Journal Article

Genetic Changes in Reintroduced Rocky Mountain Bighorn Sheep Populations

Buskirk, Steven W., Fitzsimmons, Nancy N., Smith, Michael H.

1997

Overview

We compared allozyme variability in 4 reintroduced populations of bighorn sheep (Ovis canadensis) with their common source population in Wyoming to understand how reintroduction affects genetic variability. Founder size was low (8-69) and effective population size (Ne) remained low 10-20 years after release. Allele frequencies at 2 of 4 polymorphic loci differed between the reintroduced herds and the common source (P < 0.01), and the number of alleles per locus was reduced in reintroduced herds (P = 0.04). Multi-locus heterozygosity (at 29 loci) was lower (P = 0.03) in 3 of the reintroduced herds than in the common source population. Simulations of genetic drift in reintroduced herds indicated that allele frequencies were within expectations of model predictions, but that heterozygosity sometimes varied from predictions. Our results indicate the operation of founder effect and subsequent genetic drift within the small reintroduced herds, but also may be influenced by small sample sizes from herds that were difficult to sample. We suggest management practices that should minimize the loss of genetic variation from reintroduced populations of bighorn sheep.

• Publisher: The Wildlife Society,Wildlife Society,Blackwell Publishing Ltd
• Subject: Alleles / Animal genetics / Animal populations / Animal, plant and microbial ecology / Applied ecology / Biological and medical sciences / Canyons / Conservation, protection and management of environment and wildlife / Fundamental and applied biological sciences. Psychology / Gene frequency / Genetic diversity / Genetic drift / Genetic loci / Genetic variation / Genetics / Herds / Parks, reserves, wildlife conservation. Endangered species: population survey and restocking / Population genetics / Population size / Sheep / Wildlife management