Effective population sizes (Ne) and bottlenecks are two of the most important concepts that must be acknowledged and dealt with in captive populations. In fact, Ne is a much better indicator for the health of any population than census size. However, it is often a difficult concept for people to grasp. Usually, because the definition includes metrics that are hard to grasp, such as an ideal population. I always like to think about it as the size of a population if you were to remove any redundancy and non-contributing individuals. So if you have 50 individuals, but 20 are too old to breed and half of the rest are inbred, you would only have an Ne of 15. Clearly, thats a much more shocking number than 50 if you are managing a species. Its not uncommon in my work with rare species that populations have effective population sizes in the single digits despite a census population size of a few hundred. So, you can see that for captive populations of rare species, this is going to be a problem. Mainly, that unless you have a way of genotyping animals in the wild (you dont) you are going to have to over-collect.
write a short (less than 2 pages) report for the president of the fictional zoo or aquarium you are building a captive population for.
***selected population is cheetahs**
Assume they are relatively aware of genetic issues in small populations, but need to know more about the dangers of Ne and bottlenecks. In your report, discuss your plans with how to deal with these issues, both initially and in the future. Feel free to use the bearded vulture article and other examples you can find in the literature to support your argument. Be sure to include the differences between drift, founder effects, Ne (and Ne/N ratio), and bottlenecks.
