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Cold Acclimation Response Of Non-Native Italian Wall Lizard (Podarcis Siculus) Populations From New York And California, Daniel Haro

Master's Theses

Understanding how organisms respond to climatic variability and novel conditions is becoming an increasingly important task for ecologists. For ectotherms in the northern hemisphere, the response to cold is of special interest, considering that poleward range expansion events and increasing variability of temperatures during winter are already being observed as consequences of a warming planet. Though direction of change in physiological variables in response to cold is well studied in ectotherms, the extent to which traits can change and the rate at which they can change is not.

We compared the extent and rate of change in cold tolerance (CT …

Indirect Food Web Interactions: Sea Otter Predation Linked To Invasion Success In A Marine Fouling Community, Maggie F. Jenkins

Master's Theses

Humans have caused grave ecological and economic damage worldwide through the introduction of invasive species. Understanding the factors that influence community susceptibility to invasion are important for controlling further spread of invasive species. Predators have been found to provide biotic resistance to invasion in both terrestrial and marine systems. However, predators can also have the opposite effect, and facilitate invasion. Therefore, recovery or expansion of native predators could facilitate the spread of invasive species. Needles et al. (2015) demonstrated that the threatened southern sea otter (Enhydra lutris nereis) facilitated the invasion of an exotic bryozoan, Watersipora subatra. …

The Thermal Ecology Of Sceloporus Occidentalis, Luis Patricio Burgos

Master's Theses

With temperatures rising globally, assessing the possible impacts of the changing climate becomes more and more urgent. Ectotherms are excellent indicators of potential climatic ramifications on biodiversity because of their heavy reliance on the environment for their thermoregulation. Studies have historically looked at thermal tolerance values to establish predictive models for population and species extinctions.

In chapter 1, we looked at recent studies that suggest that thermal tolerance may be a plastic trait and test the effects empirically. Most studies are based on captive lizards acclimated to laboratory conditions that do not necessarily reflect natural environments, and if thermal tolerance …

Climactic Niche Model For Overwintering Monarch Butterflies In A Topographically Complex Region Of California, Ashley Fisher, Kiana Saniee, Charis Van Der Heide, Jessica Griffiths, Daniel Meade, Francis X. Villablanca

Biological Sciences

We use climatic conditions that are associated with known monarch butterfly overwintering groves in California to build a Maxent model, and focus on the fine scale probability of overwintering grove occurrence in a topographically complex region of the state (Santa Barbara County). Grove locations are known from recent and historical surveys and a long-term citizen science database. The climatic niche model performs well, predicting that overwintering habitat is most likely to occur along the coast and at low elevations, as shown by empirical data. We then use climatic variables in conjunction with climate change scenarios to model the future location …

Intracanopy Adjustment Of Leaf-Level Thermal Tolerance Is Associated With Microclimatic Variation Across The Canopy Of A Desert Tree (Acacia Papyrocarpa), Ellen M. Curtis, Charles A. Knight, Andrea Leigh

Biological Sciences

Tree crowns are spatially heterogeneous, sometimes resulting in significant variation in microclimate across the canopy, particularly with respect to temperature. Yet it is not known whether such localised temperature variation equates to intracanopy variation in leaf-level physiological thermal tolerance. Here, we studied whether microclimate variation across the canopy of a dominant desert tree equated to localised variation in leaf thermal thresholds (T₅₀) among four canopy positions: upper south, upper north, lower south, lower north. Principal component analysis was used to generate a composite climatic stress variable (C_STRESS) from canopy temperature, vapour pressure deficit, and …

Impacts Of Nutrient Enrichment On Native And Non-Native Plants In Serpentine Soil, Amber R. Williams, Mary Devlin, N. Rajakaruna

STAR Program Research Presentations

Serpentine soil, derived from serpentinite, California’s state rock, is characterized by its harsh nature - due to its low levels of essential nutrients and exceptionally high levels of toxic heavy metals.In California, serpentine soils are characterized by high levels of plant endemism and rarity. Plants occurring in serpentine soil exhibit extreme tolerance of harsh soil conditions, and are typically out-competed in ‘normal’ soils due to the cost associated with physiological specialization. Atmospheric nutrient deposition is contributing to a greater invasion of non-native grass species on serpentine soils, outcompeting the native species and threatening them with local extinction. Our greenhouse study …

The Roles Of Tid1, Ndj1, And Spo16 In Distributive Segregation During Saccharomyces Cerevisiae Meiosis, Ethan Atticus Shaw

Master's Theses

Meiosis is a specialized form of cell division in sexually reproducing eukaryotes. Crossovers are physical connections formed between homologous chromosomes during meiosis; these connections help ensure normal segregation of homologous chromosomes at meiosis I. However, the yeast Saccharomyces cerevisiae and other eukaryotes can still segregate homologs properly even in the absence of some crossovers. This is due to a backup mechanism known as distributive segregation, which correctly segregates non-crossover chromosomes at a higher rate than if segregation were completely random. To study distributive segregation, we have generated diploid yeast with one homeologous chromosome pair consisting of a Saccharomyces cerevisiae chromosome …

Inducing Ni Sensitivity In The Ni Hyperaccumulator Plant Alyssum Inflatum Nyárády (Brassicaceae) By Transforming With Cax1, A Vacuolar Membrane Calcium Transporter, Rasoul Ghasemi, Hoorieh Share, Roza Sharif, Robert S. Boyd, Nishanta Rajakaruna

Biological Sciences

The importance of calcium in nickel tolerance was studied in the nickel hyperaccumulator plant Alyssum inflatum by gene transformation of CAX1, a vacuolar membrane transporter that reduces cytosolic calcium. CAX1 from Arabidopsis thaliana with a CaMV35S promoter accompanying a kanamycin resistance gene was transferred into A. inflatum using Agrobacterium tumefaciens. Transformed calli were subcultured three times on kanamycin-rich media and transformation was confirmed by PCR using a specific primer for CAX1. At least 10 callus lines were used as a pool of transformed material. Both transformed and untransformed calli were treated with varying concentrations of either calcium (1–15 mM) or …

Preparation And Characterization Of Eva/Cort Microparticles For Rattlesnake Endocrinology Studies, Alexander C. Pauer

Materials Engineering

No abstract provided.

Zinc Sunscreens Affect Development Of Strongylocentrotus Purpuratus Embryos, Brittany E. Cunningham, Nikki L. Adams

Master's Theses

The growing popularity of physical sunscreens will also lead to an increased release of the ingredients from zinc oxide (ZnO) sunscreens into marine environments. Though zinc (Zn) is a necessary micronutrient in the ocean, greater than natural Zn concentrations are being released into marine environments by use of sunscreens. The extent of the consequences of the addition of Zn to the ocean are not fully understood. We investigated effects of materials released by zinc oxide (ZnO) sunscreens on the development of California purple sea urchin, Strongylocentrotus purpuratus. Embryos developed in various concentrations of Zn, the sources of which included …

Foraging Ecology Of Parrotfishes In The Greater Caribbean: Impacts Of Specialization And Dietary Preferences On Marine Benthic Communities, Madelyn V. Roycroft

Master's Theses

Coral reefs are one of the world’s most diverse yet heavily impacted marine ecosystems. As a result of many direct and indirect stressors, coral reefs have experienced major degradation over the last several decades. Declines in coral reefs in the Caribbean have been particularly acute and generally associated with the loss of key herbivores and an increase in algae. Herbivorous fishes such as parrotfishes can positively impact coral reefs by removing algae that compete with corals for light and space. However, many parrotfishes are also important coral predators. Predation on corals, known as corallivory, can adversely affect coral growth, reproduction …

Biological Crusts Of Serpentine And Non-Serpentine Soils From The Barberton Greenstone Belt Of South Africa, Arthurita Venter, Stefan Siebert, Nishanta Rajakaruna, Sandra Barnard, Anatoliy Levanets, Arshad Ismail, Mushal Allam, Bianca Peterson, Tomasz Sanko

Biological Sciences

Climate and geography can influence biological soil crust (BSC) community composition, but local heterogeneity in variables such as soil characteristics or microclimate gradients can also impact cryptogamic diversity. Heavy metals and nutrient imbalances in serpentine soils are known to influence the distributions of higher plants, but cryptogamic species appear to be more tolerant of substrate. The aim of this study was to compare the cryptogamic composition of serpentine and non-serpentine soils by using integrative taxonomy, which combines morphological and DNA barcoding data, to determine how soil characteristics in combination with rainfall can influence BSC community composition. Samples from serpentine and …

Senecio Conrathii N.E.Br. (Asteraceae), A New Hyperaccumulator Of Nickel From Serpentinite Outcrops Of The Barberton Greenstone Belt, South Africa, Stefan Siebert, Nadine Carol Schutte, Stoffel Pieter Bester, Dennis Mmakgabo Komape, Nishanta Rajakaruna

Biological Sciences

Five nickel hyperaccumulators belonging to the Asteraceae are known from ultramafic outcrops in South Africa. Phytoremediation applications of the known hyperaccumulators in the Asteraceae, such as the indigenous Berkheya coddii Roessler, are well reported and necessitate further exploration to find additional species with such traits. This study targeted the most frequently occurring species of the Asteraceae on eight randomly selected serpentinite outcrops of the Barberton Greenstone Belt. Twenty species were sampled, including 12 that were tested for nickel accumulation for the first time. Although the majority of the species were excluders, the known hyperaccumulators Berkheya nivea N.E.Br. and B. zeyheri …

Sympatric Serpentine Endemic Monardella (Lamiaceae) Species Maintain Habitat Differences Despite Hybridization, Kathleen M. Kay, Suzie Woolhouse, Brett A. Smith, Nathaniel S. Pope, Nishanta Rajakaruna

Biological Sciences

Ecological differentiation and genetic isolation are thought to be critical in facilitating coexistence between related species, but the relative importance of these phenomena and the interactions between them are not well understood. Here, we examine divergence in abiotic habitat affinity and the extent of hybridization and introgression between two rare species of Monardella (Lamiaceae) that are both restricted to the same serpentine soil exposure in California. Although broadly sympatric, they are found in microhabitats that differ consistently in soil chemistry, slope, rockiness and vegetation. We identify one active hybrid zone at a site with intermediate soil and above-ground characteristics, and …

A Global Forum On Ultramafic Ecosystems: From Ultramafic Ecology To Rehabilitation Of Degraded Environments, Guillaume Echevarria, Alan J. M. Baker, Robert S. Boyd, Antony Van Der Ent, Takafumi Mizuno, Nishanta Rajakaruna, Shota Sakaguchi, Aida Bani

Biological Sciences

The 9th International Conference on Serpentine Ecology (ICSE) was held in Tirana and Pogradec (Albania) from June 5 to 9, 2017. More than 100 delegates from 29 countries around the world gathered to present their research on recent advances in: (i) ultramafic soils, (ii) biogeochemistry, (iii) diversity of ultramafic flora, microflora and fauna, (iv) ecophysiology of ultramafic-adapted organisms, (v) interactions between ultramafic organisms and their ecology, (vi) nature rehabilitation of degraded ultramafic environments (resulting from mining activities), and (vii) the production of bio-based metals through agromining technology. Additionally, the ICSE featured the first symposium on ultramafic aquatic ecology and ecotoxicology. …

Ultramafic Vegetation And Soils In The Circumboreal Region Of The Northern Hemisphere, Anzhelika Teptina

Biological Sciences

The paper summarizes literature on climate, soil chemistry, vegetation and metal accumulation by plants found on ultramafic substrata in the circumboreal zone (sensu Takhtajan, Floristic regions of the world, 1986) of the Northern Hemisphere. We present a list of 50 endemic species and 18 ecotypes obligate to ultramafic soils from the circumboreal region of Holarctic, as well as 30 and 2 species of Ni and Zn hyperaccumulators, respectively. The number of both endemics and hyperaccumulators are markedly lower compared to that of the Mediterranean and tropical regions. The diversity of plant communities on ultramafics soils of the circumboral region is …

Diversity And Functional Traits Of Lichens In Ultramafic Areas: A Literature Based Worldwide Analysis Integrated By Field Data At The Regional Scale, Sergio E. Favero-Longo, Enrica Matteucci, Paolo Giordani, Alexander G. Paukov, Nishanta Rajakaruna

Biological Sciences

While higher plant communities found on ultramafics are known to display peculiar characteristics, the distinguishability of any peculiarity in lichen communities is still a matter of contention. Other biotic or abiotic factors, rather than substrate chemistry, may contribute to differences in species composition reported for lichens on adjacent ultramafic and non-ultramafic areas. This work examines the lichen biota of ultramafics, at global and regional scales, with reference to species-specific functional traits. An updated world list of lichens on ultramafic substrates was analyzed to verify potential relationships between diversity and functional traits of lichens in different Köppen–Geiger climate zones. Moreover, a …

Lessons On Evolution From The Study Of Edaphic Specialization, Nishanta Rajakaruna

Biological Sciences

Plants adapted to special soil types are ideal for investigating evolutionary processes, including maintenance of intraspecific variation, adaptation, reproductive isolation, ecotypic differentiation, and the tempo and mode of speciation. Common garden and reciprocal transplant approaches show that both local adaptation and phenotypic plasticity contribute to edaphic (soil-related) specialization. Edaphic specialists evolve rapidly and repeatedly in some lineages, offering opportunities to investigate parallel evolution, a process less commonly documented in plants than in animals. Adaptations to soil features are often under the control of major genes and they frequently have direct or indirect effects on genes that contribute to reproductive isolation. …

Effect Of The Specific Carbohydrate Diet On The Microbiome Of A Primary Sclerosing Cholangitis And Ulcerative Colitis Patient, Alanna Dubrovsky, Christopher Kitts

Biological Sciences

A 20-year-old female was diagnosed with ulcerative colitis (UC) at age 14 and primary sclerosing cholangitis (PSC) at age 16. The PSC was successfully treated with high doses of oral vancomycin; however, the UC was more difficult to manage. After many drug treatments failed to treat the UC, the patient began following the specific carbohydrate diet (SCD). This report documents fecal microbiome changes resulting from following the SCD for two weeks. The DNA extracted from fecal samples was subjected to 16S rRNA gene sequencing to quantify bacterial species abundance. Not only were substantial changes in the fecal bacterial composition detectable …