Small Population Problems
Small populations face three interacting threats. Demographic stochasticity—random variation in birth and death rates—can cause extinction when a population drops below 50-100 individuals. For example, if a small population happens to produce mostly male offspring in one generation, it may fail to reproduce. Genetic drift—random changes in gene frequency—reduces genetic diversity in small populations, limiting adaptive potential. Inbreeding depression occurs when closely related individuals mate, expressing harmful recessive alleles that reduce survival and reproduction. The Florida panther population fell to 20-30 individuals by the 1990s, suffering kinked tails, heart defects, and low sperm quality due to inbreeding—problems reversed after introducing eight female Texas cougars to restore genetic diversity.