Napa County Research Articles

Social and Sexual Behavior of Intersex Mallards: A Literature Review and a New Case Study

Spontaneous sex reversal is a form of intersexuality in which one sex, usually a female, acquires traits of the other sex. We reviewed previously published accounts of intersex Mallards (Anas platyrhynchos) resulting from sex reversal, of which four individuals behaved as females and four behaved as males, and two of the latter mounted other females. Video analyses of an intersex Mallard in Napa, Napa County, California, revealed that it was less social, spending much more time alone than either sex of normal Mallards during the breeding season, and behaved like a female by spending much more time with males than with females. It is unknown why some intersex Mallards behave as females and others as males.

Large Community Outbreak of Legionnaires Disease Potentially Associated with a Cooling Tower — Napa County, California, 2022

Large Community Outbreak of Legionnaires Disease Potentially Associated with a Cooling Tower — Napa County, California, 2022

Top-down proteomic identification of protein biomarkers of Xylella fastidiosa subsp. fastidiosa using MALDI-TOF-TOF-MS and MS/MS

Protein biomarkers were identified from bacterial cell lysates of two sequenced strains of Xylella fastidiosa subsp. fastidiosa (Xff), the causal agent of Pierce's Disease of grapevine, using MALDI-TOF-TOF tandem mass spectrometry (MS/MS) and top-down proteomic analysis. Proteins were identified from their intact masses as well as sequence-specific fragment ions resulting from the aspartic acid effect detected by MS/MS and post-source decay (PSD). Two Xff strains from California were studied, M23 isolated from almond in Kern County and Stag's Leap isolated from grapevine in Napa County. The two strains are pathogenically identical or highly similar. Most of the proteins identified were highly conserved, e.g., 10 kDa chaperonin, cold-shock and/or DNA-binding, ribosomal and hypothetical proteins. The amino acid sequences and post translational modifications (PTM) of these conserved proteins were identical between the two Xff strains. However, the amino acid sequence of an outer membrane/hypothetical protein differed significantly between the two strains and could be a useful biomarker to distinguish between these closely related strains. In silico signal peptide analysis suggest that the outer membrane/hypothetical protein are secreted lipoproteins (SPII) with a putative prosthetic group attached to the only cysteine residue (C19) before or after removal of an 18-residue N-terminal signal peptide. However, only y-type fragment ions were detected by MS/MS-PSD which precluded confirmation of the site of sequence truncation and/or attached PTM. The annotated genomes of the two strains indicate ten to twenty proteins that are either lipoproteins or are associated with assembly, modification, or transport of lipoproteins. In consequence, a variety of prosthetic groups, e.g. diacylglycerol, may be attached to C19 in the mature protein.

Cover Crops and No-Tillage Show Negligible Effects on Grapevine Physiology in Mediterranean Vineyard Agroecosystems

This study aimed to evaluate the effects of annual or perennial cover crops and tillage regimes on whole grapevine physiology and berry composition. We studied the interactive effects of tillage and cover crops on grapevine water status, leaf gas exchange, components of yield, berry composition and resulting water footprint in two contrasting production regions (Fresno County-hot climate and Napa County-warm climate) of California. The treatments included a perennial grass (PG), resident vegetation (RV), and an annual grass (AG) grown under conventional tillage (CT) and no-till (NT) settings. Neither cover crop nor tillage affected grapevine leaf gas exchange. However, at the Napa County vineyard, NT detrimentally affected grapevine water status compared to CT. Grapevine mineral nutrition, when assessed during anthesis revealed no effects of cover cropping in either year or at either location. Cover crop type did not affect yield components or berry composition, however CT increased titratable acidity (TA) at both sites. The water footprint of vineyards at either location was not affected by cover crops or tillage. Our results provided evidence that both in hot and warm climate vineyards cover cropping had negligible beneficial effects on grapevine physiology, mineral nutrition or productivity with no detrimental effects on vineyard water footprint; tillage was beneficial in younger vineyards to improve plant water status in semi-arid regions.

THE STRENGTHS AND LIMITATIONS OF VEGETATION MAPS FOR DETECTING CONSERVATION PERFORMANCE IN NAPA COUNTY'S NATURAL VEGETATION AND AGRICULTURAL LANDS

We report the second edition of Napa County's vegetation map using California's Manual of Vegetation classification system and aerial imagery from 2016. It covers 2053.54 km2, increases polygon resolution by 23.8%, contains 35,244 polygons, and has 71 landcover types, 60 of which are dominated by natural vegetation. It has an overall error rate of 2.6%, includes canopy density measures for 24 vegetation types, and contains explicit measures of structures in the Wildland Urban Interface (WUI). We compared the new map to the one based on 1993 imagery to ask how effective Napa county's agricultural preservation and conservation regulations have been at preventing conversion of natural vegetation across the county and of agricultural lands within and beyond the county's Agricultural Preserve, established in 1968. We examined net change and change detected using a transition matrix, to seek concealed landcover conversion. The net change shows small increases in Agriculture and Urban extents. However, the transition matrix found substantial Urban expansion into Agriculture, 12.9 km2 overall and 226.9 ha (2.24%) within the Agricultural Preserve; and 30 km2 of agricultural expansion into natural vegetation, including 595 ha of high conservation-value oak woodlands. Due to increased map resolution in the 2016 map, we identified stands of natural vegetation (Oak Woodlands, Grassland, and Chaparral) in areas previously mapped as Agriculture and Urban, as well as Oak Woodlands in areas previously mapped as other vegetation types. Their inclusion in net measures of landcover change substantially obscures actual loss in natural vegetation types and agricultural lands. The net loss for Oak Woodlands is 191 ha, but the transition matrix identifies 782 ha converted to urban or agriculture, which suggests only moderate performance for the county's conservation measures. We also found rates of vegetation change in wildfire-burned areas three times higher than in unburned areas. Conversion of agricultural lands to urban was about 2.3% in the Agricultural Preserve, but 6.3% beyond, showing that county zoning slowed urban expansion. We found changes in spatial resolution and mapping details between vegetation map editions made net measures of landcover change inaccurate, and that transition matrix-analyses provided more accurate accounting and identification of mapping methods errors.

From Fire, Love Rises: Stories Shared from the Artist Community

ABSTRACT In this essay the author recalls the process of organizing and interpreting an exhibition of art and language made in response to a catastrophic fire that devastated California’s Sonoma and Napa counties in late 2017. The Sonoma Valley Museum of Art invited a group of artists and writers to be part of its small exhibition planning team to help establish the exhibition’s focus, compile the checklist of artworks and writing, compose the interpretive labels, and participate as presenters in the public programs. What follows is a reflection on the process that resulted in unique approaches to organizing, presenting, and interpretation as the artists, writers, and museum staff collaborated to engage the audience directly through first-person stories, with the intention of honoring their shared experience and healing their community.

Preserving Winescapes amid North America’s Urban Sprawl*

Ontario’s Niagara Peninsula and California’s Napa Valley, both smaller than most of the world’s famed wine regions, exist within two of the most densely populated regions in North America. Their fields, orchards, and vineyards faced pressure from expanding metropolises and became part of ongoing debates about the loss of prime agricultural lands in Canada and the United States. In 1968, Napa County created one of the world’s first agricultural preserves to stave off sprawl. In 2005, after decades of debate, the Ontario government included the Niagara Peninsula in a greenbelt for the larger Toronto metropolitan region; its agricultural provisions mimicked Napa’s preserve. Boosters in both regions have emphasized the multifunctionality of the countryside. In the end, however, wine production and the tourism it engendered offered financial benefits that few other crops provided. Winescapes proved essential to protecting rural spaces. Yet differences also emerge in these histories. The complexity of land use and of municipalities in Niagara complicated efforts to preserve agricultural lands.

“What Really Happened?”: The Life and Death of Olivia Coombs

“What Really Happened?”: The Life and Death of Olivia Coombs

Predicting Wildfire Susceptibility in Napa County, California using Machine Learning

Wildfires have long been a part of the natural environment, however through climate change and increased human activity, they have become a significant problem to both humans and wildland. Stopping the expansion of wildfires would be critical in mitigating the dangerous outcomes of them. Firefighters stopping the spread of wildfires must know which parts of the environment are most vulnerable to the spread of wildfires, and vegetation is one of the key determining factors in the wildfire susceptibility of a given area. Previous works have used several different machine learning algorithms for the purpose of determining wildfire susceptibility. The algorithm used in this study for wildfire susceptibility prediction is a random forest applied to a vegetation dataset of Napa County, California provided by the California Department of Fish and Wildlife (CDFW). The random forest works by creating a set of decision trees to get an overall probability for each vegetation area. The model has a 91.7% accuracy in predicting wildfire burn probability in a vegetation area.

Suspect Screening and Chemical Profile Analysis of Storm-Water Runoff Following 2017 Wildfires in Northern California.

The combustion of structures and household materials as well as firefighting during wildfires lead to releases of potentially hazardous chemicals directly into the landscape. Subsequent storm-water runoff events can transport wildfire-related contaminants to downstream receiving waters, where they may pose water quality concerns. To evaluate the environmental hazards of northern California fires on the types of contaminants in storm water discharging to San Francisco Bay and the coastal marine environment, we analyzed storm water collected after the northern California wildfires (October 2017) using a nontargeted analytical (NTA) approach. Liquid chromatography quadrupole time-of-flight mass spectrometric analysis was completed on storm-water samples (n = 20) collected from Napa County (impacted by the Atlas and Nuns fires), the city of Santa Rosa, and Sonoma County (Nuns and Tubbs fires) during storm events that occurred in November 2017 and January 2018. The NTA approach enabled us to establish profiles of contaminants based on peak intensities and chemical categories found in the storm-water samples and to prioritize significant chemicals within these profiles possibly attributed to the wildfire. The results demonstrated the presence of a wide range of contaminants in the storm water, including surfactants, per- and polyfluoroalkyl substances, and chemicals from consumer and personal care products. Homologs of polyethylene glycol were found to be the major contributor to the contaminants, followed by other widely used surfactants. Nonylphenol ethoxylates, typically used as surfactants, were detected and were much higher in samples collected after Storm Event 1 relative to Storm Event 2. The present study provides a comprehensive approach for examining wildfire-impacted storm-water contamination of related contaminants, of which we found many with potential ecological risk. Environ Toxicol Chem 2022;41:1824-1837. © 2022 SETAC.

Avian Abundance and Diversity on Knoxville Wildlife Area in California Following the County Fire of 2018

Wildfires can have negative impacts on wildlife during and immediately after a burn event, yet these fires are also necessary for plant succession and biodiversity. Knoxville Wildlife Area (KWA) in Napa County, California, USA is a diverse environment that contains oak woodlands, chaparral, grasslands, and riparian corridors. In July 2018, the County Fire burned 36,353 ha in the Northern California Interior Coast Ranges, including 2,429 ha on KWA. California Department of Fish and Wildlife employees used this opportunity to monitor avian abundance and diversity as the burned area revegetates. From 10 June through 14 June 2019, we began a pilot season of distance-based point counts on KWA. We conducted 5-minute point counts at 80 points spaced 1 km apart. Twenty points were within the burned area. We used the half cosine model in Program Distance version 7.2 to determine density for the 5 most frequently detected species. We detected 47 avian species; the most frequently detected species were California quail (Callipepla californica), acorn woodpecker (Melanerpes formicivorus), mourning dove (Zenaida macroura), California scrub-jay (Aphelocoma californica), and oak titmouse (Baeolophus inornatus). California quail populations were slightly denser in the burned area (0.22 birds/ha, 95% confidence interval [CI] = 0.11–0.44), compared to the nonburned area (0.19 birds/ha, 95% CI = 0.12–0.31). Acorn woodpecker density was similar in the burned (0.59 birds/ha, 95% CI = 0.34–1.02) and nonburned areas (0.58 birds/ha; 95% CI = 0.42–0.80). Mourning dove, California scrub-jay, and oak titmouse populations were slightly denser in the nonburned area; however, 95% CIs overlapped. We conducted approximately approximately 1 year post-burn, and revegetation had started, due in part to the wet winter and spring. Birds were using the burned area, though not at significantly higher densities compared to the rest of the wildlife area. The coronavirus pandemic and a second fire prevented us from surveying the site in 2020 and 2021, but we intend to conduct point counts for at least 2 more years to further monitor avian response to wildfire.

A PRELIMINARY SPECIMEN-BASED CATALOGUE OF THE MOSS SPECIES FOUND IN NAPA COUNTY, CALIFORNIA

Napa County, in California's North Coast Range, is well known for its plant diversity. However, until now no one has published a listing of bryophytes for Napa County. I present a catalogue of 158 moss species in 77 genera and 31 families collected and confirmed as occurring within Napa County. The catalogue summarizes 1701 collections (1550 by me). Collection dates encompass 1866 through 2018. I examined selected collections at CAS, UC, and other herbaria, and sent many of my collections to specialists for their identification. I did not collect 11 species reported previously by others. Eighty-six species are collected at only one or two locations. The catalogue includes a summary of the distribution of each species in Napa County and a citation of reference collections deposited in herbaria (CAS, ILL, and UC). In addition to the cited collections, I deposited most of my other Napa County materials at CAS and UC. The number of collections of each species, their number of locations where collection occurred, and whether specimens were collected by me or others is presented. A comparison of the increasing numbers of mosses collected in the Napa County over time with that of nearby areas and California is summarized.

Wildfires pose a burning problem for wines and winemakers

On a pleasant evening in October 2017, winemaker Alisa Jacobson and her friends picked the last of the Cabernet grapes at her friends’ winery in southern Napa. They were taking advantage of the cool evening temperatures, which help reduce damage to the fruit. Later that night, the pleasant evening air turned acrid—Jacobson was surprised to smell smoke wafting through her bedroom window despite only seeing wildfires on her radar to the far north, in Santa Rosa, CA. Smoke from wildfires can make the skies an eerie yellow, as seen here over a Napa Valley, CA, vineyard in September 2020. The smoke’s effects on winery grapes continue to perplex growers, winemakers, and researchers. Image credit: Science Source/Peter Menzel. A new fire had flared up—the largest in California’s history. Dubbed the Tubbs fire, it spread from Napa County to Santa Rosa, jumped across US Highway 101 in the middle of the night, and burned nearly 37,000 acres before it could be contained, killing 22 people and destroying more than 5,000 buildings, half of them homes. Winemakers like Jacobson, who is vice president for winemaking at Joel Gott Wines, felt the fire’s impact not only in the looming threat to their homes but to their livelihoods as well. Months after evacuation orders were lifted, the region inched back to normalcy. Then winemakers began to detect smoke in their wine. Grapes exposed to smoke absorb chemicals that can alter—and sometimes ruin—the taste and smell of resultant wines. This so-called “smoke taint” has become a growing concern for the industry. Chemicals in smoke obscure wine’s flavor and fragrance, Jacobson says. “You can smell the taint on the aroma, like a campfire, and when you taste it it’s like an ashtray,” she says. “It lingers for minutes after you spit or swallow.” But not all wines …

Framework for nontargeted investigation of contaminants released by wildfires into stormwater runoff: Case study in the northern San Francisco Bay area

Wildfires can be extremely destructive to communities and ecosystems. However, the full scope of the ecological damage is often hard to assess, in part due to limited information on the types of chemicals introduced to affected landscapes and waterways. The objective of this study was to establish a sampling, analytical, and interpretive framework to effectively identify and monitor contaminants of emerging concern in environmental water samples impacted by wildfire runoff. A non-targeted analysis consisting of comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) was conducted on stormwater samples from watersheds in the City of Santa Rosa and Sonoma and Napa Counties after the three most destructive fires during the October 2017 Northern California firestorm. Chemicals potentially related to wildfires were selected from the thousands of chromatographic features detected through a screening method that compared samples from fire-impacted sites versus unburned reference sites. This screening led to high confidence identifications of 76 potentially fire-related compounds. Authentic standards were available for 48 of these analytes, and 46 were confirmed by matching mass spectra and GC×GC retention times. Of these 46 compounds, 37 had known commercial and industrial uses as intermediates or ingredients in plastics, personal care products, pesticides, and as food additives. Nine compounds had no known uses or sources and may be oxidation products resulting from burning of natural or anthropogenic materials. Preliminary examination of potential toxicity associated with the 46 compounds, conducted via online databases and literature review, indicated limited data availability. Regional comparison suggested that more structural damage may yield a greater number of unique, potentially wildfire-related compounds. We recommend further study of post-wildfire runoff using the framework described here, which includes hypothesis-driven site selection and non-targeted analysis, to uncover potentially significant stormwater contaminants not routinely monitored after wildfires and inform risk assessment. This article is protected by copyright. All rights reserved.

Areawide mating disruption for vine mealybug in California vineyards

The mealybug, Planococcus ficus (Signoret), is one of the more damaging vineyard pests and an important vector of Grapevine leafroll-associated viruses. Pheromone-mediated mating disruption is a commercially available and environmentally sustainable control tool for P. ficus. Here we report on a three-year areawide study of P. ficus mating disruption in Napa County, California, where pheromone dispensers were deployed across large (53–66 ha) multi-owner sites that were paired with sites that did not receive pheromone. Male P. ficus captures in pheromone traps were correlated with mealybug numbers and crop damage, and were useful in identifying ‘hotspots’ to be targeted with insecticide applications for areawide control. Trap catches at mating disruption sites were far lower than untreated sites, although mealybugs were still present at mating disruption sites. Evidence indicated that mating disruption reduced P. ficus density and spread, particularly in areas with low initial mealybug densities. In the third year, areawide mating disruption was discontinued at the former mating disruption sites and, as evidence of its impact, P. ficus trap captures increased. These results suggest that mating disruption and well-timed, effective insecticide applications play complementary roles, and that monitoring the areawide distribution of pests is a critical component of programs for controlling P. ficus.

Identification of grapevine Pinot gris virus in free-living Vitis spp. located in riparian areas adjacent to commercial vineyards.

Grapevine Pinot gris virus (GPGV) is a recently identified pathogen of grapevines in California. To advance our knowledge about the epidemiology of GPGV, we investigated if free-living Vitis spp. can represent a source of virus infection. In 2019 a field survey of GPGV infection was conducted in Napa County. During the inspection 60 free-living vines in riparian habitats near commercial vineyards with GPGV infection were sampled. Samples were tested by real-time reverse transcription PCR (RT-PCR), identifying 23 free-living Vitis spp. positive for GPGV. Later, GPGV infection was confirmed in these plants via end-point RT-PCR and Sanger sequencing. Based on sequence analysis, detected GPGV isolates are more related to the asymptomatic variant of the virus. Vitis species ancestry was determined by DNA fingerprinting. GPGV-infected material included V. californica, V. californica × V. vinifera hybrids and hybrid rootstock cultivars. Here, GPGV is reported for the first time in free-living Vitis spp. The results of this study will support the development of management strategies for GPGV in California and beyond.

Incidence and Genetic Diversity of Grapevine Pinot gris Virus in California

Grapevine Pinot gris virus (GPGV) was discovered in 2012 by high throughput sequencing (HTS) analysis of Pinot gris vineyards in Italy. GPGV is often symptomless but has also been associated with chlorotic mottling and leaf deformation. In 2015, this new member of the genus <i>Trichovirus</i> was first reported in the United States, in California. To assess the incidence of GPGV throughout grapegrowing regions in California, we tested multiple vineyards using real-time quantitative reverse transcription PCR. HTS and phylogenetics were used to evaluate the genetic diversity of GPGV strains recovered. GPGV was detected in 170 out of 716 (23%) grapevine samples, including white and red grape varieties, from several commercial vineyards and one nursery increase block. Moreover, GPGV was identified in three different counties (Yolo, Solano, and Napa) situated in northern California. In the case of Napa County, a widespread distribution of GPGV was determined. During the survey, symptomatic and asymptomatic plants tested positive for GPGV; however, characterized isolates shared close homology (&gt;97% identity) with asymptomatic reference isolates, which was confirmed by phylogenetics. HTS revealed that GPGV-positive grapevines were also infected with other viruses and viroids. Finally, the relationship between GPGV infection and symptom expression is discussed.

Piloting the Adult Protective Services’ Identification, Services, and Outcomes Matrix: Focus Group Findings

The historical lack of outcomes-related data in Adult Protective Services (APS) has affected funding coming to the program. Without data quantifying the effectiveness of APS services, policymakers have been unable to justify budget increases to improve wages for workers or professionalize the field. For the first time in APS history, the U.S. Administration for Community Living sponsored a pilot project to implement a novel evidence-based assessment tool into APS electronic systems, called the Identification, Services, and Outcomes (ISO) Matrix. The goal was to improve APS’ ability to reduce harm of abuse and neglect and maintain client’s independence to live in the community. APS workers in San Francisco and Napa Counties were trained and phased into using the ISO Matrix over a six-month implementation period. This poster presents findings from six focus groups conducted between February 13 and March 28, 2019, with 34 San Francisco and Napa County APS workers and supervisors. Utilizing semi-structured, in-depth interviewing techniques, APS workers and supervisors expressed their views and experiences. Facilitators and barriers of implementing the ISO Matrix were assessed and opportunities for improvements were identified. Findings revealed a tension between their hopefulness that the ISO Matrix could modernize APS data-tracking and yield evidence of improved client outcome to bolster the field, and their frustrations about new burdens the ISO Matrix placed on their labor and workflow. Understanding frontline perspectives of APS workers and supervisors has practical and policy implications for adopting the ISO Matrix in other counties and states across the U.S.

Quantifying Planococcus ficus (Hemiptera: Pseudococcidae) Invasion in Northern California Vineyards to Inform Management Strategy.

The spread and impact of invasive species in exotic ranges can be mitigated by increased understanding of pest invasion dynamics. Here, we used geospatial analyses and habitat suitability modeling to characterize the invasion of an important vineyard pest, vine mealybug (Planococcus ficus Signoret, Hemiptera: Pseudococcidae), using nearly 15,000 trapping records from throughout Napa County, California, between 2012 and 2017. Spatial autocorrelation among P. ficus detections was strongest at distances of ~250 m and detectable at regional scales (up to 40 km), estimates of the rate and directionality of spread were highly idiosyncratic, and P. ficus detection hotspots were spatiotemporally dynamic. Generalized linear model, boosted regression tree, and random forest modeling methods performed well in predicting habitat suitability for P. ficus. The most important predictors of P. ficus occurrence were a positive effect of precipitation in the driest month, and negative effects of elevation and distance to nearest winery. Our results indicate that 250-m quarantine and treatment zones around P. ficus detections are likely sufficient to encompass most local establishment and spread, and that implementing localized regulatory procedures may limit inadvertent P. ficus spread via anthropogenic pathways. Finally, surveys of P. ficus presence at >300 vineyard sites validated that habitat suitability estimates were significantly and positively associated with P. ficus frequency of occurrence. Our findings indicate that habitat suitability predictions may offer a robust tool for identifying areas in the study region at risk to future P. ficus invasion and prioritizing locations for early detection and preventative management efforts.

FE Evaluation of Hillside Excavation for a Construction Contract Dispute

This paper presents a forensic evaluation of an earthwork grading dispute between a grading contractor (plaintiff) and property owner (defendant) associated with construction of an approach driveway and hill-side cut for a new residential property. The plaintiff’s allegations were that “changed conditions” had been encountered through the presence of a landslide and/or geologic fault. These conditions resulted in schedule delays and increased costs. Finally, the plaintiff alleged breach of contract after being terminated. The allega-tions were investigated through both on-site field reconnaissance and desktop studies. The forensic analyses found no basis for the changed conditions claims. The case was tried in Napa County California Superior Courts via bench trial. The judge’s decision mirrored the findings of the forensic analyses.