My research focuses on applied wildlife disease, conservation and management issues around the Greater Yellowstone Ecosystem.
Research Interests
I try to integrate multiple different scientific fields, but my specific background is in field ecology, behavior and mathematical modeling. There are two central themes in my research: (1) the integration of empirical data and mathematical modeling, and (2) the effects of host behavior on disease dynamics. Currently, my research focuses on brucellosis, chronic wasting disease, canine distemper and sarcoptic mange.
Professional Experience
Research Wildlife Biologist, USGS, Northern Rocky Mountain Science Center, 2005-present.
Education and Certifications
Ph.D. Environmental Science, Policy, and Management. 2005. University of California, Berkeley
B.A. Environmental Science. 1998. University of Virginia, Charlottesville
Science and Products
Evaluating management alternatives for Wyoming elk feedgrounds in consideration of chronic wasting disease
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Evaluating noninvasive methods for estimating cestode prevalence in a wild carnivore population
Disease outbreaks select for mate choice and coat color in wolves
Defining an epidemiological landscape that connects movement ecology to pathogen transmission and pace-of-life
Eyes on the herd: Quantifying ungulate density from satellite, unmanned aerial systems, and GPScollar data
Population structure, intergroup interaction, and human contact govern infectious disease impacts in mountain gorilla populations
Epidemiological differences between sexes affect management efficacy in simulated chronic wasting disease systems
Examination of the interaction between age-specific predation and chronic disease in the Greater Yellowstone Ecosystem
Disease and secondary sexual traits: Effects of pneumonia on horn size of bighorn sheep
Sustaining transmission in different host species: The emblematic case of Sarcoptes scabiei
Scavengers reduce potential brucellosis transmission risk in the Greater Yellowstone Ecosystem
Natural history of a bighorn sheep pneumonia epizootic: Source of infection, course of disease, and pathogen clearance
COVID-19 Pathways and Wildlife Dynamics
Evaluating Transmission of Chronic Wasting Disease in the Environment
USGS Chronic Wasting Disease Research at NOROCK
Quantitative Disease Ecology
Moose and Winter Ticks in Western Wyoming
Impacts of Disease on Wolves in Yellowstone National Park
Pneumonia in Bighorn Sheep
Brucellosis
NOROCK Large Carnivore Research Program
COMPLETED: Using thermal imagery to assess wolf hairloss from sarcoptic mange
Remotely sensed elk locations on the National Elk Refuge, Wyoming, 2017-2019
Time to removal of fetal materials by scavengers in SW Montana 2017 - 2018
Soil sample locations for chronic wasting disease prion surveillance in Grand Teton National Park and National Elk Refuge 2019
Canine distemper virus antibody titer results for grizzly bears and wolves in the Greater Yellowstone Ecosystem 1984-2014
Elk GPS collar data from National Elk Refuge (2006-2015)
Elk movement and predicted number of brucellosis-induced abortion events in the southern Greater Yellowstone Ecosystem (1993-2015)
CWD Simulation App
Chronic wasting disease (CWD) is a fatal disease of deer, elk, and moose transmitted through direct contact and via environmental contamination. This software provide tools to simulate CWD and harvest management scenarios. These models were developed by the U.S. Geological Survey (USGS) in collaboration with Montana Fish, Wildlife, and Parks.
Simulating chronic wasting disease on Wyoming elk feedgrounds
CWDsims version v0.2.2
Bighorn Sheep Risk of Contact Tool
Science and Products
- Publications
Filter Total Items: 108
Evaluating management alternatives for Wyoming elk feedgrounds in consideration of chronic wasting disease
This product is temporarily unavailable.
AuthorsJonathan D. Cook, Paul C. Cross, Emily M. Tomaszewski, Eric K. Cole, Evan H. Campbell Grant, James M. Wilder, Michael C. RungeEvaluating noninvasive methods for estimating cestode prevalence in a wild carnivore population
Helminth infections are cryptic and can be difficult to study in wildlife species. Helminth research in wildlife hosts has historically required invasive animal handling and necropsy, while results from noninvasive parasite research, like scat analysis, may not be possible at the helminth species or individual host levels. To increase the utility of noninvasive sampling, individual hosts can be idAuthorsE E Brandell, M.K. Jackson, Paul C. Cross, A.J. Piaggio, D. R. Taylor, Douglas W. Smith, B Boufana, Daniel R. Stahler, PJ HudsonDisease outbreaks select for mate choice and coat color in wolves
We know much about pathogen evolution and the emergence of new disease strains, but less about host resistance and how it is signaled to other individuals and subsequently maintained. The cline in frequency of black-coated wolves (Canis lupus) across North America is hypothesized to result from a relationship with canine distemper virus (CDV) outbreaks. We tested this hypothesis using cross-sectioAuthorsSarah Cubaynes, E E Brandell, Daniel R. Stahler, Douglas W. Smith, Emily S. Almberg, Susanne Schindler, Robert K. Wayne, Andrew P. Dobson, Bridgett M. vonHoldt, Daniel R. MacNulty, Paul C. Cross, Peter J. Hudson, Tim CoulsonDefining an epidemiological landscape that connects movement ecology to pathogen transmission and pace-of-life
Pathogen transmission depends on host density, mobility and contact. These components emerge from host and pathogen movements that themselves arise through interactions with the surrounding environment. The environment, the emergent host and pathogen movements, and the subsequent patterns of density, mobility and contact form an ‘epidemiological landscape’ connecting the environment to specific loAuthorsKezia R. Manlove, Mark Q. Wilber, Lauren White, Guillaume Bastille-Rousseau, Alan Yang, Marie L. J. Gilbertson, Meggan E. Craft, Paul C. Cross, George Wittemyer, K. M PepinEyes on the herd: Quantifying ungulate density from satellite, unmanned aerial systems, and GPScollar data
Novel approaches to quantifying density and distributions could help biologists adaptively manage wildlife populations, particularly if methods are accurate, consistent, cost-effective, rapid, and sensitive to change. Such approaches may also improve research on interactions between density and processes of interest, such as disease transmission across multiple populations. We assess how satelliteAuthorsTabitha Graves, Michael Yarnall, Aaron Johnston, Todd M. Preston, Geneva W. Chong, Eric K Cole, William Michael Janousek, Paul C. CrossPopulation structure, intergroup interaction, and human contact govern infectious disease impacts in mountain gorilla populations
Infectious zoonotic diseases are a threat to wildlife conservation and global health. They are especially a concern for wild apes, which are vulnerable to many human infectious diseases. As ecotourism, deforestation, and great ape field research increase, the threat of human-sourced infections to wild populations becomes more substantial and could result in devastating population declines. The endAuthorsChristopher A. Whittier, Felicia B. Nutter, Philip L. F. Johnson, Paul C. Cross, James O. Lloyd-Smith, Barrett D. Slenning, Michael K. StoskopfEpidemiological differences between sexes affect management efficacy in simulated chronic wasting disease systems
Sex-based differences in physiology, behaviour and demography commonly result in differences in disease prevalence. However, sex differences in prevalence may reflect exposure rather than transmission, which could affect disease control programmes. One potential example is chronic wasting disease (CWD), which has been observed at greater prevalence among male than female deer.We used an age- and sAuthorsWilliam J. Rogers, Ellen E. Brandell, Paul C. CrossExamination of the interaction between age-specific predation and chronic disease in the Greater Yellowstone Ecosystem
Predators may create healthier prey populations by selectively removing diseased individuals. Predators typically prefer some ages of prey over others, which may, or may not, align with those prey ages that are most likely to be diseased.The interaction of age-specific infection and predation has not been previously explored and likely has sizable effects on disease dynamics. We hypothesize that pAuthorsEllen E. Brandell, Paul C. Cross, Douglas W. Smith, William J. Rogers, Nathan L. Galloway, Daniel R. MacNulty, Daniel R. Stahler, John J. Treanor, Peter J. HudsonDisease and secondary sexual traits: Effects of pneumonia on horn size of bighorn sheep
Secondary sexual traits (e.g., horns and antlers) have ecological and evolutionary importance and are of management interest for game species. Yet, how these traits respond to emerging threats like infectious disease remains underexplored. Infectious pneumonia threatens bighorn sheep (Ovis canadensis) populations across North America and we hypothesized it may also reduce horn growth in male sheepAuthorsAlynn Marie Martin, John T. Hogg, Kezia R. Manlove, Tayler N LaSharr, Justin M. Shannon, Douglas E. McWhirter, Hollie Miyasaki, Kevin L. Monteith, Paul C. CrossSustaining transmission in different host species: The emblematic case of Sarcoptes scabiei
Some pathogens sustain transmission in multiple different host species, but how this epidemiologically important feat is achieved remains enigmatic. Sarcoptes scabiei is among the most host generalist and successful of mammalian parasites. We synthesize pathogen and host traits that mediate sustained transmission and present cases illustrating three transmission mechanisms (direct, indirect, and cAuthorsE Browne, MM Driessen, Paul C. Cross, L. E. Escobar, Janet E. Foley, JR López-Olvera, KD Niedringhaus, Liza Rossi, Scott CarverScavengers reduce potential brucellosis transmission risk in the Greater Yellowstone Ecosystem
Scavengers likely play an important role in ecosystem energy flow as well as disease transmission, but whether they facilitate or reduce disease transmission is often unknown. In the Greater Yellowstone Ecosystem, scavengers are likely to reduce the transmission and subsequent spread of brucellosis within and between livestock and elk by consuming infectious abortion materials, thereby removing thAuthorsKimberly E Szcodronski, Paul C. CrossNatural history of a bighorn sheep pneumonia epizootic: Source of infection, course of disease, and pathogen clearance
A respiratory disease epizootic at the National Bison Range (NBR) in Montana in 2016–2017 caused an 85% decline in the bighorn sheep population, documented by observations of its unmarked but individually identifiable members, the subjects of an ongoing long-term study. The index case was likely one of a small group of young bighorn sheep on a short-term exploratory foray in early summer of 2016.AuthorsT. E. Besser, E. Frances Cassirer, Amy Lisk, Danielle Nelson, Kezia R. Manlove, Paul C. Cross, John T. Hogg - Science
COVID-19 Pathways and Wildlife Dynamics
Below are the USGS 2020 Coronavirus Aid, Relief and Economic Security Act (CARES Act) research projects related to COVID-19 pathways and wildlife dynamics. Select tabs above for related items.Evaluating Transmission of Chronic Wasting Disease in the Environment
Chronic wasting disease (CWD) is a fatal disease of deer, elk, and moose and has been spreading in North America for the past two decades. The disease is spread by infected body fluids. Animals can become infected by coming into direct contact with a CWD-infected animal, or an infected animal can leave behind fluids (e.g., saliva, urine) that an uninfected animal will come into contact later...USGS Chronic Wasting Disease Research at NOROCK
Over the past 20 years, chronic wasting disease (CWD) in Wyoming has been spreading slowly outward from the southeastern corner of the state toward the Greater Yellowstone Area and Wyoming's elk feed grounds, where more than 24,000 elk are supplementally fed each winter.Quantitative Disease Ecology
Researchers at the USGS are working on developing new quantitative methods to study disease dynamics in wildlife systems as well as systems at the wildlife-domestic-human interface. Much of our work focuses on how host population structure affects disease invasion, persistence and control in wildlife disease systems. We tackle these issues with a combination of simulation and statistical modeling...Moose and Winter Ticks in Western Wyoming
Moose are an important game species in Montana, Idaho and Wyoming but hunter opportunities have been reduced in many areas over the last two decades as populations have declined at this southern limit of the species’ geographic range. In the Jackson, Wyoming area moose populations have declined by an estimated 80% since the early 1990s. Rising temperatures, pathogens, and parasites represent someImpacts of Disease on Wolves in Yellowstone National Park
In 1995 and 1996, wolves were reintroduced into the Northern Rockies where they have since established and spread. Within Yellowstone National Park, one of the core protected release sites, the unmanaged population steadily increased to high densities, producing a large wolf population susceptible to infections such as canine parvovirus (CPV), canine distemper virus (CDV) and sarcoptic mange.Pneumonia in Bighorn Sheep
Bighorn sheep populations are often impacted by outbreaks of pneumonia that are suspected to come from domestic sheep and goats.Brucellosis
Brucellosis is a nationally and internationally regulated disease of livestock with significant consequences for animal health, public health, and international trade.NOROCK Large Carnivore Research Program
NOROCK has substantial expertise in large carnivore research, primarily involving species listed as Threatened or Endangered. NOROCK’s Large Carnivore Research Program includes scientists from NOROCK’s Headquarters, West Glacier Field Station, and the Southern Appalachian Field Station. Studies are conducted in a wide variety of landscapes throughout the U.S., as well as international research...COMPLETED: Using thermal imagery to assess wolf hairloss from sarcoptic mange
Researchers at NOROCK and their partners used thermal cameras at the Grizzly and Wolf Discovery Center in Montana to assess the amount of heat lost under a range of environmental conditions with and without hair. These methods help scientists better understand how mange operates in wild wolves throughout the Greater Yellowstone Ecosystem. - Data
Remotely sensed elk locations on the National Elk Refuge, Wyoming, 2017-2019
Remotely sensed elk locations were derived from satellite and Unmanned Aerial Systems (UAS) imagery collected during the winter of 2018 and the winter and spring of 2019 at the National Elk Refuge in Jackson, Wyoming and compared to locations from Global Positioning System (GPS) collars from 2017 - 2019. This data release provides the source, date, time, latitude, and longitude of elk locations anTime to removal of fetal materials by scavengers in SW Montana 2017 - 2018
We investigated the time to removal of bovine fetal materials, meant to simulate elk abortion materials, by scavengers in southwest Montana at 233 sites in February – June 2017 and 2018. Scavengers are likely to reduce the transmission risk of brucellosis, a bacterial disease that can lead to reproductive failure in infected elk, by consuming and removing infectious fetal materials from the landscSoil sample locations for chronic wasting disease prion surveillance in Grand Teton National Park and National Elk Refuge 2019
A total of 200 soil samples were collected in the Greater Yellowstone Ecosystem in Grand Teton National Park and the National Elk Refuge in July 2019 for chronic wasting disease (CWD) monitoring purposes. To collect samples from locations where ungulates are most likely to be shedding or encountering CWD, we targeted elk collar data locations, known migration routes of mule deer and elk, and areasCanine distemper virus antibody titer results for grizzly bears and wolves in the Greater Yellowstone Ecosystem 1984-2014
We investigated the dynamics of canine distemper virus (CDV) in grizzly bears (Ursus arctos) and wolves (Canis lupus) of the Greater Yellowstone Ecosystem using serological data collected from 1984 to 2014. 565 sera samples were obtained from 425 unique grizzly bears (134 females and 291 males) from 1984 to 2014 and 319 sera samples were obtained from 285 unique wolves (130 females and 155 males)Elk GPS collar data from National Elk Refuge (2006-2015)
17 adult female elk were captured on or around the National Elk Refuge and monitored with GPS collars from 2006 to 2015. Each of these elk were monitored for 1 to 2 years and migrated from the National Elk Refuge to Yellowstone National Park during the spring. Here we provide the unique identifier for each individual elk, the date/time stamp of each GPS location, the GPS location of the elk in UTMElk movement and predicted number of brucellosis-induced abortion events in the southern Greater Yellowstone Ecosystem (1993-2015)
Using data from 288 adult and yearling female elk that were captured on 22 winter supplemental elk feedgrounds in Wyoming and monitored with GPS collars from 2007 - 2015, we fit Step Selection Functions (SSFs) during the spring abortion season and then implemented a master equation approach to translate SSFs into predictions of daily elk distribution for five plausible winter weather scenarios (fr - Multimedia
- Web Tools
CWD Simulation App
Chronic wasting disease (CWD) is a fatal disease of deer, elk, and moose transmitted through direct contact and via environmental contamination. This software provide tools to simulate CWD and harvest management scenarios. These models were developed by the U.S. Geological Survey (USGS) in collaboration with Montana Fish, Wildlife, and Parks.
- Software
Simulating chronic wasting disease on Wyoming elk feedgrounds
This software release contains the code necessary to run the chronic wasting disease (CWD) and elk habitat selection models used to support the U.S. Forest Service decision on whether to continue to permit supplemental feeding of elk on USFS land. The models allow for four different management alternatives: continued feeding, emergency feeding, phase-out after three years, or no feeding. The CWD mCWDsims version v0.2.2
This is a repository with R code for CWD simulation models and interactive Shiny applications. Currently there are deterministic and stochastic models that are intended to model hunting scenarios for a 5 to 10 year time horizon. The models are sex and age structured with direct and indirect transmission.Bighorn Sheep Risk of Contact Tool
The Risk of Contact Tool (RoCT) is an R-based implementation of the Risk of Contact model described in O'Brien et al. (2014). It uses a variety of spatial inputs (including telemetry point data, a core herd home range (CHHR) polygon, a habitat raster model, and a set of active domestic sheep allotments) together with estimates of bighorn sheep foray behavior to estimate the probability and rate of - News