One of the most important aspects of establishing a new ex situ population is obtaining sufficient founder animals (unrelated individuals who help establish a population), but unfortunately, this is often over-looked when new programs are established.
Amphibian Ark recommends that at least twenty pairs of animals (or groups of individuals) are collected as founder animals. Ideally these would be unrelated and will successfully reproduce, but of course that cannot be guaranteed. Realize that many more than this number may have to be captured to ensure that twenty pairs actually survive and successfully reproduce.
Collection of founders should be targeted towards obtaining as many unique lineages as possible (e.g., collect from different locations and, if possible, different sites at each location to reduce the probability of collecting related animals). This assumes that a phylogenetic study has been done among these different populations to verify that they are in fact the same species.
Amphibian Ark has developed a tool to help calculate the number of founders that should be collected, based on the reproductive biology of the species being considered. The tool uses data from our Amphibian Population Management Guidelines (en Español – Lineamientos para el Manejo de Poblaciones de Anfibios).
Enter the species name in the tool, and then select the appropriate biological values and management type from the options listed. Then click the Show results button to display the number of founders that should be collected, and target population sizes for that type of reproductive model.
See the Establishing Ex Situ Amphibian Programs page for additional information on implementing amphibian conservation programs.