The Question: Is the Mummy Range bighorn sheep population subject to negative eﬀects from inbreeding after a recent pneumonia-induced population die-oﬀ?
Bighorn sheep (Ovis canadensis canadensis) of the park’s Mummy Range suﬀ ered a population size reduction associated with a pneumonia die-oﬀ in the 1990s. Some managers wondered if the event was enough to induce a “population bottleneck,” an evolutionary event that reduces genetic variation and results in increased inbreeding due to the reduced pool of possible mates. The smaller gene pool can subsequently reduce ﬁ tness (e.g., lamb survival, reproduction) and the ability to adapt to future environmental changes (e.g., disease, environmental stress). If a severe bottleneck was detected in the Mummy Range band, management actions could be undertaken to supplement the population numbers as a way to improve genetic ﬁ tness and bolster the probability of the band’s survival.