No abstract

Many wide-ranging mammal species have experienced significant declines over the last 200 years; restoring these species will require long-term, large-scale recovery efforts. We highlight 5 attributes of a recent range-wide vision-setting exercise for ecological recovery of the North American bison (Bison bison) that are broadly applicable to other species and restoration targets. The result of the exercise, the "Vermejo Statement" on bison restoration, is explicitly (1) large scale, (2) long term, (3) inclusive, (4) fulfilling of different values, and (5) ambitious. It reads, in part, "Over the next century, the ecological recovery of the North American bison will occur when multiple large herds move freely across extensive landscapes within all major habitats of their historic range, interacting in ecologically significant ways with the fullest possible set of other native species, and inspiring, sustaining and connecting human cultures." We refined the vision into a scorecard that illustrates how individual bison herds can contribute to the vision. We also developed a set of maps and analyzed the current and potential future distributions of bison on the basis of expert assessment. Although more than 500,000 bison exist in North America today, we estimated they occupy <1% of their historical range and in no place express the full range of ecological and social values of previous times. By formulating an inclusive, affirmative, and specific vision through consultation with a wide range of stakeholders, we hope to provide a foundation for conservation of bison, and other wide-ranging species, over the next 100 years.

Bison (Bison bison) and elk (Cervus elaphus) of the Greater Yellowstone Area (GYA) are the last remaining reservoirs of bovine brucellosis (Brucella abortus) in the United States. An important factor in evaluating the risk of transmission to cattle is the persistence of bacteria and infectious birth materials shed on pastures where cattle graze. We selected 2 study areas near the northern and western boundaries of Yellowstone National Park (YNP) to determine the persistence of bacteria on fetal tissue, soil, and vegetation, and scavenging on infectious materials from birth and abortion sites. We performed 3 independent field experiments to determine: 1) persistence of Brucella abortus (RB51) purposely applied to fetal tissues, 2) scavenging of fetuses by native scavengers, and 3) natural contamination of birth or abortion sites in the GYA. Results from these field experiments established that Brucella bacteria can persist on fetal tissues and soil or vegetation for 21-81 days depending on month, temperature, and exposure to sunlight. Bacteria purposely applied to fetal tissues persisted longer in February than May and did not survive on tissues beyond 10 June regardless of when they were set out. Brucella abortus field strain persisted up to 43 days on soil and vegetation at naturally contaminated bison birth or abortion sites. Fetuses were scavenged by a variety of birds and mammals in areas near YNP and more rapidly inside YNP than outside the Park boundary. Models derived from our data determined a 0.05% chance of bacterial survival beyond 26 days (95% Credible Interval of 18-30 days) for a contamination event in May. May 15 is the final date for hazing all bison into Yellowstone National Park under the current interagency bison management plan. With these data managers can predict when it is safe to graze cattle onto pastures previously occupied by bison. ß 2011 The Wildlife Society.

Our objective in this prospective study was to determine the natural course of Brucella abortus infection in cohorts of seropositive and seronegative, female bison (Bison bison) and their offspring in Yellowstone National Park (YNP) for 5 yr. We collected specimens from 53 adult females and 25 calves at least once and from 45 adults and 22 calves more than once. Annual seroconversion rates (negative to positive) were relatively high (23% for calves and juvenile bison, 6% in the total sample of adult female bison in our study, and 11% in the adult females that began the study as seronegatives). Antibody was not protective against infection, even for calves that passively received antibody from an infected mother's colostrum. Antibody levels stayed remarkably constant, with only a slow decline over time. We found only two seroconversions from a weak positive status to negative. Infected bison aborted and shed viable bacteria. Risk of shedding infective Brucella was highest for bison in the 2 yr following seroconversion from negative to positive. In one bison, we detected shedding for 3 yr following seroconversion. Regardless of serostatus of dams and neonates, most calves were seronegative by 5 mo of age. There was no relationship between the antibody status of the dam and the tendency of a calf to seroconvert to positive during the duration of the study.