California Agriculture
California Agriculture
California Agriculture
University of California
California Agriculture

Current issue and featured articles

Special Issue
Community and citizen science
January-March 2021
Volume 75, Number 1
Community and citizen science: Inviting the public into UC ANR research
by Glenda Humiston
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Community and citizen science fosters an appreciation for the scientific process, building scientific literacy and public support for research.
Special issue: Community and citizen science
by Ryan Meyer, Sabrina Drill, Christopher Jadallah
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In this special issue, California Agriculture presents research and news on community and citizen science projects across California.
Report: Assessing community and citizen science at UC ANR
by Ryan Meyer, Sabrina Drill
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The authors uncovered a rich diversity of projects that engage Californians in UC ANR research, and a variety of challenges and opportunities for expanding this work.
Community and citizen science projects around UC ANR
by Lucien Crowder
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What do coyotes, eggs and leafy greens have in common? They're all subjects of UC ANR research projects to which everyday Californians have contributed.

Peer-reviewed research and review articles

Data parties engage 4-H volunteers in data interpretation, strengthening camp programs and evaluation process
by Marianne Bird, Kendra M. Lewis
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A practice associated with citizen science allows 4-H stakeholders to better engage in program evaluation.
Participatory evaluation is a form of citizen science that brings program stakeholders into partnership with researchers to increase the understanding and value that evaluation provides. For the last four years, 4-H volunteers and staff have joined academics to assess the impact of the California 4-H camping program on youth and teen leaders in areas such as responsibility, confidence and leadership. Volunteers and nonacademic staff in the field informed the design of this multiyear impact study, collected data and engaged in data interpretation through “data parties.” In a follow-up evaluation of the data parties, we found that those who participated reported deeper understanding of and buy-in to the data. Participants also provided the research team insights into findings. By detailing the California 4-H Camp Evaluation case study, this paper describes the mutual benefits that accrue to researchers and volunteers when, through data parties, they investigate findings together.
The CALeDNA program: Citizen scientists and researchers inventory California's biodiversity
by Rachel S. Meyer, Miroslava Munguia Ramos, Meixi Lin, Teia M. Schweizer, Zachary Gold, Dannise Ruiz Ramos, Sabrina Shirazi, Gaurav Kandlikar, Wai-Yin Kwan, Emily E. Curd, Amanda Freise, Jordan Moberg Parker, Jason P. Sexton, Regina Wetzer, N. Dean Pentcheff, Adam R. Wall, Lenore Pipes, Ana Garcia-Vedrenne, Maura Palacios Mejia, Tiara Moore, Chloe Orland, Kimberly M. Ballare, Anna Worth, Eric Beraut, Emma L. Aronson, Rasmus Nielsen, Harris A. Lewin, Paul H. Barber, Jeff Wall, Nathan Kraft, Beth Shapiro, Robert K. Wayne
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By connecting different grassroots eDNA projects, and making data open to explore, we are finding patterns that may help guide eDNA-based biomonitoring.
Climate change is leading to habitat shifts that threaten species persistence throughout California's unique ecosystems. Baseline biodiversity data would provide opportunities for habitats to be managed under short-term and long-term environmental change. Aiming to provide biodiversity data, the UC Conservation Genomics Consortium launched the California Environmental DNA (CALeDNA) program to be a citizen and community science biomonitoring initiative that uses environmental DNA (eDNA, DNA shed from organisms such as from fur, feces, spores, pollen or leaves). Now with results from 1,000 samples shared online, California biodiversity patterns are discoverable. Soil, sediment and water collected by researchers, undergraduates and the public reveal a new catalog of thousands of organisms that only slightly overlap with traditional survey bioinventories. The CALeDNA website lets users explore the taxonomic diversity in different ways, and researchers have created tools to help people new to eDNA to analyze community ecology patterns. Although eDNA results are not always precise, the program team is making progress to fit it into California's biodiversity management toolbox, such as for monitoring ecosystem recovery after invasive species removal or wildfire.
4-H youth advance biosecurity at home and in their communities
by Martin H. Smith, Woutrina A. Smith, Cheryl L. Meehan
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Yuba-Sutter youth successfully completed the 4-H Bio-Security Proficiencies Program and effected change as community science experts.

Youth participants in 4-H animal science projects are involved extensively with raising and exhibiting agricultural animals, often on backyard farms (Smith and Meehan 2012). Since backyard farms can serve as sources and vectors of pathogens (FAO 1999; WHO 2011), it is critical that 4-H youth take an active role in preventing the introduction and spread of economically important animal diseases. Fifteen 4-H youth from two counties in California participated in the 4-H Bio-Security Proficiencies Program, a long-term community and citizen science project focused on animal and zoonotic disease risk education and mitigation. Then, in the role of community science experts, they acted upon the risk assessments and mitigation plans they had developed to improve biosecurity practices and reduce the likelihood of disease spread on their home premises and at their local county fair. They also extended their knowledge to the broader livestock exhibition community through outreach videos.  

Engaging the importance of community scientists in the management of an invasive marine pest
by Edwin Grosholz, Sabrina Drill, Linda McCann, Kate Bimrose
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Sustainable management of a nonnative predatory crab in a coastal lagoon in Northern California succeeded due to the involvement of community scientists.
The introduction of nonnative invasive pests is among the many threats facing coastal ecosystems worldwide. Managing these pests often requires considerable effort and resources, and community scientists can be essential for providing the capacity needed for management and monitoring activities. In response to the invasion of a Northern California estuary by the predatory European green crab, a collaborative team of academic researchers and community scientists initiated a local eradication program. The green crab is listed among the world's 100 worst invaders, and threatened both native species and commercial shellfisheries. The program dramatically reduced the green crab population over a 5-year period, but it rebounded, which necessitated a switch in project goals from eradication to population suppression. Community scientists were essential for facilitating this switch by providing the necessary capacity to quantify population characteristics and maintain reduced crab populations. The result was a sustainable program that successfully maintained low green crab densities, which will likely improve habitat for native species.

Early view articles

Integration of grazing and herbicide application improves management of barb goatgrass and medusahead in pasture and rangelands
by Travis M. Bean, Josh S. Davy, Guy B. Kyser, Elise S. Gornish
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The combination of high-intensity, short-duration grazing with precisely timed applications of glyphosate improves management of invasive annual grasses.
The invasive annual grasses barb goatgrass (Aegilops triuncialis L.) and medusahead (Elymus caput-medusae L.) are widespread in western states and present management challenges on grasslands. To develop an integrated management strategy for these species, we treated sites in five pastures in Mendocino County, comparing combinations of intensive sheep grazing, glyphosate herbicide (low and high), and application timings (tillering, boot and heading stage). We found that grazing alone reduced barb goatgrass spikelet densities by 68% and the number of seeds per spikelet by 35%. Both rates of glyphosate application without grazing had similar effects on seed production. High and low glyphosate application at tillering resulted in almost complete control of both target species. Boot- and heading-stage applications reduced barb goatgrass density by 39% and 32%, respectively. Application at the boot stage also resulted in an 82% reduction in number of seeds per barb goatgrass spikelet. Our results suggest that intensive grazing may be a useful management strategy to reduce barb goatgrass and medusahead spikelet densities and barb goatgrass seed numbers, especially when integrated with a boot- or heading-stage glyphosate application.
Robotic strawberry harvest is promising but will need improved technology and higher wages to be economically viable
by Timothy Delbridge
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An analysis of harvest efficiencies and wage rates suggests that adoption of robotic harvesters is not yet economically feasible for large strawberry growers.
While the prospect of robotic harvest in strawberry production has received much attention within the strawberry industry and the popular press, there is little available information on the economic feasibility of this technology. It is not clear how close the industry is to being able to profitably adopt robotic harvest systems; also unclear is the relative importance of wage rates, robotic harvest efficiencies and machinery field speeds on the adoption threshold. This study aims to clarify these issues by estimating the net income to strawberry production under robotic harvest scenarios, and comparing the values to standard enterprise budgets for strawberry production in California under different wage rates for harvest labor. Results confirm that robotic harvest remains economically unviable under current wage rates and the field speeds and harvest efficiencies achieved by leading robotic harvest development teams. However, results indicate that with expected increases in wage rates in the coming years, and with modest improvements in the technical parameters, use of robotic systems will likely become profitable in some form.
The first SGMA groundwater market is trading: The importance of good design and the risks of getting it wrong
by Sarah Heard, Matthew Fienup, E. J. Remson
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Groundwater markets are a promising tool for basins implementing SGMA, but they are complex, and good design is essential.
Growers follow the label: An analysis of bee-toxic pesticide use in almond orchards during bloom
by Jennie L. Durant, Brittney K. Goodrich, Kelly T. Chang, Evan Yoshimoto
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Pesticide use data indicate that almond growers have reduced labeled bee-toxic pesticide use, but unlabeled bee-toxic agrochemicals are still applied during bloom.
California almond orchards are most U.S. beekeepers' first stop on their pollination and honey production circuit, so the agrochemicals bees are exposed to in almonds can shape the vitality of their colony for the rest of the year. We explored the potential for honey bee exposure to bee-toxic agrochemicals during almond bloom by utilizing the California Department of Pesticide Regulations' Pesticide Use Report database from 1990 to 2016. We found that overall, growers are observing the pesticide labels and reducing their use of labeled bee-toxic pesticides during almond bloom. However, we also found that insect growth regulators, fungicides and organosilicone surfactants — agrochemicals often not labeled as toxic to bees — are commonly applied during almond bloom. These agrochemicals can be sublethally or synergistically toxic to adult honey bees and bee larvae, presenting potential harm to colonies during almond pollination. Our findings demonstrate the need for a shift in the U.S. Environmental Protection Agency's labeling requirements, as well as continued communication between almond growers, pesticide applicators and beekeepers to keep colonies at a low risk of bee-toxic agrochemical exposure.


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