The work focuses primarily on the fen ecosystem and the implementation of this topic into the indoor and outdoor educational setting. Central aims are the explanation of the theoretical basis of the fen ecosystem and the development of teaching concepts for the application in lower and upper grades.Therefore, the first part of this thesis focuses on the theory of ecosystems in general and of the fen ecosystem in particular. The fen ecosystem is discussed with reference to the predominant vegetation and fauna, the importance and endangerment of this ecosystem as well as its geographical distribution in Styria. The contents which are addressed are relevant to the syllabus. Furthermore, didactic considerations on extracurricular learning places and outdoor teaching are taken into account.The second part of this thesis consists of two teaching concepts, which are based on the theory of the first part. One of these concepts is designed for lower grades and the other for upper grades. To ensure successful implementation in the educational context, the concepts are divided into three phases: prearrangement phase, excursion and post processing phase. On the one hand, the task of the prearrangement phase is to serve as a help of orientation for the students and to initiate the acquisition of competences. The excursion, on the other hand, is characterized by a student-centered and activity-oriented educational approach. Furthermore, the post processing phase is designed to deepen the students` knowledge and thus to achieve a sustainable gain in knowledge.