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Brian Halstead

Dr. Brian Halstead is a Research Wildlife Biologist with the Western Ecological Research Center.

He focuses on conservation of reptiles and amphibians, particularly applications of population ecology to species conservation. In particular, he combines field methods like capture-mark-recapture and radio telemetry with flexible Bayesian hierarchical models to learn about demographic parameters and the individual, biotic, and environmental variables that affect them. Central themes of his research include the influence of land use, climate, and biotic interactions on species distributions and demographic rates; the behavioral response of individuals to habitat change; and providing relevant information for wildlife conservation to resource managers and private landowners. Currently, Dr. Halstead's research focuses on the effects of water availability on the distribution, behavior, and demography of giant gartersnakes (Thamnophis gigas); the response of San Francisco gartersnakes (Thamnophis sirtalis tetrataenia) to grazing and management of aquatic invasive species; and the influence of abiotic and biotic variables on the distribution and demography of amphibian populations in northern California. Additional research projects include the distribution, growth, and demography of island night lizards (Xantusia riversiana) on San Nicolas Island and monitoring Townsend’s big-eared bat (Corynorhinus townsendii) maternal colonies at Point Reyes National Seashore.

RESEARCH INTERESTS

  • Population Ecology
  • Conservation Biology
  • Herpetology
  • Bayesian Statistics

Education and Certifications

  • B.S. in Biology, Carroll College (Waukesha, WI), 1999

  • Ph.D. in Biology, University of South Florida, 2008

Science and Products

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SFGS

Ecology and Conservation of Reptiles

This project improves our understanding of the ecology of reptiles in California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of reptiles to understand factors that affect where they are found and how populations change. He further explores the relationships of reptiles with their abiotic and...
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Ecosystems, Wildlife Program, Western Ecological Research Center (WERC)
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Ecology and Conservation of Reptiles

This project improves our understanding of the ecology of reptiles in California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of reptiles to understand factors that affect where they are found and how populations change. He further explores the relationships of reptiles with their abiotic and...
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Image: California Red-legged Frog

Ecology and Conservation of Amphibians in Northern California

This project improves our understanding of the ecology of amphibians in northern California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of amphibians to understand factors that affect where amphibians are found and how populations change. He further explores the relationships of amphibians with...
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Ecosystems, Wildlife Program, Western Ecological Research Center (WERC)
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Ecology and Conservation of Amphibians in Northern California

This project improves our understanding of the ecology of amphibians in northern California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of amphibians to understand factors that affect where amphibians are found and how populations change. He further explores the relationships of amphibians with...
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hoary bat

Bat Research in California

The primary goal of this bat research program is to develop projects that increase our understanding of basic ecology and natural history of western bat species, while simultaneously providing needed data to inform conservation measures and management decisions in the West. Dr. Brian Halstead, together with Gabriel Reyes, studies the habitat and resource selection, movement ecology, demography...
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Ecosystems, Energy & Wildlife, Invasive Species Program, Status and Trends Program, Western Ecological Research Center (WERC)
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Bat Research in California

The primary goal of this bat research program is to develop projects that increase our understanding of basic ecology and natural history of western bat species, while simultaneously providing needed data to inform conservation measures and management decisions in the West. Dr. Brian Halstead, together with Gabriel Reyes, studies the habitat and resource selection, movement ecology, demography...
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Filter Total Items: 16

Northwestern Pond Turtle Survey Data in Northern California Forest Streams (2021)

These data are from joint visual encounter and environmental DNA (eDNA) surveys conducted for northwestern pond turtles (Actinemys marmorata) in streams on privately-owned timberlands in northern California.
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Western Ecological Research Center (WERC)

Amphibian Chytrid Swab Data from Churchill County, Nevada (2019-2021)

This dataset includes results from external skin swabbing of Anaxyrus williamsi and Lithobates catesbeianus to test for the fungus Batrachochytrium dendrobatidis from the Dixie Valley in Churchill County, Nevada, in 2019-2021.
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Western Ecological Research Center (WERC)

Western Spadefoot Habitat Selection Based on Radio Telemetry in Orange County, California 2019

We conducted a radio telemetry study of adult western spadefoots (Spea hammondii) at 2 sites in southern California to characterize their survival, behavior, and movements from breeding through aestivation to inform conservation and management for the species. These data support the following publication: Halstead, B.J., Baumberger, K.L., Backlin, A.R., Kleeman, P.M., Wong, M.N., Gallegos, E.
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Western Ecological Research Center (WERC)

Shasta Salamanders Surveys for the Shasta-Trinity National Forest (ver. 2.0, July 2020)

The Shasta salamander (Hydromantes shastae) has been petitioned for listing under the Endangered Species Act. The greatest threat to the species is likely habitat loss that will be caused by the increase in elevation of Shasta Lake that will occur with proposed increases in the height of Shasta Dam to increase water storage capacity and maintain cold water for Chinook salmon (Oncorhynchus tshawyts
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Western Ecological Research Center (WERC)

Characteristics of Sites Sampled for eDNA of Amphibians in Mendocino County, California, 2016

Stream-obligate amphibians are important indicators of ecosystem health in the Pacific Northwest, but distributional information to improve forest management is lacking in many regions. We analyzed archived DNA extracted from water samples in 60 pools within streams in private timberlands in Mendocino County, California, for 3 California Species of Special Concern - Coastal Tailed Frogs (Ascaphus
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Western Ecological Research Center (WERC)

Site and Survey Data for Dixie Valley Toads in Churchill County, Nevada, 2019

These data include site- and survey-specific information for occupancy surveys of Dixie Valley Toads (Anaxyrus williamsi) collected in the Dixie Valley, Churchill County, Nevada, in May 2019. The data include both multiple surveys of the same sites and time-to-detection information to quantify detection probabilities and account for imperfect detection in assessments of Dixie Valley Toad occupancy
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Western Ecological Research Center (WERC)

Site and Survey Data for Amphibian Surveys in Yosemite National Park, 2018

These data represent occupancy surveys conducted in long-term monitoring sites in Yosemite National Park in 2018 for three anurans, the Yosemite Toad (Anaxyrus canorus), the Sierran Treefrog (Pseudacris sierra), and the Sierra Nevada Yellow-legged Frog (Rana sierrae). The data include independent double-observer surveys and time-to-detection data to calculate detection probabilities and account fo
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Western Ecological Research Center (WERC)

Code and Data to fit an Integrated Population Model for the Foothill Yellow-legged Frog, Rana boylii, in northern California

These data include egg mass counts and adult capture-mark-recapture histories for Foothill Yellow-legged frogs (Rana boylii) at two streams in northern California. Data were collected from the South Fork Eel River and its tributary, Fox Creek, from 1993-2019. Data from Hurdygurdy Creek were collected from 2002-2008. This code and data support the following publication: Rose, JP, Kupferberg,
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Western Ecological Research Center (WERC)

Dixie Valley Toad Radio Telemetry Data from Churchill County, Nevada, 2018-2019

This U.S. Geological Survey data release includes tabular data collected to characterize the habitat and movement of Dixie Valley toads. Data were collected in Dixie Valley, Nevada, in autumn 2018 and spring 2019. These data support the following publication: Halstead, B.J., Kleeman, P.M., Rose, J.P. and Fouts, K.J., 2021. Water Temperature and Availability Shape the Spatial Ecology of a Ho
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Western Ecological Research Center (WERC)

Code and data files to construct an Integral Projection Model for Giant Gartersnakes (Thamnophis gigas) in the Sacramento Valley, California, 1995-2017

This dataset includes data on the growth, fecundity, and survival of Giant Gartersnakes (Thamnophis gigas) in the Sacramento Valley of California from 1995-2017. In addition, the dataset includes R code to replicate the Integral Projection Model construction and analysis presented in the paper "Demographic drivers of population growth in a threatened snake" by Rose et al. publish
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Western Ecological Research Center (WERC)

Amphibian capture mark-recapture

These data represent capture mark recapture data along with associated disease status for boreal toads (Anaxyrus boreas) from Wyoming and Montana from 2004-2016 and four frog species (Rana draytonii, R. muscosa, R. pretiosa, R. sierrae) from 2001-2016.
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Ecosystems, Fish & Wildlife Disease, National Wildlife Health Center

Coastal California San Francisco Gartersnake Capture-Mark-Recapture Data (2008-2013)

These data are multi-state capture histories of 273 individual San Francisco gartersnakes collected at a site before and after a portion of the site was burned. Data collection began in 2008 and continued until 2013, and the prescribed fire was applied in the fall of 2010. These data support the following paper: Halstead, B. J., Thompson, M. E., Amarello, M. , Smith, J. J., Wylie, G. D., Routman,
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Western Ecological Research Center (WERC)
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Filter Total Items: 72

Conservation implications of spatiotemporal variation in the terrestrial ecology of Western spadefoots

Conservation of species reliant on ephemeral resources can be especially challenging in the face of a changing climate. Western spadefoots (Spea hammondii) are small burrowing anurans that breed in ephemeral pools, but adults spend the majority of their lives underground in adjacent terrestrial habitat. Western spadefoots are of conservation concern throughout their range because of habitat loss,
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Ecosystems, Western Ecological Research Center (WERC)

A tale of two valleys: Endangered species policy and the fate of the giant gartersnake

By the mid-20th Century, giant gartersnakes (Thamnophis gigas) had lost more than 90% of their Central Valley marsh habitat and were extirpated from more than two-thirds of their range. This massive habitat loss led to their inclusion in the inaugural list of rare species under the California Endangered Species Act (CESA). Listing under the CESA provided giant gartersnakes legal protection and mec
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Ecosystems, Western Ecological Research Center (WERC)

Metal accumulation varies with life history, size, and development of larval amphibians

Amphibian larvae are commonly used as indicators of aquatic ecosystem health because they are susceptible to contaminants. However, there is limited information on how species characteristics and trophic position influence contaminant loads in larval amphibians. Importantly, there remains a need to understand whether grazers (frogs and toads [anurans]) and predators (salamanders) provide comparabl
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Ecosystems, Water Resources, Columbia Environmental Research Center, Forest and Rangeland Ecosystem Science Center, New Jersey Water Science Center, Northern Rocky Mountain Science Center, Western Ecological Research Center (WERC)

Combining genetic and demographic monitoring better informs conservation of an endangered urban snake

Conversion and fragmentation of wildlife habitat often leads to smaller and isolated populations and can reduce a species’ ability to disperse across the landscape. As a consequence, genetic drift can quickly lower genetic variation and increase vulnerability to extirpation. For species of conservation concern, quantification of population size and connectivity can clarify the influence of genetic
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Ecosystems, Western Ecological Research Center (WERC)

Water temperature and availability shape the spatial ecology of a hot springs endemic toad

Desert amphibians are limited to exploiting ephemeral resources and aestivating or to inhabiting scarce refuges of permanent water, such as springs. Understanding how amphibians use these resources is essential for their conservation. Dixie Valley Toads (Anaxyrus williamsi) are precinctive to a small system of cold and hot springs in the Dixie Valley, Nevada, USA. The toads have been petitioned fo
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Ecosystems, Western Ecological Research Center (WERC)

When introduced prey violates trophic hierarchy: Conservation of an endangered predator

Introduced species often disrupt established food webs, but some native predators can come to rely on introduced prey. Understanding the net effects of the non-natives on imperiled predators is crucial for planning conservation measures. The invasive American bullfrog (Lithobates catesbeianus) can be prey, predator, and competitor for the critically endangered San Francisco garter snake (Thamnophi
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Ecosystems, Western Ecological Research Center (WERC)

Estimating the survival of unobservable life stages for a declining frog with a complex life-history

Demographic models enhance understanding of drivers of population growth and inform conservation efforts to prevent population declines and extinction. For species with complex life histories, however, parameterizing demographic models is challenging because some life stages can be difficult to study directly. Integrated population models (IPMs) empower researchers to estimate vital rates for orga
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Ecosystems, Western Ecological Research Center (WERC)

Hatchling emergence ecology of Ouachita map turtles (Graptemys ouachitensis) on the lower Wisconsin River, Wisconsin, USA

Despite its biological importance in shaping both individual fitness and population structure, much remains to be learned about the hatchling emergence ecology of most freshwater turtles. Here, we provide some of the first details on these early life stages for the Ouachita map turtle (Graptemys ouachitensis) obtained during 2015–2017 along the lower Wisconsin River, Iowa County, Wisconsin, and in
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Ecosystems, Western Ecological Research Center (WERC)

Occurrence of a suite of stream-obligate amphibians in timberlands of Mendocino County, California, examined using environmental DNA

Stream-obligate amphibians are important indicators of ecosystem health in the Pacific Northwest, but distributional information to improve forest management is lacking in many regions. We analyzed archived DNA extracted from water samples in 60 pools in streams on private timberlands in Mendocino County, California, for 3 California Species of Special Concern—Coastal Tailed Frogs (Ascaphus truei)
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Ecosystems, Western Ecological Research Center (WERC)

Dispersal of hatchling Ouachita map turtles (Graptemys ouachitensis) from natural nests on the lower Wisconsin River, Wisconsin, USA

Despite its importance to individual fitness and population dynamics, the dispersal behaviors of most neonate freshwater turtles after nest emergence are poorly known. We studied the initial dispersal tendencies of neonate Ouachita map turtles (Graptemys ouachitensis) exiting natural nests during 2015–2017 along the Wisconsin River, Wisconsin. Overall, dispersal was nonrandom, and hatchlings large
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Ecosystems, Western Ecological Research Center (WERC)

Time-to-detection occupancy methods: Performance and utility for improving efficiency of surveys

Occupancy methods propelled the quantitative study of species distributions forward by separating the observation process, or the imperfect detectability of species, from the ecological processes of interest governing species distributions. Occupancy studies come at a cost, however: the collection of additional data to account for nondetections at sites where the species is present. The most commo
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Ecosystems, Western Ecological Research Center (WERC)

Virome of bat guano from nine northern California roosts

Bats are hosts to a large variety of viruses, including many capable of cross species transmissions to other mammals or humans. We characterized the virome in guano from five common bat species in 9 Northern California roosts and a pool of 5 individual bats. Genomes belonging to 14 viral families known to infect mammals and 17 viral families infecting insects or of unknown tropism were detected. N
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Ecosystems, Western Ecological Research Center (WERC)
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WERC Scientists Find that Threatened Snakes Depend on Agriculture (TWS Wildlife News)

SACRAMENTO – A new study shows how giant gartersnakes use Central Valley rice fields

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A Unified Research Strategy for Disease Management

As wildlife diseases increase globally, an understanding of host-pathogen relationships can elucidate avenues for management and improve conservation...

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