Ecotypic variation in population dynamics of reintroduced bighorn sheep

Abstract

Selection of bighorn sheep (Ovis canadensis) for translocation historically has been motivated by preservation of subspecific purity rather than by adaptation of source stocks to similar environments. Our objective was to estimate cause-specific, annual, and age-specific mortality of introduced bighorn sheep that originated at low elevations in southern British Columbia, Canada (BC ecotype), or in the Missouri River Breaks region of central Montana, USA (MT ecotype). In North Dakota, USA, mortality was similar and typically low for adult female bighorn sheep from Montana (0.09 AE 0.029 [SE]) and British Columbia (0.08 AE 0.017) during 2000-2016. Median life expectancy was 11 years for females that reached adulthood (2 yrs old); however, mortality accelerated with age and reached 86% by age 16. Mortalities resulted primarily from low rates of predation, disease, accidents, and unknown natural causes (<0.04 [upper 90% CI]). Similar survival rates of female bighorn sheep from British Columbia and Montana, coupled with greater recruitment of bighorn sheep from Montana, resulted in a greater projected rate of increase for the MT ecotype (l ¼ 1.21) than for the BC ecotype (1.02), and a more youthful age structure. These results support translocation of bighorn sheep from areas that are environmentally similar to areas that will be stocked. Potential benefits include more rapid population growth, greater resilience to and more rapid recovery from densityindependent losses, an increased possibility that rapidly growing populations will expand into adjacent habitat, increased hunter opportunity, increased connectivity among herds, and a more complete restoration of ecosystem processes. Ó 2017 The Wildlife Society.

Evaluating wildlife translocations using genomics: A bighorn sheep case study

“…To evaluate evolution of newly founded populations and inform reintroduction planning, we compared herds thought to be reintroduced with their suspected founding source. Other studies suggested that bighorn sheep reintroduction efforts may be more successful when founders are sourced from either matching environmental conditions, due to greater recruitment when ecotypes are matched, or native populations, due to typically higher levels of genetic diversity (Bleich et al., 2018; Fitzsimmons et al., 1997; Singer et al., 2000). We evaluated eight populations that originated from reintroductions where a founding source was in our study.…”

Effect of dietary fiber levels on bacterial composition with age in the cecum of meat rabbits

“…may reflect elevated production (Luo et al, 2018). On the other hand, Bibersteinia is an important pathogen that is associated with serious infection (Bleich, Sargeant, & Wiedmann, 2018;Parr, Smith, Jenks, & Thompson, 2018;Heinse, Hardesty, & Harris, 2016) and is implicated in the high incidence of diarrhea in Diet D at 52 days.…”

Impact ofMycoplasma ovipneumoniaeon juvenile bighorn sheep (Ovis canadensis) survival in the northern Basin and Range ecosystem

“…Previously, other subspecies were recognized (e.g., Peninsular bighorn sheep, O. c. cremnobates, and California bighorn sheep, O. c. californiana ) ( Cowan, 1940 ). Debate remains about whether those putative lineages reflect important independent evolutionary trajectories and important local adaptation ( Buchalski et al, 2016 ; Bleich, Sargeant & Wiedmann, 2018 ; Barbosa et al, in press ).…”