leopard lizards in the purported hybrid zone between these two species in the Cuyama Valley in Santa Barbara and Ventura counties has not been evaluated using modern molecular techniques. Understanding the genetic identity of leopard lizards in the Cuyama Valley has practical as well as systematic implications. I investigated the sister taxon relationship of G. sila and G. wislizenii using 603 base pairs of sequence from the mitochondrial cytochrome oxidase III (CO3) gene from 37 individuals representing the two species sampled from various populations in western North America. Phylogenetic analysis revealed 17 haplotypes that are partitioned into two major clades that correspond to the range of G. sila and that of G. wislizenii haplotype groups, thus supporting the recognition of both lizards as distinct species. Additionally, I sequenced 682 base pairs of the mitochondrial cytochrome oxidase b (cyt b) gene from 34 individuals representing six populations of G. sila, including lizards from a remnant hybrid population. Phylogenetic analysis indicated that the cyt b sequences consisted of 18 haplotypes that are partitioned into three geographic clades: northern, central, and southern. All lizards from the Cuyama Valley exhibited the G. sila mitochondrial DNA signature and formed the "southern" clade that was joined as a sister group to the "central" clade. My morphological analysis placed some leopard lizards from the hybrid zone with true G. sila, whereas some aggregated with G. wislizenii, indicative of hybrid status. However, genetic signatures suggest that all lizards in the hybrid zone are true G. sila, and not hybrids.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Tennant, Erin Nicole
- Description:
- The Tipton kangaroo rat (Dipodomys nitratoides nitratoides), is an endangered subspecies of the San Joaquin Valley kangaroo rat, found in the Tulare basin of the San Joaquin Valley. Dipodomys n. nitratoides and the larger Heermann’s kangaroo rat (Dipodomys heermanni) are often found sympatrically throughout the San Joaquin Valley. However, potential competitive interactions and the nature of population fluctuations between these two species are largely unknown. Because I thought that D. heermanni could be negatively affecting a translocated population D. n. nitratoides on Allensworth Ecological Reserve, Tulare County, California, I initiated a study on potential competitive interactions between these two species. In this study my objectives were to (1) determine whether the presence of D. heermanni affects space use and foraging behavior of D. n. nitratoides and (2) compare D. n. nitratoides abundance and population trends between areas with and without D. heermanni. I found that in an exclusion area where D. heermanni were removed, D. n. nitratoides increased exponentially since the start the study, whereas on a control site with both species, D. n. nitratoides decreased significantly. My results suggest that D. heermanni are competitively depressing a population of translocated D. n. nitratoides on the study site. Furthermore, eliminating competitive effects of larger, coexisting species during reintroduction or translocation efforts for D. n. nitratoides may be an important factor in success. To further test optimal translocation and reintroduction methods for protected kangaroo rats in the San Joaquin Valley, possibly an important conservation strategy, I translocated the group of non-protected D. heermanni that was removed from the exclusion area during the competitive interactions part of my study. During this part of my research, my objective was to determine whether soft-release methods, which involve a 30-day acclimation period in a wire mesh cage, help to improve survivorship of translocated kangaroo rats. My results indicated that hard-released individuals had higher survivorship than soft and semi soft- released individuals. I believe that one of the factors that may have contributed to the success of hard-released individuals was the high number of available burrows on the translocation site, often not found at sites, which provided refugia for translocated individuals. ii
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Keldgord, Heather Elayne
- Description:
- Rhus ovata is an evergreen shrub species that is common to low elevations in southern California. This species is subdioecious, i.e. some individuals are functionally females and produce fruit while others are functionally male and produce flowers with pollen. I hypothesized that because female plants allocate greater resources to reproduction through the formation of both flowers and fruit, female plants have fewer resources available for vegetative growth, survival, and defense. Therefore, I predicted that female plants would be smaller and less competitive. I sampled Rhus ovata populations at six sites across a rainfall gradient (221mm/yr to 701 mm/yr) and predicted that populations would be male dominated at drier sites because of their greater stress tolerance. At each site I measured the ratio of male to female plants within the sampled population. For a subset of individuals at each site, I measured crown size, stem tissue density, specific leaf area, reproductive investment, and distance to the nearest neighbor. As expected, female plants had greater total reproductive investment although the amount of investment was highly variable and females exhibited more variability than males. However, this differential reproductive investment did not lead to sexual size dimorphism. Ratios of functional male plants to functionally female plants differed among sites, but these differences were not correlated with rainfall and across sites the ratio of males to females did not significantly differ from a one to one. Plasticity in allocation to reproduction among females in this long-lived woody species may mitigate reproductive costs and reduce sexual dimorphism.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Atwood, Robert Christopher
- Description:
- Opuntia basilaris Engelm. & Bigelow var. treleasei (J.M. Coult.) Toumey (OBT), commonly known as Bakersfield cactus, is endemic to parts of Kern County, California. O. b. var. treleasei is one of four varieties of Opuntia basilaris and is state and federally listed as endangered (USFWS 1990). The purpose of this study was to assess the genetic differentiation between OBT and Opuntia basilaris var. basilaris (OBB), and within and among populations of OBT throughout its range. Samples were collected from 200 individual plants representing 32 populations of OBT and one population of OBB and were analyzed using amplified fragment length polymorphisms (AFLP). The AFLP protocol was successfully used to differentiate between an outgroup population of OBB and the great majority of the sampled populations of OBT using 195 polymorphic fragments. Two dendrograms were created using unweighted pair group method with arithmetic mean (UPGMA); one for all individuals and the other where each population was treated as a discreet unit. In the dendrogram based on all individuals, most samples did not cluster as distinct geographic populations, suggesting little genetic differentiation, due to a partial or complete restriction of gene flow, among the majority of OBT populations. Extensive genetic variation was found within and among OBT populations based on an analysis of molecular variance (AMOVA). Twenty three percent of the genetic differentiation was found among fragmented populations and 77%from within individuals of OBT populations suggesting that genetic variation exists between individuals within the OBT populations analyzed. In the UPGMA diagram by population, all five of the Wheeler Ridge populations clustered together. Moreover, three of the Wheeler Ridge populations formed a distinct cluster in a principal coordinates analysis (PCoA) suggesting some level of genetic structure among OBT populations. The only population with a large sample size where virtually all representative samples grouped together was for ‘OEO2’, which is located in the eastern portion of the Southern San Joaquin Valley. The results of this population genetics study will likely be useful in the conservation management of this endangered taxon.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Castaneda, Alejandro Realivazquez
- Description:
- The purpose of this study is to investigate the level of genetic divergence among populations of Vaejovis confusus in the southern San Joaquin Valley and across the state of California. Although there has been considerable research to measure genetic variation among and within scorpion species, little work has been done to investigate the impact of anthropogenic factors on genetic variation within populations. Anthropogenic factors such as man-made barriers can fragment populations and may serve as mechanisms of reproductive isolation. Particularly in the southern San Joaquin Valley, vast arrays of canals and artificial channels have been constructed to divert water from the Kern River for agricultural purposes. In the southern San Joaquin study, the level of genetic divergence is examined in a fragmented population as a result of an anthropogenic barrier, the California Aqueduct, at Coles Levee Ecosystem Preserve. Sequencing of the mitochondrial 16S ribosomal RNA gene in 20 Vaejovis confusus individuals of each fragmented population was performed. Neighbor-joining and maximum parsimony analysis of DNA sequences elucidated the level of genetic divergence. For comparison, an identical analysis was performed across a natural barrier, the Kern River at the Panorama Vista Preserve, which has separated Vaejovis confusus populations for a much longer period of time. The results of this study showed the presence of five haplotypes at the Coles Levee Ecosystem Preserve, with three haplotypes common to both sides of the California Aqueduct. Similarly at Panorama Vista Preserve, five haplotypes were found, with two haplotypes shared at both field sites across the Kern River. These results indicate that scorpion populations across the California Aqueduct and Kern River are not genetically partitioned, despite the isolating effect of these barriers. The existence of the California Aqueduct for over 50 years is not enough time to cause genetic divergence among fragmented populations. The occasional drying of the Kern River may promote gene flow between the populations or amount of time after reproductive isolation may be insufficient to cause evolutionary divergence between the two populations. In the California analysis the mitochondrial 16S rRNA gene is examined in 22 individuals from 9 counties to determine the effects of isolation by distance on the geographic-genetic structure of Vaejovis confusus populations. Scorpions were obtained from a collection of samples from the California Academy of Sciences, San Francisco. Neighbor-joining and maximum parsimony analyses were used to resolve the level of evolutionary relatedness among the populations of Vaejovis confusus throughout California. Fourteen haplotypes were found in this analysis. Eleven haplotypes were unique to their field site, whereas three were common across the state across large geographic distances (approximately 350 miles). Mitochondrial markers found high genetic variation (9.6%) in this species. Nearly half (154/325) of pairwise distance comparisons showed a 2.0% or higher sequence divergence and supported an overall isolation by distance effect. The occurrence of three haplotypes across the state results in a weak association between geography and genetic structure of V. confusus. Notably however, there is some geographic partitioning between haplotype D common in western California and haplotypes A and C common in eastern California. However, the overall lack of genetic partitioning with respect to geography among the California populations is likely due to an insufficient amount of elapsed time to promote genetic differentiation.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Hayes, Christine C.
- Description:
- The phorid fly genus Apocephalus is the largest assemblage of ant-parasitizing Phoridae. Apocephalus is currently organized into two subgenera: A. (Apocephalus) and A. (Mesophora). The species of A. (Mesophora) attack a wide variety of non-ant hosts including stingless bees, spiders, wasps, bumble bees, and cantharoid beetles. The species of A. (Apocephalus) are the true “ant-decapitating flies” and are divided into six species groups: the A. attophilus group (parasitoids of attine leaf-cutting ants), “A. miricauda group” (parasitoids of ponerine ants), A. pergandei group (parasitoids of Camponotus carpenter ants), A. mucronatus group, A. feeneri group, and A. grandipalpus group. Here I report on a preliminary molecular phylogenetic study of Apocephalus, including representatives of both subgenera and exemplars of five currently recognized species groups. Maximum parsimony, maximum likelihood, and Bayesian phylogenies were inferred using four nuclear (AK, TPI, CAD, 28S) and four mitochondrial (12S, 16S, COI, ND1) gene fragments (4284 bp total). For all analyses Apocephalus was recovered as a monophyletic group relative to the outgroup taxa included in the study. In addition, subgenus A. (Mesophora) was recovered as a monophyletic group, but was not a sister group to the subgenus A. (Apocephalus).A phylogenetic hypothesis for exemplars of five Apocephalus species groups is presented and compared to hypotheses based on morphology.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Duquette, Marc Roland
- Description:
- With over 1,300 known species, the genus Megaselia Rondani is the largest phorid genus, largely the result of high cryptic diversity and a past tendency for researchers to lump species into the genus that defied convenient classification. For many of these species, little information is available beyond one or two morphological characters. The first molecular study of such a species, Megaselia sulphurizona Borgmeier, is presented here. New sequence data from two mitochondrial loci (cytochrome oxidase, COI; NADH 1 dehydrogenase, ND1) for a total of 792 bp were obtained from 22 M. sulphurizona specimens collected from four populations in California, plus 12 other phorid taxa using standard DNA extraction and PCR techniques. Neighbor-joining, maximum likelihood, and maximum parsimony analyses revealed M. sulphurizona to be a cryptic species complex, constituting three distinct species in the Riverside, Monrovia, and Bakersfield/Tehachapi areas. These findings suggest greater cryptic diversity within M. sulphurizona, and have broader implications for phorid biodiversity.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Blackhawk, Nicole Cherri
- Description:
- The Giant Kangaroo Rat (Dipodomys ingens) is a federally and state-listed endangered species, endemic to the San Joaquin Valley, Carrizo and Elkhorn Plains, and the Cuyama Valley. Populations of the endangered Giant Kangaroo Rat (Dipodomys ingens) have decreased over the past 100 years because of habitat fragmentation and isolation. Changes in the population structure that can occur due to habitat fragmentation can significantly affect the population size and the dispersal of these animals. Dr. David Germano and I collected small ear clippings from male and female Giant Kangaroo Rats from six sites along the southern San Joaquin Valley to determine the genetic population structure of this species in this part of their range. We predicted that geographic distance and isolation of populations would decrease genetic relatedness compared to populations closer together. Having a better understanding of the genetic structure in this species will help with conservation actions, such as translocating individuals within the range of the species. These data were compared to published estimates of genetic diversity of Giant Kangaroo Rats in the Carrizo Plain to the west and the Panoche area to the north, the other large population centers of this species.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- MacKinnon, Evan D.
- Description:
- Non-native grass invasion is a major concern for land management and native plant conservation. In the southern San Joaquin Valley of California, human-disturbed environments that are heavily invaded by non-native grasses often contain some native annual species. These “weedy” native species apparently have the functional traits and life history characteristics to compete and persist in disturbed and invaded landscapes. We categorized several native plants into either a weedy or non-weedy habit based on several criteria, and confirmed this habit designation using a field trial where we controlled for other factors likely to influence species abundance under field conditions. We then measured functional traits for a group of five non-weedy species that occur locally but are not abundant in invaded areas, to a group of four weedy plant species that included the invasive grass red brome. We hypothesized that a suite of functional traits would define the weedy plant habit. We examined this hypothesis in a specific community, where we compared functional traits between weedy and non-weedy plant habits, and between native species and red brome. A principal components analysis (PCA) identified three distinct ecological clusters among the analyzed species (weedy native forbs, non-weedy native forbs, and grasses), and suggested the presence of a weedy functional type. Weedy species were different from non-weedy species in several traits (larger leaf area investment, larger root biomass allocation, heavier diaspores, and dormant seeds requiring cold-stratification for germination). The PCA suggested complementarity as an explanation for the co-occurrence of weedy native species and red brome, but individual trait similarities and a competition experiment suggested that competition can occur for some resources. Further understanding of the traits shared among weedy native plant species may lead to cost-effective approaches to restoring invaded landscapes.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Turnbull II, John
- Description:
- Examination of fish skeletal remains from archaeological sites serves both archaeological and biological interests. For archaeologists, it can establish the role of fish consumption in a people’s diet, provide clues to their fishing technology and overall maritime capability, and even suggest movement patterns and settlement (Rick et al. 2001, Erlandson et al. 2008, Des Lauriers 2010). Analysis of fish bones from excavations on San Miguel Island, of the southern California coast, suggested use of boats and early evidence of hook-and-line fishing techniques, concurrent with an estimate that fish comprised over 50% of the edible meat for the early islanders (Rick et al. 2001). Fishbone identifications have contributed to determining where early Paleocoastal peoples settled, to indicating occupation in some areas earlier than previously thought, and to suggesting that at least some southward Pacific coastal migration in North American may have been by sea (Erlandson et al. 2008). For ichthyologists, identifications of fish remains provide a historical or prehistorical survey of fishes in an area, and with comparison to modern surveys of those same areas, provide bases for examining fish distribution, fish diversity, and marine habitats over time (Gobalet 2000, Salls 2000, Erlandson et al. 2008). In supporting Point Conception, California, as a landmark for a marine faunal break, Gobalet (2000) compared the distribution of fishes identified from the archaeological record to their current distributions. Salls (2000) used bone identifications from archaeological sites on Southern California’s San Clemente Island to describe probable offshore habitats for as early as 9,000 calendar years before the present (cal BP). For over a decade, archaeological excavations on Cedros Island, which lies off the Pacific coast of the Baja California peninsula, have unearthed evidence of early colonization in the Cedros area, with implications for Paleo-human migrations (Des Lauriers 2010). Unfortunately, no on-site scientific survey of the fishes or marine habitats at Cedros Island has been published against which to compare fishbone analysis, but modern surveys of the waters close to Cedros Island exist and can be useful. Regarding habitats, Quast (1968), Engle (1993), and Bond et al. (1999) represent influential earlier studies that established the use of fish species associated with specific habitats. More recent marine faunal surveys that included the Cedros marine environment (but not specifically Cedros Island) also describe fish assemblages associated with habitats. Stephens et al. (2006) examined such associations for the rocky reef/kelp bed habitats of the southern San Diego Province, as did Pondella II et al. (2005) for the San Benito islands that lie close to Cedros. Allen and Pondella II (2006) provided a comprehensive ecological review of the California coast south to central Baja and identified fish species associations with a wide range of habitats. In this thesis, I report the identifications of fish bones from archaeological excavation sites on Cedros Island. The archaeological investigation indicates the settlement of the area about 12,000 cal BP and the establishment of a society that existed into the 18th century of our current era (CE; Des Lauriers 2005, 2008, 2010). These identifications then are provided to assist this investigation on Cedros in its efforts to better understand the Cedros islanders and to lend some insight as to the types of fishes they harvested and the predominant habitats those fishes represented.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Madsen, Angela
- Description:
- Ecological interactions can vary in strength depending on environmental conditions. The outcomes of these interactions are often dependent on the abiotic environment, but can also depend on the presence of other biotic species, including mutualists, which can further alter these effects due to trade-offs in nutrient allocation for multiple interactions. For example, some plants produce extrafloral nectar, a specialized nectar used to attract ants that will defend the plant against herbivory. If plants with extrafloral nectaries also have a second mutualistic relationship with the soil bacteria rhizobia, this second mutualism has been shown to alter the attraction of ants to the extrafloral nectar of the plant. This change in ant attraction could be caused by changes in nectar production or nectar composition, although the exact reason is unknown. Plants do alter extrafloral nectar production and composition for other reasons, for example if a plant is experiencing herbivory the plant will increase the quantity of the extrafloral nectar which will attract more ants. What is not well understood is what specific changes to the nectar, if any, cause it to become more attractive or if the attraction is simply due to a higher quantity of the extrafloral nectar. In my thesis research I explored how the chemical composition of extrafloral nectar, specifically nectar quantity and sugar, is affected by rhizobia mutualists, soil nutrients, and herbivory. Moreover, I explored how these changes influence the ant community and herbivorous arthropod community, as well as plant traits and overall fitness of the Vicia faba plant and its associated mutualistic rhizobia. I tested the effects of these factors through a series of greenhouse and field experiments, running the extrafloral nectar through a total carbohydrate assay to quantify carbohydrate (i.e. sugar) content. I found that under most conditions, the composition of the extrafloral nectar remained constant. However, when plants associated with the soil bacteria rhizobia, the rhizobia mutualism caused a decrease in sugar content in extrafloral nectar but increased the overall quantity of extrafloral nectar produced when outside of herbivory pressure. The reason for this could be due to limited resources, as the plant has a finite amount of carbon and has to allocate this carbon to both the extrafloral nectar and to rhizobia. This need for resource allocation and the altered quantity and composition of extrafloral nectar had no effect on plant fitness traits nor on ant or arthropod visitation in my study, although so few ants were present that conclusions on ant visitation effects cannot be made. These results allow for other new and exciting questions in plant and insect ecology, such as what effect these resource allocations have on plant competition, growth, fitness, and how it impacts the broader ecological community.
- Resource Type:
- Masters Thesis
- Identifier:
- 10091
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Castro, Viridiana
- Description:
- Transporting water efficiently is one of the chief functions of plant vascular systems. Highly efficient transport is generally beneficial; however, tradeoffs arise because vascular systems have multiple functional roles that interact with one another. One example of a tradeoff may be related to how plants respond to water deficits. Some plants growing in arid and semi-arid environments form xylem networks that are able to tolerate water deficiencies and cope with embolism spread. Distinguishing patterns in embolism spread is important to understand how plants are vulnerable to water stress and what tradeoffs are involved in water stress resistance. Flowering plants found in mediterranean-type ecosystems differ in conduit (vessels and tracheids) presence and abundance. Little is known about how embolism spreads in plant vascular systems and the role tracheids play in the spread of emboli in vessel-bearing plants. I hypothesized that patterns in vessel embolism spread are linked to the type of conduit connections. I assumed that the propagation of embolism most commonly occurs through vessel-to-vessel connections. Therefore, I predicted that the presence of tracheids minimizes embolism spread compared to species with only vessels that have greater numbers of vessel-to-vessel connections. By contrast, greater vessel-to-vessel connections promote greater hydraulic transport efficiency. To test this hypothesis, I quantified embolism spread using computer assisted tomography (microCT) and hydraulic efficiency (hydraulic conductivity per unit xylem area; Ks) in six different species of woody plants that differ in tracheid presence, vessel structure, and hydraulic function. In Chapter 1, I briefly review how plants respond to water stress and what effects have been noticed to occur within their xylem conduits as a result. In Chapter 2, I present microCT, hydraulic efficiency, and percentage loss in conductivity (PLC) results from dehydration treatments for six species native to mediterranean-type climate regions in California, Cercoparpus betuloides, Malosma laurina, and Heteromeles arbutifolia; and the Mediterranean Basin, Laurus nobilis, Olea europaea, and Cistus ladanifer. In Chapter 3, I summarize my findings in the broader context of plant vascular function. My chief conclusion is that the connections between vessels are a key determinant of the tradeoff between hydraulic safety from cavitation and transport efficiency.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Stevens, Samantha K.
- Description:
- Purpose of the Study: The Russian River watershed stretches across a significant portion of Sonoma and Mendocino counties, covering 1,485 square miles, and is home to not only humans, but countless fish and wildlife species as well. The Russian River valley is famous for being an ideal place to grow wine grapes and other agriculture, in part for its fertile soil, as well as the region’s Mediterranean climate. In addition to this, the Russian River is a year-round recreational hotspot for both tourists and locals alike. Maintaining a high quality of water in any area is important, and this is especially true when the local economy relies so heavily upon surface water. According to the North Coast Regional Water Quality Control Board, the entire Russian River watershed is impaired for sediment and temperature, and recent data also show pathogen impairment throughout the watershed. The Laguna de Santa Rosa sub-watershed is also impaired for phosphorus and dissolved oxygen, in addition to the impairments throughout the watershed (Russian River Watershed Overview, 2019). Land uses and water quality are interconnected in the Russian River watershed, but causal patterns between the two are not well understood. Procedure: Water quality data was obtained via the United States Geological Survey (USGS) and input into Microsoft Excel to generate time series graphs of different water quality constituents. The three sites selected are Jimtown, Digger Bend, and Hacienda Bridge. A model from the USGS ScienceBase inventory was utilized for this project, which consists of future land use, land cover, and population projections for the state of California for the period of 2001-2101. This model was projected as a layer in ArcGIS Pro in order to estimate the land cover changes based on low, medium, and high population projections for the years 2050 and 2100. In order to estimate the nutrient input for these different scenarios, models were constructed using WikiWatershed’s Model My Watershed tool. Within Model My Watershed, the land cover was altered to emulate the six models by adding polygons of the desired land cover, running the model, and observing the resulting nutrient and total suspended sediment load output. An additional aspect of this project is to conduct an analysis of policies. Findings: As land is developed into managed cropland, nutrients are typically added in order to increase production and profit. As a result, the runoff from cropland is typically nutrient rich when infiltration rates are low. Records from the Sonoma County Crop Reports indicate that the acreage of vineyards nearly doubled between 1990 and 2000. The exploration of potential land use and land cover changes through the projection of the USGS ScienceBase layers in ArcGIS and the modeling of nutrient load in Model My Watershed showed both an increase in agricultural land use as well as an increase in nutrient load, which is expected. The data obtained from the USGS Water Quality monitoring site did not show many points of interest or concern and generally followed a seasonal pattern. The policies in place in Sonoma County regulate both point source and non point source pollution, which is an extremely effective way to minimize polluted runoff from entering the streams and river in the Russian River watershed. The federal, state, and county regulations seem to be adequately minimizing point source agricultural pollution, and could benefit from increased riparian vegetative buffer zones to help slow the flow of polluted runoff, increase infiltration, and minimize the amount of nutrients that reach the waterways throughout the watershed. Conclusion: While this project did not result in a definitive answer as to what is causing the most nutrient pollution in the Russian River watershed, based on the findings of project, it is safe to speculate that total loads of suspended sediment, nitrogen, and phosphorus were lower throughout Sonoma County when there was less agricultural land use since the modeling data predicts higher total loads as agricultural land use increases. In addition to an increase in vineyard, the Sonoma County Crop Reports recorded a two - fold increase in the number of cattle in the county between 1990 and 2018.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Phalen, Carol Marie
- Description:
- Paralabrax clathratus, commonly known as the kelp bass, is an important sportfish to the Southern California angler, ranking among the top sportfish on commercial passenger fishing vessels since the 1950's. They commonly occur in a patchy distribution from Monterey Bay, CA to central Baja California, Mexico, preferring a habitat associated with structure. They are broadcast spawners and have the potential for high levels of gene flow during the 28-30 day pelagic larval stage. The purpose of this investigation was to determine the extent of genetic variation of the kelp bass at various locations throughout their range. Seven populations were examined for genetic variation and population subdivision using two variable molecular markers. Restriction fragment length polymorphism (RFLP) of the internal transcribed spacer regions (ITS) of the nuclear ribosomal DNA repeat unit revealed no genetic variation or geographic subdivision. Although direct sequence analysis of the 5' portion of the mitochondrial DNA revealed a high level of genetic variation , no geographic subdivision was detected based on neighbor joining, maximum parsimony, and analysis of molecular variance (AMOVA). These results suggest that a high level of gene flow exist among locations, most likely due to the dispersal of pelagic larvae via prevailing currents, episodic events, and adult movements.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Biology