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Reproduction and Survival of Yellowstone Bison
Author(s) -
FULLER JULIE A.,
GARROTT ROBERT A.,
WHITE P.J.,
AUNE KEITH E.,
ROFFE THOMAS J.,
RHYAN JACK C.
Publication year - 2007
Publication title -
the journal of wildlife management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.94
H-Index - 111
eISSN - 1937-2817
pISSN - 0022-541X
DOI - 10.2193/2006-201
Subject(s) - bison bison , brucellosis , fecundity , reproduction , biology , demography , vaccination , zoology , birth rate , fertility , medicine , veterinary medicine , population , immunology , ecology , sociology
The conservation of bison ( Bison bison ) from near extinction to >4,000 animals in Yellowstone National Park has led to conflict regarding overabundance and potential transmission of brucellosis ( Brucella abortus ) to cattle. We estimated survival and birth rates from 53 radiocollared adult female bison during 1995–2001, and we used calf:adult (C:A) ratios to estimate reproduction with the combined effects of pregnancy, fetal loss, and neonatal mortality during 1970–1997. Annual survival of adult females was high (0.92; 95% CI = 0.87‐0.95) and constant. Birth rates differed by brucellosis status and age. Birth rates were 0.40 calves per female (95% CI = 0.15‐0.65) for brucellosis‐positive 3 year olds, 0.63 (95% CI = 0.39‐0.87) for individuals testing negative, and 0.10 (95% CI = 0.00‐0.24) for individuals contracting brucellosis that birth year (sero‐converters). Birth rates were 0.64 (95% CI = 0.52‐0.76) for brucellosis‐positive individuals ≥4 years old, 0.81 (95% CI = 0.73‐0.89) for brucellosis‐negative individuals, and 0.22 (95% CI = 0.00‐0.46) for sero‐converters. Spring C:A ratios were negatively correlated with snow pack (β = −0.01 to −0.03, R 2 = 0.26‐0.60, P < 0.05). Growth rate was highly elastic to adult survival (0.51), and juvenile survival (0.36) was 3 times more elastic than fecundity (0.12). Simulations suggested brucellosis eradication via vaccination would result in increased birth rates and a 29% increase in population growth (γ = 1.09), possibly leading to more bison movements outside the park. Our results will help park managers evaluate bison population dynamics and explore consequences of management actions and disease control programs.