Faunal succession is the process by which different groups of animals, or fauna, replace one another in a specific area over time. This occurs in response to changes in the environment, such as climate shifts or habitat alterations. Each group of animals has a distinct time period during which it thrives, allowing scientists to use these patterns to understand the history of an ecosystem. This concept is important in fields like paleontology and ecology, as it helps researchers identify the age of rock layers and the conditions that existed when certain species lived. By studying faunal succession, scientists can reconstruct past environments and predict how current ecosystems might change in the future.