Habitat management practices include purchases of grazing allotments from willing sellers, operator conversion of domestic sheep grazing allotments to cattle to reduce the chance of disease transmission, vegetative treatments, and water developments. The Division and BLM have partnered in a program to create suitable bison habitat on the Henry Mountains. Efforts include rangeland prescribed burns, mechanical treatments and reseedings. The Division has funded such projects covering over 6,700 acres. Also, two wild fires occurred in 2003, encompassing over 34,000 acres, most of which were reseeded. The work dramatically increased the quality of habitat on the Henry Mountains for livestock, bison and mule deer. Conservation organizations are active in negotiating, funding, and participating in habitat enhancement projects.
On the Henry Mountains, bison have been very adaptable and utilized a wide variety of habitat types. The Henry Mountains herd has used grassland flats at just over 5000 feet in elevation on Blue Bench, pinyon-juniper woodlands and chainings from 5000 feet at Swap Mesa to over 8000 feet at McMillian Springs. Bison also use sub-alpine meadows at over 11,000 feet on Mount Ellen and Pennell. At times they prefer the shade of Douglas fir stands on the east side of Pennell during the summer, but they may also be found on the stark indian ricegrass/globemallow flats on Stevens Mesa during the hottest days of the year.
Disease
There are three diseases of major concern to bison in Utah, brucellosis, tuberculosis and malignant catarrhal fever.
Blood from hunter-harvested bison is tested annually for brucellosis. There have been no reactors since 1963 and the Henry Mountains bison herd is considered brucellosis free.
Tuberculosis, when found in conjunction with brucellosis, can affect the survival and reproductive capabilities of cow bison. No reactors were found among 12 yearlings tested before being transplanted to Arizona from the Henry Mountains in 2001. Bison are also susceptible to a related disease, paratuberculosis, or Johne’s disease. Johne’s is a viral infection that can have devastating effects on bison.
Malignant catarrhal fever (MCF) is the most serious viral disease affecting ranched bison. It is also known to affect other bovine species, domestic sheep and deer. Related to the herpes virus, it is transmitted through lacrimal, nasal, oral and vaginal secretions, but has occurred in other situations and direct contact is not necessary. Bison have contracted MCF from sheep grazed over 2 miles away (Haigh et. al. 2002). Wind-borne infections have been reported and deer contracted the disease after traveling in a truck that carried sheep with MCF.
Malignant catarrhal fever is invariably fatal. In the most extreme cases, the animal dies showing no clinical symptoms. Treatment of chronic cases is considered hopeless. There is no vaccine. Prevention requires that sheep or wildebeest do not have contact with susceptible species (Haigh et. al. 2002). It is recommended that domestic sheep herds not be grazed within two miles of bison to protect the population from MCF and Johne’s disease.
Genetics
The Henry Mountains herd is one of only four free roaming, genetically pure herds remaining on public lands in North America. It is recognized as a key population in maintaining the bison genome. The others include: Yellowstone National Park, Wind Cave National Park, and Elk Island in Alberta, Canada (Kunkel et. al. 2005). Additionally, the Henry Mountains herd is tested annually, and has been designated as >brucellosis free= since 1962.
Kunkel et.al. (2005) assessed management strategies for minimizing the potential negative effects of inbreeding, the goal being to maintain 90% of the genetic diversity of the gene pool over a 500-year period. They recommend that each population have at least 430 individuals, including both adults and young, to maintain a minimum viable population. This will ensure survival of the plains bison genome.
This information has been retrieved from a 2007 report found here: https://wildlife.utah.gov/hunting/biggame/pdf/bison_15.pdf