North Coastal California Research Articles

Mapping vineyard leaf area with multispectral satellite imagery

Vineyard leaf area is a key determinant of grape characteristics and wine quality. As is frequently the case in agriculture, available ground-based leaf area measurements employed by growers are not well suited to larger area mapping. In this study, IKONOS high spatial resolution, multispectral satellite imagery was used to map leaf area throughout two commercial wine grape vineyards (approximately 800 ha) in California's North Coast growing region. The imagery was collected near harvest during the 2000 growing season, converted to at-sensor radiance, geo-referenced and transformed to normalized difference vegetation index (NDVI) on a per pixel basis. Measurements at 24 ground calibration sites were used to convert NDVI maps to leaf area index (LAI; m 2 leaf area m −2 ground area); planting density was then used to express leaf area on a per vine basis (LA v). Image-based LA v was significantly correlated with ground-based LA v estimates developed at 23 validation sites ( r 2=0.72; P<0.001). Despite challenges posed by the discontinuous nature of vineyard canopies and architectural differences imposed by shoot positioning trellis systems, remote sensing appears to offer a basis for mapping vineyard leaf area in low LAI vineyards. Such maps can potentially be used to parameterize plant growth models or provide decision support for irrigation and canopy management.

Avian cholera on north coast California: distinctive epizootiological features.

Between 1945 and 2001, avian cholera (Pasteurella multocida infection) was confirmed at 27 epizootics in 18 different years on northcoastal California. Estimated mortality ranged from 1 to 6750 birds per site, with a median total mortality of about 1000 birds per year. Eight epizootics involved < 150 birds; thus, minor epizootics were common. Annual total wildfowl mortality ranged from 0.4% to 7.0% of estimated live populations; median annual mortality for American coots (Fulica americana) (11.5%) surpassed that of tundra swans (Cygnus columbianus) (0.2%) and ducks (0.2%). Coots comprised > 50% of total wildfowl mortality in 16 of 17 epizootics. Overall, coots comprised 82% of known avian cholera mortality, but only 34% of the live wildfowl present; ducks and swans died much less frequently. Wildfowl at one site consistently died in a sequential pattern; there was no sequential mortality at other sites.

Outcomes Assessment and the Paradox of Nonprofit Accountability

AbstractLeaders of nonprofit organizations face a particular bind in responding to the demands for results‐based accountability. If they focus only on the project‐level outcomes over which they have the most control or for which indicators are readily available, they risk default on the larger question of accountability to publicly valued goals. On the other hand, if they try to demonstrate the impact of their particular projects on communitywide outcomes, they risk taking credit inappropriately or shouldering the blame for indicators beyond their control. Here, I present findings from a research project, conducted in collaboration with economic development organizations on the north coast of California, that explored the practical demands and dynamics associated with this paradox. The key challenges are more civic and political than technical.

Shelf record of climatic changes in flood magnitude and frequency, north-coastal California

Research Article| May 01, 2002 Shelf record of climatic changes in flood magnitude and frequency, north-coastal California Christopher K. Sommerfield; Christopher K. Sommerfield 1University of Delaware, College of Marine Studies, Lewes, Delaware 19958, USA Search for other works by this author on: GSW Google Scholar David E. Drake; David E. Drake 2Drake Marine Consulting, 1711 Quail Hollow Road, Ben Lomond, California 95005, USA Search for other works by this author on: GSW Google Scholar Robert A. Wheatcroft Robert A. Wheatcroft 3Oregon State University, College of Oceanic and Atmospheric Sciences, Corvallis, Oregon 97331, USA Search for other works by this author on: GSW Google Scholar Geology (2002) 30 (5): 395–398. https://doi.org/10.1130/0091-7613(2002)030<0395:SROCCI>2.0.CO;2 Article history received: 28 Aug 2001 rev-recd: 20 Dec 2001 accepted: 20 Dec 2001 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Christopher K. Sommerfield, David E. Drake, Robert A. Wheatcroft; Shelf record of climatic changes in flood magnitude and frequency, north-coastal California. Geology 2002;; 30 (5): 395–398. doi: https://doi.org/10.1130/0091-7613(2002)030<0395:SROCCI>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Continental-shelf deposits off the Eel River, north-coastal California, document a recent increase in the magnitude and frequency of major hydrologic floods (≥10 yr recurrence interval). The shelf record reveals a sudden, three-fold increase in sedimentation rate ca. 1954 and a concomitant increase in the frequency of preserved flood beds. Comparison of sedimentary and river-discharge records reveals that major floods after ca. 1950 had a more pronounced effect on coastal sediment delivery and accumulation offshore than previous recorded events of similar magnitude, and that stratigraphic preservation of flood events is highly dependent on flood frequency and net sedimentation rate. We contend that this change in marine sedimentation is a response to documented climatic phenomena that have increased the frequency of major floods throughout the western United States during the past half century, together with intrabasinal impacts of extreme floods in 1955 and 1964. Anthropogenic increase in watershed-sediment production is a probable secondary factor. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Shelf record of climatic changes in flood magnitude and frequency, north-coastal California: Correction

Shelf record of climatic changes in flood magnitude and frequency, north-coastal California: Correction

A NewCladoniafrom California

Abstract Cladonia lacryma sp. nov., a previously overlooked species from north coastal California and adjacent Oregon, is characterized by the teardrop-like shape of its podetium. The unusual shape develops when the indistinct, immature cup is deformed by the vertical growth of a single proliferation along its margin. Cladonia lacryma is similar to other species in section Cladonia, which are characterized by closed cups and the presence of fumarprotocetraric acid. The pattern of growth dynamics of C. lacryma suggests its affinity with C. prolifica, which grows on similar soil types in California.

Sperm storage in the oviduct of the internal fertilizing frog Ascaphus truei.

This study provides the first descriptions of sperm storage at the tissue and cellular levels in a female frog or toad. Oviducal anatomy was studied by light and electron microscopy in Ascaphus truei from north coastal California. Ascaphus truei is one of the few species of anurans in which fertilization is internal. Unlike other anurans with internal fertilization, however, mating in A. truei consists of a unique combination of amplectic and copulatory mechanisms that we term "copulexus." Posterior to a short, aglandular infundibular region, the oviduct possesses: 1) a proximal, convoluted ampullary region where intrinsic tubular glands secrete gelatinous envelopes around eggs; 2) a middle ovisac region where fertilization occurs; and 3) a distal oviducal sinus formed by medial junction of the ovisacs. Sperm storage tubules (SSTs) occur in the anterior portions of the ovisacs and consist of simple tubular glands. SSTs and the rest of the oviducal lining stain positively with the periodic acid-Schiff's procedure for neutral carbohydrates and this reaction is especially intense in reproductively active females. Sperm were found in the SSTs of gravid females as well as some nonvitellogenic females. The sperm are in orderly bundles in the SSTs, and although occasionally sperm nuclei were embedded in the epithelium, no evidence for spermiophagy was found. Oviducal sperm storage in A. truei is homoplastic, with closest structural similarities to squamate reptiles. Oviduct/sperm design constraints appear to limit the options for expression of features associated with oviducal sperm storage.

Demography of a Declining Population of Warbling Vireos in Coastal California

Abstract We investigated population trends, adult survival, and productivity indices of a breeding population of Warbling Vireos (Vireo gilvus) in north coastal California using capture-recapture data from 19 years of standardized mist-netting conducted at Point Reyes National Seashore. We found significant long-term declines in abundance of both breeding and migratory Warbling Vireos. In addition, we found a significant long-term decline of hatching-year birds captured during the breeding season. The number of new adults in a given year, defined as those birds not previously banded and assumed to be an index of adult recruitment, was significantly correlated with the capture rate of hatching-year birds in the previous year, suggesting a link between reproductive success and adult abundance and recruitment. Our analysis of capture-recapture data provided an estimate of 50.4% for adult annual survival, similar to estimates for other species in stable populations. We could detect no temporal trend in survival. Nest survivorship from areas near our netting site was relatively low. We suggest that the decline of breeding and migratory populations of Warbling Vireos observed in coastal California may be the result of low productivity on the breeding grounds.

Density and spatial distribution of Ixodes pacificus (Acari: Ixodidae) in two recreational areas in north coastal California.

The density and distribution of Ixodes pacificus was assessed at 2 parks in north coastal California. The density of I. pacificus adults and nymphs varied significantly between years, trails, and sides of trails. Adult ticks occurred on vegetation along sun-exposed trails in January through March, their density (0-1.93 per 20 m) correlated with brush density, trail width, and presence of an uphill slope. Nymphs (0.06-5.10 per 20 m) occurred in leaf litter along shaded trails in May-July. Adult I. pacificus were rare at picnic sites (0.00-0.24 per 20 m), but nymphal densities (0.93-2.37 per 20 m) were comparable with those along some shaded trails. The prevalence of Borrelia burgdorferi in ticks (2.8% overall) did not differ significantly between locations, years, or stages. We conclude that the risk of acquiring Lyme disease in these sites is low, but varies among trails, seasons, and years.

DEMOGRAPHY OF A DECLINING POPULATION OF WARBLING VIREOS IN COASTAL CALIFORNIA

Abstract We investigated population trends, adult survival, and productivity indices of a breeding population of Warbling Vireos (Vireo gilvus) in north coastal California using capture-recapture data from 19 years of standardized mist-netting conducted at Point Reyes National Seashore. We found significant long-term declines in abundance of both breeding and migratory Warbling Vireos. In addition, we found a significant long-term decline of hatching-year birds captured during the breeding season. The number of new adults in a given year, defined as those birds not previously banded and assumed to be an index of adult recruitment, was significantly correlated with the capture rate of hatching-year birds in the previous year, suggesting a link between reproductive success and adult abundance and recruitment. Our analysis of capture-recapture data provided an estimate of 50.4% for adult annual survival, similar to estimates for other species in stable populations. We could detect no temporal trend in surviv...

Seismicity of California's North Coast

At least three moment magnitude (M) 7 earthquakes occurred along California9s north coast in the second half of the nineteenth century. The M 7.3 earthquake on 23 November 1873 occurred near the California-Oregon coast and likely was located on the Cascadia subduction zone or within the North American plate. The M 7.0+ earthquake on 9 May 1878 was located about 75 km offshore near the Mendocino fault. The surface-wave magnitude ( M S ) 7.0 earthquake on 16 April 1899 was located about 150 km offshore within the Gorda plate. There were at least three M 7 north-coast earthquakes in the 35 years before 1906, two M 7 earthquakes in the 20 years after 1906, no M 7 earthquakes from 1923 until 1980, and four M 7 earthquakes since 1980. The relative seismic quiescence after 1906 for M 7 earthquakes along California9s north coast mimics the post-1906 seismic quiescence in the San Francisco Bay area for M 6 earthquakes. The post-1906 relative quiescence did not extend to lower magnitudes in either area. The 18 April 1906 earthquake apparently influenced the rate of occurrence of M 7 north-coast earthquakes as it apparently influenced the rate of M 6 earthquakes in the San Francisco Bay area. The relative seismic quiescence along the California north-coast region after 1906 should be taken into account when evaluating seismic hazards in northwest California.

Building on Tradition: Promoting Physical Activity with American Indian Community Coalitions

The native people of California's north coast are building upon the strength of their cultural traditions to regain and promote healthy lifestyles. This cultural health and mobilization program is designed to increase physical activity among the local tribal population and reduce the incidence of diabetes and cardiovascular disease. In this article we describe how community coalitions were formed, implemented, and maintained to teach culturally appropriate fitness activities to groups of community members. We examine the details of development of the coalitions, as well as examples of cultural fitness events for American Indian communities. Successful institutionalization of community events by tribal governments and American Indian agencies resulted in ongoing support in various communities for events that promote physical activity. Circumstances relating to low participation rates in some coalitions are discussed. This program presents a prevention strategy framework that is based on values inherent in traditional native cultures. Organization of community coalitions is an effective way to promote physical activity.

Territoriality and Breeding Status of Coyotes Relative to Sheep Predation

Coyote (Cauis latrans) depredation is a chronic problem for sheep producers in the western United States. Due to increasingly localized control efforts, behavior of individual coyotes in sheep-ranching environments is becoming a more important consideration. We radiotracked 14 coyotes on a year-round sheep-ranching facility in north-coastal California during September 1993-December 1995. Breeding coyote pairs used mutually exclusive territories (maximum overlap between 90% adaptive kernel home ranges = 4%). Nonbreeding coyotes were transient or varied in their degree of fidelity to putative natal territories but generally avoided cores of nonnatal territories. Breeding coyotes whose territories contained sheep were the principal predators of sheep. In the 1994 lambing period (1 Jan-31 May). radiotelemetry indicated that 1 breeding male was responsible for 71% of 65 kills. In the 1995 lambing period, 4 breeding pairs were strongly implicated in 92% of 48 kills and were suspected of 85% of 26 additional kills; nonbreeders were not associated with sheep depredation. Depredation was reduced only when territorial breeders known to kill sheep were removed. These results suggest the need for management to target breeding adults in the immediate vicinity of depredation. Efforts to remove individuals > 1 territory-width away from problem sites are unlikely to reduce depredation and may exacerbate the problem by creating vacancies for new breeders that might kill sheep.

Distribution and Habitat of Ascaphus truei in Streams on Managed, Young Growth Forests in North Coastal California

Distribution and Habitat of Ascaphus truei in Streams on Managed, Young Growth Forests in North Coastal California

Distribution of edaphic‐endemic butterflies in the Sierra Nevada of California

ABSTRACTFive edaphically‐restricted or ‐endemic butterflies, mostly associated with serpentine, are shown to be distributed in the western foothills of the Sierra Nevada in addition to their previously documented areas of occupancy in the California North Coast Ranges. Two species are absolutely limited by the edaphic restriction of their host plants, while the other three seemingly are not. The controversies concerning the origins of serpentine endemism in plants apply to butterflies as well. Long‐term relictualism can presumably apply only at the metapopulation level, not the local population level, due to the frequency of fire in these habitats. Development and habitat‐conversion trends pose a high risk to the long‐term survival of these species in the Sierra Nevada.

Distribution of the Rare Serpentine Sunflower, Helianthus exilis (Asteraceae): The Roles of Habitat Availability, Dispersal Limitation and Species Interactions

Helianthus exilis, an annual forb endemic to California's North Coast Ranges, occurs in isolated microhabitats within serpentine outcrops, which are themselves insular. Extensive field surveys and transplant experiments showed that nearly all suitable habitats, although widely separated, are occupied by H. exilis. Small serpentine patches (< I ha) contain little or no suitable habitat, thus explaining the complete absence of H. exilis from these sites. Experiments also showed that H. exilis is an obligate outcrosser and that natural populations were somewhat pollen limited. Nevertheless, isolation of local populations within large serpentine outcrops did not significantly reduce pollination rates. Seed predation rate by a tephritid fly decreased with increasing patch isolation, but seed predation by a moth was not significantly correlated with isolation. In metapopulation terms, our results suggest that H. exilis may be relatively resilient to a reduction in the number of habitat patches or populations, because of its high persistence within the most suitable microhabitats.

Forest Stand Characteristics and Reproduction of Northern Spotted Owls in Managed North-Coastal California Forests

We monitored reproductive success of northern spotted owls (Strix identalis caurina) at 51 sites on Simpson Timber Company's (STC) managed, young-growth forests in northwestern California from 1991 to 1995. We compared habitat characteristics between sites with high and low fecundity at 5 spatial scales (concentric circles of 7. 50, 114, 203, and 398 ha), using 2 stratifications of annual reproductive success (upper 50% vs. lower 50% and upper 25% vs. lower 75% of the proportion of years when ≥1 owlet fledged). Habitat features included number of residual trees per hectare and mean proportion of 6 categories of stand age and 4 categories of basal area. Using the 50th percentile categories, we found there were higher proportions of age class 21-40 years and basal area classes 23-45 and 46-69 m 2 /ha (P ≤ 0.05), but lower proportions of recent clearcuts (0-5 yr) and basal area >69 m 2 /ha (P ≤ 0.05) at sites with high reproductive success. Using the upper 25% and lower 75% categories, we found there were higher proportions of basal area class 23-45 m 2 /ha, lower proportions of 61-80-year-old stands and more residua trees per hectare at sites with high reproductive success (P ≤ 0.05). We also compared random sites to occupied sites via the above parameters, Spotted owl sites contained lower proportions of basal area class 69 m 2 /ha than did random sites (P < 0.05). There was less young forest (6-40 vr) and more forest of age class 41-60 vears at spotted owl than at random sites (P < 0.05). Low prey abundance around spotted owl nest sites, roost sites, or both mav explain why older stands with more basal area were found in higher proportions at sites with lower fecundity. Spotted owls that chose younger stands with smaller trees mav have benefited from higher woodrat (Neotoma fuscipes) availability in young stands. Managing habitat by retaining residual trees and limiting clearcutting to at least 1.1 km bevond lest sites may prove useful in increasing reproductive success of northern spotted owls.

Length of the Larval Cycle of Ascaphus truei in Coastal Streams of the Redwood Region, Northern California

Length of the Larval Cycle of Ascaphus truei in Coastal Streams of the Redwood Region, Northern California

Common Roots and Entangled Limbs: Earth First! and the Growth of Post‐Wilderness Environmentalism on California's North Coast

Conflicts over the protection of redwood trees on California's North Coast are often depicted as following the trajectory of the radical wing of the larger American environmental movement, in which “radical” refers to the sharpness of the boundary drawn and defended between human despoliation and pure nature or “wilderness.” Earth First!—an environmental organization characterized by their slogan, “No compromise in the defense of Mother Earth!”—is often depicted as simply the leading edge of this deepening rift between nature and culture. I argue, on the contrary, that the Earth First! branches on California's North Coast should be understood as making bold, if incomplete, attempts to cast off the problematic nature–culture dichotomy and to define social justice and ecological health as struggles with a common root. By moving beyond wilderness, the North Coast Earth First! offers the promise of a truly radical movement, by which I mean one which truly confronts capital's interlinked degradation of both natural and human communities. This article examines the efforts by the North Coast Earth First! to inscribe a new community of activists and timber‐workers joined in the struggle to contest corporate claims on the redwood forest. It explores the ambiguous effects of activists' “embodied” and “home‐based” practices on this budding alliance, particularly the ways in which such practices also have alienated workers by redefining the redwood forest as the exclusive property of the activists' themselves.

A Comparison of Bobcat and Coyote Predation on Lambs in North-Coastal California

je in\.estigated predation on lambs by bobcats (Lynr mfusi relative to coyotes car ti.^ lntrcit~s) horn J~ine 1994 through November 1995 at Hopland Kesearcli and Extension Center (HREC) in north-coastal C;alifornia, where both predators occur at equally high densities. Larnh losses during this study were t)pical for HKEC and surrounding ranches and inciuded 64 (5.3% of lambs pastured) confirmed predator kills and 134 (11.18)missing individuals. Fift>-seven of the preciator-killed lambs were attribi~ted to coyotes, whereas none were assigned to bobcats. The proportion of bobcat scats containing sheep remains was small i4.2%), and occurrence did not peak in the lambing season, suggesting that sheep consumed by bobcats were scav- enged Sheep were co~nrnon in colote scats (21.4%) and occnrred most freqr~entlv in scats from the ulnter- - . sphng lambkg season. Coyotes were responsible for all lamb kills in intensi~rely monitored pastures for which predator species could be identified. Use of space by radiocollared bobcats was not noticeably influenced by the presence of lambs. \Ve concluded that bobcats were not important predators of lambs at HKEC and not the cause for the relatively large nuirlbers of lambs missing and unaccounted for each year.