mainland-island model

The mainland-island model describes how populations of a species are distributed across a large main area (mainland) and smaller neighboring areas (islands). The mainland can supply individuals to the islands through migration, helping maintain or boost populations there, especially if local conditions are poor. Conversely, some individuals also move back from islands to the mainland. This model helps explain how species persist and spread in fragmented habitats, with the mainland acting as a source of individuals and islands serving as secondary habitats that depend on this connection for their populations to survive.