Timothy Bargar, Ph.D.
Biography
EDUCATION
Ph.D., Environmental Toxicology, Texas Tech University, 2000
RESEARCH
Tim Bargar moved joined the USGS in 2008 and has worked to build research collaborations with federal partners to evaluate contaminant impacts on the nation’s trust resources. He has developed working partnerships with biologists at the Everglades, Biscayne Bay, and Virgin Islands National Parks to better understand the potential impacts from existing and potential future contamination. Owing to his previous employment with the USFWS, he has continued his work with the National Key Deer Refuge to evaluate the impacts of mosquito control operations on species that are candidates for listing under the Endangered Species Act.
BACKGROUND
His dissertation investigated a potential non-lethal, non-invasive method for assessing oviparous organism exposure to persistent organic contaminants. Prior to joining the U.S. Geological Survey, Dr. Bargar worked with the National Oceanic and Atmospheric Administration, the U.S. Environmental Protection Agency, and the U.S. Fish and Wildlife Service. While with NOAA, he participated in the investigation of pesticide impacts in the Everglades National Park while completing his PhD. He moved on to the Office of Pesticide Programs of the USEPA where his responsibility was the conduct of pesticide ecological risk assessments within the Federal Insecticide, Fungicide, and Rodenticide Act process. He then joined the South Florida Ecological Services Office of the USFWS in 2003 and participated in activities related to the Comprehensive Everglades Restoration Plan (CERP). His responsibilities primarily involved the assessment, and associated ecological risks to federally listed species, of contamination on properties acquired for incorporation within the CERP. Additional responsibilities included evaluation of pesticide risk to federally listed species as a result of pesticide use on national wildlife refuges.
Science and Products
Contaminants Assessment in the Coral Reefs of the Virgin Islands National Park and Virgin Islands Coral Reef National Monument
USGS collected samples at reef locations within the Virgin Islands National Park and analyzed for the presence of contaminants, organotin compounds, or sunscreen compounds.
Environmental Management of Vector-borne Diseases
Effective management programs for vector-borne pathogens, such as West Nile Virus and the Lyme disease spirochete, are necessary to protect public health. However, some vector control methods, such as landscape manipulations and pesticide applications, can also adversely affect nontarget species and environmentally sensitive natural systems. Efficient targeting and integration of vector...
Land Stewardship Science Team
The Land Stewardship Integrated Science Team focuses on the potential for contaminant exposures in the environment that might originate from land management activities like wildfire and dust suppression, vector control (for example: mosquitos and rodents) and invasive species (Asian carp and nuisance plants). Perceived health risks to humans and other organisms will be...
Effect of Chronic Neonicotinoid Insecticide Exposure upon Monarch Development
The long-term viability of monarch butterfly (Danaus plexippus) populations in North America is in doubt.
Relative Sensitivity of Adult Mosquitoes and Butterflies to Adult Mosquito Control Pesticides
Mosquito control on Department of the Interior (DOI) managed lands is a resource management challenge. The pesticides used to control mosquitoes may also affect nontarget organisms whose conservation is one of the primary responsibilities of resource managers.
Monarch Butterfly Utilization of Milkweed Plants Grown in Close Proximity to Corn Treated by a Neonicotinoid Insecticide (Seed Treatment)
Monarch butterfly populations have declined sufficiently to result in noticeably fewer overwintering at sites in central Mexico as in California.
Baseline Aquatic Contamination and Endocrine Status in Resident Fish Populations of Biscayne National Park and in the Adjacent Coastal Environment
As part of the Comprehensive Everglades Restoration Plan, water managers are planning to use treated wastewater from the South District Wastewater Treatment Plant (WWTP) to supplement the canal waters that will be used to rehydrate wetlands adjacent to the Biscayne National Park (Park).
Methylmercury Impacts to Reproduction in the Eastern Mosquitofish (Gambusia holbrooki)
USGS researchers investigate the effects of methylmercury contamination on reproduction of the Eastern mosquitofish, a common fish in South Florida.
Mosquito Control Pesticide Impacts to Butterflies: Implications for Imperiled Butterfly Conservation on a National Wildlife Refuge
USGS researchers evaluate the impact of a pesticide on two imperiled butterfly species in the Florida Keys.
Mortality and cholinesterase inhibition in butterflies following aerial naled applications for mosquito control on the National Key Deer Refuge
Natural resource managers are concerned about the impacts of aerial ultra-low volume spray (ULV) of insecticides for mosquito control (i.e., mosquito adulticides) and seek science-driven management recommendations that reduce risk but allow vector control for nearby human populations. Managers at the National Key Deer Refuge (Florida Keys, FL) are...
Bargar, Timothy; Anderson, Chad; Sowers, Anthony Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption
Recent concern for the adverse effects from neonicotinoid insecticides has centered on risk for insect pollinators in general and bees specifically. However, natural resource managers are also concerned about the risk of neonicotinoids to conservation efforts for the monarch butterfly (Danaus plexippus) and need additional data to help estimate...
Bargar, Timothy A.; Hladik, Michelle; Daniels, Jaret C. Petroleum hydrocarbons in semipermeable membrane devices deployed in the Northern Gulf of Mexico and Florida keys following the Deepwater Horizon incident
The Deepwater Horizon (DWH) oil spill from April to July of 2010 contaminated Gulf of Mexico waters through release of an estimated 4.1 × 106 barrels of oil. Beginning in June of 2010, semipermeable membrane devices (SPMDs) were deployed near areas with sensitive marine habitats (Alabama Alps and Western Shelf) potentially exposed...
Bargar, Timothy; Alvarez, David; Stout, Scott A.
Assessment of bird exposure to lead at Tyndall and Beale Air Force Bases, 2016–17
Soil contamination by lead (Pb) from past small munitions training on Beale Air Force Base, California, and Tyndall Air Force Base, Florida, may result in adverse effects for passerine birds that utilize the locations. A study was conducted during 2016-17 by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service and U.S...
Bargar, Timothy A. Management of arthropod pathogen vectors in North America: Minimizing adverse effects on pollinators
Tick and mosquito management is important to public health protection. At the same time, growing concerns about declines of pollinator species raise the question of whether vector control practices might affect pollinator populations. We report the results of a task force of the North American Pollinator Protection Campaign (NAPPC) that examined...
Ginsberg, Howard S.; Bargar, Timothy A.; Hladik, Michelle L.; Lubelczyk, Charles Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park
Surface water, sediment, and fish from Biscayne Bay, coastal wetlands adjacent to the Bay, and canals discharging into the Bay were sampled for determination of baseline contamination in Biscayne National Park. While the number of contaminants detected in canal waters was greater during the wet season than the dry season, no seasonal difference...
Bargar, Timothy A.; Whelan, Kevin R.T.; Alvarez, David; Echols, Kathy R.; Peterman, Paul H. Synthetic ultraviolet light filtering chemical contamination of coastal waters of Virgin Islands National Park, St. John, U.S. Virgin Islands
Contamination of surface waters by synthetic ultraviolet light (UV) filtering chemicals is a concern for the Virgin Islands National Park (VINP). Discrete water samples were collected from VINP bays to determine UV filter chemical presence in the coastal waters. Spatial distribution and the potential for partitioning between subsurface waters and...
Bargar, Timothy A.; Alvarez, David; Garrison, Virginia H. Custom microarray construction and analysis for determining potential biomarkers of subchronic androgen exposure in the Eastern Mosquitofish (Gambusia holbrooki)
Background The eastern mosquitofish (Gambusia holbrooki) has the potential to become a bioindicator organism of endocrine disrupting chemicals (EDCs) due to its androgen-driven secondary sexual characteristics. However, the lack of molecular information on G. holbrooki hinders its use as a bioindicator coupled with biomarker data....
Brockmeier, Erica K.; Yu, Fahong; Amador, David Moraga; Bargar, Timothy A.; Denslow, Nancy D. Contaminants assessment in the coral reefs of Virgin Islands National Park and Virgin Islands Coral Reef National Monument
Coral, fish, plankton, and detritus samples were collected from coral reefs in Virgin Islands National Park (VIIS) and Virgin Islands Coral Reef National Monument (VICR) to assess existing contamination levels. Passive water sampling using polar organic chemical integrative samplers (POCIS) and semi-permeable membrane devices found a few emerging...
Bargar, Timothy A.; Garrison, Virginia H.; Alvarez, David A.; Echols, Kathy The relationship between total cholinesterase activity and mortality in four butterfly species
The relationship between total cholinesterase activity (TChE) and mortality in four butterfly species (great southern white [Ascia monuste], common buckeye [Junonia coenia], painted lady [Vanessa cardui], and julia butterflies [Dryas julia]) was investigated. Acute contact toxicity studies were conducted to evaluate the response (median lethal...
Bargar, Timothy A. Risk assessment for adult butterflies exposed to the mosquito control pesticide naled
A prospective risk assessment was conducted for adult butterflies potentially exposed to the mosquito control insecticide naled. Published acute mortality data, exposure data collected during field studies, and morphometric data (total surface area and fresh body weight) for adult butterflies were combined in a probabilistic estimate of the...
Bargar, Timothy A. A water quality criteria-based evaluation of copper impacts to south Florida's freshwater environment
No abstract available.
Bargar, Timothy A.