ORAL ABSTRACTS IN PROGRAM ORDER

URBAN BIODIVERSITY

1. ASSESSING AND IMPROVING THE ECOLOGICAL FUNCTION OF LINEAR PARKS ALONG THE LOWER LOS ANGELES RIVER CHANNEL

D.S. Cooper¹, N.D. Katz², M. Rogers², and F.M. Osborn².

¹ Resource Conservation District, Santa Monica Mountains, 540 S. Topanga Canyon Blvd., Topanga, CA 90290,        ² University of California, Los Angeles, CA 90095

Long overlooked by conservation groups and ecologists, urban open spaces are now seen as important contributors to biodiversity at various scales. Urban greenspaces often represent the only “nature” millions of human residents around the world ever interact with, and provide cooling and aesthetic relief from the urban hardscape. In the Los Angeles Metropolitan area, over the past three decades, non-profit advocacy groups and institutions have established a network of bike paths, neighborhood access points, habitat restoration, and recreational amenities along the Los Angeles River, a major urban waterway. We investigated the environmental contribution provided by numerous linear landscaped parks along the river, focusing on climate amelioration (i.e., cooling within heat islands) in the parks and surrounding neighborhoods, and on their contribution to local biodiversity, utilizing an indicator species approach. We conducted plant surveys of the parks, documenting locally native, non-local California native, and non-native species, and examined the occurrence of 15 riparian indicator species of wildlife in the parks and in 500-meter buffer zones surrounding each park utilizing citizen science data. We then explore correlations between indicator species richness and environmental variables. We note important occurrences of relict riparian vegetation in several linear parks, as well as both planted and naturally-occurring special-status plant and wildlife species. Finally, we discuss challenges to managing natural habitat in highly-urban parks, many of which support important relict vegetation and/or special-status species, and offer suggestions on how they may be improved.

2. HARNESSING INATURALIST TO QUANTIFY HOTSPOTS OF URBAN BIODIVERSITY IN GREATER LOS ANGELES

T.W. Delaney³, J. Beninde^1,2, G. Gonzalez³, H. B. Shaffer^1,3

¹La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, University of California Los Angeles, Los Angeles, CA 90095, USA, ² Member, IUCN WCPA Connectivity Conservation Specialist Group, ³ Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA

An important goal in conservation planning is the identification, prioritization, and management of appropriate areas for species and ecosystem protection. However, such spatial prioritization is often hampered by limited data availability and driven by a handful of iconic species rather than overall biodiversity protection. Given that patches of optimal habitat and corridors connecting them are necessary for the long-term survival of virtually all species, we argue that generating a very large set of spatially explicit habitat suitability models drawn from as many local species as possible should enable optimal, place-based conservation prioritization. Focusing on parts of the Greater Los Angeles metropolitan area, we modeled habitat suitability for 1,200 terrestrial species, each with at least 25 occurrence records available from the community-science platform iNaturalist. Joint suitability models from across this data set provides the basis for data-driven management actions, elevating the benefit of those actions both for the sampled and unsampled biodiversity of the region. We generated models using different algorithms, settings and spatial extents, and validated those models using an independent testing dataset. Given the increasing availability of urban biodiversity data on platforms such as iNaturalist, this modeling framework can be applied to other regions to quantify habitat suitability for a large, representative subset of the locally occurring species pool. This provides a data-driven baseline for further ecological research, conservation decision-making, and prioritization of local biodiversity hotspots, allowing for maximum impact of current and future conservation efforts.

3. QUANTIFYING AND VALIDATING HABITAT CONNECTIVITY ACROSS GREATER LOS ANGELES

M. Harris¹, L. “Bucky” Squier¹, L. Thomas¹, L. Villa¹, J. White¹, K. Dutko¹, E. Ha¹, A. Mahadi¹, J. Saum¹,  M. Barton², K. Superfisky²,  S. Parker³ H. B. Shaffer^1,4, Z. MacDonald^1,4, and J. Beninde^1,4

¹UCLA Institute of the Environment and Sustainability Senior Practicum

²LA Sanitation, The City of Los Angeles

³The Nature Conservancy

⁴UCLA La Kretz Center for California Conservation Science

Two factors are paramount in maintaining urban biodiversity: 1) suitable habitat patches within urban areas, and 2) connectivity among these habitat patches. Connectivity is an essential condition for long-term species persistence because it maintains natural movement dynamics, reduces potential inbreeding, and allows recolonization of uninhabited, but suitable habitat. The City of Los Angeles and The Nature Conservancy (TNC) are currently involved in multiple local and regional efforts to incorporate connectivity into urban biodiversity conservation planning efforts, but quantifications of connectivity are still only available for a handful of species or rest on a singular assessment of habitat quality, making spatial prioritization for all species difficult. Our project, which is a collaboration with the City of Los Angeles and TNC, has three primary goals: 1) generate current flow connectivity surfaces for 1023 species, using the spatial modeling frameworks of MaxEnt and Omniscape, 2) validate the connectivity surfaces using both community science data from iNaturalist and field observations generated by our team, and 3) produce combined connectivity surfaces across functional groups of species to generate “heatmaps” of connectivity that can be implemented into urban conservation planning to maximize connectivity for many species.  Our study is the first to quantify species-specific connectivity surfaces that can be utilized in conservation planning to preserve overall connectivity across Los Angeles’ fragmented urban landscape, and help minimize the risk of local species extinction and maximize the potential to maintain high levels of urban biodiversity.

4. LARGE CITIES FALL BEHIND IN “NEIGHBORHOOD BIODIVERSITY”

D.S. Cooper¹, E.M. Wood², N.D. Katz³, K. Superfisky⁴, F.M. Osborn⁵, A. Novoselov⁶, J. Tarczynski⁶ and L. K. Bacasen¹

¹ Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, 90095. ² Department of Biological Sciences, California State University Los Angeles, Los Angeles, CA, 90095. ³ Department of Sustainability, University of California, Los Angeles, Los Angeles, CA, 90095. ⁴ Department of City Planning, City of Los Angeles, Los Angeles, CA, 90012. ⁵ Department of Geography, University of California, Los Angeles, Los Angeles, CA, 90095. ⁶ Institute of Environment and Sustainability, University of California, Los Angeles, Los Angeles, CA, 90095.

Urbanization is a major driver of global species loss. While cities with suitable habitats and conservation policies may support locally-high biodiversity levels, we suspected that the complexity of managing large cities might counteract the advantage of geographic area, and these cities may be less effective at biodiversity conservation. To answer this, we examined the relationship between the number of native indicator wildlife species (mean and maximum) in 112 cities across three metropolitan areas in California (Los Angeles, San Diego, and San Jose), with metrics related to scale and environmental variables. We found that indicator species richness is positively related to area, income (the luxury effect), and pervious cover—including trees, shrubs, and grasses. Despite having a high maximum number of indicator species within their boundaries, the largest cities in our study, Los Angeles, San Jose, and San Diego, do a relatively poor job compared with smaller cities at distributing native biodiversity throughout neighborhoods, as measured by their mean species richness. Such variation in “neighborhood biodiversity” may exacerbate existing inequities in residents' access to nature. Using Los Angeles County as a case study, we compared biodiversity management within the County's 88 cities of various sizes and characteristics. We ranked General Plan wording in terms of references to biodiversity and conservation and created a management metric. We found that municipalities of various sizes that had high management scores generally had high indicator species richness. This suggests that robust policies may be able to overcome the challenges posed by city size and population.

5. WILDLIFE AFFORDANCES OF URBAN INFRASTRUCTURE: A FRAMEWORK TO UNDERSTAND HUMAN-WILDLIFE SPACE USE

C.A. Niesner¹, R.V. Blakey¹, D.T. Blumstein^1,2, and E.S. Abelson³

The Institute of the Environment and Sustainability, University of California, Los Angeles, Los Angeles, CA. ²Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA.³Department of Integrative Biology, University of Texas at Austin, Austin, TX.

Landscape affordances, or what the environment offers an animal, are inherently species-specific to the extent that each taxon has unique needs and responses to landscape characteristics. Wildlife responses to landscape features range on a continuum from avoidance to attraction, and quantifying these habits are the backbone of wildlife movement ecology. In anthropogenically modified landscapes, many taxa do not occupy areas heavily influenced by humans, while some species seem to flourish, such as coyotes (Canis latrans) and pigeons (Columba livia). Sufficient overlap in landscapes designed for human purposes (e.g., freeway underpasses, channelized waterways, and cemeteries) but which are also suitable for wildlife (e.g., by providing sources of food, shelter, and refuge) underlies wildlife persistence in urban areas and is increasingly important in the world's largest metropolises. Studying these overlapping worlds of humans and wildlife in cities provides a rich foundation for broadening human perceptions of cities as ecosystems that exhibit emergent hybridity, whereby certain anthropogenic features of urban landscapes can be used by wildlife even as they maintain their utility for humans. By examining scaling dynamics of the infrastructural signature, the phenomena of urban wildlife movement patterns conforming to the shapes of human infrastructural forms, we hope to expand on prior research in wildlife landscape ecology by stressing the importance of understanding the overlapping worlds of humans and wildlife. Further knowledge of the urban ecological commons is necessary to better design cities where emergent hybridity is leveraged toward the management goals of reducing human wildlife conflict and promoting biodiversity.

6. BALANCING BIODIVERSITY AND HUMAN DEVELOPMENT IN THE CITY OF LOS ANGELES, CALIFORNIA

K. Superfisky, City of Los Angeles, 200 N. Spring Street, Los Angeles, California 90012

Urban areas are uniquely positioned to have a significant impact on biodiversity and the health and resilience of ecosystems and therefore play an essential role in advancing conservation goals. Unlike more “wildland” ecosystems, urban ecosystems are not solely owned and/or managed by public entities or with the sole goal of ecosystem restoration. The important plants, animals and ecosystems in cities are scattered across open spaces and public parks that are already protected and being managed for conservation, as well as on private properties that often comprise the majority of land in cities, which supports the need to address biodiversity and climate resiliency at multiple scales, on various land uses, and through a diverse array of strategies. Municipal governments, such as the City of Los Angeles (City), can play an essential role in addressing biodiversity and habitat connectivity on both public and private land in cities through plans, reports and policies that can help to create more “symbiotic cities”. Since public lands are largely already “protected”, it is critical to look to private property protections to ensure a cohesive approach to managing urban ecosystems. As such, the City’s Department of City Planning is proposing a Wildlife Ordinance that will enact a set of land use regulations that aim to balance private development with the need for wildlife habitat and connectivity (via standards related to grading; residential floor area; lot coverage; vegetation and landscaping; height; fences and walls; lighting, windows; and trash enclosures).

7. BIG CITY BLUES: THE EFFECTS OF URBANIZATION ON WESTERN FENCE LIZARD (SCELOPORUS OCCIDENTALIS) BODY SIZE AND ECTOPARASITES

E.R. Urquidi¹, B.J. Putman², ^1,2Department of Biology, California State University San Bernardino, San Bernardino, CA 92407

As urbanization increases, animals are subjected to new stressors caused by human activity. If they adapt to these new conditions, animals are still left with limited land and resources. These harsh conditions along with novel stressors may affect animal health. The health of animals can affect reproduction and survival (i.e., their fitness). Here, we compared body measurements from 145 lizards caught at two replicate urban and natural sites located in two different areas of Southern California: San Bernardino and Claremont. One sample was taken from an urban population, which consists of relatively high human population densities and high levels of impervious surface, and another from a natural population, which consists of mostly intact sage scrub habitat. We focused on measurements such as body size (SVL), body mass, body condition, and ectoparasites. Due to limited space and shifts in food availability caused by fragmentation, we predicted that urban lizards would be of smaller size, mass, and ultimately be in worse body condition. Some ectoparasites have complex life cycles, so we predicted that lizards from urban areas would have fewer parasites. We found that both the level of urbanization and study site affected SVL, as lizards in urban Claremont had significantly lower SVLs compared to lizards in the natural Claremont site. We also found there were fewer ectoparasites in urban areas.  Lastly, we found that urbanization had no significant effect on body condition. In conclusion, our study shows that urbanization may affect certain aspects of health in western fence lizards
 

8. URBANIZATION AFFECTS THE COLORED THROAT PATCHES OF WESTERN FENCE LIZARDS (SCELOPORUS OCCIDENTALIS)

B.J. Stevens¹, B.J. Putman¹. ¹Department of Biology, California State University, San Bernardino, CA 92407.

As urban environments increase, animals are subjugated to an increasing amount of human-induced stressors. These stressors force animals to either flee, adapt, or perish. Habitat fragmentation, unnatural surfaces (e.g., concrete), and busier or more colorful backgrounds are all stressors introduced by urbanization. These novel stressors may cause disruptions in communication between visually communicating animals. We compared 120 Western Fence Lizards (Sceloporus occidentalis) that were captured at two parallel urban and natural sites located in different cities of Southern California, San Bernardino and Claremont. The natural samples came from mostly intact sage scrub habitat and urban samples came from areas with heavy traffic and a high impervious surface concentration. Our focus was on the ventral colored patches of the lizards that are used for visual communication between males. We predicted that there would be a difference in the size of the patches relative to body length between lizards from a natural versus urban environment. We thought this because of the novel challenges for visual communicators in urban environments. We found that urbanization did affect the throat patch size with urban lizards having significantly larger throat patches than their natural counterparts. Further research on this could show us if the larger patches are truly an adaptation to urbanization, meaning that they improve communication between territorial males in urban areas based on the signaling background (i.e., the signal to noise ratio).

9. TERRESTRIAL MOLLUSK DISCOVERIES IN PARTNERSHIP WITH iNATURALIST PARTICIPANTS

J.E. Vendetti^1
1 Urban Nature Research Center & Department of Malacology, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, CA, 90007

Introduced land snails and slugs (versus native species) make up the majority of the terrestrial molluscan fauna in urban and developed parts of Southern California. Species from around the world have been introduced accidentally or intentionally; with horticultural goods, in shipping containers, and for culinary use. For highly pestiferous and invasive snail and slug species, early detection is essential for removal or population control. Specimen collection from introduced population(s) is also imperative for natural history museums, which care for collected specimens and enable their scientific study. The online biodiversity community iNaturalist is a valuable resource for determining new species introductions and documenting their spread. In two recent examples, the introduced snails Polygyra cereolus (Muhlfeld, 1816) and Veronicella cubensis (Pfeiffer 1840) in California were made aware to the author via iNaturalist users and their observations. These led to specimen collecting and genetic analysis of both species, yielding insights into their identity and provenance. Therefore, thoughtful use of iNaturalist observations can reduce detection time for newly introduced species and create relationships between professional and avocational naturalists.

10. Community Science Reduces Detection Times for Invasive Reptiles and Amphibians in Southern California

G. B. Pauly¹

¹Urban Nature Research Center and Department of Herpetology, Natural History Museum of Los Angeles County, Los Angeles, CA 90007

Urbanization presents one of the world’s greatest biodiversity threats. Not only is urbanization responsible for habitat modification, but the number of people and goods moving through urbanized areas also increases the chance of nonnative species being introduced. Because of the increased availability of water and thermal retreats, urban areas can also allow nonnative species to get established in regions that otherwise would prove inhospitable. As a further complication, urbanized areas largely consist of private properties (e.g., backyards) that are difficult for biologists to access. Fortunately, community science can be an effective method for documenting urban biodiversity. By partnering with community scientists via the iNaturalist platform, we have documented seven new state records and 25 new county records of nonnative reptiles and amphibians in California over the past 10 years. New state records include the recent (summer 2022) discovery of two introduced lizard species, one of which occurs in two populations on opposite sides of the Transverse Ranges. Early detection and rapid response (EDRR) is widely recognized as being essential to minimizing impacts of invasive species. Community science efforts are dramatically improving early detection for a broad suite of taxa. These results highlight that implementation of EDRR approaches in California and elsewhere are now mostly dependent on having the resources available to quickly mount a rapid response once an invasive species is detected. Thus, more efficient and economical control of invasive species requires policymakers to increase funding mechanisms for rapid response efforts.

11. POPULATION AND LANDSCAPE GENETICS OF BLACK-BELLIED SLENDER SALAMANDERS ON SANTA CRUZ ISLAND AND IN THE SANTA MONICA MOUNTAINS, CALIFORNIA

R.V. Hogg¹, K.S. Delaney², M.A. Murphy³, G.B. Pauly^1,4, J.M. Robertson^1,4

¹Department of Biology, California State University, Northridge, Northridge, CA, 91330; ²U.S. National Park Service, Thousand Oaks, CA, 91360; ³University of Wyoming, Laramie, WY, 82071; ⁴Natural History Museum of Los Angeles County, Los Angeles, CA, 90007

To identify conservation priorities for populations of Black-bellied Slender Salamanders (Batrachoseps nigriventris), we collected and analyzed 280 tissue samples from Santa Cruz Island and the Santa Monica Mountains, California. We quantified genetic divergence between island and mainland populations and found high levels of divergence. We characterized genetic structure within our study areas. Finally, we tested alternative hypotheses for landscape factors which would best explain observed genetic distances using remotely sensed GIS layers. We contrast these results for the island and mainland populations and discuss implications for management.

12. WHY ARE THERE SO MANY BUGS IN MY BACKYARD? HOW PATTERNS OF WEALTH AND LOCAL ENVIRONMENT DRIVE INSECT BIODIVERSITY ACROSS THE LOS ANGELES METROPOLITAN AREA

T. Baiotto¹, A. Baker^1,2, B.V. Brown², Y.Y. Cheung¹, C. Lehnen³, J. Lewthwaite¹, V. Shirey¹, J. Willoughby¹ and L.M. Guzman¹

¹Ecological Data Science Lab, Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089. ²Natural History Museum of Los Angeles County, Los Angeles, CA 90007. ³ Integrative and Evolutionary Biology,

Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089.

Insects are a vastly understudied group, and understanding the landscape and environmental drivers of insect distributions is of utmost importance. Urbanized environments are significantly different from their natural counterparts and may have unique biodiversity patterns as a result of environmental gradients and human-made landscapes. The luxury effect hypothesis - which suggests higher biodiversity is associated with areas of higher socioeconomic status in urban areas - has been linked to urban avian biodiversity patterns in several cities. Here, we seek to assess and compare the strength of the luxury effect hypothesis to environmental predictors in explaining insect biodiversity across Los Angeles. To accomplish this, we use family-specific occupancy models to quantify the association of neighborhood land value and several environmental covariates (monthly precipitation, average temperature) to species occupancy for hundreds of insect species. Preliminary results show neighborhood wealth to be a strong predictor, further supporting the luxury effect hypothesis for urban biodiversity for taxa beyond avians.

13. THE BACKYARD BAT SURVEY: ACOUSTIC BAT SURVEYS AND ROOST EMERGENCE COUNTS IN LOS ANGELES, CA

M.A. Ordeñana¹, A.J. Jones¹, R.V. Blakey², and T. Weller³

¹Urban Nature Research Center, Natural History Museum of Los Angeles County, Los Angeles, CA 90007. ²Biological Sciences Department, Cal Poly Pomona, Pomona, CA 91768. ³Pacific Southwest Research Station, United States Forest Service, 1700 Bayview Drive, Arcata, CA 95521.

Collecting biodiversity data from urban areas is extremely challenging because the mosaic of private properties limits access. Most bat species are considered intolerant of urbanization, though 16 known bat species persist in Los Angeles County. Previous local studies focused on large urban wildernesses, and little is known about bat habitat use in the urban core. In 2016, we began the Backyard Bat Survey, an acoustic community science survey, to conduct the first large-scale study of habitat usage by bats in urban and suburban habitats of Southern California. A total of 72 sites were surveyed between 2016 and 2021, and 12 bat species were detected, including four California Species of Special Concern. Some urban adapted species that are common throughout North America are surprisingly scarce, whereas some foliage roosting specialists are more common than expected and more widely distributed compared to what is represented in museum collections. Our preliminary results suggest certain species are more adaptable or sensitive to urban settings than previously thought. Further investigations into urban bat habitats can guide urban planning for the benefit of bat conservation, especially when supplemented by bat roost emergence counts. Community science roost surveys were initiated in 2021 and conducted at 11 sites, indicating that Los Angeles County bats utilize a variety of urban bat structures, but more research is needed to identify species-specific preferences, especially for more sensitive species.

14. THE RELATIVE EFFECTS OF DROUGHT AND URBANIZATION ON TERRESTRIAL MAMMAL OCCUPANCY IN SOUTHERN CALIFORNIA

B.A. Rawles¹, E.M. Wood¹ and A.J. Zellmer²

¹California State University, Los Angeles.  ²Occidental College.

Urbanization and climate change are two dominant forces that negatively affect biodiversity globally. While numerous studies have examined the effects of urbanization or climate change on biodiversity, few have explored how extreme weather events, which are related to climate change, have affected animal occupancy within urban ecosystems. To fill this gap, we quantified the potential for a global megacity, Greater Los Angeles (LA), to function as a refuge for mammalian communities during a historic drought. We collected camera-trap data during the rainy season (November through March) from 2018 to 2022 at three transects situated along an urban-rural gradient. During the sampling period, the region experienced three abnormally dry years, and one abnormally rainy year, which allowed for a comparison of mammalian occupancy patterns among dry and wet years. Using auto-logistic occupancy modeling and multivariate analyses, we found that prey species such as rabbits (Sylvilagus spp.) and mule deer (Odocoileus hemionus) were more common during the 2020/21 and 2021/22 drought years within the wildland-urban interface, as opposed to more natural areas, where they were more common during the wet years of 2018/19 and 2019/20. Predators, such as the bobcat (Lynx rufus) and coyote (Canis latrans) followed similar patterns, suggesting both prey and their potential predators shifted occupancy patterns between wet and dry years. Our results highlight effects of drought on mammalian communities within and adjacent to LA and may inform conservation e.g., wildlife corridors, through illumination of the seasonal use of cities by wildlife.

15. DESCRIBING THE ECOLOGY OF TICKS AND RELATED VERTEBRATE HOSTS IN URBAN GREENSPACES OF SOUTHERN CALIFORNIA

C. Sandoval¹, J.L. Ortiz¹, and R. Hanselmann²

¹California State Polytechnic University, Pomona, Pomona, CA 91768 ²Western University of Health Sciences, Pomona, CA 91766

A major way the intersection between people and wildlife may emerge is through ectoparasites, specifically hard ticks (family: Ixodidae), and their potential spread from urban wildlife hosts to people and their pets. This project explores the dynamics of potential risks for tick exposure and related conflicts with urban wildlife along a gradient of urbanization in Southern California. The study area is within the San Gabriel Valley in Los Angeles County and is composed of various urban greenspaces, including hiking areas, city parks, or other open spaces where people and their pets may recreate. Camera traps are used to document urban wildlife species which have the potential to act as tick hosts. The drag cloth method is used to detect the presence of ticks in the greenspaces, and ticks are collected and identified to species. Finally, a survey of pet owners was developed to gauge public knowledge and perceptions surrounding pet ownership, outdoor recreation, urban wildlife, and ticks. This information will be synthesized to describe the ecology of urban wildlife and ticks within urban greenspaces of the San Gabriel Valley, and results from the survey will identify areas of needed outreach and education to answer concerns of potential tick-borne disease exposure in, or around, urban areas. Two species of ticks have been collected and identified so far, and numerous potential vertebrate host species have been documented by the array of camera traps.

16. BEYOND SIDEWALKS: USING A DYNAMIC URBAN CLASSIFICATION SYSTEM TO STUDY THE EVOLUTION OF AN INVASIVE PLAN

A. Dant¹

¹Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85705.

In the past 200 years, urbanization has changed environments dramatically across the globe. In response to these new urban environments, organisms are experiencing new ecological and  evolutionary changes. A major open question is how exactly different aspects of urban environments favor different phenotypic traits. Using the invasive, annual plant Centaurea melitensis as a focal organism, I am testing how the classification of urban environments can be applied to understanding phenotypic and genotypic differentiation across an urban gradient in California. To classify urbanization, I have categorized census tracts across California into different urban types through a hierarchical cluster analysis. I collected seeds from sixteen populations of C. melitensis across multiple urban types in California and am growing them in greenhouse conditions to quantify phenotypic variation. I am measuring life history traits involving growth and reproduction including the number of leaves, number of flower heads, specific leaf area, and total above ground biomass. Preliminary results show significant differences for the number of leaves and flower heads across urban types. Future directions include a genome-wide association study (GWAS) and genome environmental association study (GEA) to identify the genetic basis of trait differentiation and its association with urban environmental heterogeneity. The results of this study will inform our understanding of how different aspects of urbanization affect ecological and evolutionary change of urban species.

17. A COLLABORATIVE SOCIAL-ECOLOGICAL RESEARCH APPROACH TO INFORM AND ADDRESS URBAN COYOTE MANAGEMENT CHALLENGES

M.J. Weaver¹, E.G. Strauss^2,3, M. Romolini², and L. Fimiani²

¹Arizona State University, Tempe, Arizona 85281
²Center for Urban Resilience, Loyola Marymount University, Los Angeles, CA 90045

³Biology Department, Loyola Marymount University, Los Angeles, CA 90045

Coyotes (Canis latrans) play an important mesopredator role in urban habitats and provide valuable ecosystem services, but also risk factors to human safety. Because of rare, but high-profile instances of human-coyote conflict, urban coyotes are often perceived as a nuisance, or even dangerous, to human populations and their domestic animals. This tension between urban wildlife and communities can result in policy and management decisions that are not effective or beneficial to either population. We believe that effective urban coyote management requires an understanding of the resident coyotes in a given city, as well as the human residents’ behavior, knowledge, and perceptions related to coyotes. This type of assessment can be done as a collaboration with researchers and city leaders to inform wildlife management and educational outreach. In this research note, we describe one such social-ecological research and outreach approach that has been implemented in two cities in Southern California: Long Beach and Culver City. Components of these projects include: identifying coyote movement patterns through motion activated cameras; examining coyote diets through analysis of scat samples; gathering information about resident knowledge and behavior through public surveys; and developing formal and informal curricula to be used in public education and outreach programming. We will describe this process in detail, provide early findings, and highlight instances of particular success and difficulty in implementation. We will close with a discussion of implications for wildlife management and environmental stewardship in urban settings.

18. EFFECTS OF COMMON DISTURBANCES ON SOIL MICROBIAL ASSEMBLAGES IN SOUTHERN CALIFORNIA

W. M. Meyer III¹

¹Pomona College, Claremont, CA 91711

Understanding how common disturbances influence soil microbial (bacteria and fungi) assemblages is a foundational step to understanding how disturbances influence ecosystem structure and function. Synthesizing data from multiple studies conducted in my lab, I provide a framework for understanding how invasive plants and fire influence soil microbial communities. In all studies, we compared microbial assemblages in intact native California sage scrub to those in adjacent invaded sites dominated by either non-native grass or mustard (forb) plant species. When examining the effects of fire, we resampled sites previously surveyed comparing microbial assemblages in sage scrub and invaded areas prior to and six months following the fire. Results highlight that microbial assemblages differ among the native and invasive habitats and that microbial abundances are elevated in invasive grasslands and reduced in non-native forblands, relative to native sage scrub. Differences in abundance correspond to soil C and N storage with sage scrub storing more C and N than non-native grasslands, while soil in non-native forblands had similar or elevated nutrient concentrations. We found that the direct effects of fire had minimal impact on microbial assemblages, and that differences in assemblages between native and invaded areas persist after the fire suggesting that modifications in plant compositions can have long-lasting legacy effects. Because direct effects of fire on soil microbial assemblages are minimal but modification of plant composition are significant, preservation of sage scrub habitat particularly after a fire is critical to preventing long-lasting changes in microbial assemblages and ecosystem structure and function.

19. RESPONSE OF THE WESTERN FENCE LIZARD (SCELOPORUS OCCIDENTALIS) TO POST-FIRE DISTURBANCES

S.E. Ruck¹, B.J. Putman². ^1,2Department of Biology, California State University, San Bernardino, CA 92407.

Wildfire activity is growing globally with increased frequency, intensity, and duration. After a fire occurs, organisms across a range of taxonomic levels are impacted by altered habitats, including reduced resources and increased predation risk. Although there are studies assessing post-fire effects on organisms, these typically address population abundances and densities after a fire. To better understand how organisms are affected at the individual level after a wildfire, we collected male and female Western Fence Lizards (Sceloporus occidentalis) from unburned (> 100 years since last known burn), recently burned (< 1 year since last burn), and older burned habitats (< 2 years since last burn) within Southern California. We conducted Flight Initiation Distance (FID) trials to better understand how animals assess risk in fire-disturbed habitats. Habitat type did not significantly affect FID. However, lizards were significantly easier to spot higher up in burned habitats as well as at farther distances. Additionally, we collected morphological data and ectoparasite counts in order to assess the effects of habitat type on lizard health. We found that lizards from older burned habitats had significantly reduced body condition compared to lizards from unburned habitats. We also found that recently burned habitats had a higher proportion of lizards with less ticks compared to unburned and older burned habitats. Conducting post-fire studies at the individual organismal level can be used to inform conservation management decisions for species that are found in fire-prone areas across the globe.

MICROPLASTICS

20. Roland Geyer.

21. PLASTIC POLLUTION OF THE SOIL AND ITS CONSEQUENCES: AN UNDERAPPRECIATED EXTERNALITY OF FOOD PRODUCTION

S. Sistla. and E. Tiwari. Natural Resources Management & Environmental Sciences, College of Agriculture, Food & Environmental Sciences, Cal Poly

Single-use plastic in the agriculture sector has grown exponentially in the past decade, with plastic mulch now covering millions of acres of land worldwide. U.S. farms generate nearly 860 million pounds of plastic waste annually; this waste stream is dominated by single-use low density polyethylene (LDPE) mulches used in row crops. Due to its thin and pliable nature, LDPE mulch aggregates with soil particles in the field, challenging removal and the potential to recycle recovered mulch material. Further, remnant mulch fragment into smaller particles which can become a serious threat to the environment and human health as these particles accumulate in the soil environment. The relationship between macro- and microplastic fragments on soil biophysical properties and how these changes relate to the extent or duration of plastic mulch use remains unknown. To address these knowledge gaps, we explored the abundance and composition of macroplastic and microplastic fragments across central CA farms which employed LDPE mulch. The concentration of macroplastic fragments—which were dominated by polyethylene— ranged from ~4000 particles/ha to over 200,000 particles/ha in surface soil following typical mulch removal, with our preliminary data suggesting MP concentrations of upwards of over 350 particles/kg dry weight of soil. We are currently exploring the relationships between plastic concentration and a suite of soil biogeochemical traits.   This study provides baseline data documenting the extent of plastic pollution in agricultural systems and can help improve land management practices by assessing the biogeochemical consequences of plastic accumulation in agricultural soils.

22. ADSORPTION OF PFAS TO SECONDARY MICROPLASTICS IN AQUATIC SYSTEMS: ROLE OF WATER CHEMISTRY AND PLASTIC AGING

A. S. Adeleye, O. A. Salawu

Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175, USA

The ecological risks of microplastics (MPs) may arise from their physical properties, chemical properties, and/or their ability to concentrate and transport other contaminants, such as per- and polyfluoroalkyl substances (PFAS). PFAS have been recovered from MPs isolated from aquatic systems, which suggests strong interactions between both contaminants in water. An understanding of how water physicochemical properties influence the adsorption of PFAS to MPs is useful for predicting PFAS loadings of MPs in waters, but this has been rarely studied for secondary MPs, which are abundant in the environment. In this study, we investigated the role of water chemistry (pH, ionic strength, natural organic matter [NOM], and temperature) and PFAS chemistry (chain length and functionality) on the partitioning of PFAS from water to the surface of secondary PET MPs. The PFAS considered include perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorobutane sulfonic acid (PFBS), and hexafluoropropylene oxide dimer acid (GenX), which are commonly detected in waters. PET MPs had higher adsorption kinetics rate constants for the carboxylic acids (PFBA and PFOA), and higher adsorption capacity (q_e) for the sulfonic acids (PFBS and PFOS). The q_e of PET MPs for PFAS decreased as pH or NOM concentration increased, and increased as salinity increased. This study shows that aqueous chemistry and physiochemical properties of MPs and PFAS influence PFAS interactions with MPs.

23. PLASTIC INGESTED BY SEABIRDS MAY RELEASE HORMONAL DISRUPTING CHEMICALS FOR MONTHS, RAISING CONCERN FOR LONG-TERM ENDOCRINE DISRUPTION

L. Van Hassel^1,2, C. Debier¹, M. Finkelstein², G. Scholl³, G. Eppe³, C. Tubbs⁴, R. Felton⁴

¹Catholic University of Louvain, Biochemistry of Nutrition and Environmental Toxicology Laboratory, 1348, Louvain-la-Neuve, Belgium ²University of California, Santa Cruz, Microbiology & Environmental Toxicology Department, Santa Cruz, CA, 95064, USA ³University of Liège, Mass Spectrometry Laboratory, 4000, Liège, Belgium ⁴San Diego Zoo Wildlife Alliance’s Beckman Center, Reproductive Science Laboratory, Escondido, CA, 92027, USA

Procellariiform seabirds are known to ingest plastics, yet data are lacking to understand the risk of exposure to plastic-associated chemicals [plastic additives and sorbed persistent organic pollutants (POPs)]. We investigated the bio-accessibility of plastic-associated chemicals released from ingested plastics over time by developing an in vitro Procellariiform seabird gastric model. Two polymers commonly ingested by seabirds, high-density polyethylene (HDPE) and polyvinyl chloride (PVC), were manufactured with two additives [decabrominated diphenyl ether (PBDE-209) and bisphenol S (BPS)], added to salt water with two POPs [2,4,4'-trichloro-1,1'-biphenyl (PCB-28) and 2,2',3,4,4',5'-hexachlorobiphenyl (PCB-138)] and tested for chemical release with our gastric model. While PCBs were completely desorbed within 5 days, < 5% of additives were released from the plastic bulk, suggesting that seabirds could be exposed to plastic-associated chemicals for many weeks or months, depending on how long the plastic was in the seabird’s digestive tract. Importantly, we found that plastic-associated chemicals can activate Procellariform seabird estrogen receptors, illustrating the potential long-term disruption of endocrine function from ingested plastic.

24. ENHANCING BREAKDOWN OF MICROPLASTICS IN CONTROLLED CONDITIONS: FUTURE SOLUTION?

A.A. Keller, Distinguished Professor, Bren School of Environmental Science & Management, University of California Santa Barbara, Santa Barbara, CA, 93106

Microplastics (MPs) are ubiquitous, and although it seems like they last forever, in fact they are slowly but surely degrading. However, their breakdown processes are generally too slow. This means that they are accumulating in landfills at an alarming rate, or they are in the environment, floating in the ocean or accumulating in soils. There are currently a few MPs that are biodegradable, but the question is: can we make many more plastics degradable? Can we compost them or reuse the monomers (building blocks) to make new materials? We present examples from recent studies that provide the path forward. The first one considers the breakdown of polyurethane foams, used in a myriad of applications, by selecting the appropriate building blocks. Next, hyperthermophilic composting is assessed for in situ biodegradation of sludge-based MPs. After 45 days of hyperthermophilic composting treatment, 43.7% of the MPs were removed from the sewage sludge, which is the highest value ever reported for MP biodegradation. Finally, we consider novel catalytic approaches such as photocatalysis, advanced oxidation process, and biotechnology as promising for transforming plastic wastes into valuable products. While these approaches are still at the research stage, there is considerable interest from industry to develop novel plastics and processes to enhance the breakdown of MPs before they reach the environment, in controlled conditions.

25. METATRANSCRIPTOMIC AND METAGENOMIC CHANGES DURING MICROBIAL COLONIZATION OF PLASTICS

Colleen Ahern¹, Elaina Blair¹, Becca Reynolds², Yuki Floyd², Patricia Holden², Michelle A. O’Malley^1,3

¹Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, United States; ² Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA; ³ Biological Engineering, University of California, Santa Barbara, Santa Barbara, CA, United States

Man-made plastics ultimately accumulate in unintended environments, where they form close contacts with microorganisms that colonize and co-exist with these recalcitrant materials. New ‘omics’ approaches offer a window to observe and quantify microbial colonization of plastics over time, and can also reveal certain metabolic pathways that are activated in the presence of plastics. Here, we use metatranscriptomic and metagenomic tools to track how microbial membership and gene regulation change in environmental settings where plastics accumulate. We focus on three representative ecosystems: marine, rumen/gut, and compost, where we have constructed different culture platforms to evaluate microbial selection and colonization of plastic materials during plastic incubation. Through this effort, we have been able to assemble genomes of microbes that associate with plastics, and also evaluate the key enzymes that are triggered during incubation. Moreover, amplicon sequencing was used to track the evolution of key taxa during incubation, as well as enrichment on target plastics in both a rumen environment and in a mock-compost environment.

26. SPECTROSCOPIC IDENTIFICATION OF MICRO/NANO PLASTIC CONTAMINATION USING OPTICAL PHOTOTHERMAL INFRARED

C. Bates¹

¹University of California, Santa Barbara, Santa Barbara, CA, United States.

Sustainability is an important goal in contemporary materials science, but many commercial applications still use conventional polymers that lack viable end-of-use recycling or degradation pathways. This talk will discuss new design strategies rooted in novel chemistry to render common pressure-sensitive adhesives recyclable and degradable without sacrificing traditional performance. Insights spanning monomer selection, copolymerization kinetics, and material properties provide a route to improve the sustainability of adhesives found in everyday consumer products and advanced technology alike.

27. SPECTROSCOPIC IDENTIFICATION OF MICRO/NANO PLASTIC CONTAMINATION USING OPTICAL PHOTOTHERMAL INFRARED

T. Yan¹, Jay Anderson¹, Mustafa Kansiz¹

¹Photothermal Spectroscopy Corp., Santa Barbara, CA, 93101.

Microplastics (MP), particles in the size range from 1 µm to 5 mm, have been recognized as a global problem. With the combination of manufactured MP’s and the breakdown of plastic waste, MPs are now ubiquitous in the environment, and have been found extensively in water, air, and soil.  There is clear recognition within the MP community that it is critical to understand the distribution of MPs, and there is increasing interest in the smaller MP particles, i.e., <20 µm in size.  The number of smaller particles grows roughly as the inverse square of their size, for example, suggesting there are ~100X more particles at 10 µm size than at 100 µm size.  Therefore, the study of these smaller MPs is critical to understanding the full scope of the impact of MPs.  Unfortunately, the primary tool used for MP analysis, µFTIR, has been shown to exhibit poor MP identification for particles <50 µm.  Raman spectroscopy has been more effective in the identification of MPs <50 µm, but it suffers from sensitivity, autofluorescence, and in some cases, can burn samples. Here we will highlight a new technique that is allowing research and identification of MPs in this smaller size fraction. This new technique is called Optical Photothermal Infrared or O-PTIR.  The O-PTIR provides IR absorption-like data even into the nanoplastic(NP) regime of <500 nm.

CONTRIBUTED PAPERS 1

28. PALOS VERDES REEF: RAPID REEF RESTORATION SUCCESS

D.J. Pondella II, J.P. Williams and C.M. Williams

Vantuna Research Group, Department of Biology Occidental College, Los Angeles, CA 90041

Palos Verdes Reef (PVR) is an artificial reef designed to restore rocky-reef associated marine species by directly restoring rocky-reef habitat that has been impacted by scour, sedimentation, and burial in the shallow subtidal portion of the Palos Verdes Peninsula. Following over a decade of design, planning, outreach, site surveying, and permitting, the reef was built in 2020 as 18 discrete high-relief modules using 52,729 tons of quarry rock placed proximate to natural rocky-reef habitat. This project was a unique endeavour as restoring lost habitat in situ and has not been attempted in a temperate rocky reef and kelp forest community. While the primary design criteria for PVR was fish production, it was also designed to be resilient to ongoing sedimentation and turbidity challenges on the peninsula. Modules, with variable relief from 1-4 m, were positioned in a formation that followed the natural orientation of existing hard substrate to allow sediment to pass through without settling and were designed to mimic a nearby natural high-relief seafloor feature that has proven to be resistant to burial and sedimentation while also featuring the highest fish biomass of any rocky reef in the region. Rocky-reef associated taxa rapidly recruited to the restoration site, with visible changes occurring within just a few months post-construction. In less than two years PVR achieved all of its restoration goals including the secondary goal of maintaining a giant kelp canopy. By any metric, this design far outperformed all other artificial rocky reefs in California.

29. THE INFLUENCE OF MARINE PROTECTED AREAS ON THE DIETARY NICHES OF CALIFORNIA REEF FISHES

M.E. Gutterman¹, M.A. Steele¹

¹California State University, Northridge, Department of Biology, Northridge, CA, 91330

A species’ diet is an indication of the role it plays in a community and the extent of its interactions with other species. However, it is not always clear to what degree these roles change at different locations and how much of the variation is tied directly to human activities degrading marine ecosystems. Marine protected areas (MPAs) have been shown to increase the population numbers and body size of harvested species, however, little is known about how these changes within MPAs influence the diets of species within them. This study looked at how MPAs influence prey availability, diet composition, and trophic position in California reef fishes. The diets of two fish species, Embiotoca jacksoni and Semicossyphus pulcher, were assessed inside and outside of MPAs. Preliminary data suggest that the diets of S. pulcher inside MPAs contain species from more taxonomic categories than those of S. pulcher from non-MPA study sites. In contrast, E. jacksoni shows the opposite pattern, with fewer taxonomic groups found in the stomach contents of fish from MPAs. These differences inside vs. outside of MPAs may reflect a shift in the dietary niche of these fishes within MPAs to accommodate increased competition due to higher population biomass within MPAs. Although many studies have documented enhanced densities and biomass of harvested species inside marine protected areas, this study supports the hypothesis that these larger populations result in tangible changes in dietary niche and trophic ecology.

30. SEASONAL MOVEMENT OF GIANT SEA BASS (STEREOLEPIS GIGAS) WITHIN THE SOUTHERN CALIFORNIA BIGHT

J. Peria¹, Steele, M.¹

1-California State University, Northridge

The giant sea bass, Stereolepis gigas, is an endangered apex predator, found in the kelp forests of California. During the summer months, there are several predictable locations at which this species is known to aggregate, most likely for spawning purposes, but little is known about the use of these sites from year to year. This study used spot pattern analysis to identify at least 179 unique individuals, photographed from 2012-2022, and monitor their use of various sites, including 8 confirmed aggregation sites in Southern California. Movement and residency of giant sea bass among the sites was monitored through photo identification. Long-distance movements among sites appeared to be rare, and movements occurred either around Catalina Island or up and down the coast. However, it appears some individuals exhibit site fidelity. Most re-sightings occurred at the same site, and many individuals were re-sighted at the same site over multiple years. Residency and aggregation sizes were both assessed among sites and between spawning and non-spawning seasons. Residency appeared to vary by site and by season, while aggregation sizes varied only by site. Hermosa had the greatest values for aggregation sizes and for residency, but the largest aggregations occurred during the winter non-spawning season, suggesting that although large aggregations form here, they may form for a purpose other than spawning.

31. MODEL APEX PREDATOR (GIANT SEA BASS) IMPACTS BEHAVIOR OF MESOPREDATORY FISHES AROUND SANTA CATALINA ISLAND, CA

K.C. Reed¹ and M.A. Steele¹

¹Department of Biological Sciences, California State University, Northridge

Giant sea bass (GSB), though once abundant on the nearshore rocky reefs of southern California, were fished to near extinction during the 20th century. Their populations have only started to recover recently. GSB fill a unique niche, being the only resident apex predator of California’s plentiful mesopredators, such as kelp bass, sheephead, and rock wrasse. The goal of this study was to test how GSB affects the behavior of smaller fishes. A life size model of a GSB and baited remote camera apparatus was used for this test. Baited camera trials were run with and without the GSB model attached. Mesopredator behavior around the bait was then analyzed when the model was present vs. not present. It was found that mesopredator fishes were less likely to feed when the GSB model was present. In an ocean where apex predators have drastically declined, it is important to track how their re-establishment through successful conservation measures may impact the surrounding systems.

32. VERIFICATION OF GIANT SEA BASS (STEREOLEPIS GIGAS) SPAWNING: THROUGH AUDITORY OBSERVATIONS

E.H. Burns¹, L.G. Allen¹, and M.P. Franklin¹

¹Nearshore Marine Fish Research Program, California State University, Northridge.

Giant Sea Bass (GSB), Stereolepis gigas, is the largest marine bony fish off the coast of California, an apex predator, and is currently listed as critically endangered on the IUCN Red List. Despite recent studies on GSB, there is no documentation of their spawning and related reproductive behaviors in their natural environment due to their depressed population size. Previous studies have shown GSB capable of producing a variety of sounds (many sounding like a “boom”). Past studies have observed that the closer in proximity you are to a GSB spawning aggregation, the louder and more numerous GSB sounds are heard. In these spawning aggregations, “booms” have been observed to be linked with antagonistic behaviors between GSB males, indicating that sound production is most likely part of spawning. In summer 2019, novel reproductive sounds labeled “snares” and “bursts” were recorded during successful spawning events of captive GSB. These novel sounds have only been observed and recorded during spawning. Using Raven Pro we examined audio samples gathered in the summers of 2014, 2015, and 2019 and identified “snare” and “burst” sounds recorded at GSB spawning aggregations. We hypothesize that GSB vocalization occurs frequently during spawning and is used in combination with courtship behaviors to signal reproduction readiness. We argue that by identifying these behaviors, we will be able to verify GSB spawning when these auditory behaviors are observed during their period of spawning.

33. IT’S ALL A BIG MISTAKE: LARVAL ERRORS AND THE FORMATION OF NEW AGGREGATIONS OF THE SERPULID ANNELID FICOPOMATUS ENIGMATICUS

A. Mendelson¹, K. Nuon¹, and B. Pernet¹

¹Department of Biological Sciences, California State University, Long Beach, CA 90840.

Adults of Ficopomatus enigmaticus typically live in aggregations formed by larval settlement: cues associated with adults induce planktonic larvae to settle in contact with those adults, leading to aggregations that may include thousands of worms. Formation of a new aggregation, however, requires a larva to settle in the absence of adult cues. “Solitary” settlement in similar species has been explained by at least three hypotheses: some larvae may make incorrect settlement decisions (“Larval Error”); larvae that do not encounter an adult cue may eventually accept a wider array of settlement substrata (“Desperate Larva”); larvae are genetically polymorphic in substratum requirement, with some being founders (settling only on uninhabited substrata) and others being aggregators (settling only on adults) (“Founder/Aggregator”). We sought to distinguish among these hypotheses in lab experiments. As larvae of six full-sibling families became competent to settle, we exposed them individually to either adult tube, field biofilm, lab biofilm, or unbiofilmed plastic and recorded settlement daily for the next six days. Overall settlement was highest on adult cue, intermediate on field and lab biofilm, and lowest on unbiofilmed plastic. Settlement patterns were inconsistent with the Desperate Larva or Founder/Aggregator hypotheses, but our results are consistent with the Larval Error hypothesis.

34. UROBATIS HALLERI STRIKES BACK!: 3D TAIL KINEMATICS OF THE ROUND STINGRAY

S. Ono¹, J.C. Sobol¹, A.R. McGinnis¹, B. Morales¹, T. Lozano¹, H. Adamson¹, K. Galindo¹, B.M. Perlman¹.

¹California State University, Long Beach, CA, 90840.

Around the coastal United States, stingray strikes account for nearly 2,500 emergency room visits on an annual basis, in addition to the several hundreds to thousands of less-serious injuries that do not warrant hospitalization. Along California beaches, the Haller’s Round Ray (Urobatis halleri) in particular, is responsible for the majority of these interactions, with anywhere between 200 and 400 stingray-related injuries being reported each year from localities like Seal Beach alone. During summer months, U. halleri aggregate en masse in warm, shallow sandy-bottom beaches, often coinciding with the locations that beach goers tend to frequent. While stingray strikes are generally non-life threatening, the morphology of ray barbs are capable of inflicting deep lacerations while potentially envenomating the victim as well. Despite the rate at which these encounters occur and the potential threat that they pose to public safety, very little is known about round stingray behavior or the biomechanical properties associated with tail-strike events; only one other study quantified the 2D kinematics of this behavior in a closely related species. In our novel study, we use 3D high speed videography and motion tracking software to describe strike behavior across the ontogeny of the species Urobatis halleri, quantify the kinematics associated with tail strikes, and use this information for applications relevant to public beach safety.

35. WATCH YOUR STEP!: STING RAY STING PREVENTION

J.C. Sobol¹, A.R. McGinnis¹, C.M. Donatelli², and B.M. Perlman¹. Stingray and Butterfly Biomechanics Lab, Department of Biological Sciences, ¹California State University, Long Beach, CA, 90840. Department of Engineering, ²Chapman University, Orange, CA, 92866.

Every year in US waters, there are roughly 2500 people being stung by stingrays, with Seal Beach being among the highest locations in California of stingray injuries at 500 or more per year (Hughes et al., 2018; Katzer et al., 2022). The great white shark (Carcharodon carcharias) poses little threat to people in comparison with round stingrays (Urobatis halleri) being the leading cause of marine organism-related injuries on the southwestern coast of the United States (Hughes et al., 2018). Currently, the only preventative measures to being stung is the “stingray shuffle,” an act of shuffling your feet in the sand while entering the surf zone, but if we better understand the forces stingrays generate when striking, sting-resistant material can be incorporated into the outerwear of surfers and beachgoers. We are collaborating with material science engineers that are prototyping footwear to withstand these tail strikes by round stingrays. Our research question is what are the exact measurements of force at which a U. halleri strike will inflict on the composite material samples and where does the artificial material meet its failing point. The forces rays generated in-situ were less than the point of failure for our material, so we can deduce that our material is strong enough to withstand sting ray strikes. By acquiring new knowledge on the striking forces that the native U. halleri can generate, we can continue to improve adequate beachwear that can be produced to protect all beachgoers.

36. CAN YOU STOMACH IT? COMPARATIVE TRANSCRIPTOMICS AND BIOCHEMISTRY OF THE STOMACHS OF PRICKLEBACK FISHES (STICHAEIDAE) CONSUMING DIFFERENT DIETS

D.P. German¹, M.J. Herrera¹, J. Buckner¹, J. Heras¹, N. Smith Christman¹, M. Hileman¹

¹Department of Ecology & Evolutionary Biology, University of California, Irvine, CA 92697.

Despite obvious whole animal, tissue level, and biochemical differences among species with different diets, dietary specialization has molecular underpinnings that are not well understood.  We used comparative transcriptomics of stomach tissues to observe how prickleback fishes (Stichaeidae) achieve dietary-driven differences in stomach function. Xiphister mucosus (herbivore), X. atropurpureus (omnivore), Phytichthys chirus (omnivore) and the carnivorous Anoplarchus purpurescens were harvested from the wild, and fed omnivore and/or carnivore diets in the laboratory. Transcriptomes were sequenced for stomach tissues from two individuals per species and diet treatment. The number of shared orthologs varied with phylogenetic relatedness of the species (i.e., sister-taxa X. mucosus and X. atropurpureus shared the most expressed genes), and differential expression and selection analyses are underway. Hydrogen-potassium ATPase appears to be under positive selection in some species. All four fish species strongly expressed pepsinogen and chitinase genes in their stomachs, yet biochemical activity levels of these two digestive enzymes matched natural diet, with the species consuming the most protein (A. purpurescens) and chitin (P. chirus) having the highest pepsin and chitinase activities, respectively. Assessing how these activities were altered by the laboratory diets is in progress. Although intestinal carbohydrases typically show support for the Adaptive Modulation Hypothesis—a match among digestive enzyme activities with concentrations of ingested substrate—gastric enzymes may also vary with diet. Thus, beyond being an important vertebrate innovation, the stomach may also provide varying digestive benefits depending on natural diet, which is not well resolved.   

DR. DONALD G. BUTH MEMORIAL PARASITOLOGY SYMPOSIUM

37. THE SCIENCE AND ART OF DESCRIBING SPECIES, A TRIBUTE TO UCLA PROFESSOR DR. DONALD G. BUTH

J.K. Passarelli

Cabrillo Marine Aquarium, San Pedro, CA 90731.

Dr. Donald G. Buth was a Professor of Biology in the Department of Ecology and Evolutionary Biology at the University of California, Los Angeles from 1980-2022. He served on the Board of Directors for the Southern California Academy of Sciences from 1994-1996 and again from 2004-2007 and was the President of the Southern California Society of Parasitologists from 2016-2018. His major research interests were phylogenetic systematics, systematics and evolution of reptiles and cypriniform, gasterosteiform, and perciform fishes, application of enzymatic methods in systematics, and parasitology of marine fishes. His love and passion for systematics and taxonomy was instilled in his teaching, and as such, he always discussed the importance of the codes of nomenclature or “rulebook” that govern biological taxonomic nomenclature. Due to his mentorship and inspiration to many of his graduate students, Don has three species named in his honor: a leech, Heptacyclus buthi (Burreson & Kalman, 2006) on sculpins, a parasitic copepod, Majalincola buthi Tang & Kalman, 2008 on pufferfishes, and the spadenose guitarfish Pseudobatos buthi Rutledge, 2019. In the parasitology field, due to the approximately 100-year lag between the discovery of parasite species compared to their vertebrate hosts, it is especially important that scientists understand the rules and processes of naming species, and perhaps even creating a new genus.

38. Pterobdella occidentalis n. sp. (Hirudinida: Piscicolidae) for P. abditovesiculata (Moore, 1952) from the longjaw mudsucker, Gillichthys mirabilis and staghorn sculpin, Leptocottus armatus, and other fishes in the Eastern Pacific

S.K. Goffredi,¹ R.G. Appy², E.M. Burreson³ and T.S. Sakihara⁴.

¹Department of Biology, Occidental College, Los Angeles, California, U.S.A. 90041-3314. ² Cabrillo Marine Aquarium, San Pedro, California, U.S.A. 90731. ³ School of Marine Science, Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, U.S.A. 23062. ⁴ Hawaii Division of Aquatic Resources, Department of Land and Natural Resources, Hilo, Hawaii U.S.A. 96720.

Pterobdella occidentalis n. sp. (Hirudinida: Piscicolidae) is described from the longjaw mudsucker, Gillichthys mirabilis Cooper, 1864 and the staghorn sculpin, Leptocottus armatus Girard, 1854 in the Eastern Pacific, and the diagnosis of P. abditovesiculata (Moore, 1952) from the ‘o ‘opu ‘akupa, Eleotris sandwicensis Vaillant & Sauvage, 1875, from Hawaii is amended. The morphology of both species conforms with the genus Pterobdella in possessing a spacious coelom, well developed nephridial system, and 2 pairs of mycetomes. Originally described as Aestabdella abditovesiculata, P. occidentalis (present along the U.S. West Coast), can be distinguished from most congeners by its metameric pigmentation pattern and diffuse pigmentation on the caudal sucker. With distinct mitochondrial gene sequences, including cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit I (ND1), P. occidentalis forms a polyphyletic clade with P. leiostomi from the Western Atlantic. Based on COI, ND1, and the 18S rRNA gene, other leech species most closely related to P. occidentalis include P. arugamensis from Iran, Malaysia and possibly Borneo, which likely represent distinct species, and P. abditovesiculata from Hawaii, one of only a few endemic fish parasites in Hawaii. Like P. abditovesiculata, P. arugamensis, and P. amara, P. occidentalis is often found in estuarine environments, frequently infecting hosts adapted to a wide range of salinity, temperature and oxygen. The physiological plasticity of P. occidentalis and the longjaw mudsucker host, and the ease of raising P. occidentalis in the lab, make it an excellent candidate for the study of leech physiology, behavior and possible bacterial symbionts.

39. AN HISTORICAL ACCOUNT OF MAJALINCOLA BUTHI TANG & KALMAN, 2008, AN UNUSUAL ERGASILID COPEPOD INFECTING BRACKISHWATER PUFFERFISHES IN NORTHERN AUSTRALIA

D. Tang¹ and J.K. Passarelli²

¹Orange County Sanitation District, Fountain Valley, CA 92708.  ²Cabrillo Marine Aquarium, San Pedro, CA 90731.

The copepod family Ergasilidae contains 30 genera and 272 species, many of which are found in freshwater and some in brackish or coastal environments.  Post-mated adult females of most genera parasitize fishes, while those of Anklobrachius, Pseudovaigamus, and Vaigamus have been collected thus far from the plankton and those of Teredophilus infect only bivalve molluscs.  Of the 26 fish-inhabiting genera, 22 are ectoparasitic, using their modified prehensile antennae to attach to the gills, fins, and nasal cavities of their hosts.  The remaining four genera, Majalincola, Mugilicola, Paeonodes, and Therodamas, are mesoparasites, living with their anterior ends buried in the host and their posterior ends protruding from the host tissue.  This presentation details the discovery and establishment of Majalincola buthi based on material collected from the gills of two pufferfish species in the genus Marilyna captured in brackish waters in northern Australia.  The fully transformed adult female of Majalincola is distinct from the other ergasilid genera by having a neck-like elongation between the first two pairs of head appendages and the mouth, a 5-segmented antennule, a 3-segmented leg 1 endopod, and a free exopod segment armed with two setae on the fifth leg.  The establishment of Majalincola is supported by the results of a cladistic analysis of Majalincola and members of its sister taxon.

40. A NEW SPECIES OF COMMENSAL COPEPOD (FAMILY: PORCELLIDIIDAE) FROM PAGURID HERMIT CRABS OFF THE PALOS VERDES PENINSULA

J.H. Morris, J.K. Passarelli

Cabrillo Marine Aquarium, 3720 Stephen M. White Drive, San Pedro, CA 90731.

Commensal copepods were discovered living inside the shells of hermit crabs (Pagurus samuelis) in 2016. The hermit crab hosts are commonly found along the southern California coastline, however the copepods only occur along the Palos Verdes Peninsula at four of six sampling localities (prevalence: Malaga Cove 0%, Golden Cove 35%, Founder’s Park 0%, White Point 20%, Point Fermin 71.3%, Cabrillo Outer Beach 15.8%). Scientific illustrations of the copepod were completed and after close examination it was determined that this species is new to science. Specimens were cleared with lactic acid and then stained with lignin pink. After producing a habitus illustration, microdissections were conducted to remove the appendages to illustrate details unobstructed. Some key defining features that set this species apart from others in the Family Porcellidiidae include the following: 1) the segments of the male antennule are uniquely shaped, 2) the male antennules have an additional segment that is not present in other species in the group, and 3) the length of the female uropods extend well beyond the abdomen. Male antennules and female uropods are often specialized in copepods, where they interlock to facilitate copulation. Additional unique features will be studied for the purpose of describing this species. In addition, given that these characteristics differ from that of other members of the family in a multitude of ways, there may be justification to erect a new genus.

41. A NOVEL COPEPOD EGG PREDATOR INFESTING COMMERCIALLY IMPORTANT ROCK CRABS

J.E. Orli¹, S.M. Lecuona¹, G.O. Plewe¹,  Z.L. Zilz¹, and A.M. Kuris¹

¹Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106

A novel copepod egg predator (Nicothoidae cf. Choniosphaera sp.) infestation has been discovered in the egg masses and gills of three commercially important crabs (Cancer anthonyi, C. antennarius, and C. productus). We document high copepod prevalence and host egg mortality in ovigerous crabs along the Santa Barbara coast. Nicothoid egg predator infestations have never been observed in crabs along the Pacific coast of the Americas, a notable extension of the geographical range of these copepods. Extensive work on cancrid crab brood mortality caused by nemertean egg predators in the 1990s found no evidence of nicothoids, indicating that this outbreak is a recent and possibly unique event. Female copepods appear highly modified, mimicking the coloration and globular shape of crab eggs. Unlike nemertean crab egg predators, these are partial egg feeders. The copepods feed by puncturing a small hole in the shell of the crab egg, stunting the development of the embryo and subsequently facilitating entry of microbial agents. We have been conducting studies into the impacts of these egg predators on their hosts and have documented entire host egg masses being overtaken by these egg predators and their progeny, with unknown impacts on total crab reproductive success. Rock crabs are common nearshore consumers and are prey to otters, octopi, and several species of rockfish and also commercially fished without consideration of the impacts of this novel egg predator. The geographical extent and host specificity of this new consumer warrants further investigation.

42. Gyrodactylus, FUNDULOTREMA and Salsuginus species (Monogenea) infecting Fundulus parvipinnis (Osteichthyes: Fundulidae) in Southern and Central California estuaries and bays.

D.K. Cone¹, R.G. Appy² and E.M. Leis³

¹83 Rhodenizer Lake Road, Dayspring, Nova Scotia, Canada, B4V 5R7; ²Cabrillo Marine Aquarium, 3720 Stephen M. White Drive, San Pedro, CA 90731; ³La Crosse Fish Health Center- Midwest Fisheries Center, U.S. Fish and Wildlife Service, 555 Lester Ave. Onalaska, WI 54650.

Four species of Monogenea were found on Fundulus parvipinnis from Southern and Central California: Gyrodactylus n. sp. 1, Gyrodactylus n.sp. 2, Fundulotrema xxx (Gyrodactylidae), and Salsuginus n. sp. (Ancyrocephalinae). Partial 18S and ITS region (ITS1/5.8/ITS2) sequence data for the two new species of Gyrodactylus linked distantly to species from estuarine and marine fishes. Fundulotrema xxx were 100% and 99.88% similar to samples from Fundulus heteroclitus in eastern North America. Salsuginus n. sp. differs morphologically from 10 previously described species, with the molecular data reported herein being the first for this genus. Gyrodactylus sp. 1 and Salsuginus n. sp. were present on the gills while Gyrodactylus sp. 1, Gyrodactylus sp. 2 and Fundulotrema xxx were present on the fins and body. The occurrence of Salsuginus from coastal California and western Mexico suggests this genus occurred on ancestral fundulids prior to isolation of Pacific species from eastern relatives by the Isthmus of Panama, estimated at 3 to 3.5 mya. Whether Gyrodactylus n. sp. 1 and Gyrodactylus n. sp. 2 have origins on ancestral fundulids or were acquired from local hosts after isolation is unclear at this time, but both species appear unrelated to species of Gyrodactylus from fundulids on the east coast. The finding of F. prolongis in California with the same morphology and almost identical 18S and ITS regions to eastern populations suggests that this parasite arrived in California from introduced fundulid hosts and should be considered non-native.

43. DISTRIBUTION AND PREVALENCE OF CANDIDATUS XENOHALIOTIS CALIFORNIENSIS (CXC) AND ITS ASSOCIATED PHAGE PCXC IN BLACK ABALONE OF BAJA CALIFORNIA

C. Delgadillo-Anguiano¹, F. Lafarga-De la Cruz², J. Lorda^3,4, C.E. Vargas-Peralta², A. Abadía-Cardoso¹

¹Universidad Autónoma de Baja California, Facultad de Ciencias Marinas, Carretera Transpeninsular Ensenada-Tijuana, No. 3917, Ensenada, Baja California, 22860, México. ²Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Departamento de Acuicultura, Carretera Tijuana-Ensenada No. 3918, Ensenada, Baja California, 22860, México. ³Universidad Autónoma de Baja California, Facultad de Ciencias, Carretera Transpeninsular Ensenada-Tijuana, No. 3917, Ensenada, Baja California, 22860, México. ⁴Tijuana River National Estuarine Research Reserve, 301 Caspian Way, Imperial Beach, California, 91932, USA.

Black abalone (Haliotis cracherodii) is distributed along California, USA and Baja California, Mexico. It has experienced massive declines since the 1980s. One of the reasons is the Withering Syndrome (WS), a lethal disease caused by the bacteria Candidatus Xenohaliotis californiensis (CXc). However, in recent years, a slow natural recovery of some populations has been detected. Additionally, the presence of a phage hyperparasite associated with CXc, called Xenohaliotis phage (pCXc), has been identified. This phage infects the CXc bacteria and reduces its pathogenicity. We present the prevalence of CXc and pCXc from 14 sites along the coast of Baja California. A total of 199 black abalones were measured (shell length) and feces were collected using a non-lethal technique. Bacteria and phrage prevalence were determined using the PCR technique with specific primers for CXc and pCXc. The prevalence of CXc was 44%, and prevalence for pCXc was 38%. We found no effect of zone, density (abalones/m²) or abalone length on the prevalence of either pathogen, except for one site, Isla Todos, where we found a positive relationship between length and prevalence. We also found a positive correlation between the prevalence of CXc and pCXc, although it was not significant. This study demonstrates that CXc and pCXc are present in black abalones from Baja California, and these populations are still at risk of being affected by the WS, especially due to the stress caused by recent drastic environmental changes.

44. Comparison of parasite communities of California grunion Leuresthes tenuis with three other species of New World silversides (Atherinopsidae) in southern California, U.S.A., and in the Gulf of California, Mexico

B. Passarelli

Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095.

In this study, the parasite communities of four host species of New World silversides (Atherinopsidae) were analyzed and compared. Samples of Atherinops affinis (Ayres, 1860), Atherinopsis californiensis Girard, 1854, and Leuresthes tenuis (Ayres, 1860) were collected in southern California, U.S.A., and samples of Leuresthes sardina (Jenkins and Evermann, 1889) were collected in the Gulf of California, Mexico. Fishes were dissected and inspected for ectoparasites and endoparasites. A total of 5,677 parasites from 25 taxa were recovered from the four host species. The most abundant parasite taxa were Contracaecum (rudolphii) (Nematoda), Galactosomum sp. (Digenea), and larval trypanorhynchs (Cestoda). Nine parasite taxa are new host records for A. affinis and eleven parasite taxa are new host records for As. californiensis. No new host records were found for L. sardina or L. tenuis. Non-Metric Multidimensional Scaling (nMDS) analysis indicated that the parasite communities were different among the four host species at the infracommunity level. A multivariate analysis of abundance (mvabund) showed significant differences in parasite communities in relation to host species. Species indicator analysis (IndVal) showed that the three most abundant parasite taxa found in this study, which combined accounted for more than 78% of the total number of parasites recovered, were associated with two host species, A. affinis and As. californiensis. Differences in diet and feeding strategies among the hosts species suggest that this may be an important factor explaining differences in parasite communities among the four host species of New World silversides studied.

45. PARASITES OF CYPRINIFORM FISHES OF THE SANTA CLARA RIVER

M.D. Murray¹

¹Dept. of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA 90095

Freshwater fishes in the southwestern United States live in some of the most highly modified habitats in the country. As a result, the relatively small number of native fish species have been impacted in many ways including the introduction of nonnative fishes and their parasites. Thirty-five Catostomus santaane (Santa Ana sucker), 61 Catostomus santaanae x Catostomus fumeiventris F2 hybrids, 18 Pimephales promelas (fathead minnow), and 214 Gila orcutti (arroyo chub) were collected and necropsied in the summers of 2017 and 2018. Ten species of macroparasites were collected from these fishes including six native and four nonnative parasites. The most abundant species of native parasite was Rhadbochona sp. while the most abundant nonnative parasite was Lernaea cyprinacae (anchor worm). The prevalence of Rhabdochona sp. was highest in G. orcutti (69%) and lowest in C. santaanae (5%). The prevalence of L. cyprinacae is highest in G. orcutti (29%) and lowest in P. promelas (5%).

46. PARASITE INDUCED METABOLIC BONE DISEASE IN A YEARLING MORELET’S CROCODILE (CROCODYLUS MORELETII)

M. Tellez¹ and E. Madsen²

¹Crocodile Research Coalition, Marine Science Institute, University of California, Santa Barbara, Belize; ²University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968.

Crocodilians have a rich diversity of host-specific parasites relative to other archosaurian descendants. While most of these relationships exhibit commensalism or mutualism, the pentastomids appear to be the only true parasite of crocodilians. Parasites like pentastomids can cause a variety of health complications in host organisms, such as vitamin and mineral deficiency in the host given the parasite absorbs these nutrients for itself. Herein, we describe the death of a wild-caught yearling Morelet’s crocodile (Crocodylus moreletii) caused by pentastomid parasites. This crocodile illustrated symptoms of metabolic bone disease (MBD), i.e., severe scoliosis, malformed digits, and stunted growth, and it was presumed death was caused by MBD. Postmortem examination revealed 7 large pentastomids (Sebekia sp.) in the lungs and trachea of the yearling crocodile, and 5 small nematodes (Dujardinascaris helicina) in the stomach. The abundance of parasites found was atypical for a yearling crocodile, likely increasing its susceptibility to complications such as MBD relative to an adult. Examining size, life cycle stage, and quantity of parasites compared to host, we hypothesized that the crocodile’s MBD could have been caused by the pentastomids absorbing nutrients that are essential for growth in a young crocodile. MBD is typically associated with poor diet in animals under human care, however our findings suggest a novel uncommon route or cause with implications on veterinary medicine for captive and wild crocodilians. Additionally, these findings further illustrate the negative parasitic relationship pentastomids share with crocodilians and could provide insight into the symbiotic relationship between crocodilians and endoparasites.

CONTRIBUTED PAPERS 2

FRIEND OR FOE? EFFECT OF EELGRASS ON FILTER FEEDER BIOMASS AND CONDITION INDEX IN A MULTI-HABITAT LIVING SHORELINE

B.A. Quintana¹, M. Silva¹, K. Kenny¹, A. Sanchez¹, D.C. Zacherl¹

¹California State University, Fullerton, Department of Biological Science, 800 North State College Blvd. Fullerton, CA 92831-3599

Over the past decades, estuarine ecosystems have suffered significant habitat loss. Implementation of multi-habitat living shorelines (MHLS) can restore lost habitat function. Researchers constructed a MHLS in 2016 in Newport Bay, California by restoring eelgrass and oyster beds together and in isolation at four locations each. Increased sedimentation from eelgrass could threaten oysters and other filter feeders if deposited onto oyster beds. We investigated whether eelgrass-induced sedimentation occurs and if it impacts filter feeder biomass (a proxy for filtration capacity) and condition index (CI) by comparing biomass and CI of native and non-native filter feeders one year (2018) and four years (2021) post-restoration. We quantified sedimentation by measuring mud deposition on oyster beds using probes and quantified eelgrass presence and densities via quadrat surveys. We excavated filter feeders from quadrats (n=10) on oyster beds, identified species, weighed to determine wet and dry tissue and shell weight, and quantified CI. In 2018, mud deposition onto oyster beds was not generally affected by eelgrass, except at PCH where deposition was higher where oyster beds were restored alone. Eelgrass presence, but not its density, sometimes increased non-native and decreased native CI. Filter feeder biomass reduced in the presence of eelgrass, but not consistently across sites. Combining eelgrass and oyster restoration may not be compatible when returning filtration services are the primary goal, but other services warrant consideration. Increasing understanding of the relationship between filter feeders and eelgrass will inform management decisions about whether to restore multi-habitat living shorelines together or in isolation.

48. SPATIAL DISTRIBUTION OF INTERTIDAL GREEN ABALONE (HALIOTIS FULGENS) POPULATIONS IN ORANGE COUNTY

H. Lin¹, N. L. Caruso¹

¹ Get Inspired, Inc., 6192 Santa Rita Ave Garden Grove, CA 92845

Abalone populations worldwide have suffered from fishery depletion historically. The situation is aggravated as climate abnormalities increase the chances of disease and habitat degradation, compounded by human disturbance. Green abalone (Haliotis fulgens), a Federally-listed Species of Concern, is native to southern California and ranges from Point Conception, California, U.S., to Magdalena Bay, Baja California, Mexico. The green abalone population is estimated to be at less than 1% of its baseline density. In order to effectively restore green abalone in Southern California, accessing the current status of the wild abalone population and understanding the spatial pattern of juvenile aggregation for effective reproduction is critical for out-plantation success. From 2017-2020, we surveyed 41 rocky tide pools in Orange County to measure green abalone size and population density to understand the spatial pattern and preferred habitat of abalones on the county's coastline. Of the 41 sites we monitored, we found 620 green abalones in 24 sites, with sizes ranging from 9mm to 221mm. Moreover, we found spatial differences in the distribution of adults and juveniles across sites, with higher juvenile densities in the Western sites with limited public access. Repeated annual surveys of these sites from 2017-2022 found a 98% to 100% reduction in juvenile densities since the initial surveys in Western sites. In San Onofre, CA, just south of the Orange County border, we uncovered a surprising juvenile green abalone population, which could be a species sink.

49. TESTING THE KEYSTONE-MOLECULE HYPOTHESIS: DO DEFENSIVE CHEMICALS FROM A COMMON GASTROPOD ALTER ESTUARINE COMMUNITIES?

H. Nguyen and P.J. Krug. California State University, Los Angeles, CA, 90032.

By analogy to keystone species, new theory proposes that compounds with disproportionate effects on an ecosystem may be keystone molecules, regulating communities with outsized impacts relative to their abundance in the environment. The release of defensive chemicals produced by a highly abundant species may alter community compositions and food web interactions, but this has not been tested for a benthic marine animal. Small but abundant sea slugs (Alderia spp.) are found in the high intertidal zone of estuarine mudflats throughout the Northern Hemisphere, and produce bioactive compounds called polyketides as a defense against predators. I tested whether polyketides act as keystone molecules by altering the invertebrate community living in the mudflats in two field experiments. I compared species abundance and diversity in mud cores exposed to slug-extracted polyketides versus control cores. Polyketide treatment reduced the abundance of microcrustaceans, polychaete worms and molluscs, thus changing the infaunal community of non-predatory species. However, polyketides also induced egg deposition from another common gastropod, the California horn snail (Cerithideopsis californica), a potential adaptation to exploit the effects of slug compounds on other community members. Although community composition of invertebrates changed with season, the effect of polyketides was largely consistent between summer and winter trials.

50. THE THREE-DIMENSIONAL WORLD OF MORPHOLOGICAL PLASTICITY AND ITS PHYSIOLOGICAL CONSEQUENCES IN PACIFIC SAND DOLLAR LARVAE

W. Ly¹ and D.A. Pace¹

¹California State University, Long Beach, Long Beach, CA 90840

Studies examining echinoid larvae have revealed food-dependent morphological plasticity. The aim of the current study was to examine changes in total larval surface area and volume in low- and high-fed larvae and to compare scaling of physiological processes to these growth patterns. Larvae of the Pacific sand dollar, Dendraster excentricus, were fed low or high amounts of algae (1,000 and 10,000 algal cells ml^-1, respectively). We measured volume, density, total surface area, protein biomass growth, aerobic respiration, and rates of dissolved amino acid transport from seawater. Despite having 10-times less food and up to 5.7-times less protein biomass, low-fed larvae had similar surface areas as high-fed larvae. Low-fed larvae possessed mass-specific transport rates of alanine (ANOVA P<0.05) and leucine (ANOVA P<0.001) that were 2.32-times and 3.46-times higher than high-fed larvae, respectively (measured at 18 days post-fertilization). Therefore, morphological changes induced in low-fed larvae not only resulted in longer arms to support higher particulate food capture, but also more surface area per unit biomass to support greater access to dissolved organic nutrients. Mass-specific respiration rates of high-fed larvae were greater compared to low-fed larvae throughout development, indicative of significant differences in physiological state. Our expanded phenotypic analysis demonstrates that larval plasticity responses involve changes beyond arm-length and have consequences at multiple phenotypic levels. Understanding the integrated plasticity response of planktotrophic larvae is necessary for predicting their adaptive capacity to mitigate stress brought on by climate change.

51. UNDERSTANDING THE TEMPORAL NATURE OF FOOD-INDUCED PHENOTYPIC PLASTICITY IN DENDRASTER EXCENTRICUS: CAN YOU TEACH AN OLD LARVA NEW TRICKS?

A.M. Lee¹, I. Villafuerte¹, D. Pace¹

¹Department of Biological Sciences, California State University, Long Beach, Long Beach, CA 90840

Echinoid larvae are well-documented for their food-induced morphological plasticity where larvae in low-food conditions develop longer arms to increase food capture rates and high-fed larvae invest in shorter arms and divert resources to growth. While most studies examine plasticity responses at the onset of feeding, it is unknown if larvae retain their plasticity to changing food conditions throughout development. We assessed the morphological and physiological plasticity responses of larvae of the Pacific sand dollar, Dendraster excentricus, when switched from low to high food conditions at 10-, 20-, and 30-days post-fertilization (DPF). Upon switching to high-food conditions, low-fed larvae quickly acquired a high-fed phenotype by shortening their arms, suggesting that upkeep of long arms is energetically expensive. These changes were accompanied by rapid changes in protein growth and respiration, demonstrating that low-fed larvae were able to maintain their plasticity response capacity until 30 DPF. Although time to metamorphosis was dependent on when high-food conditions were initiated, larvae switched at 10 and 20 DPF and constantly high-fed larvae had similar total energetic costs of development while larvae switched at 30 DPF and low-fed were higher. All treatments had similar protein biomass at metamorphosis. These results demonstrate that phenotypic responses to changes in food conditions can be initiated throughout larval development; an important discovery since food conditions likely change frequently in the marine environment. Our results also suggest both energetic and biochemical composition constraints to achieving metamorphosis. This information is critical for modeling how larvae respond to changing conditions due to anthropomorphic activities.

52. Using Dune Restoration on an Urban Beach as a Coastal Resilience Approach

K. K. Johnston¹, J. E. Dugan¹, D. M. Hubbard¹, K. A. Emery², and M. Grubbs³

¹ Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA, 93106.

² Department of Geography, University of California Los Angeles, Los Angeles, CA, 90095.

³ Morro Bay National Estuary Program, Morro Bay, CA, 93442.

Coastal dunes are globally recognized as natural features that can be important adaptation approaches for climate change along urban shores. We evaluated the recovery of coastal dunes on an intensively groomed urban beach in southern California over a six-year period after mechanical grooming was discontinued. To track recovery, we conducted physical and biological surveys of the restoration site and an adjacent control site (groomed beach) using metrics including sand accretion, elevation, foredune and hummock formation, vegetation recovery, and wildlife use. Sediment accretion, elevation, and geomorphic complexity increased over time in the restoration site, largely in association with sand fencing and dune vegetation. A foredune ridge (maximum elevation increase of 0.9 m) and vegetated hummocks developed, along with an overall increase in elevation across the restoration site (0.3 m). After six years, an estimated total volume of approximately 1,730 m³ of sand had accreted in the restoration site and an approximate volume of 540 m³ of sand had accreted in the foredune ridge. Groomed control areas remained flat and uniform. Native dune plants covered approximately 7% by the sixth year. No vegetation was observed on the groomed control site. Native plant species formed distinct zones across the restoration site, with dune forming species aggregating closest to the ocean in association with the foredune ridge. Our findings on geomorphic and ecological responses of a low-cost pilot dune restoration on a heavily groomed urban beach provide new insights on the opportunities and expectations for restoring dunes as nature-based solutions for climate adaptation.

53. UPDATED POPULATION ASSESSMENT OF PISMO CLAMS (TIVELA STULTORUM) AT TWO BEACHES IN ORANGE COUNTY, CA

B.E. Hyla¹, N.L. Caruso¹

¹Get Inspired Inc., 6192 Santa Rita Ave Garden Grove, CA 92845

Recent reports have indicated population increases for an iconic California species, the Pismo clam (Tivela stultorum), for various parts of the state. However, populations of Pismo clams in Orange County remain largely unstudied due to low densities and limitations to time and resources. The last census surveys of Pismo clams in Orange County were conducted by the then California Department of Fish and Game (CDFG) between 1975-76. In the current study we surveyed Bolsa Chica State Beach, CA, a site previously surveyed CDFG, to acquire updated baseline data about the Pismo clam population in this historically surveyed area. Between February-May 2022 we surveyed 5184.5 m² of shoreline and found n = 287 Pismo clams, 5 of which were legal sized (≥ 114mm length). Size distribution showed two main peaks in size at 48 ± 0.61 mm and 94 ± 0.83 mm. Density varied largely by location in the study site with values between 0.0178 - 0.1748 clams/m². Catch per hour of legal sized clams in the present study is lower than previously recorded for this area (1975 = 1.170; 2022 = 0.029 clams/hr.), and catch per hour of sublegal sized clams is higher than previously recorded for the study area (1975 = 0.21; 2022 = 0.755 clams/hr.) We also present preliminary results from surveys conducted in Newport Beach, CA from November 2022-March 2023. This study contributes to informational needs for the species statewide while also evaluating the potential of sites for future restoration work in Orange County.

54. A NEW ESTIMATE OF BIOCRUST CONTRIBUTION TO CARBON AND NITROGEN FLUX IN GLOBAL TERRESTRIAL ECOSYSTEMS

S.V. Janapaty^1,2, E Monier¹

¹Global Environmental Change Group, University of California-Davis, Davis, CA, 95616.

² Department of Applied Mathematics, Columbia University, New York, NY, 10027.

Biocrusts are communities of photoautotrophic organisms, such as cyanobacteria, lichen, and bryophytes, that are found ubiquitously in terrestrial ecosystems and play a vital role in regulating carbon and nitrogen fluxes at a local scale. Despite their importance, the global contributions of biocrusts to carbon and nitrogen fluxes are not well understood and estimates from over a decade ago need to be updated. This study analyzed 362 flux records from 1976 to 2021 to derive updated estimates of carbon and nitrogen uptake by biocrusts. We estimate that biocrusts absorb 3.07 Pg of carbon and 102.33 Tg of nitrogen annually, accounting for 7 percent of terrestrial primary productivity and over 50 percent of biological nitrogen fixation. We used random forest regression analysis and Landsat 8 spectral bands to identify drivers of flux with root mean square error of 4.59% and ERA5 reanalysis to predict flux for forecasted climatologies. Sensitivity analysis indicated that in-situ flux measurements are sensitive to temporal and geospatial scaling factors, with up to 86 percent error in predictions. Our findings dramatically update previous estimates of biocrust contributions to global biogeochemical cycles and highlight the need for future research to sample data from understudied ecosystems.

55. AN INTEGRATIVE APPROACH TO ELUCIDATE THE UNDERLYING MECHANISMS OF SPECIATION IN A POLYMORPHIC NEOTROPICAL TREEFROG, Agalychnis callidryas

S.A. Wikramanayake¹, K. L. Hoke², A. Vega³ and J. M. Robertson¹

¹Department of Biology, California State University, Northridge, Northridge, CA, 91330. ²Department of Biology, Colorado State University, Fort Collins, CO, 80521. ³AMBICOR, Tibas, Costa Rica

I examined the mechanisms underlying speciation in the red-eyed treefrog (Agalychnis callidryas). The red-eyed treefrog shows population-level variation in colour patterns, call characteristics, skin peptides, and courtship behaviors among Costa Rican populations. Premating reproductive isolation between populations is incomplete, indicating that they could be in the early stages of speciation. We combined neuronal and behavioral approaches to ascertain the role of mate choice in lineage diversification and speciation. We assessed if behavioral responses and neuronal activation are correlated with lineage divergence. We exposed wild gravid female frogs to stimulus treatments from increasingly divergent lineages. Females’ brains were removed and used to quantify neural activation. We found that time spent escaping increased as lineage divergence increased. Frequency of courtship behaviors showed differences between the focal population and two heterospecific stimuli treatments. Although we found no effect of stimulus type on neural activation levels, neural activation differed by brain regions that correspond to different functions related to courtship. I will discuss how patterns of behavioral responses and neural activation help us understand the contributions of female mate-choice to speciation.

POSTER SESSION: 5:00 – 7:00 PM

56. UNDERSTANDING RESEARCH-BASED POLLUTION IN SANCTUARIES; SCOPING PROJECT FOR NEW OCEAN-DEGRADABLE PLASTIC DEVELOPMENTS

A. Ramirez Fromm¹, R.M. Freedman¹, C. Stuart¹, M.O. Aguirre Paden², and

A. Santoro³

¹Channel Islands National Marine Sanctuary, Ocean Education Building, University of

California, Santa Barbara, CA 93106. ²Center for Science and Engineering Partnerships,

University of California, Santa Barbara, CA 93106. ³Santoro Research Group, Marine

Biotechnology Laboratory, University of California, Santa Barbara, CA 93106.

Although research and monitoring equipment are vital to our understanding of marine ecosystems, a growing number of expendable ocean instrumentation continues to contribute to our ocean’s plastic pollution. Informally known as the ‘ocean internet of things’, this rapidly expanding web of interconnected monitoring equipment has presented a growing problem within marine sanctuaries as research and conservation efforts clash. The research permit data for discharges and all otherwise prohibited activities within sanctuaries is stored within the OSPREY database. In order to understand the level of plastic pollution generated through unretrieved scientific instrumentation in West Coast marine sanctuaries, the OSPREY database will be used to conduct a meta-analysis on the amount of plastic deposited. Instrumentation deposit hotspots, deposited instrument use cases, and deposited plastic mass per operation will be estimated from the permit application data between 2013 and 2023. This study thus aims to help reduce microplastic and plastic pollution within sanctuary boundaries by identifying possible marine equipment prospects for bioplastic alternatives, raising awareness about the amount of plastic pollution generated from research activities, and informing future marine sanctuary permit policy regarding non-degradable marine deposits.

57. UTILIZING BENTHIC HABITAT MAPPING AND BIOLOGICAL SURVEYS TO DETERMINE THE ECOLOGICAL FUNCTION OF ARTIFICIAL STRUCTURES OFFSHORE SOUTHERN CALIFORNIA

C. Williams¹, J. P. Williams¹, D. J. Pondella, II¹, J. T. Claisse^1,2, B. Cohn1, D. M. Schroeder³

¹Vantuna Research Group, Occidental College, Los Angeles, CA, 90041. ²Department of Biological Sciences, California Polytechnic University, Pomona, CA 91768. ³Department of the Interior, Bureau of Ocean Energy Management, Pacific OCS Region, Camarillo, CA 93010.

Marine infrastructure from offshore energy development can change the distribution and abundance of local marine habitats and species via introduction of artificial hard substrate. This “artificial reef” effect potentially modifies a variety of local and regional processes, including those that drive ecological dynamics of managed, sensitive, or non-native species. Decision makers must therefore understand how offshore projects that introduce significant amounts of hard substrate to the marine environment may be evaluated, managed, and potentially incorporated into an artificial reef program. In accordance with California’s goal to achieve 90% clean energy by 2035, the current administration recently launched initiatives to deploy 15GW of floating offshore wind capacity on the west coast. However, in southern California it remains unclear to what extent platform habitat and other artificial structures contribute to regional-scale ecological dynamics. Understanding how these artificial habitats interact with regional drivers will improve forecasts about consequences of decisions related to marine infrastructure and support environmental review. We are using bathymetry and side scan sonar data to confirm the location and physical state of known artificial reefs in the Southern California Bight. Biological characteristics are assessed using visual surveys via SCUBA (depths <30m) or remotely operated vehicles (>30m) outfitted with stereo camera systems. Similar data on nearby natural habitats is also being collected to provide basis for comparison. The goal is to determine what physical, biological, or geographical features are important for productivity of planned and de-facto artificial reef structures, and what criteria should be used to evaluate future artificial reef proposals.

58. BENT INTO SHAPE: FISH ARMOR INSPIRED BIO-BRACES

O. Armstrong*¹, E. Chier*², M.L. Vandenberg³, C.M. Donatelli⁴

*These authors contributed equally to this work. ¹Data Analytics, Fowler School of Engineering, Chapman University. ²Computer Science, Fowler School of Engineering, Chapman University. ³Friday Harbor Laboratories, University of Washington. ⁴Fowler School of Engineering, Chapman University.

Throughout evolutionary history, fishes have used biological armor for a multitude of functions particularly protection, sexual selection, and hydrodynamics. Interlocking armor stiffens the body, providing anisotropic resistance to forces and motion. Biological armor is as diverse as vertebrates themselves, ranging from the small interlocking bony scales of the gray bichir, to the large overlapping scutes of the northern spearnose poacher. The diversity of armor is a great source of inspiration for the creation of biomedical devices. Design principles derived from studying this piscine armor can be used to create tools, such as medical braces, to protect human joints. Overpronation is a leading cause in foot related injuries among athletes. Distance runners are especially susceptible to overpronation due to the repetitive nature of running. We investigated the role of shape, spacing, and size of armored plates in the mechanics of bioinspired models and fabrics. Our goal is to create a custom ankle brace using these principles which selectively resists motion in some directions (overpronation) and allows for motion in other directions (flexion). We used two different techniques to create our models: 1) printing full 3D models on a polyjet printer (Stratasys J850) and 2) printing 2D armored plates on fabric with an FDM printer (Ultimaker S3, S5) and wrapping them around a silicone center (Ecoflex-0035). This combination of techniques gives us not only the means to answer questions about how morphology affects the flexural mechanics of a 3D structure, but apply them to present concerns in the field of human biomechanics.

59. EVALUATING THE IMPACTS OF NOISE POLLUTION ON A MARINE FISH, THE GARIBALDI (HYPSYPOPS RUBICUNDUS)

R.C. Jones¹ and M.A. Steele¹

¹Department of Biological Sciences, California State University, Northridge, CA 91330

Human activities are increasing ocean sound beyond natural levels, and little is known about how anthropogenic noise pollution can impact fish in a sound-filled environment. One native California damselfish species that communicates through sound is the garibaldi (Hypsypops rubicundus). This study aims to test how garibaldi respond to boating noise. Different sites around Santa Catalina Island were recorded and analyzed; photos of garibaldi nests were used to evaluate reproductive output. GoPro cameras were used to record territorial and mating behaviors at each site. GoPros were also used to monitor how nest-guarding garibaldi behaved toward a model garibaldi with and without a boat operating above the nest. I hypothesize that garibaldi that are more exposed to boat noise will have lower reproductive output and exhibit more territorial behaviors. By studying the impacts of boating noise on a fish like the garibaldi, my research may highlight impacts of anthropogenic noise on marine fish.

60. ANTHROPOGENIC IMPACTS ON CITHARICHTHYS POPULATIONS IN THE COASTAL WATERS OF SAN DIEGO

A. Brooks¹ and A.K. Latker¹

¹City of San Diego, Department of Marine Biology and Ocean Operations, San Diego, CA 92106.

Sanddab fish populations assessed over a 24 year period, from the Southern California Bight Regional Monitoring Program (SCBRMP), were mapped using ArcGIS to understand the impact of anthropogenic runoff and wastewater discharge. Surveys for the SCBRMP were conducted every 5 five years between 1994 and 2018. Population distribution maps showed the density and overlap of four species of sanddabs over the same period. Analysis of water quality data during this time found no strong correlation between water quality and sanddab abundance. Further, there was no direct relationship between the distribution of these species and proximity to either the Point Loma Wastewater Treatment Plant Outfall discharge or the South Bay Wastewater Treatment Plant Outfall discharge. Natural factors, such as El Niño and climate change, were thought to more likely influence sanddab distribution than localized anthropogenic impacts.

61. EFFECTS OF LOW TIDE TEMPERATURE ON INTERACTIONS BETWEEN A PREDATOR AND ITS MOBILE PREY

V. Sieu, J.L. Burnaford

Department of Biological Science, California State University Fullerton, Fullerton, CA 92831.

Stress manifests as a decline in an organism’s performance upon exposure to environmental conditions outside its optimal range. Exposure to high temperatures during low tide emersion can affect growth and feeding rates for intertidal organisms over the long term.  Sea stars are important generalist predators in intertidal systems. Previous studies have found that temperature affects their consumption of sessile prey, but we lack information about how temperature affects interactions with mobile prey items. We examined the effect of low tide temperature on interactions between sea star predators Leptasterias and mobile prey Lottia scutum in Washington State. In the laboratory, we exposed predator/prey pairs to one of three treatments: no low tide (underwater, 12.81±1.1°C, mean±SD), cool low tide (14.19±1.25°C, mean±SD), or warm low tide (20.69±1.63°C, mean±SD) and then returned them to ambient temperature seawater to observe their interactions. Our preliminary data indicate that this set of experimental treatments had a larger effect on sea stars than on limpets. We saw little effect of treatment on limpet time to first movement or the proportion of time spent moving. However, sea stars exposed to low tide treatments had a delay in the time to first movement and a decrease in the proportion of time spent moving compared to those that did not experience a low tide. Understanding effects of thermal stress on the predator-prey interactions between a sea star and a limpet will give insights into how climate change will affect the ecology of intertidal organisms.

62. ASSESSING THE SPATIAL DISTRIBUTION OF TISSUE CHEMISTRY IN INTERTIDAL BROWN ALGAE

T.E. Naquin¹ and J.L. Burnaford¹

¹Department of Biological Science, California State University Fullerton, Fullerton, CA 92831.

The health of algae, which form the base of the intertidal food chain, can determine the quality of food for grazers. Stress, nutrient content, and concentrations of potentially defensive compounds (e.g., phlorotannins) differ between algal individuals at local and regional scales. I used intertidal individuals from two brown algal species (Egregia menziesii and Petalonia fascia) to determine if: 1) there are predictable relationships between the degree of low-tide stress and the concentrations of carbon, nitrogen, and phlorotannins; 2) the relationships differ between individuals at high and low edges of the vertical distribution within a site; and 3) the relationships between stress and the three aspects of tissue chemistry differ among sites. I measured Maximum Quantum Yield as an indicator of physiological stress of the alga and collected tissue during low tide from one CA island and three CA mainland sites to evaluate tissue chemistry parameters. Preliminary results indicate that for both species, individuals at the high edge of the vertical distribution had higher concentrations of nitrogen (as % of dry mass) than individuals at the low edge of the vertical distribution. These data will help us to determine whether it is possible to make reasonable assumptions about patterns of tissue chemistry at one site based on information from another site, or whether we need site-specific analyses to characterize the quality of food at any given location. Therefore, this study will provide insight on the generalizability of classic herbivory studies on brown algae.

63. BEHAVIORAL THERMOREGULATION UNDER CHRONIC AND ACUTE HEAT STRESS IN INTERTIDAL NUDIBRANCHS

L. Munoz¹, M. Beltran², E.J. Armstrong³, N.P. Burnett⁴, and R. L. Tanner¹

¹Chapman University, Orange, CA. ²University of San Diego, La Jolla, CA. ³Université de Perpignan, Perpignan, France. ⁴University of California at Davis, Davis, CA.

Scientists and amateur tidepoolers alike have noticed an anecdotal increase in nudibranch abundance and an expansion of their geographic distribution in California in recent warm years, but little is known about why and how nudibranchs are thriving in present conditions. Our previous work has shown that there is a physiological trade-off between heat tolerance and the ability to rapidly increase heat tolerance through acclimation. These species coexist in the same tidepools, which led us to ask: are there behavioral mechanisms at play in microhabitat use that distinguish nudibranch species’ thermal tolerance (i.e., do some nudibranchs seek thermal refuge and others use biochemical strategies to mitigate heat stress)? We collected intertidal nudibranchs from sites across Southern California to characterize their thermoregulatory behavior in the context of climate change-induced warming and extreme heat days. Nudibranchs were acclimated to cool and warm temperatures for two weeks and subsequently placed in simulated hot and cold tidepools for two days, representing chronic and acute heat stress. Nudibranchs in the warmer chronic acclimation temperatures were more likely to engage in escape behaviors (i.e., floating on surface tension) but nudibranchs in the acutely hot tidepools were less active and less likely to float than in cool tidepools. Because nudibranchs are more abundant during warm periods, understanding the interplay between physiology and behavior for nudibranch species may serve as an indicator of intertidal community health under climate change scenarios.

64. EXPLORATORY ANALYSIS OF 20+ YEARS OF DATA ON KELP FOREST COMMUNITY STRUCTURE FROM THE SANTA BARBARA COASTAL LONG TERM ECOLOGICAL RESEARCH SITE

B.J. Allen¹, S. Alonzo¹, E. Baker¹, K. Drennen¹, J. Frank¹, R. Ichimaru¹, E. Mascota¹ and I. Pellerin¹

¹Department of Biological Sciences, California State University, Long Beach, CA, 90840.

Giant kelp (Macrocystis) is among the fastest growing plants found on earth. Reaching from the seafloor to the ocean surface, it provides extensive vertical habitat that is the foundation for one of the most species-rich, productive, and widely distributed ecological communities in the world. The Santa Barbara Coastal Long Term Ecological Research (SBC LTER) site is an interdisciplinary program established in 2000 to understand the ecology of southern California coastal kelp forest ecosystems. We used data from their ongoing 20+ year monitoring at 11 sites to explore a variety of ecological theories about how natural communities are structured and function. We evaluated the presence and/or strength of trophic cascades, biodiversity-ecosystem function relationships, correlations between species and functional group diversity, links to local and regional climate drivers, and more. Although many hypotheses were supported, others were not – even those generated from other kelp forest datasets. Overall, our results highlight the importance of replicating previous studies and suggest that large-scale observational data can complement small-scale experimental manipulations, particularly when replicating a given experiment in the field would be difficult or impossible.

65. ASSESSING THE IMPACTS OF A RANGE-SHIFTING WHELK, MEXACANTHINA LUGUBRIS, ON PREY SPECIES ACROSS ITS NATIVE AND EXPANDED RANGE

S. Sherzai, R. Beshai, and C.J.B. Sorte

Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697.

Species undergoing range-shifts in response to climate change can profoundly impact recipient communities; range-shifting predators in particular are expected to have large impacts on lower trophic levels. Mexacanthina lugubris, a predatory whelk, recently expanded from Baja California into Southern California and consumes crustaceans, bivalves, and potentially gastropods. To evaluate the impacts of Mexacanthina on prey species, we conducted community surveys at 17 sites between Baja California and Southern California and examined how Mexacanthina abundances correlated with prey abundances. We predicted high Mexacanthina abundance will correlate with low abundances of all evaluated prey species. We found impacts do not appear to vary across the range and associations with whelk abundance varied highly based on prey species. As Mexacanthina abundance increased, we found fewer periwinkle snails, more barnacles, and no change in mussel abundance. These results counter our predictions, suggesting more complicated interactions between these range-shifting predators and prey.   

66. EFFECT OF SOLAR EXPOSURE ON THE DISTRIBUTION OF OSTREA LURIDA AND MAGALLANA GIGAS IN SAN DIEGO BAY, CA, USA 

M.B. Perez, L. De Leon, D. Zacherl, Department of Biology, California State University, Fullerton, Fullerton, CA, 92831

Intertidal marine bivalves experience variable fluctuations in environmental conditions, especially during emersion. Solar exposure is one source of variation that can significantly affect bivalve body temperature, physiological performance, survival, and distribution. We explored whether solar aspect impacts the density and distribution of native oysters, Ostrea lurida, and non-indigenous (NIS) oysters, Magallana gigas on the north and south-facing sides of an outfall pipe at Kellogg Beach, San Diego Bay, California. We are also exploring whether solar exposure affects the distribution of NIS mussels, Mytilus galloprovincialis. We surveyed O. lurida and M. gigas within randomly-placed 15 x 50 cm quadrats (n=10 per side) on two sides of an outfall pipe to test the hypothesis that their spatial distribution and densities were negatively impacted by southern exposure. Using two-way ANOVA testing for the effects of solar aspect and tidal elevation we showed that densities were higher on the north than the south side for O. lurida, but on both sides they declined at the same rate as tidal elevation increased, indicating that vertical distribution was not affected by solar aspect. M. gigas density was the same on the north versus south, but their vertical distribution was shifted lower on the south side. A follow-up paired t-test will analyze the upper distributional limits of M. gigas. Our data are consistent with the hypothesis that solar exposure impacts the distributions of major space-occupying intertidal invertebrates, which has important implications for managing native and non-indigenous species.

67. EFFECTS OF NON-NATIVE WATERSIPORA ON THE ABUNDANCE AND PERCENT COVER OF NATIVE OLYMPIA OYSTERS, OSTREA LURIDAK.S. Yumul¹, L. Rodriguez², B. Quintana¹ and D.C. Zacherl¹

¹California State University, Fullerton, Department of Biology, 800 N State College Blvd, Fullerton, CA 92831-3599. ²University of California, Santa Barbara, Department of Ecology, Evolution, and Marine Biology, UCEN Rd Building 535, Goleta, CA 93117.

Non-native fouling organisms settling onto natural hard substrata in estuaries can harm native species via mechanisms like space competition and predation. Understanding how non-native foulers influence native species recruitment is critical in predicting future native species composition. The effects of the non-native bryozoan, Watersipora subtorquata, and other foulers on Ostrea lurida recruitment were studied to determine whether their percent cover affects native oyster abundance and cover. Terracotta tiles were deployed in Newport Bay, California at tidal elevations between -0.5 and -1.0 feet MLLW during oyster’s spawning and recruitment season. Four treatment groups (n=10 per treatment) were established to examine the effects of foulers on O. lurida recruitment: unmanipulated controls, W. subtorquata removal, other fouler removal, and all fouler removal. Treatments were maintained by monthly removal of W. subtorquata and other foulers as appropriate per treatment. Oysters recruiting to the tiles were measured for length and width, identified, and quantified. Point contact technique was used to record cover of species recruiting to tiles. We hypothesized that presence of W. subtorquata and other foulers would lead to low abundance and cover of O. lurida recruits. Surprisingly, W. subtorquata and other foulers had no significant effect on abundance or cover of O. lurida. Fouling species, including ubiquitous non-natives like W. subtorquata may not be as harmful to native species in local estuarine habitats as predicted. 

68. DO NATURAL HABITATS SUPPORT BETTER BIVALVE HEALTH RELATIVE TO HUMAN-INTRODUCED HABITATS?

L. De Leon, LM. Rodriguez, B. Quintana, B. Herrera, J. Demoranville, T. Miller, D. Zacherl, California State University, Fullerton

Estuarine habitats worldwide have been extensively modified by human-introduced structures such as seawalls. Human-introduced structures may favor non-indigenous species (NIS), but few studies have directly compared species health (i.e. condition index) on various habitat types. NIS Mytilus galloprovincialis is a dominant space-occupier on seawalls throughout Southern CA estuaries including Newport Bay. In a preliminary study, it had better condition on natural cobble vs. human-introduced seawall (2-way ANOVA, site*habitat, p=0.0001) but tidal elevation was not controlled, confounding our ability to discern a habitat effect. Lower tidal elevation should improve species condition due to longer immersion time, so for this follow-up study, we hypothesized that condition index (CI) would vary both across habitats and among tidal elevations. M. galloprovincialis were collected from a seawall and from cobbles at a site in upper Newport Bay, CA, and on the north and south-facing surfaces of an outfall pipe in San Diego Bay, CA, while recording tidal elevation for each individual. M. galloprovincialis experienced a nominally significant habitat*elevation interaction (2-way ANOVA, elevation*substrate, p=0.0595) with higher CI at lower elevations on seawalls only, and higher CI on cobble versus seawall but only at higher tidal elevations. Data from the outfall pipe are still being processed. Understanding habitat and tidal elevation effects on the health of a broader selection of both native and non-native bivalves will inform future management decisions about the use of natural and anthropogenic habitats.

69. EXTENT OF SEDIMENT BURIAL IN NATIVE, OSTREA LURIDA, AND NON-NATIVE, MAGALLANA GIGAS, OYSTER POPULATIONS IN SOUTHERN CALIFORNIA, USA

S.C. Timbadia¹, Y. Fakhro² and D.C. Zacherl¹

¹California State University, Fullerton, CA, 92831. ²Santiago Canyon College, Orange, CA, 92869.

The Olympia oyster (Ostrea lurida) is the only oyster native to North America’s west coast but it lives alongside the Pacific oyster (Magallana gigas) which is native to Japan but was introduced and has increased in population density in Southern California over the past decade. Oyster reef persistence relies on oyster growth, which must outpace reef degradation and oyster burial due to sediment deposition. Exact tolerances to burial and the extent of oyster burial in soft sediment habitats are unknown for both oyster species. To build an understanding of the extent of sediment burial, we completed surveys at Pacific Coast Highway (PCH), Newport Bay, and Kellogg Beach, San Diego Bay, CA. At each site, random quadrats (0.5m x 0.5m) were surveyed for both oyster species; we recorded the extent of burial of each individual oyster and analyzed the effects of species and site on the % of each population that were buried and the average extent of burial per individual shell using 2-way ANOVA. More oysters were buried at Kellogg Beach (23-27% of the population) compared to PCH (3-13%). Among buried individuals,  O. lurida was buried more deeply than M. gigas at Kellogg Beach (65% of shell length buried compared to 41%) and compared to O. lurida (38%) at PCH. This investigation provides a conceptual framework about the extent of sedimentation in native and non-native oyster populations and improves the likelihood of success in restoring native oyster populations.

70. IMPACTS OF OCEAN ACIDIFICATION ON THE SHELL STRUCTURE OF TWO ECOLOGICALLY IMPORTANT SHELLFISH SPECIES, THE PACIFIC BLUE MUSSEL (MYTILUS TROSSULUS) AND THE CALIFORNIA MUSSEL (MYTILUS CALIFORNIANUS) FROM DIFFERING LATITUDES OVER TIME

V. Lau¹, R. Rangel¹, and C. Sorte¹

¹Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697.

Ocean acidification can weaken the shells of calcifying species. As anthropogenic climate change accelerates, ocean acidification is increasing over time, particularly at high latitudes. The goal of this study was to investigate how future climate change may affect the shell structure of calcifying species. To do this, shell thickness and area of corrosion were examined in shells collected from different time points and latitudes. We predicted that shells would be thinner and more corroded for mussels collected more recently and from higher latitudes. Four sets of mussel samples were analyzed: modern Mytilus californianus (Year 2018) and historical M. californianus (Years 1924–1976) from Southern California representing low-latitude species, and modern Mytilus trossulus (Year 2019) and historical Mytilus edulis (Years 1962–1966) from Southern Alaska representing high-latitude species. Shell thickness was measured for each mussel shell at the lip, middle point, and base using calipers, and shell corrosion was quantified using digital image analysis in ImageJ. Linear models (ANOVA) were performed to determine differences between species collected from two latitudes and time points. We found that modern shells from both species had thinner shells in the middle compared to historical shells. Furthermore, modern shells were more corroded compared to their historical counterparts. Corrosion tended to be slightly greater in modern M. trossulus compared to modern M. californianus. These findings were consistent with the prediction that ocean acidification impacts increase over time and that higher latitude individuals may experience greater effects compared to low latitude individuals.

71. BIRD OCCUPANCY OF DIVERSE HABITATS WITHIN A RESTORED TIDAL WET- LAND IN THE CALIFORNIA DELTA

M. Barajas¹, D. Ayers², C. Woidat³, C. Gilbert³, J. Takekawa⁴, and R.L. Tanner^1,3

¹Environmental Science & Policy Program, Chapman University. ²Center for Watershed Sciences, University of California at Davis. ³Animal Science Department, University of California at Davis. ⁴Suisun Resource Conservation District.

Suisun Marsh in the California Delta is the largest wetland in the United States and is a crucial part of the Great Pacific Flyway. This habitat is important for endemic and migratory birds, but it is also home to several duck hunting clubs. As a mosaic of privately owned duck clubs and public lands (including managed and tidal wetlands), we are interested in quantifying how different types of wetland habitat can attract and sustain diverse bird populations throughout the year. There are very few datasets on the use and occupancy of birds in wetlands because of how vegetation stands obscure observations. Here, we focus on characterizing how restored tidal wetlands support diverse birds. We quantified songbirds, waterfowl, and waders in marsh ponds, tidal channels, and on the marsh plain across two restored and one pre-restoration wetland using trail cameras and a series of 50m aural surveys. We found that songbirds like the Marsh Wren occupy spaces with tall, dense vegetation, smaller waterfowl and waders utilized tidal channels, and larger waterfowl species were found in marsh ponds. The distribution of these habitat types therefore must be prioritized in the design of new tidal restoration projects to support endemic and migratory bird populations.

72. PHRAGMITES DISTURBANCE DECREASES INVERTEBRATE BIODIVERSITY IN A TIDAL WETLAND IN THE CALIFORNIA DELTA

A. Gonzalez¹, S. Landa¹, L. Haworth², and R.L. Tanner¹

Environmental Science & Policy Program, Chapman University, Orange, CA 92866. ²Wildlife Biology Division, Dudek, Sacramento CA 95811.

Wetland ecosystems are vulnerable to plant invasion because of disturbance, which contributes to an already highly variable and intensive environment for organisms living within. In a tidal wetland in Suisun Marsh in the California Delta, invader Phragmites australis (common reed) presence has gone up 325% between 1999 and 2015. Various efforts to control Phragmites have been expensive and unsuccessful due to its vigorous nature of growing in monocultures reaching 15 feet tall. We investigated if there was a relationship between invertebrate biodiversity and plant biodiversity along a tidal gradient in native and invaded habitats in benthic, pelagic, and terrestrial zones quarterly in 2021. We hypothesized that invertebrate communities would be less biodiverse in canopies where P. australis is most prevalent compared to those with the most prevalent native plant species under the intermediate disturbance hypothesis. While we found some species can coexist with P. australis, it largely outcompetes other plant species, whereas native canopies are more likely to be mixed species. The intermediate disturbance hypothesis postulates that biodiversity is maximized when disturbance is not too rare or frequent, which we hypothesize is maximized in native-dominant canopies in the tidal wetlands. It is important to understand how canopy structure and species diversity impacts higher trophic levels so that we can make better management decisions for tidal wetland ecosystem health.

73. COMPARATIVE ANALYSIS OF THE GUT OF MARINE INTERTIDAL PRICKLEBACKS (FAMILY: STICHAEIDAE) FOR ACCUMULATION OF MICROPLASTICS

C. Saldana¹ and J. Heras¹

¹Department of Biology, California State University San Bernardino, 5500 University Pkwy, San Bernardino, CA 92407.

Pricklebacks (Stichaeidae) are long, eel-like fishes that can be found around the coastal zones specifically near the shore and the tidal habitats of Oregon to Baja California. Pricklebacks are best known for dietary diversity, ontogenetic (the course of development of an organism from embryo to adult) dietary shifts, sister taxa with different diets, and convergent evolution of herbivory as well as independent intertidal invasion. Here we focused on three different intertidal species of pricklebacks to characterize and quantify the number of microplastics that have accumulated in the guts due to different dietary specializations. We examined Xiphister mucosus (ontogenetic shift from carnivory to herbivory), X. atropurpureus (ontogenetic shift from carnivory to omnivory), and Anoplarchus purpurescens (carnivores, no shift). Our samples were collected during the summer of 2022 from Friday Harbor Laboratories, Washington. Thirteen fishes were collected and brought back to California State University, San Bernardino to be dissected which included taking out the stomach and the intestine in which we measured gut length and standard length. We are currently working with the Moore Institute for Plastic Pollution Research in Long Beach, California to examine the types and quantity of microplastics present in the gut of each fish. This study was developed to address how much microplastics have accumulated in intertidal fishes, which gives us a better understanding of how humans have impacted our local marine communities.

74. MEASURING IN-SITU DEGRADATION RATES OF BIOPOLYMER POLYHYDROXYBUTYRATE (PHB) AND IMPLICATIONS FOR MARINE SCIENTIFIC INSTRUMENTATION

J. Huynh¹, R. M. Freedman¹, C. Stuart¹, M. O. Aguirre Paden², and A. Santoro³

¹ Channel Islands National Marine Sanctuary, Ocean Education Building, University of California, Santa Barbara, CA 93106. ²Center for Science and Engineering Partnerships, University of California, Santa Barbara, CA 93106. ³Santoro Research Group, Marine Biotechnology Laboratory, University of California, Santa Barbara, CA 93106.

Conventional scientific instrumentation is often made with non-degradable plastic materials and designed to withstand extreme environmental conditions, further contributing to the persistent accumulation of plastic pollution in oceans. Therefore, it is crucial to explore sustainable alternatives that will minimize ecological impacts. This study aims to test the viability of the biopolymer polyhydroxybutyrate (PHB) as a sustainable alternative to conventional plastics in marine scientific equipment. PHB differs from conventional plastics because PHB is a compound naturally made by bacteria. Many marine bacteria have evolved to degrade PHB to carbon dioxide and water, without the creation of microplastics or other harmful byproducts. To determine rates of degradation, six prototypes of PHB will be deployed at six study sites within the Channel Islands National Marine Sanctuary (CINMS) and Olympic Coast National Marine Sanctuary (OCNMS) under ambient marine conditions. A subset of samples will be retrieved every six months to evaluate degradation rates over the duration of the project. The ultimate goal of this study is to develop a more sustainable approach to scientific monitoring and marine research equipment applications. By providing evidence for the viability of PHB as an alternative to conventional plastics in marine scientific equipment, this study has the potential to reduce the environmental impact of plastic pollution in oceans.

75. THE EFFECTS OF PHRAGMITES AUSTRALIS INVASION ON FOOD RESOURCES FOR JUVENILE FISHES IN THE CALIFORNIA DELTA

M. Burrous¹; S. Landa¹; L. Haworth²; R.L. Tanner¹

¹Environmental Science & Policy Program, Chapman University, Orange, CA 92866.

²Wildlife Biology Division, Dudek, Sacramento, CA 95811.

California Delta tidal wetlands have been impacted by human interference through the introduction of invasive species. Invasive species impose stress on native species through resource competition. One invasive plant in Suisun Marsh is Phragmites australis. We examined the effects of Phragmites on the tidal marsh ecosystem by comparing community function between invaded and native habitats in March of 2021. In this study, we compared invertebrate abundance and diversity within the Phragmites canopy and the native canopy, specifically focusing on species that are known food resources for Chinook salmon. We collected invertebrate samples across benthic, pelagic, and terrestrial zones using a transect method in a restored tidal wetland. We calculated the total biomass of food resources present beneath the Phragmites and native canopy. We hypothesized that there would be greater biomass under the Phragmites canopy because it provides lower temperatures which could act as a better safe haven for the invertebrates during extreme temperatures. While species richness was found to be higher in the native canopy, we did find that the invertebrates growing underneath the Phragmites canopy grew larger and were more abundant than under the native canopy. Our data suggest potential benefits that Phragmites may provide for key food resources, despite reductions in biodiversity. We must consider the potential benefits of the Phragmites and their community function when enacting invasion control measures in tidal wetlands.

76. LOS ANGELES RIVER CONTAMINATION FROM UPRIVER WATER SOURCES, JET PROPULSION LABORATORY AND SANTA SUSANA FIELD LABORATORY

M.P. Crawford¹

¹Department of Geography and Environmental Studies, California State University Northridge, Northridge, CA 91330.

This poster will examine the Los Angeles watershed. It will focus on the Los Angeles River contamination from upriver water sources including the contribution from Jet Propulsion Laboratory and Santa Susana Field Laboratory. The Los Angeles region is heavily reliant on groundwater resources as water is a limited commodity. It is important to assess the possible contamination of an essential resource that provides a population of almost 4 million people. With data from the Department of Toxic Substance Control, I utilized GIS to spatially analyze contamination sites in the vicinity of the study area. This project also conducted brief interviews with Los Angeles residents to assess the awareness of large contamination sites within their local areas that were possibilities for additional contamination to the Los Angeles River.

77. SURVEY OF THE WESTERN POND TURTLE POPULATION IN PHAKE LAKE

Z. Beaty¹, P.H. Duchild¹, H. Kim¹, and N.J. Karnovsky¹

¹Pomona College, Dept. of Biology, Claremont, CA 91711

The Western Pond Turtle (WPT, Actinemys marmorata) population is declining across the Western region of the United States. This decline is due to habitat loss and interactions with invasive species. At the Bernard Field Station in Claremont, CA there is a small (1 acre) man-made pond with WPTs. The purpose of our study was to assess the population of WPT in pHake lake. We used 10 traps (5 minnow and 5 hoop) with bait to capture WPTs. We checked these traps every day for 4 days, twice during the summer of 2022. When we captured a turtle, we took measurements, determined the sex of the turtle, and if they were recaptures, checked the turtles for PIT tags. We found that the WPT population has decreased from 2010 when 6 WPTs were caught. In 2022 we recaptured two individuals. One was a male WPT that was originally tagged in 2010 and another was a female WPT that had been rescued from a fountain in an urban mall (Victoria Gardens) and placed in the lake in January, 2022. We also caught three non-native species: a large red-eared slider (Trachemys scripta elegans) and an American bullfrog (Lithobates catesbeianus), and several large-mouth bass (Micropterus salmoides), all of which we removed. The WPT population is vulnerable to bullfrog and largemouth bass predation on small hatchlings and can compete for food and basking space with red-eared sliders. Future studies should continue monitoring this WPT population and removing invasive species as a management strategy.

78. RECLASSIFYING THE PHOTOSYNTHETIC MECHANISM OF TWO SOUTHERN CALIFORNIA PLANT SPECIES

J.L. Read¹ and D. Smith¹

¹Department of Biology, California State University, San Bernardino, CA 92407.

Various types of photosynthesis have been identified in plants, including the most common C3 photosynthesis and the water-saving crassulacean acid metabolism (CAM) photosynthesis. CAM is characterized by temporal separation of photosynthetic processes: carbon is stored as malic acid overnight to be transformed and utilized when light is available during daytime. Though it is typically assumed that arid habitat-dwelling species are exclusively CAM, such species may be solely C3, CAM, or have the ability to do both in response to environmental conditions. Previous research has classified Hesperoyucca whipplei (chaparral yucca) and Yucca brevifolia (Joshua tree) as purely C3 species. To investigate this, leaves were collected from members of these species at dusk and dawn at multiple sites in southern California and preserved in liquid nitrogen. These leaves were then subjected to acid-base titration to compare acidity of dusk and dawn samples, as CAM species will acidify overnight due to accumulation of malic acid. We predicted there would be no significant difference in acidity between dusk and dawn measurements, which would indicate these species are strictly C3; however, our data show strong significant differences in dusk/dawn acidity in both species, which provides support for the reclassification of these species as CAM users.

79. FACILITATING RESTORATION OR AIDING INVASION: ROLE OF ACMISPON GLABER AS A NURSE SHRUB

I. Jones¹ and W. M. Meyer²

¹W.M. Keck Science Department, Pitzer College, Claremont, CA 91711. ²Pomona College, Claremont, CA 91711

Following a fire, nurse shrubs can facilitate the re-establishment of other native plant species and the recovery of native ecosystems. We explored if Acmispon glaber, an N-fixing fire-following shrub, facilitates native shrub and forb establishment following a fire in the highly endangered California sage scrub (CSS) ecosystem. We assessed plant assemblages in and outside of A. glaber canopies five years after a fire burned a portion of the CSS habitat at the Robert J. Bernard Field Station, an inland CSS site in Claremont, CA. Plant assemblages differed in and outside the shrub canopies. Differences were driven by increased cover of non-native Festuca myuros and Erodium spp. outside A. glaber canopies, and increased cover of the native forb, Phacelia distans, and the non-native grass Bromus madritensis under canopies. While the native annual forb, P. distans preferred A. glaber canopies, cover of other native forbs was elevated outside canopies. In addition, we found no evidence that A. glaber facilitated Artemisia californica recovery. Our results highlight that A. glaber may represent a source of vulnerability in CSS fire recovery, as it facilitates establishment and growth of non-native Bromus grasses and does not seem to facilitate native species other than P. distans. While nurse shrubs may in some ecological contexts facilitate native plant recovery, in other ecological contexts they may enhance the cover of invasive species. Consequently, restoration practitioners should assess the role of various nurse shrubs before implementation as a restoration practice.

80. DEVELOPING GROWTH PROMOTION STRATEGIES FOR CRESSA TRUXILLENSIS TO IMPROVE SUCCESS OF RESTORATION ACTIVITIES

H.R. Lyford^1,2, M.R. Lum^1,2, K. Arjomand ^1,,2,  C. Ehren^1,2, and K. Johnston³

¹Biology Department, Loyola Marymount University, Los Angeles, CA 90045. ²Coastal Research Institute, Loyola Marymount University, Los Angeles, CA 90045. ³University of California Santa Barbara, Santa Barbara, CA 93106.

Cressa truxillensis, commonly known as alkali weed, is native to western North America and is used in revegetation projects in saline or alkaline soils at locations such as the Ballona Wetlands Ecological Reserve. This research aimed to (i) determine methods to improve C. truxillensis seed germination, (ii) characterize the impact salt has on seed germination and growth, and (iii) identify and characterize bacterial seed endophytes and their potential as plant growth promoting bacteria (PGPB). Results showed that seed scarification, either through mechanical or chemical methods, substantially improved seed germination rates. The presence of salt at 300 mM NaCl delayed germination, and both 150 mM and 300 mM NaCl decreased seedling size. Two different strains of Paenibacillus peoriae were found to reside within C. truxillensis seeds collected from the Ballona Wetlands. Although neither strain alleviated the salt sensitivity displayed by C. truxillensis, both strains showed tolerance to heavy metals and salt, and showed additional properties suggestive that they may function as PGPB. Methods used in this study can serve as guidelines for preparation of seed of C. truxillensis prior to seeding in appropriate habitats throughout the species’ range.

81. MULCH MATTERS: QUANTIFYING MULCH DECOMPOSITION RATES AND IDENTIFYING PRIMARY DRIVERS OF MULCH DECOMPOSITION IN SOUTHERN CALIFORNIA URBAN AREAS

M. Landon¹, A. Lopez-Ruiz², A. Rondon³, E. Denver⁴, A. Lesso¹, H. Collom⁵, S. Reichard⁶, A. Bowen¹, C. Fissore¹, G. Vourlitis⁵, W.M. Meyer III², M. Maltz⁶, E.J. Questad³, J. Blauth⁴, D. VanOverbeke⁴.

¹ Department of Biology and Environmental Science, Whittier College, Whittier, CA 90602. ²Biology Department, Pomona College, Claremont, CA 91711. ³Department of Biological Sciences, California Polytechnic State University at Pomona, Pomona, CA 91768. ⁴ Department of Biology, University of Redlands, Redlands, CA 92373. ⁵Department of Biological Sciences, California State University at San Marcos, San Marcos, CA 92096. ⁶ W.M. Keck Science Department, Claremont, CA 91711.

Mulching is an increasingly common landscaping practice that aims to reduce water subsidies in urban and suburban areas of southern California. While largely viewed as sustainable, the effects of mulching on the carbon cycle are poorly understood. Previous studies have shown that mulched areas enhance decomposition belowground. However, decomposition processes on the surface are understudied, particularly in semi-arid regions. As mulch sits on the surface it is exposed to direct sunlight, and in semi-arid and arid areas, UV is a primary driver for decomposition. To better understand how mulching influences regional carbon budgets, we quantified mulch decomposition rates in semi-arid urban southern California and examined the importance of key factors (chemical properties of the mulch, abiotic conditions, and UV exposure). In June 2022, we deployed 560 litter boxes at seven college campuses across southern California. Litter boxes were assigned to treatments in a 2x2 factorial design. Litter treatments consisted of either: (1) shredded wood, from both construction and trimmed tree material, or (2) redwood tree bark, both common mulch types used in many gardens across southern California. UV treatments consisted of a UV-allowed treatment and a UV-blocked treatment with a Gila® UV-blocking window screening covering that blocked 97% of the UV in the 250 to 400 nm range. Final litter bag collection will be completed in mid-March with analyses to follow. A better understanding of the factors influencing decomposition will allow us to comprehend the trade-offs between reduced water use and enhanced carbon emissions to inform landscaping management.

82. THE EFFECT OF URBANIZATION ON FLIGHT INITIATION DISTANCE IN WESTERN SIDE-BLOTCHED LIZARDS (UTA STANSBURIANA ELEGANS)

B. Stone and Z. Nisani. Department of Biological and Environmental Sciences, Antelope Valley College, 3041 West Ave K, Lancaster, CA 93536.

Escape strategies are an economic trade-off for prey animals, balancing the escape from predation with essential activities to maximize fitness such as foraging, mating, and basking. Flight initiation distance (FID), the distance between the predator and the prey animal when the prey begins to escape, plays an important role in observing the balance between the cost of fleeing versus the chance of predation. Studies show that biotic and abiotic factors such as climate, sex, and habitat affect FID. We hypothesized that Western Side-Blotched lizards’ (Uta stansburiana elegans) FID in urban areas will differ compared to lizards in rural habitats due to artificial structures. To test this, we compared the FID of lizards in a high-trafficked urban city to a protected (rural) park in relation to the substrate they were found on by walking toward a lizard at a constant speed and measuring the distance between the researcher and the lizard’s initial position before fleeing. The mean FID was significantly different in the two populations with our urban population having a larger mean FID than our rural population. Lizards on brick walls had the largest FID causing a significant difference among populations. We believe that human exposure has caused some habituation yet urban lizards are altering their escape responses in relation to the substrate they are on, which plays an important role in their survival.

83. GOAT GRAZING AS A METHOD FOR INVASIVE SPECIES MANAGEMENT AND FUEL REDUCTION

A. K. M. Bowen¹, F. Ramirez¹, and L. Vela¹

¹Department of Biology, Whittier College, Whittier CA

In the face of the damaging effects of invasive plants, it is essential to better understand how to best manage plant communities.  Goat grazing as a targeted foliage management practice presents a unique alternative to conventional methods. It does not rely on chemical intervention, and it has the potential to be less damaging and labor intensive than hand weeding. The evidence of the effectiveness of using goat grazing as a management tool is mixed, but several studies have shown that this method can significantly reduce undesirable plants.  More research into the effectiveness for goat grazing as a restoration technique is essential, especially in Southern California.  This study took place in the Puente Hills Preserve in Whittier, CA, where we established two grazing areas and one control area: the first treatment area was grazed in mid-May through mid-June in 2022, while the second area was grazed from mid-June through mid-July.  We monitored plots in each treatment area prior to and after grazing, including the following winter/spring.  In a separate set of plots, we measured aboveground biomass of litter and all standing invasive species in the fall following grazing.  Preliminary results indicate that total invasive cover was significantly reduced in both treatment areas following grazing, indicating that goats could be an effective tool to reduce fuel loads in the summer and fall months.  However, grazing did not reduce the amount of litter and standing invasive biomass.  Future research this summer will help elucidate whether these results will persist over time.

84. LATITUDINAL VARIATION IN FEATHER STRUCTURE AND COLOR IN NORTHERN BOBWHITES (COLINUS VIRGINIANUS)

B. T. Higa^1,2, J. F. Salter^2,3, K. C. Bell³, and A. J. Shultz²

¹Glendale Community College, Glendale, CA 91208. ²Ornithology Department, Natural History Museum of Los Angeles County, Los Angeles, CA 90007. ³Mammalogy Department, Natural History Museum of Los Angeles County, Los Angeles, CA 90007.

Understanding how the environment affects phenotypic traits within species has been a focus of ornithological research for over a century. Repeated observations of convergent traits across taxa in response to similar environmental conditions have been formalized as ecogeographic rules, such as Gloger’s Rule, which describes the relationship between temperature, humidity, and animal coloration. In birds, feather structure and coloration together may be shaped by the phenomena that drive Gloger’s Rule. Support for Gloger’s Rule is widespread among birds, yet geographic variation in feather structure, such as the proportion of down at the base of body feathers and the color of the down itself, have received far less attention. Recent studies of bird species across elevational gradients found that populations at higher elevations that experience colder temperatures have a greater proportion of down and down that is darker in color, both of which improve heat retention. To investigate whether the length and color of down follows similar patterns across a latitudinal temperature gradient, we examined feathers in Northern Bobwhites (Colinus virginianus), a sedentary quail species that is widely distributed across the eastern United States. We photographed belly feathers collected from 80 bobwhite museum specimens (36 males, 44 females) spanning 20 degrees of latitude from Massachusetts to south Florida and used ImageJ to measure the proportion of down on each feather and the color of the down. We analyzed these data using regression analyses to test the hypothesis that bobwhites at higher latitudes will have proportionally more down and darker down.

85. CHANGES IN WOODRAT HUT DISTRIBUTION 2005–2022

P.H. Duchild¹, Z. Beaty¹, H. Kim¹, and N.J. Karnovsky¹

Pomona College, RESCUE-Net, Dept. of Biology, Claremont, CA, 91711.

The purpose of the study was to assess changes in woodrat hut distribution in the 85 acres of coastal sage scrub habitat of the Bernard Field Station (BFS) in Claremont, California. Woodrats are declining locally due to habitat loss and poisoning. We compared the distribution and number of huts found during surveys in 2005 to those found in June and July 2022. The BFS is home to both the desert woodrat Neotoma lepida (designated Vulnerable) and dusky-footed woodrat N. fuscipes. We used a GPS and ArcGIS Field Maps to relocate the huts mapped in 2005. We recorded contemporary hut presence, absence, and condition. In addition, we recorded any newly discovered huts incidentally found during the surveys. We classified sites previously recorded in 2005 as either “rediscovered” or “absent,” and newly discovered huts as “new.” In total, we revisited 164 of the 293 hut site coordinates recorded in 2005 (56.0%). Of these revisited sites, 92 huts (56.1%) were intact, and 72 huts were absent (43.9%). We discovered an additional 30 new huts in the process of relocating past hut coordinates. Many huts previously recorded along major roads were absent in 2022, which may be the result of environmentally disruptive construction on the Robert Redford Conservancy buildings within the BFS. Our study shows that without disturbance, huts can persist for decades. In order to more fully understand changes in hut distribution and number, we will continue to survey for new huts and monitor old huts.

86. SEASONAL TRENDS FOR INSECT COMMUNITIES ACROSS THE LOS ANGELES METROPOLITAN AREA 

Y.Y. Cheung¹, B.V. Brown², V. Shirey¹, T. Baiotto¹, A. Baker^1,2, C. Lehnen³, J. Lewthwaite¹, J. Willoughby¹, and L.M. Guzman¹

¹Ecological Data Science Lab, Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089. ²Natural History Museum of Los Angeles County, Los Angeles, CA 90007. ³Integrative and Evolutionary Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089.

With urbanization increasing rapidly, understanding what drives changes in urban biodiversity is becoming more important. In our study, we are examining the insect communities across Greater Los Angeles, a megacity where urban sprawl threatens close-by natural areas. We are using data from the insect-focused Biodiversity Science: City and Nature (BioSCAN) project to reveal how biodiversity could be altered in a highly populated area with highly diversified land usage, such as commercial, residential, and industrial areas. Our preliminary results show that there was a seasonal trend in the insect communities across Los Angeles County during 2014 to 2018. In particular, the phorid flies shifted distinctly season to season in repeatable ways across years. The vinegar flies, sweat bees, fungus gnats, and hoverflies, however, showed less distinctive seasonal trends. We hypothesize that seasonal environmental variations also interact with the spatial distribution of canopy cover, to create distinct micro-climates that can explain spatial and temporal species turnover. We expect that there will be a positive correlation between primary production (canopy cover) and insect diversity.

87. Effects of Temperature on Sprint Performance and Lactate Dehydrogenase Activity in Paruroctonus marksi (Scorpiones: Vaejovidae)

D. Gardner¹, A. Hamdan¹, B. Larrick¹, S. Tran¹, Z. Nisani¹, and A. Carrillo¹.

¹Department of Biological and Environmental Sciences, Antelope Valley College, 3041 West Ave K, Lancaster CA, 93536.

Lactate dehydrogenase (LDH) in scorpions provides rapid sources of energy used during anaerobic metabolism, such as sprint activities. In ectotherms, the body temperature can affect the LDH activity, which may influence the sprint performance of sit-and-wait predators, namely scorpions. The sprint performance of scorpions is limited by the time to fatigue, which may be related to body temperature. It was hypothesized that body temperature positively correlates with LDH activity, and that body temperature negatively correlates with fatigue time in scorpions. The fatigue time was measured by running scorpions (Paruroctonus marksi) at 22°C, 27°C, and 32°C until they were fully fatigued and unable to sprint. The LDH activity of the scorpion body was measured using the spectrophotometer method at the same temperatures used to measure fatigue time. There was a positive correlation between temperature and LDH activity, however it was non-significant. There was no correlation between fatigue time and temperature, although the sprint speed of scorpions was highest at 27°C. The Q₁₀ of LDH (anaerobic) activity was approximately 1.68 in this study, which is lower than previously reported for aerobic activity (Q₁₀ = 2.97) for this species. This indicates that the LDH activity is not as significantly affected by temperature as aerobic activity is, which supports the sprint activities of sit-and-wait predators, such as scorpions.

88. INTERACTING EFFECTS OF HEAT AND WATER STRESS ON LEAF THERMOTOLERANCE OF Q. AGRIFOLIA AND Q. ENGELMANNII

M. Ranganath and G. North

Department of Biology, Occidental College, Los Angeles, CA, 90041.

Increasingly frequent droughts and heat waves in the southwestern U.S. test limits of tree tolerance to heat and water stress. Here, we studied leaf heat tolerance of native California species, Q. agrifolia (Coast live oak) and Q. engelmannii (Engelmann oak) to evaluate: (1) combined effects of heat and water stress (2) impacts of leaf habit (evergreen or drought deciduous) and (3) season on leaf heat tolerance. Photosynthetic efficiency measurements (Fv/Fm) at increasing temperatures were used to calculate T50 values of leaves from irrigated and unirrigated oaks before and after extreme heat waves in Southern California, USA. Additionally, water stress under the two irrigation conditions was estimated using stomatal conductance measurements. Decrease in stomatal conductance from irrigated to unirrigated trees was greater in Q. engelmannii than Q. agrifolia in response to extreme heat during late summer. Otherwise, no significant differences were observed in stomatal conductance rates or T50 between the species. Rather, irrigation was more impactful on heat tolerance, with irrigated plants having T50 values ranging from 54.1 - 54.2 ℃ and unirrigated trees from 55.2 - 56.4℃. Seasonality also impacted heat tolerance, with variance in photosynthetic efficiency and differences between treatment groups decreasing as heat and water stress increased. The data indicate that trees that have undergone chronic water stress may be more tolerant of future extreme heat and drought episodes. Further inquiries into long term impacts of water stress on the ability of Quercus species to withstand future drought and heat waves are still needed.

89. CHARACTERIZING THE EFFECTS OF WILDFIRE DISTURBANCE ON MAMMAL OCCUPANCY IN FIRE-PRONE ECOSYSTEMS OF CALIFORNIA

E.N. Weiner¹ and T. Stankowich¹

¹Department of Biological Sciences, California State University, Long Beach, CA 90804.

Wildfires have historically been a part of California ecosystems, playing a key role in shaping vegetated landscapes. However, anthropogenic disturbances such as urbanization and climate change are altering fire regimes, posing a growing threat to native flora and fauna. While the effects of wildfire on plant and small mammal communities have been well-studied, there has been little research concerning postfire succession of mesocarnivore species. Our project goals are to conduct long-term monitoring of mammal occupancy in recently burned areas of Santa Cruz and Orange County, California, and to determine how occupancy is related to environmental covariates and species-specific life history traits. We collected pre- and postfire detection data at burned and unburned sites in areas affected by three fires in Orange County and the CZU Lightning Complex in the Santa Cruz mountains. Single species autologistic occupancy models were fit to compare occupancy of burned and unburned areas over time. Preliminary results suggest that generalist species (e.g., coyotes) do not display strong preference for burned versus unburned sites, while dense vegetation specialists (e.g., bobcats) displayed an avoidance of burned sites. The interspecific variability in postfire site selection suggests that generalist species may be more capable of exploiting postfire resources at early successional stages, creating “winners” and “losers” under shifted fire regimes. Our future directions are to explore postfire succession of other common California mammal species (e.g., mountain lions) and determine how mammal occupancy at burned and unburned sites is related to environmental covariates.

90. IMPACTS OF URBAN HEAT ISLAND INTENSITY AND ARTIFICIAL LIGHT AT NIGHT ON URBAN MAMMALS

E. Blackwell¹ and T. Stankowich¹

¹California State University, Long Beach, CA, 90840.

While many mammal species survive and even thrive in cities, urban living is associated with sublethal stressors that can impact occupancy and activity, such as urban heat and artificial light. The urban heat island effect leads to localized increases in temperature. Interspecific differences in thermal physiology, body size, and home range might influence responses to urban heat islands and alter community composition across spatial gradients of heat stress. Artificial light is an anthropogenic sensory pollutant pervasive in cities. The introduction of artificial nighttime lighting to the landscape is a significant departure from the natural conditions in which wildlife evolved. Nocturnal animals that rely on dark nighttime conditions for foraging or hunting behavior may be particularly impacted. To investigate the impacts of these two stressors on wildlife, detection data from wildlife cameras along urbanization gradients in 32 cities across the US will be paired with remotely sensed measurements of urban heat island intensity and artificial light levels. The resulting multi-city, multi-species occupancy models will show how these stressors affect species’ spatial distribution and community composition.

RESEARCH TRAINING PROGRAM POSTER SESSION: 5:00 – 7:00 PM

91. INTERNET-OF-THINGS CONNECTED FOLEY CATHETER URINE COLLECTION SYSTEM TO AUTOMATICALLY AND CONTINUOUSLY MEASURE URINE OUTPUT

A. Lee

Walnut High School, Walnut, California 91789.

Urine output is an important indicator of the level of renal impairment in patients. Accurately measuring urine output is critical in the treatment of hospitalized patients with renal injury, heart failure, and other life-threatening conditions. Currently, the most common way to collect urine uses a Foley catheter connected to a urine collection bag that has volume gradation markings. This measurement method has a low level of accuracy and is labor-intensive, requiring a nurse to manually measure the urine collected periodically. This project developed an Internet-of-Things enabled system that captures urine output automatically in real time, by continuously monitoring the urine volume collected via the Foley catheter. The device is built utilizing a strain gauge load cell, an integrated circuit that contains an amplifier and analog-to-digital converter, and a WiFi-enabled microcontroller. The data is sent via wireless networking to a data collection and analysis server which provides accurate analyses of urine output. A mobile application utilizing the Blynk.io system is used to display the data. This device and mobile application was built at a minimal cost of $35 USD. The device has been tested multiple times and reported urine output accurately, with as little as 1% difference between actual vs measured volumes. In the future, further development of this device can provide hospitals and physicians worldwide with easy access to affordable, accurate, and real-time urine measurement, which would translate into better, life-saving medical care.

92. A NOVEL STRATEGY FOR THE REVERSAL OF TUMOR CELL IMMORTALITY

S.H. Wu¹, N.O. Stevers² and J.F. Costello²

¹Dublin High School, Dublin, CA 94568. ²Department of Neurological Surgery, University of California, San Francisco, CA 94158.

Glioblastoma (GBM) is the most common malignant adult brain tumor. With minimal clinical innovation, the prognosis for GBM patients remains grim. However, a commonality exists between 83% of GBMs: Telomerase Reverse Transcriptase promoter (TERTp) mutations. TERT, the catalytic component of telomerase, is responsible for telomere elongation and maintenance. The TERTp mutation creates a de novo ETS motif, allowing the GA-binding protein (GABP) transcription factor complex to reactivate the mutant allele. While direct targeting of telomerase has proven broadly toxic, targeting GABP to target TERT reactivation is a potential alternative. However, direct small-molecule inhibition of transcription factors like GABP is challenging. To overcome this therapeutic barrier, we designed, engineered, and evaluated a GABPB1L transactivation-domain-null dominant-negative (B1-DN) transgene. We hypothesize that the B1-DN will sterically displace wildtype GABPB1L from the mutant TERTp, resulting in loss of TERT expression. Indeed, the B1-DN reduced TERT expression by up to 75% in TERTp mutant GBM, melanoma, and bladder cancer cell lines, but not in TERTp wildtype cells. This inhibitory effect was sustained throughout a 60-day time course, shortening telomeres throughout. Furthermore, since we have determined that GABP is a regulator of the mutant TERTp across 16 distinct cancer types, this B1-DN could eventually be valuable to the treatment of more than a million patients diagnosed with TERT promoter mutant tumors per year. Studies investigating replicating retroviral vectors as a clinically relevant means to deliver the B1-DN are ongoing. In summary, this transgene may be able to reverse tumor cell immortality across all TERTp mutant tumors.

93. AUTOMATIC SEGMENTATION OF MENINGIOMA TUMORS ON MULTIPARAMETRIC 3D MRI USING CONVOLUTIONAL NEURAL NETWORKS

D. Sreedhar¹ and F. Kazerooni². ¹Troy High School, Fullerton, CA 92831. ²University of Pennsylvania, Philadelphia, PA 19104.

As meningioma accounts for 40% of adult brain tumors worldwide, timely tumor assessment is required to ensure patient health. Currently, manual tumor segmentation imposes a high burden on the radiologists and lacks intra- and inter-observer repeatability. Furthermore, many of the current methods for tumor assessment in neuro-oncology practice are based on 2D tumor measurements which cannot provide accurate information about the tumor and its response to treatments. Algorithmic approaches can also be subject to inefficiencies and bias. This project develops an automated segmentation framework that can facilitate tumor assessments and improve prediction of patient prognosis by producing reliable and reproducible volumetric measurements. Four types of magnetic resonance images (MRIs) were used - T1, T2, T1CE, and FLAIR - from a collection of 357 meningioma patients. The prediction of the nnUNet algorithm was cross-checked with the ground truth labels to assess prediction accuracy. The nnUNet model classified regions of the tumor on MRI scans into edema or tumor-enhancing regions. The dataset was split into 82% for training, 15% for validation, and 3% for testing. The inference model was run on both the validation and testing sets. The whole tumor label achieved a mean DICE score of 0.88 and sensitivity of 89.6%. The enhancing core label achieved a mean DICE score of 0.86 and sensitivity of 83.1%. The automated segmentation method created in this project based on nnUnet framework  shows reliable performance for tumor subregion segmentation of meningioma.

94. HUMAN DERMAL FIBROBLASTS CAN REDUCE INFLAMMATORY MARKERS OF SEPSIS IN VIVO

A.R. Bharathwaj¹ and Y. Yung²

¹Westview High School, San Diego, CA 92129. ²Scintillon Institute for Biomedical and Bioenergy Research, San Diego, CA 92121.

Sepsis, which is characterized as an extreme immune response to infection, is a major public health issue and one of the leading causes of death worldwide. Currently, there are no effective pharmacological treatments for sepsis, and its management focuses on antibiotic application and organ function support. Stem cell therapies, such as mesenchymal stem cell (MSC) administration, have recently been shown to reverse sepsis-related inflammation. Human dermal fibroblasts (HDF) are functionally similar to MSCs, but have not yet been investigated as a potential therapeutic for sepsis. In this study, C57Bl/6J male mice were injected with either lipopolysaccharide (LPS) from E. coli to induce sepsis or vehicle solution as a negative control. Different doses of LPS (2.5 and 4.0 mg/kg) were used to elicit moderate and severe sepsis respectively, along with their comorbid inflammation and cytokine storm. One hour post sepsis induction, mice were treated with HDF (1 million cells). As positive controls for efficacy, novel TNF-alpha trimer and dimer nano-antibodies (nAbs) were delivered to the mice, as they have been shown previously by our lab to reduce inflammation. ELISA assays were performed on collected blood from various time points to determine the levels of proinflammatory cytokines, including IL-1beta, TNF-alpha, and other interleukins. Tissue histology of the lungs was examined to determine the treatment’s effect on organ damage. Our preliminary results suggest a significant decrease in IL-1beta levels 24 hours post LPS and HDF treatment administration, which indicates that immune modulation from HDF may ameliorate sepsis-related inflammation.

95. FOURIER TRANSFORM OF ELECTROCARDIOGRAM DATA FOR 3D MODELS OF CARDIAC ELECTRICAL ACTIVITY FOR IMPROVED DISEASE DIAGNOSTICS

A. Sriram¹, S. Smith?²

¹The Harker School, San Jose, CA, 95129. ²Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada, K1N 6N5.

Five percent of the U.S. population has a form of arrhythmia, while about 20.1 million adults age 20 and older were reported to have coronary artery disease. Electrocardiograms (ECG or EKG) are devices that record the movement of electrical signals to and from different parts of the heart by placing electrodes on the chest to measure the signals; and while ECG’s are often accurate, they are not necessarily the best tool to diagnose any heart condition. The goal of this study is to generate a 3D model of an ECG graph using Fourier transforms and coordinate system shifts. ECGs follow a repetitive wave pattern or irregular sinusoid, so we used a Fourier series analysis to identify a trigonometric sum equation for an ECG graph. We used “A large scale 12-lead electrocardiogram database for arrhythmia study” dataset with 45,152 samples. We linked the time series data to Matlab’s Fast Fourier Transform method to identify fourier coefficients of our ECG model. We transformed the fourier equation from rectangular to spherical coordinates using Matlab’s cart2sph algorithm. Our algorithm allowed us to develop a 3D model of the heart’s electrical activity with a 97% accuracy. By testing the same algorithm on other heart conditions, we identified focal points in the 3D electrical pathway activity in different heart conditions. This model of whole heart electrical activity can aid doctors in understanding the placement of electrodes during ECG measurement and also contribute towards the development of heart 3D models to improve diagnostic accuracy.

96. SUPERVISION: A NOVEL INTEGRATED SENSING AND COMPUTATIONAL FRAMEWORK TO ENABLE SUPERHUMAN EPIRETINAL PROSTHESES

W. Huang¹ ​​

¹Palos Verdes Peninsula High School, Rolling Hills Estates, CA 90274.

The current gold standard to restore vision to patients suffering from retinal degenerative diseases is through retinal prostheses. However, these FDA-approved implants are limited to low-resolution grayscale images, making object identification and prosthesis adaptation difficult for patients. Furthermore, current studies focus on vision recovery and do not fully leverage state-of-the-art sensing and computational advancements. For the first time, this study develops a paradigm that creates visual capabilities superseding the standard visual acuity. The framework aims to turn patient disadvantages to advantages, effectively creating superhuman vision. It consists of two new integral components in addition to my previous research: 1) a modular plug-and-play (PnP) system to enable the adoption of advanced visual schemes; 2) a tunable optimal transportation theory (OT)-based virtual magnifier to localize and enlarge regions of interest (ROIs) while preserving important features and curvatures; and finally, the resulting images are processed through a real-time image optimization framework and an autoencoder-OT model developed in the previous year’s project. The PnP system provides patients with images at a 120, 180, and 360 degree visual angle. Further, the second generation prototype system was developed to optimize these captured images in both indoor and outdoor scenes. Five computational experiments including visual and area-preserving tests showed that the magnifier enlarged the ROIs with minimal distortion at the varying visual angles. Attention mechanisms and color scheme comparisons demonstrated that the image optimization framework maximized the amount of both spatial and color information displayed to patients.

97. A REPRODUCIBLE PROTOCOL FOR BENCHMARKING WASTEWATER-BASED GENOMIC SURVEILLANCE TECHNOLOGIES

A. Wesel¹ and S. Mangul²

¹Harvard-Westlake School, Los Angeles, CA 91604. ²Department of Clinical Pharmacy, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033.

Wastewater-based genomic surveillance (WBGS) is an emerging technology that has demonstrated tremendous potential in combating pandemics by enabling rapid detection of infections within a community. Low overhead costs make it an attractive alternative to individual testing. However, the lack of a standardized approach to the benchmarking of WBGS technology is an obstacle to establishing a comprehensive and scalable WBGS program. This paper presents a set of potential benchmarking norms for WBGS technology, studying the ability of simulated genomes to replicate real-world conditions. The paper focuses on CliqueSNV, a haplotype reconstruction approach specifically designed to work with low-frequency and novel variants, as a case study. Our results show that different alignment methods don’t impact CliqueSNV’s performance; with each method, CliqueSNV found a similar number of haplotypes with similar characteristics.  However, the different alignment tools took vastly different times to run with the Burrows-Wheeler Aligner (BWA) being by far the fastest for this task. Additionally, the position of short reads from similar variants greatly impacted results.  For example, when the reads generated from the Alpha sequence were grouped at the very beginning, CliqueSNV would find Alpha perfectly and nothing else.  However, when the ordering was random, as would be encountered in real-world sequencing, CliqueSNV had difficulty isolating variants and constructing haplotypes with small differences from the SARS-CoV-2 consensus genome. The reproducible pipeline presented in this paper and the lessons about data simulation can be used to benchmark the accuracy and effectiveness of other wastewater-based genomic surveillance technologies.

98. EFFECT OF DIFFERENT PLASTIC FILMS (HDPE AND LDPE) AND FOAMS (PE AND PS) ON THE FITNESS OF SUPERWORMS (ZOPHOBAS MORIO)

E. Chen¹ and D. Chu²

¹Carlmont High School, 1400 Alameda de las Pulgas, Belmont, CA, 94002. ²Chu Lab, Department of Biology, San Francisco State University, CA, 94132.

Polyethylene (PE) and polystyrene (PS) are the most commonly used plastics in industrial and consumer products, but few natural organisms can break down the substances. As a result, it takes multiple decades, at the very least, for a single plastic bag to break down. In recent studies, a variant of the mealworm species, the superworm (Zophobas morio), could degrade both polyethylene and polystyrene foams. In this study, the fitness of superworms consuming films of low-density polyethylene (LDPE), high-density polyethylene (HDPE), PE foam, PS foam, and control (cabbage and oat bran) were measured through their change in weight and behavior for 14 days. Experiments were done in replicate; worms were kept inside jars, fed on the plastics, and weighed every 24 hours, while the plastic materials were checked for holes and weighed once weekly. The total weight loss of the superworms was -14.24 (±2.95) % for LDPE, -13.744 (± 1.64) % for HDPE, -14 (±1.77) % for PE foam, and -12.27 (0.01) % for PS, in comparison to the control, which had a total weight gain of 21.35% (±1.275%), from the start to end of the testing period. These results indicate that the relative fitness of the superworms declined due to a combination of starvation and insufficient nutrients from the plastics, but also indicate the presence of enzymes capable of plastic degradation in the saliva of larvae.

99. A COMPARATIVE ANALYSIS OF EXISTING EDUCATIONAL RECOMMENDER SYSTEMS

E. C. Xiong¹

¹Canyon Crest Academy, San Diego, CA 92130.

Due to the widespread availability of online learning resources, recommender systems have been increasingly utilized as tools to support teaching and learning activities in the educational domain. Among the various types of recommender systems, hybrid educational recommender systems have emerged as a promising approach to improve the accuracy and effectiveness of recommendations. Hybrid recommender systems combine two or more recommendation strategies in different ways to benefit from their complementary advantages. In contrast, traditional educational recommender systems rely on a single recommendation strategy, such as collaborative filtering or content-based filtering, to provide personalized recommendations. Ontological recommender systems are designed to use domain knowledge to enhance recommendation quality, whereas matrix factorization recommender systems use machine learning techniques to factorize user-item rating matrices and identify latent factors that influence user preferences. Thus, while collaborative and content-based filtering remain the mainstays of traditional systems, newer hybrid, ontological, and matrix factorization systems are viewed as viable alternatives. As such, using several evaluation criteria that account for diverse aspects of recommendation accuracy, such as diversity, originality, and serendipity, can yield more useful results. This systematic review of the literature on recommender systems for technology-enhanced learning examines the effectiveness of these different types of recommender systems in the educational domain, emphasizing the importance of using multiple evaluation metrics.

100. A DEEP LEARNING-BASED, BIOINFORMATIC ANALYSIS OF FOLIAR FUNGAL ENDOPHYTES IN LITTER DECOMPOSITION

M. Chang¹ and A. Apigo²

¹Woodbridge High School, Irvine, CA 92614. ²Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106.

Litter decomposition is a key ecological process that plays a vital role in the global carbon cycle. While the effect of soil microbes in decomposition has been well studied, the role of fungal microbes within the leaf, or foliar fungal endophytes, is largely unclear. In the present study, the relationship between endophyte abundance and litter mass loss was examined in the Torrey pine (Pinus torreyana). Total DNA and RNA was extracted, followed by next-generation sequencing and bioinformatic analysis to identify core endophyte species across geographic regions. Endophyte abundance was discovered to be positively correlated with mass loss, and endophytes OTU4 and OTU211 were most prevalent throughout all samples. In addition, based on open-source data, OTU4 has not been previously discovered in Southern California, where the samples were collected. This understanding of plant decomposition and its relevance to the global carbon cycle is essential, particularly in the current climate change era.

101. HUMBOT: BIO-INSPIRED HUMMINGBIRD AIRCRAFT

A. Liu, University High School, Irvine, CA, 92612.

To strengthen the current aerodynamic abilities of drones, various ornithopters were prototyped based on the hummingbird’s unique method of flight. Each model used a consistent assortment of light carbon-fiber rods, mylar, ABS gears, micro-motors, ESC mini-receivers, and a BETAFPV-remote, while wing shapes and flight-systems differed. Following each model’s construction, computational fluid dynamic simulations (CFDs) were used to verify the physical results: sustained flight, energy-consumption, and wing-oscillation speeds assessments. Initially, a barebones model body built with a rubber band-powered staggered crank system was used as control for future models, to test varying wing aspect ratios of hummingbird species from the Mellisuga helenae (3) to Calypte anna (4.5). Each physical prototype was replicated digitally in a 3-dimensional model that was placed through artificial physics simulations. A wing aspect ratio of around 4.3 was found to be ideal for unsteady aerodynamic flight, and used in all following models. The physical tests for later models revealed the importance of having a high angle of attack and the effectiveness of a four-wing duo dual-crank motor system, which had a 112% increase in efficiency when compared to the standard dual-crank gearbox, despite the additional parasitic drag being generated from the increased surface area. The CFDs revealed ideal body-shapes, wing aspect ratios, and strong correlations between the center of gravity and the incident angle. The current system successfully replicates the hummingbird’s ability in generating thrust from both up and downstrokes, as one paired wing is always traveling in a lift-generating downstroke in every flap.