Brian Gray, PhD
Brian Gray
Education and Certifications
Ph.D., Biostatistics, University of South Carolina, 2001
M.S., Biology, University of Kentucky, 1993
Diploma in Natural Resources, Lincoln University, 1982
B.Sc., Botany, University of Auckland, 1981
Science and Products
Filter Total Items: 51
Distribution and foraging patterns of common loons on Lake Michigan with implications for exposure to type E avian botulism
Common loons (Gavia immer) staging on the Great Lakes during fall migration are at risk to episodic outbreaks of type E botulism. Information on distribution, foraging patterns, and exposure routes of loons are needed for understanding the physical and ecological factors that contribute to avian botulism outbreaks. Aerial surveys were conducted to document the spatiotemporal distribution of common
Authors
Kevin P. Kenow, Steven C. Houdek, Luke J. Fara, Brian R. Gray, Brian R. Lubinski, Darryl J. Heard, Michael W. Meyer, Timothy J. Fox, Robert Kratt
Effects of air temperature and discharge on Upper Mississippi River summer water temperatures
Recent interest in the potential effects of climate change has prompted studies of air temperature and precipitation associations with water temperatures in rivers and streams. We examined associations between summer surface water temperatures and both air temperature and discharge for 5 reaches of the Upper Mississippi River during 1994–2011. Water–air temperature associations at a given reach ap
Authors
Brian R. Gray, Dale M. Robertson, James T. Rogala
Separable correlation and maximum likelihood
We consider estimation of the covariance matrix of a multivariate normal distribution when the correlation matrix is separable in the sense that it factors as a Kronecker product of two smaller matrices. A computationally convenient coordinate descent-type algorithm is developed for maximum likelihood estimation. Simulations indicate our method often gives smaller estimation error than some common
Authors
Karl Oskar Ekvall, Brian R. Gray
Differences in breeding bird assemblages related to reed canary grass cover cover and forest structure on the Upper Mississippi River
Floodplain forest of the Upper Mississippi River provides habitat for an abundant and diverse breeding bird community. However, reed canary grass Phalaris arundinacea invasion is a serious threat to the future condition of this forest. Reed canary grass is a well-known aggressive invader of wetland systems in the northern tier states of the conterminous United States. Aided by altered flow regimes
Authors
Eileen M. Kirsch, Brian R. Gray
Lethal and sub-lethal responses of native freshwater mussels exposed to granular Bayluscide®, a sea lamprey larvicide
The invasive sea lamprey (Petromyzon marinus) poses a substantial threat to fish communities in the Great Lakes. Efforts to control sea lamprey populations typically involve treating tributary streams with lampricides on a recurring cycle. The presence of a substantial population of larval sea lampreys in the aquatic corridor between Lakes Huron and Erie prompted managers to propose a treatment us
Authors
Teresa Newton, Michael A. Boogaard, Brian R. Gray, Terrance D. Hubert, Nicholas A. Schloesser
Estimating linear temporal trends from aggregated environmental monitoring data
Trend estimates are often used as part of environmental monitoring programs. These trends inform managers (e.g., are desired species increasing or undesired species decreasing?). Data collected from environmental monitoring programs is often aggregated (i.e., averaged), which confounds sampling and process variation. State-space models allow sampling variation and process variations to be separate
Authors
Richard A. Erickson, Brian R. Gray, Eric A. Eager
Mortality, movement and behaviour of native mussels during a planned water-level drawdown in the Upper Mississippi River
Managers in the Upper Mississippi River (UMR) are using reductions in the River's water levels during summer to mimic historical water regimes and rehabilitate habitats for vegetation and other species. Concerns for the unintended effects of these actions on mussel populations threatened to halt these projects.
Our objective was to characterise the survival and movement of two mussel species in t
Authors
Teresa J. Newton, Steven J. Zigler, Brian R. Gray
Estimation of river and stream temperature trends under haphazard sampling
Long-term temporal trends in water temperature in rivers and streams are typically estimated under the assumption of evenly-spaced space-time measurements. However, sampling times and dates associated with historical water temperature datasets and some sampling designs may be haphazard. As a result, trends in temperature may be confounded with trends in time or space of sampling which, in turn, ma
Authors
Brian R. Gray, Vyacheslav Lyubchich, Yulia R. Gel, James T. Rogala, Dale M. Robertson, Xiaoqiao Wei
Influence of in ovo mercury exposure, lake acidity, and other factors on common loon egg and chick quality in Wisconsin
A field study was conducted in Wisconsin (USA) to characterize in ovo mercury (Hg) exposure in common loons (Gavia immer). Total Hg mass fractions ranged from 0.17 mg/g to 1.23mg/g wet weight in eggs collected from nests on lakes representing a wide range of pH (5.0–8.1) and were modeled as a function of maternal loon Hg exposure and egg laying order. Blood total Hg mass fractions in a sample of l
Authors
Kevin P. Kenow, Michael W. Meyer, Ronald Rossmann, Brian R. Gray, Michael T. Arts
Host–parasite behavioral interactions in a recently introduced, whooping crane population
The whooping crane Grus americana has a long conservation history, but despite multiple attempts across North America, introduction success is lacking. Recently introduced, captively reared whooping cranes have had periods of poor reproductive performance in central Wisconsin that sometimes coincided with black fly (Diptera: Simuliidae) emergences. Sandhill crane Grus canadensis reproductive perfo
Authors
Rich King, Patrick C. McKann, Brian R. Gray, Michael S. Putnam
Can mercury in fish be reduced by water level management? Evaluating the effects of water level fluctuation on mercury accumulation in yellow perch (Perca flavescens)
Mercury (Hg) contamination of fisheries is a major concern for resource managers of many temperate lakes. Anthropogenic Hg contamination is largely derived from atmospheric deposition within a lake’s watershed, but its incorporation into the food web is facilitated by bacterial activity in sediments. Temporal variation in Hg content of fish (young-of-year yellow perch) in the regulated lakes of th
Authors
James H. Larson, Ryan P. Maki, Brent C. Knights, Brian R. Gray
Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River
River eutrophication may cause the formation of dense surface mats of free floating plants (FFP; e.g., duckweeds and filamentous algae) which may adversely affect the ecosystem. We investigated associations among hydraulic connectivity to the channel, nutrient cycling, FFP, submersed aquatic vegetation (SAV), and dissolved oxygen concentration (DO) in ten backwater lakes of the Upper Mississippi R
Authors
Jeffrey N. Houser, Shawn M. Giblin, William F. James, H.A. Langrehr, James T. Rogala, John F. Sullivan, Brian R. Gray
Science and Products
Filter Total Items: 51
Distribution and foraging patterns of common loons on Lake Michigan with implications for exposure to type E avian botulism
Common loons (Gavia immer) staging on the Great Lakes during fall migration are at risk to episodic outbreaks of type E botulism. Information on distribution, foraging patterns, and exposure routes of loons are needed for understanding the physical and ecological factors that contribute to avian botulism outbreaks. Aerial surveys were conducted to document the spatiotemporal distribution of common
Authors
Kevin P. Kenow, Steven C. Houdek, Luke J. Fara, Brian R. Gray, Brian R. Lubinski, Darryl J. Heard, Michael W. Meyer, Timothy J. Fox, Robert Kratt
Effects of air temperature and discharge on Upper Mississippi River summer water temperatures
Recent interest in the potential effects of climate change has prompted studies of air temperature and precipitation associations with water temperatures in rivers and streams. We examined associations between summer surface water temperatures and both air temperature and discharge for 5 reaches of the Upper Mississippi River during 1994–2011. Water–air temperature associations at a given reach ap
Authors
Brian R. Gray, Dale M. Robertson, James T. Rogala
Separable correlation and maximum likelihood
We consider estimation of the covariance matrix of a multivariate normal distribution when the correlation matrix is separable in the sense that it factors as a Kronecker product of two smaller matrices. A computationally convenient coordinate descent-type algorithm is developed for maximum likelihood estimation. Simulations indicate our method often gives smaller estimation error than some common
Authors
Karl Oskar Ekvall, Brian R. Gray
Differences in breeding bird assemblages related to reed canary grass cover cover and forest structure on the Upper Mississippi River
Floodplain forest of the Upper Mississippi River provides habitat for an abundant and diverse breeding bird community. However, reed canary grass Phalaris arundinacea invasion is a serious threat to the future condition of this forest. Reed canary grass is a well-known aggressive invader of wetland systems in the northern tier states of the conterminous United States. Aided by altered flow regimes
Authors
Eileen M. Kirsch, Brian R. Gray
Lethal and sub-lethal responses of native freshwater mussels exposed to granular Bayluscide®, a sea lamprey larvicide
The invasive sea lamprey (Petromyzon marinus) poses a substantial threat to fish communities in the Great Lakes. Efforts to control sea lamprey populations typically involve treating tributary streams with lampricides on a recurring cycle. The presence of a substantial population of larval sea lampreys in the aquatic corridor between Lakes Huron and Erie prompted managers to propose a treatment us
Authors
Teresa Newton, Michael A. Boogaard, Brian R. Gray, Terrance D. Hubert, Nicholas A. Schloesser
Estimating linear temporal trends from aggregated environmental monitoring data
Trend estimates are often used as part of environmental monitoring programs. These trends inform managers (e.g., are desired species increasing or undesired species decreasing?). Data collected from environmental monitoring programs is often aggregated (i.e., averaged), which confounds sampling and process variation. State-space models allow sampling variation and process variations to be separate
Authors
Richard A. Erickson, Brian R. Gray, Eric A. Eager
Mortality, movement and behaviour of native mussels during a planned water-level drawdown in the Upper Mississippi River
Managers in the Upper Mississippi River (UMR) are using reductions in the River's water levels during summer to mimic historical water regimes and rehabilitate habitats for vegetation and other species. Concerns for the unintended effects of these actions on mussel populations threatened to halt these projects.
Our objective was to characterise the survival and movement of two mussel species in t
Authors
Teresa J. Newton, Steven J. Zigler, Brian R. Gray
Estimation of river and stream temperature trends under haphazard sampling
Long-term temporal trends in water temperature in rivers and streams are typically estimated under the assumption of evenly-spaced space-time measurements. However, sampling times and dates associated with historical water temperature datasets and some sampling designs may be haphazard. As a result, trends in temperature may be confounded with trends in time or space of sampling which, in turn, ma
Authors
Brian R. Gray, Vyacheslav Lyubchich, Yulia R. Gel, James T. Rogala, Dale M. Robertson, Xiaoqiao Wei
Influence of in ovo mercury exposure, lake acidity, and other factors on common loon egg and chick quality in Wisconsin
A field study was conducted in Wisconsin (USA) to characterize in ovo mercury (Hg) exposure in common loons (Gavia immer). Total Hg mass fractions ranged from 0.17 mg/g to 1.23mg/g wet weight in eggs collected from nests on lakes representing a wide range of pH (5.0–8.1) and were modeled as a function of maternal loon Hg exposure and egg laying order. Blood total Hg mass fractions in a sample of l
Authors
Kevin P. Kenow, Michael W. Meyer, Ronald Rossmann, Brian R. Gray, Michael T. Arts
Host–parasite behavioral interactions in a recently introduced, whooping crane population
The whooping crane Grus americana has a long conservation history, but despite multiple attempts across North America, introduction success is lacking. Recently introduced, captively reared whooping cranes have had periods of poor reproductive performance in central Wisconsin that sometimes coincided with black fly (Diptera: Simuliidae) emergences. Sandhill crane Grus canadensis reproductive perfo
Authors
Rich King, Patrick C. McKann, Brian R. Gray, Michael S. Putnam
Can mercury in fish be reduced by water level management? Evaluating the effects of water level fluctuation on mercury accumulation in yellow perch (Perca flavescens)
Mercury (Hg) contamination of fisheries is a major concern for resource managers of many temperate lakes. Anthropogenic Hg contamination is largely derived from atmospheric deposition within a lake’s watershed, but its incorporation into the food web is facilitated by bacterial activity in sediments. Temporal variation in Hg content of fish (young-of-year yellow perch) in the regulated lakes of th
Authors
James H. Larson, Ryan P. Maki, Brent C. Knights, Brian R. Gray
Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River
River eutrophication may cause the formation of dense surface mats of free floating plants (FFP; e.g., duckweeds and filamentous algae) which may adversely affect the ecosystem. We investigated associations among hydraulic connectivity to the channel, nutrient cycling, FFP, submersed aquatic vegetation (SAV), and dissolved oxygen concentration (DO) in ten backwater lakes of the Upper Mississippi R
Authors
Jeffrey N. Houser, Shawn M. Giblin, William F. James, H.A. Langrehr, James T. Rogala, John F. Sullivan, Brian R. Gray