Brian Halstead
Biography
Dr. Brian Halstead's research 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
- B.S. in Biology, Carroll College (Waukesha, WI), 1999
- Ph.D. in Biology, University of South Florida, 2008
Science and Products
Responses of riparian reptile communities to damming and urbanization
Various anthropogenic pressures, including habitat loss, threaten reptile populations worldwide. Riparian zones are critical habitat for many reptile species, but these habitats are also frequently modified by anthropogenic activities. Our study investigated the effects of two riparian habitat modifications-damming and urbanization-on overall and...
Hunt, Stephanie D.; Guzy, Jacquelyn C.; Price, Steven J.; Halstead, Brian J.; Eskew, Evan A.; Dorcas, Michael E. Waste rice seed in conventional and stripper-head harvested fields in California: Implications for wintering waterfowl
Waste rice seed is an important food for wintering waterfowl and current estimates of its availability are needed to determine the carrying capacity of rice fields and guide habitat conservation. We used a line-intercept method to estimate mass-density of rice seed remaining after harvest during 2010 in the Sacramento Valley (SACV) of California...
Fleskes, Joseph P.; Halstead, Brian J.; Casazza, Michael L.; Coates, Peter S.; Kohl, Jeffrey D.; Skalos, Daniel A. Relative value of managed wetlands and tidal marshlands for wintering northern pintails
Northern pintail Anas acuta (hereafter, pintail) populations have declined substantially throughout the western US since the 1970s, largely as a result of converting wetlands to cropland. Managed wetlands have been developed throughout the San Francisco Bay estuaries to provide wildlife habitat, particularly for waterfowl. Many of these areas were...
Coates, Peter S.; Casazza, Michael L.; Halstead, Brian J.; Fleskes, Joseph P. Bayesian shared frailty models for regional inference about wildlife survival
One can joke that 'exciting statistics' is an oxymoron, but it is neither a joke nor an exaggeration to say that these are exciting times to be involved in statistical ecology. As Halstead et al.'s (2012) paper nicely exemplifies, recently developed Bayesian analyses can now be used to extract insights from data using techniques that would have...
Heisey, D.M. Using avian radar to examine relationships among avian activity, bird strikes, and meteorological factors
Radar systems designed to detect avian activity at airfields are useful in understanding factors that influence the risk of bird and aircraft collisions (bird strikes). We used an avian radar system to measure avian activity at Beale Air Force Base, California, USA, during 2008 and 2009. We conducted a 2-part analysis to examine relationships...
Coates, Peter S.; Casazza, Michael L.; Halstead, Brian J.; Fleskes, Joseph P.; Laughlin, James A. Demography of the San Francisco gartersnake in coastal San Mateo County, California
The San Francisco gartersnake Thamnophis sirtalis tetrataenia has been federally listed as endangered since 1967, but little demographic information exists for this species. We examined the demography of a San Francisco gartersnake population on approximately 213 ha of California coastal prairie in San Mateo County, California, from 2007 to 2010....
Halstead, Brian J.; Wylie, Glenn D.; Amarello, Melissa; Smith, Jeffrey J.; Thompson, Michelle E.; Routman, Eric J.; Casazza, Michael L. Bayesian adaptive survey protocols for resource management
Transparency in resource management decisions requires a proper accounting of uncertainty at multiple stages of the decision-making process. As information becomes available, periodic review and updating of resource management protocols reduces uncertainty and improves management decisions. One of the most basic steps to mitigating anthropogenic...
Halstead, Brian J.; Wylie, Glenn D.; Coates, Peter S.; Casazza, Michael L. Rapid assessment of rice seed availability for wildlife in harvested fields
Rice seed remaining in commercial fields after harvest (waste rice) is a critical food resource for wintering waterfowl in rice-growing regions of North America. Accurate and precise estimates of the seed mass density of waste rice are essential for planning waterfowl wintering habitat extents and management. In the Sacramento Valley of California...
Halstead, B.J.; Miller, M.R.; Casazza, Michael L.; Coates, P.S.; Farinha, M.A.; Gustafson, K. Benjamin; Yee, J.L.; Fleskes, J.P. Habitat suitability and conservation of the giant gartersnake (Thamnophis gigas) in the Sacramento Valley of California
Resource managers often have little information regarding the habitat requirements and distribution of rare species. Factor analysis-based habitat suitability models describe the ecological niche of a species and identify locations where these conditions occur on the landscape using existing occurrence data.We used factor analyses to assess the...
Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L. Abundance and sexual size dimorphism of the giant gartersnake (Thamnophis gigas) in the Sacramento valley of California
The Giant Gartersnake (Thamnophis gigas) is restricted to wetlands of the Central Valley of California. Because of wetland loss in this region, the Giant Gartersnake is both federally and state listed as threatened. We conducted markrecapture studies of four populations of the Giant Gartersnake in the Sacramento Valley (northern Central Valley),...
Wylie, G.D.; Casazza, Michael L.; Gregory, C.J.; Halstead, B.J. Temporal and maternal effects on reproductive ecology of the giant gartersnake (Thamnophis gigas)
We used mixed-effects models to examine relationships of reproductive characteristics of the giant gartersnake (Thamnophis gigas) to improve population modeling and conservation planning for this species. Neonates from larger litters had lower mass, and mass of neonates also was affected by random variation among mothers. Length of mother did not...
Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L.; Coates, Peter S. Masticophis flagellum selects florida scrub habitat at multiple spatial scales
The use of space by individual animals strongly influences the spatial extent, abundance, and growth rates of their populations. We analyzed the spatial ecology and habitat selection of Masticophis flagellum (the coachwhip) at three different scales to determine which habitats are most important to this species. Home ranges and mean daily...
Halstead, B.J.; Mushinsky, H.R.; McCoy, E.D.