Wetlands are very important elements of the landscape in almost every environment. Addressing the continued loss of wetland area worldwide, wetlands are recognized as highly vulnerable with regard to natural and anthropogenic system changes. Consequently, the research of their natural and socio-economical functions, importance for the water and nutrient cycles as well as their role as wildlife habitats received increasing scientific and public awareness in the past decades. The landscape of the semiarid Eastern Cape Province, South Africa, is characterized by the occurrence of different types of palustrine wetlands. Intensive afforestation in the headwaters of the Umzimvubu catchment since 1989 has changed downstream wetland characteristics, but little attention has been given to evaluate and quantify these impacts. Addressing this research deficit, the main objectives of this dissertation are the development of an integrated, landscapebased research approach to improve the understanding of the formation, functioning and dynamics of palustrine wetlands and the prognostic modeling and assessment of afforestation impacts on these wetland systems.