Assistant Unit Leader - Pennsylvania Cooperative Fish and Wildlife Research Unit
After finishing his Ph.D., David served as a post-doctoral Researcher at the National Wildlife Research Center for nearly 5 years. A majority of his research explores spatial ecology of various species throughout the U.S. using GIS to further our understanding of wildlife presence/absence, nutrition, and disease.
Research Interests
David's primary research interests have focused on using various modeling techniques to understand spatial ecology of disease in ungulates in various regions of North America. He also uses stable isotopes to understand movements, nutritional ecology, and effects of invasive species on native non-game species at the landscape level.
Teaching Interests
David teaches graduate courses in spatial ecology, movement analyses, home range estimation, and disease epidemiology.
Professional Experience
Assistant Unit Leader, Pennsylvania Cooperative Fish and Wildlife Research Unit, 2011-
Education and Certifications
Ph D Oklahoma State University 2006
MS University of New Hampshire 2000
BS SUNY - College of Environmental Science and Forestry 1995
Science and Products
Input for Habitat Risk Software
Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy that was first detected in captive cervids in Colorado, United States (US) in 1967, but has since spread into free-ranging white-tailed deer (Odocoileus virginianus) populations across the US and Canada. In some areas, the disease is considered endemic in wild deer populations, and governmental wildlife agencies have employ
Evaluation of DNA yield from various sources for use in single nucleotide polymorphism panels
Genetics studies are used by wildlife managers and researchers to gain inference into a population of a species of interest. To gain these insights, micro-satellites have been the primary method, however, there currently is a shift from micro-satellites to single nucleotide polymorphisms (SNPs). With the DNA requirements being different, an investigation into which samples can provide adequate DNA
Filter Total Items: 29
Landscape features fail to explain spatial genetic structure in white-tailed deer across Ohio, USA
Landscape features influence wildlife movements across spatial scales and have the potential to influence the spread of disease. Chronic wasting disease (CWD) is a fatal prion disease affecting members of the family Cervidae, particularly white-tailed deer (Odocoileus virginianus), and the first positive CWD case in a wild deer in Ohio, USA, was recorded in 2020. Landscape genetics approaches are
Authors
Javan M. Bauder, Christine S. Anderson, H. Lisle Gibbs, Michael J. Tonkovich, W. David Walter
Landscape features fail to explain spatial genetic structure in white-tailed deer across Ohio, USA
Landscape features influence wildlife movements across spatial scales and have the potential to influence the spread of disease. Chronic wasting disease (CWD) is a fatal prion disease affecting members of the family Cervidae, particularly white-tailed deer (Odocoileus virginianus), and the first positive CWD case in a wild deer in Ohio, USA, was recorded in 2020. Landscape genetics approaches are
Authors
Javan M. Bauder, Christine S. Anderson, H. Lisle Gibbs, Michael J. Tonkovich, W. David Walter
Comparison of sample types from white-tailed deer (Odocoileus virginianus) for DNA extraction and analyses
Collection of biological samples for DNA is necessary in a variety of disciplines including disease epidemiology, landscape genetics, and forensics. Quantity and quality of DNA varies depending on the method of collection or media available for collection (e.g., blood, tissue, fecal). Blood is the most common sample collected in vials or on Whatman Flinders Technology Associates (FTA) cards with s
Authors
Jessie Edson, Justin Brown, William L. Miller, W. David Walter
Ecology of an isolated muskrat population during regional population declines
Evidence indicating a decline in muskrat populations in the United States during the past 40 years has led to speculation regarding factors influencing muskrat survival. In order to understand population dynamics and survival, it is important to first define the ecology of local populations. We investigated the dwelling structure use, movements, home range, and survival of radio-tagged muskrats (n
Authors
Laken S. Ganoe, Matt J. Lovallo, Justin D. Brown, W. David Walter
Resource use by American black bear in suburbia: A landholder step selection approach
Range expansion of American black bear (Ursus americanus; bear) and residential development has resulted in a growing presence of bear in suburbia. Suburban landscapes exhibiting patchworks of variable-sized parcels and habitats and owned by landowners with diverse values, can create large areas of suitable habitats with limited public access. These landscapes thereby may limit the effectiveness o
Authors
Farshid S. Ahrestani, Mark A. Ternent, Matthew J. Lovallo, W. David Walter
The influence of hunting pressure and ecological factors on fecal glucocorticoid metabolites in wild elk
Climate change and human population growth have increased anthropogenic threats to biodiversity and habitat fragmentation. Ecologists and conservationists need tools to assess the effect of these ecological and environmental perturbations on organismal fitness. One possibility is glucocorticoids (e.g., cortisol and corticosterone) which integrate various factors such as anthropogenic disturbances,
Authors
David C. Ensminger, Catharine Pritchard, Tracy Langkilde, Tess Gingery, Jeremiah E. Banfield, W. David Walter
A review of pathogens, diseases, and contaminants of muskrats (Ondatra zibethicus) in North America
Over the last 50 years, significant muskrat (Ondatra zibethicus) harvest declines have been observed throughout North America. Several theories for the decline have been proposed, including increased parasite infections and disease within muskrat populations. No existing wholistic review of muskrat exposure to pathogens, contaminants, and diseases exists. To address this knowledge gap, we conducte
Authors
Laken S Ganoe, W. David Walter, Justin D. Brown, Michael J. Yabsley, Matthew J Lovallo
Assessment of spatial genetic structure to identify populations at risk for infection of an emerging epizootic disease
Understanding the geographic extent and connectivity of wildlife populations can provide important insights into the management of disease outbreaks but defining patterns of population structure is difficult for widely distributed species. Landscape genetic analyses are powerful methods for identifying cryptic structure and movement patterns that may be associated with spatial epizootic patterns i
Authors
William L. Miller, Cassandra M. Miller-Butterworth, Duane R. Diefenbach, W. David Walter
Can genetic assignment tests provide insight on the influence of captive egression on epizootiology of chronic wasting disease?
Identifying the sources of ongoing and novel disease outbreaks is critical for understanding the diffusion of epizootic diseases. Identifying infection sources is difficult when few physical differences separate individuals with different origins. Genetic assignment procedures show great promise for assessing transmission dynamics in such situations. Here, we use genetic assignment tests to determ
Authors
William L. Miller, W. David Walter
Chronic wasting disease—Research by the U.S. Geological Survey and partners
IntroductionChronic wasting disease (CWD) is the only transmissible spongiform encephalopathy, a class of invariably fatal neurodegenerative mammalian diseases associated with a misfolded cellular prion protein found in wild free-ranging animals. Because it has a long incubation period, affected animals in Cervidae (the deer family; referred to as “cervids”) may not show signs of disease for sever
Authors
M. Camille Hopkins, Christina M. Carlson, Paul C. Cross, Christopher J. Johnson, Bryan J. Richards, Robin E. Russell, Michael D. Samuel, Glen A. Sargeant, Daniel P. Walsh, W. David Walter
Evaluation of a microsatellite panel for use across North American populations of white-tailed deer (Odocoileus virginianus)
Background Microsatellite loci have been used extensively over the past two decades to study the genetic characteristics of non-model species. The relative ease of microsatellite development and ability to adapt markers from related species has led to the proliferation of available markers, particularly for those species that are intensively studied and managed. Because it is often infeasible to g
Authors
William L. Miller, Jessie Edson, Peter Pietrandrea, Cassandra Miller-Butterworth, W. David Walter
Spatial heterogeneity of prion gene polymorphisms in an area recently infected by chronic wasting disease
Genetic variability in the prion protein (Prnp) gene influences host susceptibility to many pathogenic prion diseases. Understanding the distribution of susceptible Prnp variants and determining factors influencing spatial genetic patterns are important components of many chronic wasting disease mitigation strategies. Here, we describe Prnp variability in white-tailed deer (Odocoileus virginianus)
Authors
William L. Miller, W. David Walter
Change-point models for identifying single behavioral transitions in wild animals
We present two change-point models for identifying singular changes in movement behavior: a location-based change-point model (LCPM) and a movement metric-based change-point model (MMCPM). This software includes R scripts to: 1) run both the LCPM and MMCPM on telemetry data in a Bayesian hierarchical framework using NIMBLE (mmcpm.R and lcpm.R), 2) generate realistic movement behavior parameters fo
Habitat Risk Software
The Habitat Risk Software leverages a previously published Bayesian hierarchical model framework (Clayton and Kaldor 1987; Banderjee et al. 2004; Gelman et al. 2004; Evans et al. 2016) with opportunistic (hunter-harvest) wildlife surveillance disease testing data and publicly available geospatial (raster) data to estimate the geographical risk that a hunter will harvest a white-tailed deer (Odocoi
Evaluation of DNA yield from various tissue and sampling sources for use in single nucleotide polymorphism panels
R code to test for differences in DNA yield from of eight sample categories to gain insights into which provided adequate DNA to be used in ddRADseq or already developed SNP panels. We calculated mean, median and standard deviation with package psych using the describe() function. Additionally, we generated boxplots using package ggplot2 where the quantity for each tissue sample is categorized by
Workflow to acquire and process large spatial data and build complex models
This software involves R scripts to download and process large-scale spatial data defined by an extent input by the user. The code then resamples data to the desired resolution, downloads metadata from a public website on West Nile virus prevalence in mosquito pools, then extracts spatial layer data as covariates for each record.
Also, this software involves R script to fit models of abundance of
Spatial modeling of two mosquito vectors of West Nile virus using integrated nested Laplace approximation
This software involves R script to fit models of abundance of mosquito vectors (' Script_for_ECS22-0193_9_13_2215.R') to landscape and environmental covariates using INLA and SPDE. The dataset used for this analysis were originally provided by the Pennsylvania Department of Environmental Protection (DEP) with a confidentiality agreement. The majority of the data used in this study, however, have s
Science and Products
- Data
Input for Habitat Risk Software
Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy that was first detected in captive cervids in Colorado, United States (US) in 1967, but has since spread into free-ranging white-tailed deer (Odocoileus virginianus) populations across the US and Canada. In some areas, the disease is considered endemic in wild deer populations, and governmental wildlife agencies have employEvaluation of DNA yield from various sources for use in single nucleotide polymorphism panels
Genetics studies are used by wildlife managers and researchers to gain inference into a population of a species of interest. To gain these insights, micro-satellites have been the primary method, however, there currently is a shift from micro-satellites to single nucleotide polymorphisms (SNPs). With the DNA requirements being different, an investigation into which samples can provide adequate DNA - Publications
Filter Total Items: 29
Landscape features fail to explain spatial genetic structure in white-tailed deer across Ohio, USA
Landscape features influence wildlife movements across spatial scales and have the potential to influence the spread of disease. Chronic wasting disease (CWD) is a fatal prion disease affecting members of the family Cervidae, particularly white-tailed deer (Odocoileus virginianus), and the first positive CWD case in a wild deer in Ohio, USA, was recorded in 2020. Landscape genetics approaches areAuthorsJavan M. Bauder, Christine S. Anderson, H. Lisle Gibbs, Michael J. Tonkovich, W. David WalterLandscape features fail to explain spatial genetic structure in white-tailed deer across Ohio, USA
Landscape features influence wildlife movements across spatial scales and have the potential to influence the spread of disease. Chronic wasting disease (CWD) is a fatal prion disease affecting members of the family Cervidae, particularly white-tailed deer (Odocoileus virginianus), and the first positive CWD case in a wild deer in Ohio, USA, was recorded in 2020. Landscape genetics approaches areAuthorsJavan M. Bauder, Christine S. Anderson, H. Lisle Gibbs, Michael J. Tonkovich, W. David WalterComparison of sample types from white-tailed deer (Odocoileus virginianus) for DNA extraction and analyses
Collection of biological samples for DNA is necessary in a variety of disciplines including disease epidemiology, landscape genetics, and forensics. Quantity and quality of DNA varies depending on the method of collection or media available for collection (e.g., blood, tissue, fecal). Blood is the most common sample collected in vials or on Whatman Flinders Technology Associates (FTA) cards with sAuthorsJessie Edson, Justin Brown, William L. Miller, W. David WalterEcology of an isolated muskrat population during regional population declines
Evidence indicating a decline in muskrat populations in the United States during the past 40 years has led to speculation regarding factors influencing muskrat survival. In order to understand population dynamics and survival, it is important to first define the ecology of local populations. We investigated the dwelling structure use, movements, home range, and survival of radio-tagged muskrats (nAuthorsLaken S. Ganoe, Matt J. Lovallo, Justin D. Brown, W. David WalterResource use by American black bear in suburbia: A landholder step selection approach
Range expansion of American black bear (Ursus americanus; bear) and residential development has resulted in a growing presence of bear in suburbia. Suburban landscapes exhibiting patchworks of variable-sized parcels and habitats and owned by landowners with diverse values, can create large areas of suitable habitats with limited public access. These landscapes thereby may limit the effectiveness oAuthorsFarshid S. Ahrestani, Mark A. Ternent, Matthew J. Lovallo, W. David WalterThe influence of hunting pressure and ecological factors on fecal glucocorticoid metabolites in wild elk
Climate change and human population growth have increased anthropogenic threats to biodiversity and habitat fragmentation. Ecologists and conservationists need tools to assess the effect of these ecological and environmental perturbations on organismal fitness. One possibility is glucocorticoids (e.g., cortisol and corticosterone) which integrate various factors such as anthropogenic disturbances,AuthorsDavid C. Ensminger, Catharine Pritchard, Tracy Langkilde, Tess Gingery, Jeremiah E. Banfield, W. David WalterA review of pathogens, diseases, and contaminants of muskrats (Ondatra zibethicus) in North America
Over the last 50 years, significant muskrat (Ondatra zibethicus) harvest declines have been observed throughout North America. Several theories for the decline have been proposed, including increased parasite infections and disease within muskrat populations. No existing wholistic review of muskrat exposure to pathogens, contaminants, and diseases exists. To address this knowledge gap, we conducteAuthorsLaken S Ganoe, W. David Walter, Justin D. Brown, Michael J. Yabsley, Matthew J LovalloAssessment of spatial genetic structure to identify populations at risk for infection of an emerging epizootic disease
Understanding the geographic extent and connectivity of wildlife populations can provide important insights into the management of disease outbreaks but defining patterns of population structure is difficult for widely distributed species. Landscape genetic analyses are powerful methods for identifying cryptic structure and movement patterns that may be associated with spatial epizootic patterns iAuthorsWilliam L. Miller, Cassandra M. Miller-Butterworth, Duane R. Diefenbach, W. David WalterCan genetic assignment tests provide insight on the influence of captive egression on epizootiology of chronic wasting disease?
Identifying the sources of ongoing and novel disease outbreaks is critical for understanding the diffusion of epizootic diseases. Identifying infection sources is difficult when few physical differences separate individuals with different origins. Genetic assignment procedures show great promise for assessing transmission dynamics in such situations. Here, we use genetic assignment tests to determAuthorsWilliam L. Miller, W. David WalterChronic wasting disease—Research by the U.S. Geological Survey and partners
IntroductionChronic wasting disease (CWD) is the only transmissible spongiform encephalopathy, a class of invariably fatal neurodegenerative mammalian diseases associated with a misfolded cellular prion protein found in wild free-ranging animals. Because it has a long incubation period, affected animals in Cervidae (the deer family; referred to as “cervids”) may not show signs of disease for severAuthorsM. Camille Hopkins, Christina M. Carlson, Paul C. Cross, Christopher J. Johnson, Bryan J. Richards, Robin E. Russell, Michael D. Samuel, Glen A. Sargeant, Daniel P. Walsh, W. David WalterEvaluation of a microsatellite panel for use across North American populations of white-tailed deer (Odocoileus virginianus)
Background Microsatellite loci have been used extensively over the past two decades to study the genetic characteristics of non-model species. The relative ease of microsatellite development and ability to adapt markers from related species has led to the proliferation of available markers, particularly for those species that are intensively studied and managed. Because it is often infeasible to gAuthorsWilliam L. Miller, Jessie Edson, Peter Pietrandrea, Cassandra Miller-Butterworth, W. David WalterSpatial heterogeneity of prion gene polymorphisms in an area recently infected by chronic wasting disease
Genetic variability in the prion protein (Prnp) gene influences host susceptibility to many pathogenic prion diseases. Understanding the distribution of susceptible Prnp variants and determining factors influencing spatial genetic patterns are important components of many chronic wasting disease mitigation strategies. Here, we describe Prnp variability in white-tailed deer (Odocoileus virginianus)AuthorsWilliam L. Miller, W. David Walter - Software
Change-point models for identifying single behavioral transitions in wild animals
We present two change-point models for identifying singular changes in movement behavior: a location-based change-point model (LCPM) and a movement metric-based change-point model (MMCPM). This software includes R scripts to: 1) run both the LCPM and MMCPM on telemetry data in a Bayesian hierarchical framework using NIMBLE (mmcpm.R and lcpm.R), 2) generate realistic movement behavior parameters foHabitat Risk Software
The Habitat Risk Software leverages a previously published Bayesian hierarchical model framework (Clayton and Kaldor 1987; Banderjee et al. 2004; Gelman et al. 2004; Evans et al. 2016) with opportunistic (hunter-harvest) wildlife surveillance disease testing data and publicly available geospatial (raster) data to estimate the geographical risk that a hunter will harvest a white-tailed deer (OdocoiEvaluation of DNA yield from various tissue and sampling sources for use in single nucleotide polymorphism panels
R code to test for differences in DNA yield from of eight sample categories to gain insights into which provided adequate DNA to be used in ddRADseq or already developed SNP panels. We calculated mean, median and standard deviation with package psych using the describe() function. Additionally, we generated boxplots using package ggplot2 where the quantity for each tissue sample is categorized byWorkflow to acquire and process large spatial data and build complex models
This software involves R scripts to download and process large-scale spatial data defined by an extent input by the user. The code then resamples data to the desired resolution, downloads metadata from a public website on West Nile virus prevalence in mosquito pools, then extracts spatial layer data as covariates for each record. Also, this software involves R script to fit models of abundance ofSpatial modeling of two mosquito vectors of West Nile virus using integrated nested Laplace approximation
This software involves R script to fit models of abundance of mosquito vectors (' Script_for_ECS22-0193_9_13_2215.R') to landscape and environmental covariates using INLA and SPDE. The dataset used for this analysis were originally provided by the Pennsylvania Department of Environmental Protection (DEP) with a confidentiality agreement. The majority of the data used in this study, however, have s