Reproductive success in wood bison (Bison bison athabascae) established using molecular techniques

Abstract

In this study, we used 21 microsatellite loci to establish the reproductive success of the wood bison (Bison bison athabascae) population at Elk Island National Park, Alberta, Canada. Wood bison are considered threatened in Canada, and this population is currently used to found new populations. Despite the low levels of genetic variation in this population, we were able to establish paternity in 253 and maternity in 295 of the 317 calves born in Elk Island National Park over the 4-year study period. Roughly 40% of the mature males were reproductively successful each year. Mature males produced a mean of 3.8 offspring over the study period, with a range of 0–24. Each year, approximately 50–70% of the cows produced calves, with a mean of 2.7 over the study period. Multiple linear regressions were performed to determine the effects of age, mass, heterozygosity, prior success, and the year of conception on male and female reproductive success. Only mass and prior success were useful in predicting male reproductive success. Female reproductive success depended on age, mass, and prior success and was also affected by environmental differences between years. No evidence was found for inbreeding avoidance in wood bison.