Nadav Nur

Nadav Nur
Point Blue Conservation Science

PhD

About

132
Publications
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5,311
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Publications

Publications (132)
Article
Full-text available
The successful adaptive management of marine protected areas (MPAs) requires knowledge of spatial variability in the rates of juvenile fish recruitment to recovering fish populations. We used the foraging rates of two piscivorous seabirds (Brandt's cormorant and pelagic cormorant) to index juvenile fish abundance at 46 sites throughout California's...
Article
Full-text available
Chen et al. (Polar Biology, 43(11):1769–1781) recently reported lagged, region-specific responses of Adélie penguin (Pygoscelis adeliae) abundance to environmental variability in the Ross Sea, Antarctica. Their study suggests that lags are important toward understanding Adélie penguin population change. Though we agree with many of their findings,...
Article
The Weddell seal is one of the best-studied marine mammals in the world, owing to a multidecadal demographic effort in the southernmost part of its range. Despite their occurrence around the Antarctic coastline, we know little about larger scale patterns in distribution, population size, or structure. We combined high-resolution satellite imagery f...
Article
Full-text available
We document changes in the number of sightings and timing of humpback ( Megaptera novaeangliae ), blue ( Balaenoptera musculus ), and gray ( Eschrichtius robustus ) whale migratory phases in the vicinity of the Farallon Islands, California. We hypothesized that changes in the timing of migration off central California were driven by local oceanogra...
Article
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Habitat prioritization is a powerful tool for identifying critical wildlife areas for conservation. This study evaluates the risk of disturbance from maritime activities to seabirds in order to prioritize critical seabird foraging habitat for conservation thereby providing a much-needed methodological contribution demonstrating how to transparently...
Article
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Wildlife managers must be able to assess the long‐term, population‐wide impacts of mortality events on long lived vertebrates, taking into account the stochastic nature of population fluctuations. Here, we present a case study of the potential impacts on Western gulls (Larus occidentalis) of a single, non‐target mortality event, potentially resulti...
Preprint
Full-text available
Citizen science programs can be effective at collecting information at large temporal and spatial scales. However, sampling bias is a concern in citizen science datasets and can lead to unreliable estimates. We address this issue with a novel approach in a first-of-its-kind citizen science survey of Weddell seals for the entire coast of Antarctica....
Article
Antarctic toothfish Dissostichus mawsoni and Weddell seals Leptonychotes weddellii are important mesopredators in the waters of the Antarctic continental shelf. They compete with each other for prey, yet the seals also prey upon toothfish. Such intraguild predation means that prevalence and respective demographic rates may be negatively correlated,...
Article
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As global ocean-bound commerce increases, managing human activities has become important in reducing conflict with threatened wildlife. This study investigates environmental factors determining abundance and distribution of blue whales (Balaenoptera musculus), humpback whales (Megaptera novaeangliae) and their prey (Euphausia pacifica and Thysanoes...
Article
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We quantify the expected demographic benefit to a seabird of conservation concern, the ashy storm‐petrel Oceanodroma homochroa, from the proposed eradication of introduced house mice Mus musculus on the South Farallon Islands, California. A key objective of the eradication is to reduce storm petrel predation by burrowing owls Athene cunicularia, wh...
Article
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Abstract Satellites Over Seals (SOS), a project initiated in late 2016, is a crowdsourced method to determine factors behind the presence/absence patterns and to ultimately determine the global population of the Weddell seal (Leptonychotes weddellii). An iconic species, the Weddell seal is proposed to be part of the Antarctic Research and Monitorin...
Article
Weddell seal Leptonychotes weddellii populations can potentially serve as indicators of change in Southern Ocean food web structure, but tracking populations at regional to continental scales has so far been impossible. Here, we combined citizen science with remote sensing to learn about environmental and biological factors that explain fine-scale...
Article
Salt marsh-dependent species are vulnerable to impacts of sea-level rise (SLR). Site-specific differences in ecogeomorphic processes result in different SLR vulnerabilities. SLR impacts to Ridgway’s rail (Rallus obsoletus) of Southern California (SC) and San Francisco Bay (SF), U.S.A. could foreshadow SLR effects on other coastal endemic species. S...
Article
We herein review the modeling approach of Pinkerton et al. (2016, Ecol. Modelling), who tested the hypothesis that fishery depletion of large, neutrally buoyant Antarctic toothfish (Dissostichus mawsoni) was implicated in the recent increase in the southern Ross Sea population of Adélie penguins (Pygoscelis adeliae). Toothfish are a trophic competi...
Article
Full-text available
Seabird aggregations at sea have been shown to be associated with concentrations of prey. Previous research identified Central California as a highly used foraging area for seabirds, with locally breeding seabirds foraging close to their colonies on Southeast Farallon Island. Herein, we focus on nonresident (i.e. non-locally breeding) seabird speci...
Article
We comment on the conjecture by Parker et al . (2016) that Antarctic toothfish recently returned to McMurdo Sound, arguing that this species never departed. Instead, as deduced from a 40-year fishing effort, toothfish water column prevalence became markedly reduced where bottom depths are <500 m, with research continuing to show their presence on t...
Article
Extraction of Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea began in 1997, following a management plan that targets the largest fish with a goal of reducing the spawning biomass by 50% over 35 years. We investigate the potential long-term consequences of the reduced availability of this prey for Weddell seals (Leptonychotes weddellii)....
Article
Full-text available
Krill (Euphausiids) play a vital ecosystem role in many of the world's most productive marine regions, providing an important trophic linkage. We introduce a robust modeling approach to link Cassin's auklet (Ptychoramphus aleuticus) abundance and distribution to large-scale and local oceanic and atmospheric conditions and relate these patterns to s...
Data
Coefficients, standard errors, z values, p values, and associated 95% confidence intervals for all quantitative variables (including year and interactions with year) for the two-part model combining logistic regression and negative binomial regression for krill. Model output assumes base year is 2004. (DOCX)
Data
Coefficients, standard errors, z values, p values, and associated 95% confidence intervals for all quantitative variables (including years and interactions with years) for the zero-inflated negative binomial regression model for Cassin’s auklets. Model output assumes base year is 2004. (DOCX)
Article
Full-text available
Understanding habitat preferences for endangered species is a high priority for management strategies to ensure minimum conflict between human uses and wildlife conservation. The purpose of this study was to identify oceanographic variables that predict occurrences of humpback whales Megaptera novaeangliae within the Cordell Bank and Gulf of the Fa...
Article
Full-text available
Understanding the characteristics of high-quality avian habitat is critical for guiding salt marsh management and restoration. Existing insights into salt marsh avian habitat are often based on the composition of marsh vegetation, e.g., individual plant species cover. This study investigated whether the spatial configuration of marsh surface cover...
Conference Paper
Background/Question/Methods Non-native house mice (Mus musculus) were introduced on the Farallon Islands in the 19th century and are now at extremely high densities. As a consequence, migratory burrowing owls (Athene cunicularia) now over-winter on the Farallon Islands during the fall and winter, feeding on the mice. However when the mice populat...
Article
Full-text available
Understanding seabird habitat preferences is critical to future wildlife conservation and threat mitigation in California. The objective of this study was to investigate drivers of seabird habitat selection within the Gulf of the Farallones and Cordell Bank National Marine Sanctuaries to identify areas for targeted conservation planning. We used se...
Article
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Birds have distinct niches in San Francisco Bay tidal marshes, based on their foraging guilds and habitat associations. Urbanization has resulted in a static system with a less resilient avian community threatened by sea-level rise, disturbance, fragmentation, invasive species, and other stressors. Large-scale restoration has increased open habitat...
Article
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Extensive habitat loss and degradation have resulted in decreases in populations of tidal marsh breeding birds in the San Francisco Estuary in the past 150 years. We conducted point count surveys and nest monitoring in tidal marsh habitat at China Camp State Park from 1996 through 2007 to assess bird abundance, species richness and reproductive suc...
Article
Rush Ranch, with the largest contiguous area of fully-tidal marsh remaining in northern Suisun Bay, is critical habitat for a number of endemic bird species that breed in brackish tidal marsh. Despite the abundance of non-native invasive plants (particularly perennial pepperweed, Lepidium latifolium) and altered hydrology, it is the best remaining...
Conference Paper
Background/Question/Methods The large uncertainty surrounding the effects of sea-level rise and climate change on tidal marsh habitats and the species that depend on them exacerbates the difficulty in planning effective conservation and restoration efforts. To help conservation practitioners address these effects, we modeled the distribution and a...
Article
Full-text available
Using acoustic telemetry methods on large numbers of tagged fish, we studied how the holding behavior of Chinook salmon and steelhead smolts could be related to habitat features and spatial and temporal variables on a highly altered section of the Sacramento River. We viewed downstream migration as a process in which fish transition between moving...
Article
We report the analyses of a dataset spanning 39 years of near-annual fishing for Dissostichus mawsoni in McMurdo Sound, Antarctica, 1972–2011. Data on total length, condition and catch per unit effort (CPUE) were derived from the > 5500 fish caught, the large majority of which were measured, tagged and released. Con-trary to expectation, the length...
Article
The Vandenberg State Marine Reserve (VSMR) was established in 1994 with the primary goal of protecting fishes and invertebrates targeted by fisheries. However, studies of other reserves have shown that effects cascade and benefit species at several trophic levels. We tested the hypothesis that the VSMR would provide benefits to nearshore foraging s...
Article
The large uncertainty associated with estimating the effects of sea-level rise and climate change on tidal marsh ecosystems exacerbates the difficulty in planning for their effective conservation. To address this uncertainty, we modeled the distribution and abundance of tidal marsh bird species in the San Francisco Estuary for the period 2010 to 21...
Conference Paper
Emergency levee repairs began in 2006 on the lower Sacramento River, California by the California Department of Water Resources. Three levee repair design types were developed and constructed to include specific habitat features, thus providing mitigation to meet the requirement of biological opinions issued by NMFS and USFWS. Our task was to evalu...
Article
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Marine protected areas (MPAs) provide an important tool for conservation of marine ecosystems. To be most effective, these areas should be strategically located in a manner that supports ecosystem function. To inform marine spatial planning and support strategic establishment of MPAs within the California Current System, we identified areas predict...
Article
Species distribution models (SDMs) based on climate variables are often used to quantify and describe the spatial distributions of species under current and projected future climate conditions. While such models are generally developed at the continental level for the purpose of projecting broad-scale range shifts, there is an increasing demand for...
Article
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Animals modulate breeding effort by balancing investment in self-maintenance against investment in their young, potentially impacting reproductive success when faced with difficult conditions. This life history trade-off model has been evaluated for flying birds, especially those that forage over large pelagic regions of relatively sparse prey avai...
Article
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Tidal marsh monitoring and restoration can benefit from the union of fine-scale remote sensing products and field-based survey data via spatial predictive models. As part of an interdisciplinary wetland monitoring project in San Francisco Bay, we developed a suite of 1-m pixel-level spatial metrics describing patterns in marsh vegetation and geomor...
Article
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Many avian species have demonstrated differential wintering of the sexes, either latitudinally across their wintering range or by habitat. We examined the large numbers of wintering Ruby-crowned Kinglets (Regulus calendula) captured as part of a long term constant effort mist-netting program in coastal California to determine if such a pattern was...
Article
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The size of the breeding population of Brandt's Cormorants Phalacrocorax penicillatus on Southeast Farallon Island, off the coast of central California, USA, shows large annual fluctuations and has declined by 50% since the 1970s. We investigated patterns of variation in adult survival, breeding probability, resighting probability, juvenile surviva...
Article
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At the southern end of its range, the Northern Spotted Owl (Strix occidentalis caurina) occurs in high densities and nests in a wide range of forest types and ages, exhibiting different foraging and nesting habits than in the northern part of its range. The intensive monitoring of this subspecies on public lands in Marin County, California, combine...
Article
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Conservation planning and management decisions often present trade-offs among habitats and species, generating uncertainty about the composition and configuration of habitat that will best meet management goals. The public acquisition of 5471 ha of salt ponds in San Francisco Bay for tidal-marsh restoration presents just such a challenge. Because t...
Article
We studied the relationships among weather, reproductive success, and population density over 21 years (1980-2000) in a resident Song Sparrow (Melospiza melodia) population in coastal scrub habitat. Our goals were to test potential relationships between annual variation in weather and reproductive success, to evaluate whether reproductive success i...
Article
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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 a...
Article
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Roth, J. E., Nur, N., Warzybok, P., and Sydeman, W. J. 2008. Annual prey consumption of a dominant seabird, the common murre, in the California Current system. – ICES Journal of Marine Science, 65: 1046–1056. Information compiled from the literature on population size, diet composition, field metabolic rate, prey energy densities, and assimilation...
Article
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We investigated relationships between riparian bird abundance and local vegetation characteristics and habitat features across the Sacramento/San Joaquin Valley, California. Number of detections was analyzed for each of 21 species from point count surveys over a 4-year period at 22 sites from three regions (Sacramento River, Cosumnes River, and San...
Article
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Understanding recruitment in demersal fish requires determination of larval survival and delivery to appropriate settling habitats. Sanddabs Citharichthys sp. are an abundant neritic fish of Central California, an area of persistent upwelling. 'Upwelling shadows' develop in the lee of coastal promontories, retain surface waters, and may promote spa...
Article
Long-term studies conducted on breeding populations on the Farallon Islands (1971 to 2007) and in the Point Reyes National Seashore (1980 to 2007), provide the means to characterize breeding phenology of seabird and landbird species and determine how that has changed over multiple temporal scales (variation among years, among decades, shifts in oce...
Article
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The genus Piper is an important component of tropical forests worldwide. Many Piper species have been reported as self-compatible (Figueiredo & Sazima 2000), and many have the ability to reproduce asexually, forming clonal aggregations (Grieg 1993). Furthermore, the main dispersers of Piper (bats) transport whole infructescences to feeding roosts (...
Article
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1. We performed demographic analyses on Cassin's auklet Ptychoramphus aleuticus, a zooplanktivorous seabird inhabiting the variable California Current System, to understand how temporal environmental variability influences population dynamics. 2. We used capture-recapture data from 1986 to 2002 to rank models of interannual variation in survival, b...
Article
Riparian vegetation along the Sacramento River— California's largest river—has been almost entirely lost, and several wildlife species have been extirpated or have declined as a result. Large-scale restoration efforts are focusing on revegetating the land with native plants. To evaluate restoration success, we conducted surveys of landbirds on reve...
Article
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Tidal-marsh vertebrates experience two distinct challenges to successful reproduction: inundation of the soil with water, which is variable and often unpredictable, and the simple vegetative structure, which offers few safe havens from predation. We review both published and unpublished studies of tidal-marsh birds and their relatives to determine...
Article
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The San Francisco Bay and delta system comprises the largest estuary along the Pacific Coast of the Americas and the largest remaining area for tidal-marsh vertebrates, yet tidal marshes have been dramatically altered since the middle of the 19th century. Although recent efforts to restore ecological functions are notable, numerous threats to both...
Article
We modeled the abundance or probability of occurrence of several tidal-marsh-dependent birds found in the San Francisco Bay estuary - the San Pablo Song Sparrow (Melospiza melodia samuelis), Alameda Song Sparrow (M. m. pusillula), Suisun Song Sparrow (M. m. maxillaris), Salt Marsh Common Yellowthroat (Geothlypis trichas sinuosa), California Black R...