Parameters of a founder group and long term viability of a newly created European bison populations

Abstract

Abstract: Simulations of the European bison population development were carried out according to scenarios that included various characteristics of a founder group: size (N = 6; 10; 20; 30), age (calves versus sexually mature individuals), and females: males ratio (1:1, 2:1, 4:1). Introduction was simulated as a single event or a series of supplementations. Probability of population extinction, level of heterozygosity and the percentage of alleles retained in the extant populations, as well as the mean population growth rate were analysed at the end of 100-year period of population development. The results led to the following conclusions that may help to keep the level of genetic variability of created populations in the long term as high as possible: 
1. The total number of founders should not be lower than 10 individuals; females : males ratio among founders is suggested to be 2:1 or higher. Founders should be selected on the basis of their pedigrees.
2. The new herds should be established in areas with possibly the highest carrying capacity. If the carrying capacity is low, the better solution would be to establish a new herd as a part of a meta-population or release bison in several stages with regular supplementations.
3. Supplementations with females or individuals of both sexes seem to be more favourable for population viability than supplementations with males only.