Biology Commons^™

The Effects Of Higher And Lower Co2 Levels In The Atmosphere On The Photosynthetic Rates And Stomatal Conductance Of Malosma Laurina In The Santa Monica Mountains, Victoria A. Thorsen, Maverick E. Turner, Colby P. Harriman

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We hypothesize that higher CO2 levels will lead to a change in photosynthetic performance in the Malosma laurina population of the Santa Monica Mountains. We used one Malosma laurina that is across the street from university’s theme tower. We chose this specific plant because it was in the sun and it was in a well irrigated area. We selected a plant that is in non-shaded areas at 12:00 pm and then dark adapt them for 20 minutes. We selected an adult plant that was between four and six feet tall. We took the measurements from the upper leaves of the …

Elevation’S Effect On Malosma Laurinais Leaf Size, Callyn E. Shelley, Nathan R. Gehring

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Our hypothesis was that the average leaf size of Malosma laurinais would be different at high and low elevations due to the variance in temperature and solar radiation. This is especially relevant considering the severe drought conditions of California. Testing the factors of growth for chaparral may help ecologists to better understand how the plants cope with abnormalities in the ecosystem. Our study examined variance in Malosma laurinais leaf length, width, area, curvature, and thickness at high elevation (610 meters to 629 meters) and low elevation (27 meters to 53 meters) located along Sycamore Canyon. Differences were only significant in …

Water Analysis Of The Malibu Lagoon And Pacific Ocean, Emily E. K. Kelly, Jillian S. Unruh, Maxwell K. Gamboa

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This experiment tested the waters of the Malibu Lagoon and the Pacific ocean to compare levels of E.coli. We hypothesized that greater amount of E.coli would be present in the waters of the Malibu Lagoon. Because of the runoff and pollution existing in the lagoon, we predicted that higher levels of this bacteria would be found there. This study is significant because many organisms living in these waters can be negatively effected by large levels of E.coli. We used the most probable number method to determine the amounts of bacteria. A collection of samples from three testing sites in both …

Nutrient Return To Soil In The Santa Monica Mountains After Combustion, Taylor Brooke Shapiro, Antonia Freund, Megan Chou

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In this study, levels of phosphorus, nitrogen, and PH from eight uniform soil samples from the Santa Monica Mountain swere assessed. Our first testing group contained four uniform samples of soil, which were tested under regular drought conditions. Our second testing group contained four identical samples, which we tested under regular drought conditions and also exposed to fire. Our hypothesis was that soil after wildfire will have different amounts of phosphorous, nitrogen, and Ph. Our research found that average phosphorus uptake in unburned samples vs. burned samples were significantly different at a P<0.0001. Nitrogen and pH levels however, were not found significantly different between burned and unburned samples.

The Mechanical Strength Of Malosma Laurina Leaves Corresponds With Survivability During Extreme Drought, Alexander Booth, Alexander Corwin, Matthew Chung

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With the recent extreme drought that Southern California is facing, many plants’ survivability adaptations have proven insufficient. The Malosma laurina plant is known for it’s incredible ability to survive through droughts and wildfires with it’s adaptations of resprouts regeneration and it’s roots that can reach a depth of 40 feet to gather deep ground waters. We theorized that the mechanical strength of the leaves directly relates to its survivability during droughts. To explore this theory we took focused our theory specifically on M. laurina resprouts. With two groups, one fully alive and one dying, we took six samples from six …

Effects Of Uv-Radiation On Feeding Behavior In Dendrobates Tinctorius, Taylor S. Stucky, Arthur Garnica

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UV-B levels have recently been increasing with the depletion of the ozone layer. Recent data have shown that amphibians are especially susceptible to UV-B, with poison dart frogs being one focus in these studies. The purpose of this study was to determine if UV-B radiation affects the foraging behavior of poison dart frogs. This study was conducted with a captive population of juvenile Dendrobates tinctorius at Pepperdine University in Malibu, California. Frogs underwent one of three treatments: UV only, Food only, and UV and Food. UV only trials were conducted using two UV lights emitting approximately 1.2 uW/cm2 of UV …

Relating Leaf Temperature On Malosma Laurina To Leaf Proximity From Soil, Brooks O'Hea, Kevin Morgan

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The Santa Monica Mountains are home to countless vegetation and plant species, many of which have been forced to adapt to southern California’s stressful environment. With recent droughts and a steady change in climate, an increase in leaf temperature within some species in the Santa Monica Mountains has been observed. One prominent plant found within the mountain range is the malosma laurina, or laurel sumac, the only species of the malosma genus. Malosma laurina is a perfect example of a specie adapting to its stressful environment. Constant brush and shrub fires within the chaparral area where it commonly grows have …

Foliar Water Uptake And Resurrection: Mechanisms Of Drought Tolerance In Eight Species Of Ferns In The Santa Monica Mountains, Victoria M. Lekson

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In a region where drought is severe, ecological surveys provide insight into the adaptations of organisms living on the edge of survival. In this study, the mechanisms of drought tolerance for eight species of ferns in the Santa Monica Mountains were assessed with a focus on foliar water uptake and resurrection strategies. We find that species are significantly different (P < 0.001) in their ability to absorb water through leaves (assessed gravimetrically) and correlate this to minimum seasonal water potential and hydrophobicity of leaf surfaces. Secondly, we irrigated Pentagramma triangularis in the field and tracked chloroplast recovery. We found possible evidence of embolism reversal. Taken together, this study explored the methods of survival of the most ancient family of vascular plants.

Differential Survival Of Chaparral Shrub Species In Response To Severe Drought, Hannah Dario

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In this experiment, we examined how the plants in the Santa Monica Mountains are responding to the driest period in recorded history for California. Our hypothesis was that plant species with the deepest roots would have highest survivorship. We thought this because deep-rooted shrubs will have greater access to soil moisture. This hypothesis was tested by collecting data on plant survival, in a mixed chaparral stand, containing eleven species, growing in the Green Valley Preserve off of Stunt road, in the Santa Monica Mountains. The chaparral stand was 21 years old, having last burned in 1993 (Old Topanga Canyon Fire). …

Correlation Between Freezing Sites And Xylem Vessel Diameter For Three Chaparral Species Of The Santa Monica Mountains, Kaitlyn E. Sauer, Theodora V. Ordog, Nicole A.P.M.K.O.M. Nakamatsu

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Coastal exposures of the Santa Monica Mountains rarely experience freezing temperatures

(0 °C) because of the ameliorating effects of the Pacific Ocean and seawater’s specific heat capacity. In contrast, inland sites of the Santa Monica Mountains frequently experience winter temperatures below -10 °C. This temperature gradient, from coast to inland, may be a major determinate of species distribution patterns. To investigate possible mechanisms by which freezing impacts chaparral distribution patterns, we examined xylem vessel diameter and vessel length of three chaparral species growing at inland freezing sites versus coastal nonfreezing sites (Malosma laurina, Umbellularia californica, and Ceanothus megacarpus). It has …