Urban ecology is a young field, defined quite varyingly even in recent English-language works. Like landscape ecology, it studies systems involving the human-environment dynamic. It approaches these systems from both a geography-landscape perspective and a bioecology-biogeography perspective. The subject is the ‘urban landscape ecosystem’—an interactive system controlled by humans (economy, politics, technology, social systems, etc.) primarily examined independently by various disciplines. Often, the real object ‘urban ecosystem’ is not referenced. In this article, the scientific approach of urban ecology is in the foreground. Depending on the city model, various subsystems of the human-city-environment system can be linked—despite methodological problems. The application of urban ecology results is pragmatic, mostly separate—at most with a sidelong glance at the ‘overall city system’.