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Full-Text Articles in Life Sciences
Root Hydraulic Conductance In Laurel Sumac Experiencing Severe Dieback In The Santa Monica Mountains, Natalie M. Aguirre, Avery N. Davis, Sarah B. Nelson
Root Hydraulic Conductance In Laurel Sumac Experiencing Severe Dieback In The Santa Monica Mountains, Natalie M. Aguirre, Avery N. Davis, Sarah B. Nelson
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Malosma laurina (laurel sumac) is a dominant species in coastal chaparral ecosystems, extending its roots down to an average of 40 feet in rocky, sandy soils. The deep root systems of M. laurina provide structural support for the steep Santa Monica Mountains. The roots also allow M. laurina to draw from the deep water table, increasing its drought tolerance. M. laurina dieback is prevalent in coastal exposures of the Santa Monica Mountains presumably due to historic drought predisposing plant tissues to infection by the fungal pathogen Botryosphaeria dothidea. In ecosystems that experience annual dry periods, a high hydraulic conductance …
Extensive Dieback In Malosma Laurina In Coastal Exposures Of The Santa Monica Mountains Associated With Unprecedented Drought In California, Gina S. Gilderman, Kaitlyn E. Sauer, Gabriella N. Palmeri
Extensive Dieback In Malosma Laurina In Coastal Exposures Of The Santa Monica Mountains Associated With Unprecedented Drought In California, Gina S. Gilderman, Kaitlyn E. Sauer, Gabriella N. Palmeri
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Throughout coastal exposures of the Santa Monica Mountains (SMM) there is a recent emergence of widespread dieback in Laurel Sumac (Malosma laurina). M. laurina is a keystone species of chaparral that dominates the SMM. A significant trait of M. laurina is an extensive root system exceeding 12 m in depth. We hypothesized that M. laurina was weakened by unprecedented drought in California (2013-2015) and predisposed to fungal pathogens. An initial study conducted in the summer of 2015 revealed all stem samples taken from dieback adult M. laurina plants were infected with Botryosphaeria dothidea, while zero stem samples taken …
Recent Dieback In A Keystone Chaparral Species Is Caused By A Fungal Pathogen, Botryosphaeria Dothidea, Frida Morales, Mariah Taylor
Recent Dieback In A Keystone Chaparral Species Is Caused By A Fungal Pathogen, Botryosphaeria Dothidea, Frida Morales, Mariah Taylor
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Due to the recent drought in Southern California, the abundance of a keystone species within the Santa Monica Mountains (SMM) has been dwindling. This species, Malosma laurina, has an average root depth of 40 feet, so it has little difficulty tapping into the watershed. Recently, this species has undergone extensive dieback, which is potentially attributed to the unprecedented drought and the introduction of the fungus B. dothidea. While this fungi appears to be innocuous to M. laurina when the plant is healthy, it is more susceptible to invasion under water stress due to the dry heated conditions of …
Effects Of High Light Exposure On Photosynthetic Rate And Fluorescence Of Eucrypta Chrysanthemifolia, Alec Flores, Gina Gilderman, Hannah Dario
Effects Of High Light Exposure On Photosynthetic Rate And Fluorescence Of Eucrypta Chrysanthemifolia, Alec Flores, Gina Gilderman, Hannah Dario
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In this experiment, we examined how a partial shade plant, Eucrypta chrysanthemifolia, found in the Santa Monica Mountains, responded to predictive models of higher light intensities created bydrought. We hypothesized that, with higher levels of light, Eucrypta chrysanthemifolia would respond with a decreased photosynthetic rate, light-adapted, and dark-adapted fluorescence. This was performed by comparing control plants grown in an artificial shade environment to plants exposed to a series of high light intensity treatments. These partial shade plants were found on Piuma Trail in the Santa Monica Mountains. Our data supported our null hypothesis, indicating the photosynthetic rates and light-adapted …
Seedling Resprouts Of Adenostoma Fasciculatum Between Wildfire Cycles Are Promoted By Environmental Conditions That Mimic Fire-Like Environments, Lexe Evans, Teal Speece, Stephen D. Davis
Seedling Resprouts Of Adenostoma Fasciculatum Between Wildfire Cycles Are Promoted By Environmental Conditions That Mimic Fire-Like Environments, Lexe Evans, Teal Speece, Stephen D. Davis
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The Santa Monica Mountains represent one of the largest Mediterranean-type environments in the world. With sustained summer droughts, this ecosystem has become prone to frequent wildfires, a phenomenon that has affected the area with regularity (approximately 21 years apart). Naturally, this cycle of wildfires has had a great effect upon the mortality and survival of the diverse chaparral varieties that inhabit the Santa Monica Mountain region. This includes the Adenostoma fasciculatum (chamise), which is the most commonly-found form of chaparral shrub in California. (Redfeldt & Davis, 1996) This species of chaparral is particularly well-adapted to survival in a climate that …
Morphological Changes In Malosma Laurina Due To Prolonged Drought In The Santa Monica Mountains, Grace S. M. Bae, Majie C. Foster, Maryelizabeth S. Stein, Mariah K. Taylor
Morphological Changes In Malosma Laurina Due To Prolonged Drought In The Santa Monica Mountains, Grace S. M. Bae, Majie C. Foster, Maryelizabeth S. Stein, Mariah K. Taylor
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Observations of Malosma laurina seedlings in Sycamore Canyon, Malibu, CA, exhibit abnormally small and wrinkled leaves. We propose that the prolonged drought in California’s Santa Monica Mountains has lead to physical malformations indicative of water strain in the leaves of M. laurina plants. In this experiment, we tested water relations of six M. laurina plants found on Pepperdine University’s Malibu campus showing similar leaf patterns to those found in Sycamore Canyon. Six M. laurina plants devoid of the abnormal leaf growth patterns functioned as our control group. Stomatal conductance, water potential, and leaf mass to area data was gathered using …
Possible Fungal Infection Leading To Malosma Laurina Dieback, Gabriella N. Palmeri, Braden S. Olsen, Kaitlyn E. Sauer, Stephen D. Davis
Possible Fungal Infection Leading To Malosma Laurina Dieback, Gabriella N. Palmeri, Braden S. Olsen, Kaitlyn E. Sauer, Stephen D. Davis
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There is a significant and apparent dieback of Malosma laurina in the Santa Monica Mountains, some which is found near Pepperdine University. Other areas near Pepperdine show a flourishing growth of M. laurina and our objective was to determine why this difference in M. laurina health exists. We initially hypothesized that in addition to water stress, the unhealthy M. laurina was effected by a pathogen. Under further inspection, the unhealthy plants contained hyphae in some of their xylem vessels, while the healthy ones did not. We sought to determine whether the existence of hyphae in the unhealthy plant’s xylem affected …
Effects Of Drought On Malosma Laurina Leaves, Suk Ho (Josh) Chang, Jingyi Chen, Sarah B. Nelson
Effects Of Drought On Malosma Laurina Leaves, Suk Ho (Josh) Chang, Jingyi Chen, Sarah B. Nelson
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Drought induced deformations in the chaparral plant Malosma laurina were observed following the lack of water availability during the years of 2013 and 2014. We hypothesized that the middle leaves grown during the drought would have the lowest productivity, the top post-drought leaves would have the highest productivity, and the bottom pre-drought leaves would have an intermediate level of productivity. We used a sample size of n = 6, representing 6 unique M. laurina plants. To obtain our data, we used the LI-6400 gas exchange system. In our comparisons of photosynthetic rate, stomatal conductance, and photosynthetic quenching of the top, …
Fitness Parameters In Malosma Laurina Seedlings Growing Near And Away From Invasive Brassica Nigra, Natalie M. Aguirre, Agustin Vargas, Phoebe Shin
Fitness Parameters In Malosma Laurina Seedlings Growing Near And Away From Invasive Brassica Nigra, Natalie M. Aguirre, Agustin Vargas, Phoebe Shin
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In this study we aim to assess the photosynthetic rate of native Malosma laurina (M. laurina) seedling, in comparison to M. laurina seedlings growing amongst several hundred B. nigra invasive plants. We predicted that there will be a difference in the stomatal conductance of each population. We measured photosynthetically active radiation (PAR), seedling height, and stomatal conductance of two isolated populations of M. laurina seedlings. One population grows near B. nigra, an invasive specie, and the other only grows amongst native plants. We found that M. laurina seedlings growing near weeds …
Difference In Chaparral Species Population On The North And South Aspect On Pepperdine University Campus, Alexandra N. Lozano, Drew N. Rasmussen, Ashlyn L. Rawls
Difference In Chaparral Species Population On The North And South Aspect On Pepperdine University Campus, Alexandra N. Lozano, Drew N. Rasmussen, Ashlyn L. Rawls
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In this experiment, we analyzed the difference in population frequencies of chaparral plants along the north and south aspect of a slope on Pepperdine University campus in the Santa Monica Mountains in Malibu, CA. We began the experiment by hypothesizing the south aspect would receive the most sunlight, and thus would hold the most amount of plants. By using the Point Quarter Sampling Method, we were able to determine if our hypothesis was correct. After analyzing our data, we found no significant difference between the north and south aspect in terms on frequency. During our experiment we also measured the …
Correlation Between Hydration And Reflectance Of Yellow Petals On Encelia Californica, Jayci M. Givens, Kaylee A. Nussbaum, Caitlin R. Kawata
Correlation Between Hydration And Reflectance Of Yellow Petals On Encelia Californica, Jayci M. Givens, Kaylee A. Nussbaum, Caitlin R. Kawata
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It is known that the NDVI can be used as a measure of hydration in plants because of the variation in pigments due to xanthophyll cycling (Schmitz et al., 2013). Flower petals can also exhibit variations in petal reflectance invisible to the naked eye (Fam & Espinoza, 2013). It was hypothesized that overall hydration levels of a plant would correlate to a difference in the pigments produced for petal color, and thus differences in hydration levels would correlate to differences in petal reflectance. To test this hypothesis, three flowers and two stems were collected from ten different E. californica plants, …
The Effects Of Salinity On The Photosynthetic Rate Of Limonium Californicum, Adriana J. Borges, Elizabeth S. Chau, Justine M. Mckitrick
The Effects Of Salinity On The Photosynthetic Rate Of Limonium Californicum, Adriana J. Borges, Elizabeth S. Chau, Justine M. Mckitrick
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Halophytic plants, unlike most plants, are able to survive in stressful saline environments. Halophytes possess adaptations to osmoregulate, which gives them a competitive edge in saline environments such as coastal salt marshes. Our group analyzed the responses to salinity of the halophytic plant, Limonium californicum, which is present in California’s coastal salt marshes. We hypothesized that the photosynthetic rate of the Limonium californicum plants would decrease with increasing saline water treatments. In order to test this hypothesis, we watered L. californicum plants with solutions of varying salinity over the course of four days. We measured the photosynthetic rates using …
Correlation Between Hydration And Reflectance Of Yellow Petals On Encelia Californica, Jayci M. Givens, Kaylee A. Nussbaum, Caitin R. Kawata
Correlation Between Hydration And Reflectance Of Yellow Petals On Encelia Californica, Jayci M. Givens, Kaylee A. Nussbaum, Caitin R. Kawata
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It is known that the NDVI can be used as a measure of hydration in plants because of the variation in pigments due to xanthophyll cycling (Schmitz et al., 2013). Flower petals can also exhibit variations in petal reflectance invisible to the naked eye (Fam & Espinoza, 2013). It was hypothesized that overall hydration levels of a plant would correlate to a difference in the pigments produced for petal color, and thus differences in hydration levels would correlate to differences in petal reflectance. To test this hypothesis, three flowers and two stems were collected from ten different E. californica plants, …