Practicum 2009-2010

The following are the final reports prepared by IoES students for the 2009-2010 Practicum.

Measuring the Ecological Status of Restoration Treatments of Coastal Sage Scrub (Cheeseboro Canyon) Using Biotic Proxies

Victoria Crandall, Karan Gupta, Kevin Huang, Angeline Kong, Allen Lee, Stephanie Macias, Phillip C. Wong.

Advisor: Dr. Travis Longcore

Client: National Park Service

Ecological restoration is the process of assisting the recovery of an ecosystem that has been disturbed, degraded, or biologically invaded. The ultimate goal is to reestablish a community that will foster both short-term resistance and long-term resilience to future threats. Several papers have suggested ways of measuring ecosystem health but the primary consensus has involved a multi-dimensional approach. This study aims at applying a similar multi-dimensional approach to experimentally restored coastal sage scrub plots located in Cheeseboro Canyon, Santa Monica Mountains National Recreation Area. We examined biological proxies, including vegetation diversity, arthropod diversity, and seed bank diversity, to compare to reference coastal sage scrub habitat. In congruence with past studies, our findings suggest that the restored habitats have higher vegetation diversity and seed bank diversity when compared to adjacent disturbed native annual grassland and similar, but lower diversity compared with reference coastal sage scrub habitat. Responding to this difference in vegetation diversity and structure, arthropod diversity is lower in restored plots compared to reference plots, and is represented by a greater abundance of scavengers and a lower abundance of herbivores.

Edaphic Properties of Stable, Shrinking and Expanding Coastal Sage Scrub Boundaries (1990-2009) in Cheeseboro Canyon, Santa Monica Mountains National Recreation Area

Monica Pacheco, Erin Mulberg, Suza Khy, Maggie Olsen, Andrew J. Price, Prodipto Roy, Eduardo Jimenez

Advisor: R. Travis Brooks

Clients: National Park Service, Santa Monica Mountains National Recreation Area

The coastal sage scrub (CSS) vegetation of southern California is an ecologically important habitat that is threatened due to losses from urban development and type-conversion in adjacent wilderness by historic land use practices and decreased fire return intervals. Many areasthat have been historically grazed and subject to frequent burning have been replaced by a dominant non-native annual grass cover (NAG). Together CSS and NAG occur in vegetation mosaics in the landscape, including in Cheeeseboro Canyon, part of the Santa Monica National Recreation Area managed by the National Park Service. Although fire history has been documented to be an important consumer pressure on CSS communities, a prior photointerpretation study in Cheeseboro Canyon found that from the early 1920s to 2003, parameters of fire history did not directly correlate with the gain or loss of CSS cover (Eckhardt 2006). CSS-NAG boundaries may be responding to other environmental factors, including edaphic factors related to soil moisture availability. It is known CSS and NAG have differing soil hydrologic patterns, NAG being dryer that CSS due to plant water utilization (Davis 1985). Therefore, we posited that edaphic boundary conditions between CSS and NAG may be correlated with the relative stability of CSS-NAG boundaries. Over a 19-year period (1990-2009) we did not find that the relative stability of individual CSS boundaries (stable, expanding or shrinking) correlated with parameters of fire history; however, we found from a stratified random sample of the edaphic properties across these boundaries that soil texture was almost always different between the CSS and NAG sites. For differences between boundary stability types, we only found a significant difference between CSS and NAG across expanding boundaries at a depth of 0-20 cm (p<0.001). We interpret this finding to indicate that while soil texture alone may not consistently explain the trajectory of expanding or shrinking boundaries, the observation that soil texture was different across these vegetation boundaries suggests that it may be interacting with another unmeasured environmental factor, which is ecologically important in determining whether a particular site would promote or suppress CSS colonization. Future research and restoration projects should consider edaphic factors in attempting to understand the long-term stability of CSS communities in the landscape.

Examining Marine Debris Along Los Angeles County Beaches: A qualitative and quanitative analysis

Alisan Amrhein, Hui Yan Terri Chan, Jonathan Chang, Gabe Kiritz, Jaimie Lee, Karestine Nga, Sean O’Connor, Jaynel Santos

Advisor: Dr. Rebecca Shipe

Client: Los Angeles Regional Water Quality Control Board

This study evaluated qualitatively and quantitatively the patterns of marine debris distribution found on the following four L.A. County Beaches: Malibu-Surfrider Beach, Venice Beach, Dockweiler State Beach, and Redondo Beach. Evaluations were characterized according to beach topography, land use characteristics, type of debris, and original use of debris found at each focus area. Each study area represented a diverse set of features that we predicted might effect the amount and type of debris collected. The intent for choosing each study area lies in the set of features identified: gentle sloping foreshores, minimal vegetation, similar beach composition, recreational sites and diverse land usage in surrounding areas. Debris was collected, classified, and analyzed during the period between February 20, 2010 and April 11, 2010. Quadrants, 4x4m in size, were randomly sampled and the number of quadrants vary with beach size. All debris, over the size of 5mm, found in these quadrants were taken to the laboratory for further examination and classification. The highest debris load was noted on Dockweiler State Beach, and the amounts were generally correlated with precipitation. Plastics were found in abundance on all beaches, however, many pieces were degraded suggesting that they had originated in upstream waterways for a significant amount of time before accumulating onto the beaches. The original use of most debris items was associated with food and beverage. After careful analysis, proper correlations and recommendations were drafted to assist the L.A. Regional Water Quality Control Board in the creation and implementation of a Total Maximum Daily Load Regulation (TMDL) for beaches in Southern California.

Marine Debris in Topanga Canyon

Nora Hakkakzadeh, Daniela Hamann-Nazaroff, Mohammed Raouf Iqbal, Mike Kelly, Rita Wong, Miriam Urena, Hannah Wilchar, Jenny Kim

Advisor: Dr. Rebecca Shipe

Client: Los Angeles Regional Water Quality Control Board

Marine debris is a global problem that affects water quality, degrades beaches, and poses health problems to humans and aquatic organisms. The majority of marine debris is from land based sources due to human activities, such as littering and illegal dumping. Under the U.S. Clean Water Act, states must determine Total Maximum Daily Loads, or TMDLs, to calculate the maximum amount of pollutants that impaired waters can assimilate in order to meet water quality standards. The Clean Water Act Section 303(d) List of Water Quality Limited Segments for California includes Topanga Beach and Topanga Canyon Creek, but there have been no TMDL determined for either location. This paper aims to fill in the gap of information about the state of marine debris accumulation in the Topanga Canyon watershed in order to aid the Los Angeles Regional Water Quality Control Board (LARWQCB) in establishing a TMDL for the area. Our research consisted of collecting, quantifying, and categorizing anthropogenic debris in the upper creek, middle creek, mouth, and beach of the Topanga Canyon watershed according to the standard Rapid Trash Assessment (RTA) guidelines, and analyzing the debris by amount, weight, and type. In general, the coastal zones had a greater abundance of small pieces of debris whereas the creek zones had larger debris at a lower abundance. Plastic was found to be a persistent problem in all four regions, and Styrofoam was especially prevalent in the mouth and beach zones. Our research guided us towards several suggestions for the LARWQCB on how the problem of marine debris in the Topanga Canyon watershed can be managed and mitigated.

Residential Use of Chemical Rodent Control from Bel-Air To the Hollywood Hills

Monica Bartos, Stephanie Falzone, Kaitlin Kelly-Reif, Cassandra Vasquez, Jennifer Ward

Advisor: Dr. Travis Longcore

Client: National Park Service

Exposure pathways of non-target species, specifically urban carnivores, to secondary anticoagulant rodenticides were identified in southern California between Bel-Air and the Hollywood hills. Habitat loss and fragmentation characterizes much of the landscape in our study site, causing carnivore home ranges to overlap with development bordering open spaces. Studies in this area have shown that urban carnivores are being exposed to anticoagulant rodenticides, and are reaching harmful biological endpoints including death and increased susceptibility to parasitic diseases. Little is known however about the pathways through which urban carnivores are coming into contact with these chemicals. To identify exposure pathways, we surveyed homeowners regarding their use of rodenticides if any, their knowledge about the effect of these chemicals on wildlife, and demographic information. We found that homeowners are applying second-generation compounds inside and outside their homes, as well as finding dead rodents inside and outside their homes. The Environmental Protection Agency has regulations that would ban the practices currently being used by homeowners in our study area. These new restrictions are not yet in effect, but when they are should substantially decrease the exposure of urban carnivores to anticoagulant rodenticides.

Rodent Control Methods and their Implications for Urban Carnivores in the San Fernando Valley, Los Angeles County, California, USA

Sylvie Dao, Dale Douk, Eric Gumerlock, Stephanie Hoekstra, David Mori, Chay Tang, Sarah Young

Advisor: Dr. Travis Longcore

Client: National Park Service

Non-target urban carnivore species are vulnerable to second-generation anticoagulant rodenticide exposure from neighboring, developed areas. To investigate the mechanisms of transmission from residential users to wildlife in the Santa Monica Mountains in Los Angeles County, California, we distributed surveys that assessed resident’s knowledge on the environmental effects of rodenticides and inquired about chemical application methods by homeowners and pest control operatives. We distributed over 1,200 fliers to households directing the respondent to a web-based survey and two homeowners associations emailed the same invitation to their members. We had 55 responses to the survey, 40 of which were in our specified study area. Results showed anticoaguant rodenticide chemicals being used outdoors, dead rodents being found outdoors, homeowners as the primary applicators, and gap in public awareness. Although the sample size was small, we were able to establish that improper rodenticide application does occur in neighborhoods that border habitats occupied by native carnivores, thereby illustrating the potential transmission pathway for rodenticides to these wildlife species.

Independent Projects

Evaluating the Characteristics of Dissolved Organic Matter and its Interactions with Hydrophobic Organic Contaminants in Natural and Treated Waters

Christina Cheng

Advisor: Dr. I.H. (Mel) Suffet

Dissolved organic matter (DOM) is a complex mixture of compounds found ubiquitously in natural waters. Sources of DOM include degraded biological materials in soil that is carried to water, as well as agricultural and urban runoffs. Previous research has shown that DOM can associate with hydrophobic organic compounds (HOCs) to lower the hazards of HOCs in the environment. Polycyclic aromatic hydrocarbons (PAHs) are a class of HOCs that can enter aquatic systems through industrial discharges and non-point source runoff. Due to its hydrophobicity, free PAHs can cross the non-polar gill membranes of fish and accumulate in the fatty tissues of aquatic organisms. However, when a free PAH binds to DOM, it forms a complex that is too large to be absorbed by aquatic organisms. This PAH-DOM interaction (PAHfree + DOM ↔ PAHbound-DOM) can be defined by a DOM-water partition coefficient, KDOM. The KDOM depends upon the nature of the DOM, as certain properties of DOM may favor PAH-DOM interaction. Using perylene as a non-toxic marker of HOC, this study will evaluate the composition, polarity, size, and other characteristics of DOM that may influence its association with HOCs in natural waters and during water treatment. By understanding the changes in DOM characteristics at different stages of water treatment, we can also provide information that is essential for optimizing the treatment process for the removal of DOM and hazardous, free PAHs.

Quantifying the Effects of the Mountain Pine Beetle on Melt Morphology and Timing in the Colorado River Basin, USA

Danielle O. Perrot

Advisors:
Noah P. Molotch, University of Colorado at Boulder: Geography | INSTAAR
Dr. Gregory S. Okin, University of California, Los Angeles: Geography

The mountain pine beetle epidemic in the Colorado River Basin has resulted in widespread tree mortality in lodgepole pine stands across the Colorado Plateau. Due to the complex interactions between vegetation and snow, it is likely that changing vegetation structure will impact water yield, as snow represents the dominant input of water into these semi-arid mountain ecosystems. We hypothesize that the affected stands will experience a change in sub-canopy hydrolometeorological fluxes and surface albedo, thus influencing snowmelt rates. The result of these impacts on the basin scale hydrology is largely unknown given the complexity of these micro-scale interactions. We developed a mechanistic approach to resolve the spatio-temporal evolution of snowmelt and snowpack characteristics at the micro-scale (i.e. < 10 cm) for stages of beetle-related tree mortality using distributed hydrologic instrument clusters, hyperspectral snowpack characterization techniques, a distributed snowpack model (SNTHERM), and hemispherical photography. Our modeling results exhibit melt rates 1.1 and 3.4 times that of rates in unaffected stands for affected stands in intermediate and advanced stages of mortality, respectively. With the aid of remotely sensed snow and vegetation information, these results will provide the basis for larger scale simulations of the hydrologic impacts of beetle infestation across the Colorado River Basin.

The Role of Zooplankton Grazers in Harmful Algal Blooms in the Santa Monica Bay, CA

Ellen Dempsey

Advisor: Dr. Rebecca Shipe

Harmful Algal Blooms (HAB) are a growing global and local problem; toxins as well as decay of high cell abundances can be deleterious to birds, mammals, and even humans. Zooplankton are consumers of phytoplankton; most have feeding preferences and thus may contribute to the preferential growth of certain taxa. In this study, we hypothesize that zooplankton will graze preferentially on non-toxic species, allowing toxic species to bloom. Weekly abundances of zooplankton were determined at the Santa Monica pier near the SCCOOS monitoring station using a vertical net tow through the first meter of sea water. During the period of sampling we observed two periods of zooplankton abundance, a bloom of non harmful diatoms, and a bloom of harmful dinoflagellates. During the study, it is likely that environmental factors, such as water temperature and salinity, exert a greater control on HAB taxa abundance than zooplankton. The complicated relationship between zooplankton and harmful algae are important to understand as we try to predict the timing and composition of HABs.

Growth of a rhizophytic and a non-rhizophytic Halimeda species in response to water column and sediment enrichment

Riley Clagett, Natalie Ma, & Casey Sheridan

Advisor: Dr. Peggy Fong

Anthropogenic nutrient input is an ever increasing problem in tropical coastal marine ecosystems. Long term nutrient enrichment of the water column leads to enrichment of benthic sediment, which could in turn affect the algal community. In our study we investigated the effect of water column nutrient enrichment and sediment nutrient enrichment on the rhizophytic algal species Halimeda incrassata and the non-rhizophytic species Halimeda opuntia. We initially proposed that sediment enrichment would lead to greater growth in H. incrassata than H. opuntia, while water column enrichment would lead to greater growth in H. opuntia than in H. incrassata. A field experiment was performed in Cook’s Bay in Moorea, French Polynesia, where both Halimeda species were exposed to no enrichment, sediment enrichment, water enrichment, or sediment and water enrichment and growth was measured by segments. A corresponding microcosm experiment with the same nutrient treatments was also done, but with each algal species either alone or with the other species to determine effect of competition on growth. We found that sediment had a negative effect on H. incrassata in both experiments, resulting in reduced growth compared to unenriched algae. In the field experiment, sediment enrichment had a positive effect on H. opuntia’s growth, but only when water enrichment was not present. In the lab experiment, however, sediment enrichment had a negative effect on H. opuntia’s growth. Overall, our results indicate that many of our sediment and sediment/water enriched samples may have become overloaded with nutrients, which resulted in death of the algae. This provides evidence that sediment of Cook’s Bay is already high in nutrients, and may be undergoing a community shift as a result continuous anthropogenic nutrient influx.

Contribution of Diatoms to Carbon Export in Coastal Oceans

Sarah E. A. Diringer

Advisor: Dr. Rebecca Shipe

Single celled marine primary producers provide a sink for excess CO2 in the atmosphere caused by burning fossil fuels and changes in land use. However, it is unclear how effectively they can sequester carbon to depth, especially in coastal regions. Diatom (class Bacilliariophyceae) blooms represent an increase in ocean surface biomass during upwelling and increased nutrient events, and are the dominant primary producers in coastal upwelling regions such as the western US coastline. However, the ability of diatoms to sequester carbon by settling out of the water column or by contributing to biomass in higher trophic levels is highly debated. Many suggest that bacterial decomposition of diatoms accounts for a large amount of carbon release before settling, significantly reducing carbon sequestration (Boyd et al. 2004). This study examines the portion of coastal biomass, as indicated by biogenic silica, which sinks below 250 meters, and evaluates three major hypotheses regarding export of organic material by diatoms to the deep ocean. Contribution of Diatoms to Carbon Export in Coastal Oceans.

Corporate Climate Stewardship – does it pay to think green? A pre- and post- Copenhagen analysis

Victor Weisberg

Advisor: Prof. Matthew Kahn

Most profit-driven managers would like to believe that it is not their responsibility to be environmentally conscious. Yet several researches have documented that on several occasions, environmentally intelligent choices by management have helped firms secure market confidence in times of regulatory uncertainty. These ‘it pays to be green’ scenarios, though infrequent, require management to address public and scientific concern prior to it becoming a material issue. This forward-thinking judgment and initial action should be seen as an investment for the long-term well-being of the company rather than an untimely deadweight costs. Climate change and climate risks are an intimate threat to both the world and financial markets, and very shortly these risks will materialize to investors and in turn, management decisions around climate change will be tested. Using CDP data of firm’s carbon reporting, I tested the effect of the Copenhagen Conference on stock price. This research discovers that non-disclosing firms were significantly less favored than reporting firms during the period that China and India signed on to the accord.

Decreased Water and Increased Yields in the Westlands Water District

Jenna Martin

Advisor: Dr. S. Trimble

Less water availability to farmers has resulted in a pursuit for new irrigation technologies and water management. My senior capstone utilized remote sensing techniques to analyze spatial, spectral, and temporal domains of water reduction in the Westlands Water District, as well as examined a case study of one farmer’s success in sustaining agricultural production in spite of restricted water availability. This project compared crop yields of conservation irrigation to conventional farming to determine if a comparable or superior yield is possible with decreased water distribution through more sustainable management decisions. Results implied that an average of 25-50% less water was required by a center pivot machine using Low-Elevation Spray Application (LESA), and produced 122% more tomatoes compared to the California average for conventionally irrigated tomatoes. These field data collections were coupled with remote sensing technology to monitor the Westlands Water District during the periods of June, July, and August of 1999 through 2009 using Landsat 4-5 Thematic Mapper+ and Moderate Resolution Imaging Spectroradiometer (MODIS) imagery. It was found that trends in fallowed land were found to be increasing, most likely in response to the trend of reduced water supply in the Westlands Water District. A definite increase in fallowed land and reduced “greenness” (cultivation) can be associated with concurrent policies to reduce water allocations. This capstone examined benefits and limitations of irrigation efficiency through sustainable irrigation strategies, as well as applied a remote sensing approach of observing water resource reductions in an agricultural region of California’s Central Valley.