Dennis Jongsomjit

Dennis Jongsomjit
Point Blue Conservation Science · Ecoinformatics and Climate Solutions

About

65
Publications
6,589
Reads
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1,637
Citations
Education
January 2019 - December 2021
San Francisco State University
Field of study
  • Geographic Information Science

Publications

Publications (65)
Article
Full-text available
By facilitating independent shifts in species' distributions, climate disruption may result in the rapid development of novel species assemblages that challenge the capacity of species to co-exist and adapt. We used a multivariate approach borrowed from paleoecology to quantify the potential change in California terrestrial breeding bird communitie...
Article
Full-text available
As the rate and magnitude of climate change accelerate, understanding the consequences becomes increasingly important. Species distribution models (SDMs) based on current ecological niche constraints are used to project future species distributions. These models contain assumptions that add to the uncertainty in model projections stemming from the...
Article
a b s t r a c t Designation of an effective marine protected area (MPA) requires substantial knowledge of the spatial use of the region by key species, particularly those of high mobility. Within the Ross Sea, Antarctica, the least altered marine ecosystem on Earth, unusually large and closely interacting populations of several marine bird and mamm...
Article
Full-text available
Although the effects of climate change on species distributions have received considerable attention, land-use change continues to threaten wildlife by contributing to habitat loss and degradation. We compared projected spatial impacts of climate change and housing development across a range of housing densities on California’s birds to evaluate th...
Article
Full-text available
Inter-individual differences in demographic traits of iteroparous species can arise through learning and maturation, as well as from permanent differences in individual ‘quality’ and sex-specific constraints. As the ability to acquire energy determines the resources an individual can allocate to reproduction and self-maintenance, foraging behavior...
Article
Full-text available
Group-size variation is common in colonially breeding species, including seabirds, whose breeding colonies can vary in size by several orders of magnitude. Seabirds are some of the most threatened marine taxa and understanding the drivers of colony size variation is more important than ever. Reproductive success is an important demographic paramete...
Article
Plumage colour variation occurs widely among bird species and is often associated with individual fitness. More specifically, colouration can affect thermoregulatory ability, mate selection and conspicuousness during foraging. Colour aberrations can be caused by genetic mutations, dietary imbalances, environmental conditions or disease and are rare...
Article
Full-text available
As part of an 11-state inventory in the western United States orga- nized by the U.S. Fish and Wildlife Service, we coordinated censuses of 15 species of breeding colonial waterbirds throughout California from 2009 to 2012. Here we describe the status of the five widespread species of colonial ardeids in California during that period, combining the...
Article
Full-text available
Understanding the causes of disease in Antarctic wildlife is crucial, as many of these species are already threatened by environmental changes brought about by climate change. In recent years, Antarctic penguins have been showing signs of an unknown pathology: a feather disorder characterised by missing feathers, resulting in exposed skin. During t...
Article
Full-text available
In 2017/18, we recorded multiple instances of Adelie Penguin Pygoscelis adeliae nests containing three chicks at Cape Crozier, Ross Island, Antarctica. In one sub-colony, 0.67 % of nests had three chicks, or two chicks and one egg. We found that some Adelie Penguin pairs were willing to brood three chicks, as well as chicks that were not their own....
Article
Full-text available
According to central place foraging theory, breeding seabirds should energetically optimize prey acquisition and, therefore, foraging is expected to be located where prey are most available, within limits defined by the energetics of the species. We have shown this previously for Adélie penguins Pygoscelis adeliae, using foraging intensity as a pro...
Article
Full-text available
Background Between 2013 and 2015, a large part of the western United States, including the Central Valley of California, sustained an extreme drought. The Central Valley is recognized as a region of hemispheric importance for waterbirds, which use flooded agriculture and wetlands as habitat. Thus, the impact of drought on the distribution of surfac...
Data
Code for calculating decay rate of water in field once draining of water is initiated.
Data
R-code for analyzing wetland flooding in the Sacramento Valley and San Joaquin Valley’s individually.
Data
Data used for Sacramento Valley level assessment of flooding in rice as part of analysis of impact of incentive programs.
Data
Data used to calculate the amount of habitat generated by incentive programs in the Central Valley.
Data
R code for evaluating impact of incentive programs in the Central Valley.
Data
The Nature Conservancy’s unpublished cover type data layer for the Central Valley.
Data
R-code for analyzing impacts of drought on open water in managed wetlands and agriculture using single model for all year types.
Data
Data used to assess open water in managed wetlands in the Central Valley.
Data
Water depth data used to model residual habitat post initiation of field draining.
Data
Data for analysis of open water in agriculture fields in the Central Valley.
Data
Data used for bias correction of estimates of water from Landsat 5 and Landsat 8.
Data
R-code for analyzing impacts of drought on open water in managed wetlands and agriculture using separate models for each year type.
Preprint
Full-text available
Between 2013 and 2015 a large part of the western United States, including the Central Valley of California, sustained an extreme drought. The Central Valley is recognized as a region of hemispheric importance for waterbirds which use flooded agriculture and wetlands as habitat. Thus, the impact of drought on the distribution of surface water neede...
Preprint
Full-text available
Between 2013 and 2015 a large part of the western United States, including the Central Valley of California, sustained an extreme drought. The Central Valley is recognized as a region of hemispheric importance for waterbirds which use flooded agriculture and wetlands as habitat. Thus, the impact of drought on the distribution of surface water neede...
Article
The family Papillomaviridae contains more than 320 papillomavirus types, with most having been identified as infecting skin and mucosal epithelium in mammalian hosts. To date, only nine non-mammalian papillomaviruses have been described from birds (n = 5), a fish (n = 1), a snake (n = 1), and turtles (n = 2). The identification of papillomaviruses...
Article
Full-text available
The Sacramento Valley of California is a site of international importance for shorebirds despite having lost >90% of its historic wetlands. Currently both managed wetlands and flooded agriculture are important habitats for shorebird populations, but the extent of flooded agriculture may be declining in early winter when shorebirds need to acquire r...
Article
We used Landsat satellite imagery to (1) quantify the distribution of open surface water across the Central Valley of California 2000-2011, (2) summarize spatio-temporal variation in open surface water during this time series, and (3) assess factors influencing open surface water, including drought and land cover type. We also applied the imagery t...
Article
Full-text available
We investigated mesopredator effects on prey availability in the Ross Sea, Antarctica, as - sessing the reasons why Adélie penguin Pygoscelis adeliae foraging trip duration (FTD) increases and diet changes from krill to fish as numbers of foraging penguins and competing cetaceans increase in the penguins' foraging area. To investigate penguins' sea...
Article
Systematic conservation planning aims to design networks of protected areas that meet conservation goals across large landscapes. The optimal design of these conservation networks is most frequently based on the modeled habitat suitability or probability of occurrence of species, despite evidence that model predictions may not be highly correlated...
Conference Paper
Background/Question/Methods Landscape predictions of suitable habitat for wildlife can be improved when fine-scale maps of existing vegetation are included as covariates in the models. The resulting models help inform managers by directing where to work and contribute to our understanding about how vegetation management can support wildlife conser...
Technical Report
Full-text available
We acquired, federated and curated approximately one million new observations to the Avian Knowledge Network. We used these new and existing observations to model the distribution and abundance of 26 species of land birds in the southern portion of the North Pacific Landscape Conservation Cooperative (NPLCC) region including CA, OR and WA. The mode...
Article
Full-text available
Restoration and conservation may be enhanced by using ecologically-based methods for prioritizing actions. Efforts are currently underway to restore river flows to the San Joaquin River in California’s Central Valley. Although fish are the primary restoration target for restored flows, complementary efforts are being designed to protect, enhance, a...
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
The population size of Antarctic minke whales Balaenoptera bonaerensis has been changing simultaneously with profound changes in the physics, i.e., mesopredator habitat features, of the Southern Ocean. Although the two trends may not be related, distinguishing among the factors responsible requires a better understanding of minke whale habitat pref...
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...
Data
Full-text available
Climate change scenario assumptions for San Francisco Bay subregions. See map in Figure 1 . (PDF)
Data
Full-text available
Data sources for mapped starting elevations within San Francisco Bay study area. (PDF)
Data
Full-text available
GPS-based vegetation corrections (m) used to adjust elevations in Suisun Bay marshes (subregions 14 and 15). (PDF)
Data
Projected area (ha) of current and potential future marsh habitat, as well as upland areas reclaimed, under various sea-level rise (SLR) and sediment availability assumptions for the San Francisco Bay (Bay) estuary. To demonstrate restoration opportunities, the potential future marsh area for currently diked lands reflects assumption that all dikes...
Article
Full-text available
Tidal marshes will be threatened by increasing rates of sea-level rise (SLR) over the next century. Managers seek guidance on whether existing and restored marshes will be resilient under a range of potential future conditions, and on prioritizing marsh restoration and conservation activities. Building upon established models, we developed a hybrid...
Article
Protected areas for conservation are intended to contain the environmental conditions that enable species and ecosystems to persist. The locations of such areas are fixed, but the environment within them may change, especially with climate change. To illustrate how multiple climate factors may change in relation to protection status, we used Princi...
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...
Data
Levels of bird community aggregation used to determine optimal no-analog thresholds for maximum entropy model predictions. A, 20 groups. B, 60 groups. C, 100 groups. (3.92 MB TIF)
Data
Vegetation classes modeled. (0.04 MB DOC)
Data
Optimal dissimilarity thresholds by level of community aggregation (number of groups) and distribution model algorithm. (0.04 MB DOC)
Data
Locations and sources of point-count data used to develop avian distribution models. Occurrence information from 16,742 point-count locations was aggregated for each species at the 800-m pixel level for modelling purposes, resulting in an effective sample size of 6,964. PRBO = PRBO Conservation Science; RSL = USDA Forest Service Redwood Sciences La...
Data
Levels of bird community aggregation used to determine optimal no-analog thresholds for generalized additive model predictions. A, 20 groups. B, 60 groups. C, 100 groups. (3.84 MB TIF)
Data
Modeled current and future vegetation distribution for California. A, current vegetation. B, future vegetation based on GFDL CM2.1, Scenario A2, 2038–2070. C, future vegetation based on NCAR CCSM3.0, Scenario A2, 2038–2069. Models were developed using California Gap Analysis vegetation data (see Table S2 for definitions of vegetation codes). Versio...
Data
Focal species, habitat categories, and migratory status. (0.10 MB DOC)
Data
Summary of bioclimatic and soil variables included in vegetation classification models1. (0.05 MB DOC)
Conference Paper
Background/Question/Methods PRBO Conservation Science has coordinated citizen science projects to improve ecosystem conservation and management since 1971. Recently we created the California Avian Data Center (CADC) as the first regional node of the Avian Knowledge Network. CADC serves as a repository of data, analysis, tools and information for st...
Article
Full-text available
Nestling growth and development studies have been a topic of interest for a greater part of the last century (Sutton 1935, Walkinshaw 1948) and continue to be of interest today. This is not surprising since studies on nestling growth can provide a wealth of biological information that has larger implications for avian management and conserva...

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Projects

Projects (5)
Project
This project has 3 main goals: 1) Determine how changing winter sea ice conditions in the Ross Sea affect the migration, behavior and survival of Adélie penguins and identify the carry-over effects (COEs) to subsequent reproduction, 2) Determine the interplay between extrinsic and intrinsic factors influencing COEs over multiple years of an individual’s lifetime, 3) Determine how climate change may affect population change at colonies via impacts to nesting habitat, interacting with individual quality and COEs.