Immune Response of Calf Elk to Strain RB51 Vaccine

Funding by: Wyoming Game and Fish Department and USDA APHIS - Veterinary Services

GYIBC participants: Terry Kreeger, tkreeger@uwyo.edu; Tom Thorne, tthorn1@missc.state.wy.us

[Index]

Response of Elk to Orally Delivered Strain RB51 Vaccine

In February 1996, forty-two elk were captured at the National Elk Refuge and transported to the Sybille Wildlife Research Unit. In July 1996 thirty-six elk (all sex and age classes) were orally inoculated with 1-5 x 10⁶ CFU of B. abortus strain RB51. Elk were inoculated every other day for three days. Six additional elk served as controls. Following inoculation, all elk were bled every other week for hemoculture and serology. Also every other week, two randomly selected elk were necropsied and examined for tissue colonization and lesions characteristic of Brucella infection. The purpose of this study was to determine the rate of seroconversion after oral inoculation and a period of time for tissue colonization.

Project participants: Wyoming Game and Fish Department (T. Kreeger, H. Edwards, W.Cook, T. Thorne); Lousiana State University (F. Enright, P. Elzer); Virginia Polytechnic University (G. Schurig); APHIS (M. Gilsdorf); University of Wyoming (E.S. Williams).

[Index]

Epizootiology of Brucellosis in the GYA: A Stochastic Model

A stochastic model will be developed to assess the epizootiology of brucellosis in the GYA. Published, unpublished and empirical data will be used to model transmission rates between and among bison, elk and cattle. The model will incorporate both the pathogenicity of brucellosis as well as population dynamics. The model will also incorporate the effects of various management actions (vaccination, test and slaughter, no action, etc.) for the control or elimination of brucellosis in the GYA. The final product will be a PC based computer program that will be made available to all interested parties.

Project Participants: Wyoming Game and Fish Department (T. Kreeger, S. Smith, W. Cook, T. Thorne); USGS Biological Resources Division (S. Anderson, T. Roffe); Colorado Division of Wildlife (M. Miller); Colorado State University (J. Gross); University of Wyoming (E.S. Williams); Grand Teton National Park (B. Schiller); Yellowstone National Park (J. Mack); USDA APHIS (D. Woody); National Elk Refuge (B. Smith).

[Index]

Environmental Persistence and Contamination by Brucella abortus in the GYA.

Uninfected bovine fetuses were selectively placed on Wyoming elk feedgrounds, National Elk Refuge and Grand Teton National Park in order to determine disappearance time. The purpose of this study is to simulate the persistence of infective fetuses aborted as a result of Brucella infection in elk or bison. The fetuses were monitored to identify types of scavengers, contact by other ungulates, and environmental degradation. In addition, at Sybille Wildlife Research Unit and the Wyoming State Veterinary Laboratory culture plates of Brucella abortus Strain19 were placed in six different environmental locations in order to assess longevity of the organism under various conditions of light, temperature and humidity.

Project participants: University of Wyoming (E.S. Williams, K. Mills): Wyoming Game and Fish Department (W. Cook, S. Smith, T. Kreeger, H. Edwards); Grand Teton National Park (B.Schiller, S. Cain); National Elk Refuge (B. Smith); Yellowstone National Park (W. Brewster, J. Mack).

[Index]

Wyoming Brucellosis-Feedground-Habitat Program.

Since 1990 Wyoming Game and Fish Department's integrated management program has addressed brucellosis in free-ranging elk through habitat enhancement, feedground elk vaccination, and modified feedground management. Habitat enhancement projects strive to reduce elk dependency on winter feedgrounds by rejuvenating spring, fall, and winter native habitat. Improving native range and dispersing elk off feedgrounds serves to decrease intraspecific transmission of brucellosis. In addition to hazing of select elk, preventative stackyard fencing is provided to livestock operations to keep elk and cattle from comingling during winter feeding periods. Feedground management plans have been developed and implemented in an effort to reduce the duration and density of elk that are reliant upon supplemental winter feeding.

Project participants: Wyoming Game and Fish Department (S. Smith, et al.).

[Index]

Strain 19 Vaccination of Feedground Elk.

Since 1985 Wyoming Game and Fish Department has used ballistic vaccination with Brucella abortus Strain 19 in feedground elk. Currently elk on 18 of the 22 state feedgrounds are vaccinated. In this period over 38,000 doses of vaccine have been administered resulting in a significant reduction in seroprevalence. Evaluation at Greys River Feedground indicates a reduction in seroprevalence since vaccination of elk began in 1985.

Project participants: Wyoming Game and Fish Department (S. Smith, T. Thorne, T. Kreeger, W. Cook, H. Edwards); USDA APHIS (D. Woody, E. Nelson).

[Index]

Surveillance of Elk in Western Wyoming for Brucellosis.

Free-ranging elk are tested serologically for the presence of brucellosis in order to define the distribution and extent of brucellosis and prioritize management actions. Samples are collected from feedground elk by trapping them and samples are collected from non-feedground elk through cooperation of hunters using blood collection kits distributed and returned via mail. Approximately 500 elk are tested each year. Other species are tested opportunistically for Brucella antibodies from throughout Wyoming when wildlife are captured for management and research purposes.

Project participants: Wyoming Game and Fish Department (S. Smith, W. Cook, H. Edwards, T. Kreeger).

[Index]

Efficacy of B. abortus Strain RB51 in Bison.

This project evaluated antibody responses and clearance following subcutaneous vaccination of bison with 10¹⁰ CFU of B. abortus strain RB51 (n=6) or strain 19 (n=3). Strain RB51 persisted in draining lymph nodes for at least 16 weeks. Bison vaccinated with strain RB51 remained seronegative on the standard tube agglutination test whereas the strain 19 vaccinates did not. Animals were pasture bred and pregnant animals were challenged at mid-gestation with 10⁷ CFU of virulent B. abortus strain 2308. This project fits GYIBC guidelines by providing factual information on new technology which may be used for recommendations for brucellosis-related management.

Project Participants: USDA Agricultural Research Service (S. Olsen, et al.).

[Index]

Biosafety, Clearance and Efficacy of Brucella abortus Strain RB51 in Bison Calves.

Bison heifer calves were subcutaneously vaccinated with 1.22 x 10¹⁰ CFU of B. abortus strain RB51 at seven months of age. Serologic responses of vaccinates and nonvaccinates were evaluated using the standard tube agglutination test and an RB51 dot-blot assay at 0, 2, 4, 6, 8, 12, 18 and 24 weeks after vaccination. Strain RB51 was not detected after vaccination in vaginal, conjunctival, nasal, or rectal swabs obtained at 1, 2, 3, 4, 6, 8, and 12 weeks post-inoculation. Serology also did not suggest that strain RB51 was laterally transmitted to non-vaccinated bison. Clearance of the vaccine strain from the draining lymph node was evaluated by culture and histological evaluation of samples obtained by surgical biopsy of four vaccinates and one nonvaccinate at 6, 12, 18 and 24 weeks. Samples obtained by biopsy were evaluated by culture and histological techniques. Proliferative responses by lymph node cells or peripheral blood mononuclear cells to RB51 antigens were detected beginning at 12 weeks after vaccination. Bison will be pasture bred and challenged at mid-gestation to evaluate the efficacy of strain RB51 as a vaccine.

Project participants: USDA Agricultural Research Service (S. Olsen, et al.).

[Index]

Use of Polymerase Chain Reaction to Detect Brucella abortus in Formalin-fixed Bison and Cattle Lymph Nodes.

In this project, the sensitivity and specificity of the polymerase chain reaction will be evaluated using formalin-fixed lymph nodes obtained from bison and cattle vaccinated with saline, B. abortus strain 19 or strain RB51 under experimental conditions. The ability of this technique to identify vaccinates will be compared to culture data which quantified the colony-forming-units per gram of tissue in each sample.

Project participants: USDA Agricultural Research Service (S. Olsen, et al.).

[Index]

Safety Evaluation of Brucella abortus RB51 Vaccine when Administered to Adult Male Bison.

Specifically, evaluate the safety of B. abortus RB51 vaccine in bison bulls for production of clinical signs of disease, persistence of infection, tissue sites of localization, and production of lesions. Twelve unexposed bison bulls will be subcutaneously inoculated with 1 x 10¹⁰ CFU of RB51. Three bulls will serve as negative controls. Animals will be characterized for natural resistance to brucellosis. Animals will be serologically tested, and blood, swabs, and feces will be cultured for brucellae prior to inoculation at 2, 6, 10, 14, 18, 20, 22, 26, and 30 weeks post-inoculation. Additionally, bulls will be electroejaculated and ejaculate cultured at 2, 6, and 10 weeks post-inoculation and monthly thereafter if the ejaculate is culture positive for strain RB51 on any of the first three collections. Animals will be observed daily for clinical signs of disease. Four inoculated bison and one control animal will be killed at the following intervals post-inoculation: 10 weeks, 20 weeks, and 30 weeks. Carcasses will be examined and tissues collected at slaughter. Specimens will be cultured for brucellae and examined by histopathology and immunohistochemistry.
Completion date: March 1998

Project participants: USDA APHIS (J. Rhyan, T. Gidlewski, M. Gilsdorf); USDA Agricultural Research Service (S. Olsen); Texas A&M University (D. Davis, J. Templeton).

[Index]

Survey of Free-Ranging Elk from Wyoming and Montana for Selected Pathogens.

From December 1991 through January 1995, a disease survey was conducted on herds of free-ranging, hunter-killed elk from three areas in proximity to the northern border of Yellowstone National Park. Blood was collected from 1334 elk and tissues from 388 elk. Eleven elk (< 1%) possessed antibodies to Brucella abortus; tissues from three of the seropositive elk were cultured and B. abortus biovar 1 was isolated from one of the three. Histologic and bacteriologic examination of the tissues from bovine tuberculosis and paratuberculosis yielded negative results. Various parasites and incidental lesions were found.
Completion date: December 1996

Project participants: USDA APHIS (J. Rhyan, D. Ewalt, J. Marquardt, J. Mertins, J. Payeur, D. Saari, E. Sheehan); Montana Department of Fish, Wildlife and Parks (K. Aune, P. Schladweiler); Montana State University (D. Worley).

[Index]

Histopathologic and Bacteriologic Examination of Selected Lymph Nodes and Genitalia from Brucella abortus-infected Young Bison Bulls.

Specimens of blood, lymph nodes, spleens, and genitalia were collected at slaughter from seven 3 and 4 year old male bison that had recently become seropositive for brucellosis. The animals were from a captive herd of approximately 3,500 bison located in central South Dakota. Brucella abortus biovar 1 was isolated from 2 or more specimens from each of six bison. Severe orchitis was present in one testicle from one bull and four animals had mild to marked seminal vesiculitis.
Completion date: January 1997

Project participants: USDA APHIS (J. Rhyan, T. Gidlewski, D. Saari, D. Ewalt, S. Hennager); USDA Agricultural Research Service (A. Jensen, S. Olsen); South Dakota Animal Industry Board (S. Holland); Iowa State University (N. Cheville).

[Index]

Biosafety of RB51 in Parentally Vaccinated Bison Calves.

Bison calves parenterally vaccinated with RB51 at Fort Niobrara National Wildlife Refuge, Nebraska, have been sacrificed at four week intervals to determine persistence and clearance, histopathological effects and shedding of RB51. Comingling adult cow bison were immobilized and serologically sampled for evidence of transmission. Non-target species (coyotes, ravens, and field mice) will also be serologically sampled to assess transmission.
Completion date: September 1999.

Project participants: USGS Biological Resources Division (T. Roffe); USDA Agricultural Research Service (S. Olsen); USDA APHIS (T. Gidlewski).

[Index]

Biosafety and Efficacy of RB51 in Parentally Vaccinated Pregnant Bison.

Adult pregnant bison were vaccinated with two doses of RB51 or saline control. Animals are being maintained in captivity, serologically sampled at two week intervals and monitored for abortion. At calving all adults will be immobilized and calves physically restrained for blood sampling (serology and culture) and samples for RB51 culture (swabs of uterus/vagina, nasopharynx, conjunctiva and rectum; colostrum/milk; placenta; and feces). Growth and development of calves will be monitored. Adult vaccinates will be used in an efficacy study in 1997/98.
Completion date: September 2000

Project participants: Idaho Fish and Game (D. Hunter); USGS Biological Resources Division (T. Roffe); USDA APHIS (M. Gilsdorf); University of Idaho (J. Zaugg).

[Index]

Brucellosis Epidemiology and Demographics in the Jackson Bison Herd.

Tweny radio-collared bison in the Jackson herd have been assessed for serostatus, pregnancy, age and body condition. These animals will be monitored for distribution and habitat use, and age and disease specific effects on reproductive success.
Completion date: 2002.

[Index]

Surveillance of Yellowstone National Park Bison Killed January - April 1997.

Specimens including blood and most common sites of tissue localization as determined by previous work were opportunistically collected from Yellowstone National Park bison at slaughter or after being shot in the field by Montana officials after the animals left the Park. Serologic and bacteriologic testing are underway. The objective of this study is to help determine the correlation between seropositivity and infection as determined by culture.
Completion date: March 1998.

Project participants: USDA APHIS (M. Philo, D. Ewalt, S. Hennager, J. Rhyan).

[Index]

Biosafety Evaluation of Non-target Species Vaccinated with Brucella abortus Strain RB51.

During the next two years, six non-target species will be evaluated for their clinical response to RB51 vaccine. The species include: moose, mule deer, bighorn sheep, pronghorn, wolf and coyote. All studies will essentially be the same. Prevaccination blood samples will be analyzed for pre-existing brucellosis titers, RB51 titers, acute phase reactants, serum chemistries, hematology, and Brucella shedding. Each species will be randomly divided into test and control groups. The test group will be vaccinated orally with a commercial preparation of Brucella abortus strain RB51; the control group will be given the vaccine dilutent as a placebo. Four weeks after vaccination, both groups will again be be blood sampled and analyzed as before. At this time, the test and control groups will be reversed and the new test group will be vaccinated as before. Four weeks after this, both groups will be blood sampled and analyzed as before. Both groups from all species tested will then be observed for at least an additional 4-8 weeks.

Project participants: Wyoming Game and Fish Department (T. Kreeger, W. Cook, T. Thorne, D. Zeiler, H. Edwards); University of Wyoming (E. Williams); USDA Agricultural Research Service (S. Olsen); NWRC Predation Ecology and Behavioral Application Project (R. Mason); Wildlife Science Center (M. Callahan).

[Index]

Efficacy of Brucella abortus Vaccine Strain RB51 in Adult Cow Elk.

Test and control groups will be each comprised of 7 brucellosis-free, pregnant elk housed at Colorado Division of Wildlife facilities in Fort Collins. Control elk will be housed separately from test elk in such a manner as to avoid fenceline contact. Prior to vaccination, elk will be blood sampled and tested for: 1) Brucella abortus using standard plate agglutination, standard tube test, rivanol, and compliment fixation; 2) Brucella abortus strain RB51 using a dot-blot test; and 3) progesterone and pregnancy-specific protein concentrations to determine pregnancy status. In January-February 1998, the test group will be vaccinated using a commercial preparation of strain RB51 vaccine. Vaccine lot potency (colony forming units) will be determined and recorded. Vaccine will be administered intramuscularly in the hindquarter musculature. The control goup will receive a placebo injection comprised of the vaccine diluent. Six-eight weeks after vaccination, both the test and control groups will be challenged with 1 x 10⁷ CFU of Brucella abortus strain 2038 administered conjunctivally in a split dose in both eyes. Following challenge, all elk will be observed daily, morning and evening, for abortion or other indications of reaction to the challenge dose. Aborted fetuses will be removed immediately, necropsied, and tissue cultured. Following normal parturition, calves will be observed for several days to assess health and fitness. Calves will also be bled and analyzed for strain 2038 and strain RB51 antibodies.

Project participants: Wyoming Game and Fish Department (T. Kreeger, W. Cook, D. Zeiler, T. Thorne, H. Edwards); Colorado Division of Wildlife (M. Miller); University of Wyoming (E. Williams); Louisiana State University (P. Elzer); USDA Agricultural Reserach Service (S. Olsen).

[Index]

Epidemiology and Pathogenesis of Brucellosis in Free-ranging Bison of Yellowstone National Park.

This project utilizes radio-collared bison that are tracked and sampled over a five year period to assess changes in serostatus; relationships between adult and calf serology; reproductive and abortion effects; prevalence, duration and persistence of infection; means of transmission; and contamination of the environment. A separate component of the study utilizes killed bison to assess the relationship between serology and infection, and the distribution of infection within the animal.
Completion date: September 2001

Project participants: USGS Biological Resources Division (T. Roffe); USDA APHIS (J. Rhyan); Montana Fish, Wildlife and Parks (K. Aune).

[Index]

Genetic Analysis of Brucella from Bison and the Generation of a PCR-based Diagnostic System for Epidemiological and Ecological Studies.

Researchers are using Polymerase Chain Reaction (PCR) to genetically analyze DNA from Brucella isolates derived from bison, cattle, and other animal hosts. These studies will aid researchers in determining how many species are in the genus Brucella and whether the genus comprises host-specific species and/or isolates. The genetic studies will be used to develop an effective, highly sensitive, PCR-based diagnostic system to detect the presence of Brucella in blood, body fluids, and environmental samples. This diagnostic system will allow managers to determine if bison are currently infected with Bruclla and the diversity of isolates or species present in the animals. Future studies will result in field applicable diagnostic systems to rapidly detect Brucella and discriminate live and dead bacterial cells.

Project participants: USGS Biological Resources Division (R. Rodriguez); USDA APHIS (B. Bricker, A. Jensen); Idaho National Engineering and Environmental Laboratory (F. Roberto); National Park Service (J. Mack).

[Index]

Seasonal Movements and Habitat Selection by Bison in Yellowstone National Park.

Approximately 2,200 bison currently inhabit Yellowstone National Park. Three major subpopulations exist, each with discrete winter ranges but which comingle on summer ranges. Approximately 90 individual bison have been radio-collared as part of several cooperating research projects. Scientists are using aerial locations of these bison to study the pattern and timing of each subpopulations' seasonal movements. Movements and distribution will be analyzed relative to environmental factors such as vegetative types, topography, and snow depth characteristics. The information will assist managers in identifying important seasonal habitats for bison within the Park, and to infer areas of seasonally suitable habitat outside the Park boundary that may be sought by bison.

Project participants: USGS Biological Resources Division (P. Gogan, E. Olexa)

[Index]

Development of Aerial Survey Methodology for Bison Population Estimation in Yellowstone National Park.

Scientists from Montana State University are developing and testing a number of aerial survey techniques for estimating bison populations and other population parameters in Yellowstone National Park. This study includes identifying high and low density strata and appropriate sampling techniques for each strata, comparing surveys conducted during the period of summer breeding and winter range aggregations, identifying conditions that provide the best opportunities for accurately counting bison, and exploring techniques for estimating the proportion of animals detected during each survey. Products of this research will include development of statistically rigorous survey methodologies, estimates with confidence intervals of Park-wide bison populations, and specific routine population monitoring recommendations for managers.

Project participants: Montana State University (R. Garrot, L. Eberhardt, S. Hess); National Park Service (J. Mack, W. Clark).

[Index]

Population Characteristics of Yellowstone National Park Bison.

Samples secured from bison slaughtered beyond the boundaries of Yellowstone National Park are providing scientists with an opportunistic source of information on the population ecology of Yellowstone bison. Data are obtained on the age structure of bison herds, the reproductive rate, fetal sex ratio and prevalence of brucellosis. Blood samples are used to explore the feasibility of using Polymerase Chain Reaction (PCR) techniques to determine the presence of Brucella abortus. In addition, tissue samples are used to assess the herd's genetic composition and the prevalence of a genome rendering bison immune to brucellosis.

Project participants: USGS Biological Resources Division (P. Gogan, E. Olexa); National Park Service (J. Mack, W. Clark).

[Index]

Statistical Analysis and Synthesis of 30 Years of bison Data.

Using statistically rigorous methods, scientists are analyzing over 30 years of bison data collected by Dr. Mary Meagher. Data on population age and sex structure, reproductive rates, distribution, and population change will be evaluated. The information will shed light on issues such as how bison are influenced by natural regulation and whether bison use of groomed and packed winter roads in Yellowstone National Park affect bison population dynamics.

Project participants: Montana State University (M. Taper); USGS Biological Resources Division (M. Meagher - retired).

[Index]

Determining Forage Availability and Habitat Use Patterns for Bison in the Hayden Valley of Yellowstone National Park.

Scientists are studying bison-vegetation interactions and testing the accuracy of various sampling methods in Hayden Valley, the central area of summer range for bison in the interior of Yellowstone National Park. Bison habitat preferences (for cow-calf herds and bull groups), seasonal use patterns, and consistency-of-use patterns at the landscape level will be determined from overlays of radio-collared bison on GIS layers related to vegetation type, topography, snow-melt patterns, and forage biomass. The resulting information will be used in the development of bison-vegetation interaction model. A pilot study on this topic is currently being conducted in the Madison-Firehole Range of Yellowstone National Park.

Project participants: Montana State University (L. Irby, B Garrot); USGS Biological Resources Division (P. Gogan).

[Index]

Bison Use of Groomed Roads in Yellowstone National Park.

A two-year field study has been initiated to investigate the ecological effects of the use of groomed roads by bison during the winter. The study includes intensive observations of bison activity and behavior to test a number of hypotheses about the effects of snowpack and use of groomed roads on bison foraging activity and distributional shifts throughout the winter. The study is being conducted in the upper Madison River drainage, a major wintering area for bison and a primary area of concern for bison exiting the Park. Products of this research will include quantifying bison use of groomed roads during the winter, identification of movement patterns and major distributional shifts, identifying major travel corridors, and other data useful in evaluating the effects of groomed roads on bison ecology.

Project participants: Montana State University (R. Garrot, D. Bjornlie); National Park Service (J. Mack, G. Kurz).

[Index]

Spatial-dynamic Modeling of bison Carrying Capacity in the Greater Yellowstone Ecosystem - a Synthesis of Bison Movements, Population Dynamics, and Interactions with Vegetation.

Estimates of ecological carrying capacity for bison are needed to interpret past increases in bison population sizes and ranges, and to assess the likelihood of future increases and movements within and across Yellowstone National Park boundaries. Population increases up until 1997 may have been responses to available habitat and forage, climate, and the nomadic tendencies of bison, as well as possibly the plowing and grooming of roads and trails in the winter and resultant effects on bison movements, energetics and survival. The effects of bison on vegetation and other ecosystem components must also be considered. Colorado State University scientists are developing a spatial-dynamic ecosystem model as a means to integrate these components, provide a broader explanation for past changes, and explore possible future scenarios.

Project participants: USGS Biological Resources Division (M. Coughenour).

[Index]

Bison Interactions with Elk and Predictive Models of Bison and Elk Carrying Capacity, Snow Models, and Population Management Scenarios in Jackson Hole.

Scientists are studying bison and elk range potential in the Grand Teton National Park and National Elk Refuge portions of Jackson Hole. Currently, elk and bison are artificially fed at several sites in the valley. Managers seek to reduce the concentrations of the two species at these feeding grounds which may contribute to high seropositive rates of brucellosis. Scientists are developing models of typical snow depths and habitat suitability models that, in concert with geographic information system analysis, will enable them to predict the natural winter habitat of elk and bison in the absence or reduction of feeding grounds. The group is also sampling biomass and availability of forages that will enable them, with use of a spatially explicit ecosystem model called SAVANNA, to predict the elk and bison numbers that might be supported under a variety of feeding scenarios. The information will provide managers with predictions for various management scenarios aimed at reducing interactions and the precence of brucellosis on elk and bison.

Project participants: USGS Biological Resources Division (F. Singer, M. Coughenour); Montana State University (P. Farnes).

[Index]

Evaluating Risk Factors for Transmission of Brucellosis from Bison to Elk in Yellowstone National Park.

Management of brucellosis in bison could potentially be complicated by transmission of the disease between elk and bison. Scientists from Montana State University are assessing the potential for such interspecies disease transmissions in the Madison-Firehole area of Yellowstone National Park. This area was selected because it is a major wintering ground for approximately 1000 bison as well as an estimated 600-800 nonmigratory elk. The restricted wintering habitats available in this area, combined with high densities of both elk and bison, suggest that the potential risk of interspecies transmission of brucellosis would be high in this area. The study includes serological surveys, studies of elk and bison distributional shifts and population estimates, habitat affinities of each species and how these change seasonally and with varying snowpack conditions, and measures of direct association and interaction between the two species during spring when probability of Brucella transmission is believed to be the highest. This research will contribute information that may be useful in developing long term management plans.

Project participants: Montana State University (R. Garrott, M. Ferrari); USGS Biological Resources Division (P. Gogan).

[Index]

Bison-forage Relationships in the Madison/Firehole Area of Yellowstone National Park.

Scientists are conducting a pilot study to test the feasibility of several approaches for estimating the forage base available to bison in the Madison/Firehole area of Yellowstone National Park, a major wintering area for bison. Researchers have used observations and fecal-count transects to determine the seasonal distribution of bison in a portion of the Madison/Firehole area. Timing and extent of forage utilization is being determined by using exclosures and clipping experiments. Estimates of standard crop are obtained from handheld radiometer readings. This information will be used to estimate maximum forage availability and to test a model for estimating standing crop from satellite imagery.

Project participants: Montana State University (L. Irby, R. Garrott); USGS Biological Resources Division (P. Gogan); National Park Service (J. Mack).

[Index]

Snow Measurements and Modeling in Relation to Animal Movement in Yellowstone National Park.

Montana State University scientists have developed an Index of Winter Severity (IWS) for elk in northern Yellowstone that may help predict seasonal elk movements. These researchers are using data from snow courses, SNOTEL sites and climatological stations, combined with information on growing degree-days and calculations of soil moisture deficit to update the IWS for elk and to calculate and IWS for bison. Indices of winter severity will be obtained for elk and bison for various winter ranges in or near Yellowstone National Park. This study will provide a critical data layer for a related project in which researchers are developing a geographic model to predict mammal migrations in the Greater Yellowstone Area.

Project participants: Montana State University (K. Hansen, P. Farnes); National Park Service (A. Rodman, J. Mack).

[Index]

Hayden Valley Bison Distribution, Movements, and Road Use Monitoring.

In response to concerns regarding impacts of winter road grooming for snowmobile use on wildlife, Yellowstone National Park personnel are monitoring bison use of groomed roads in the Fishing Bridge to Canyon area. This effort, proposed to last a minimum of 3 years, is providing baseline descriptive data on bison use of roads, location of entry and exit points, and bison movement patterns, as well as bison use of adjacent non-groomed, off-road areas. Managers will use this information to determine whether road closures are needed to more fully understand the impacts of groomed roads on wildlife. Information gathered from this monitoring study may be used in future studies as a basis for possible comparison with closed road segments.

Project participants: National Park Service (G. Kurz, D. Reinhart, J. Sacklin).

[Index]

Prevalence of Brucellosis in Southern Greater Yellowstone Ecosystem Moose.

GYIBC participants: Tom Roffe, fwptr@montana.edu .

Moose have been considered a species sensitive to brucellosis, although very little data exist on the effects of B. abortus on individual moose and on moose populations. As part of a collaborative effort, scientists are utilizing data from another ecology project that involves capturing and radio-collaring moose to assess brucellosis seroprevalence, pregnancy rates and calving in moose coexisting with brucellosis endemic bison and elk.

Project participants: USGS Biological Resources Division (T. Roffe); University of Nevada-Reno (J. Berger).

[Index]

Snowpack Distribution Across Lower Elevations of Grand Teton National Park and National Elk Refuge.

Prior to 1975, most bison that summered in Grand Teton National Park wintered in the Park's lower elevations north of the National Elk Refuge. Heavy snows in 1975 displaced bison to even lower elevations, where they discovered supplemental feed on the NER. Since 1980 most bison now travel to the NER early in winter regardless of snow conditions or forage availability. Scientists are using historic snowpack distribution data across the lower elevations of GTNP and the NER to determine when bison might migrate into this area, and over what portion of the winter range bison may be able to obtain adequate forage. This information may assist managers in developing plans to entice bison to winter farther north, rather than mixing with elk on the NER.

Project participants: Montana State University (K. Hansen, P. Farnes); USGS Biological Resources Division (M. Coughenour).