Small infield pools in the Pleistocene landscape are widespread and important island habitats for wetland species within an intensively treated, homogeneous agricultural landscape. In this study the hydrological regime of small infield pools was modeled for a period of 50 years. Trends in hydrological characteristics could be explained by observed trends in rising temperatures. An explanation is given why studies with habitat description due to short time observations are only valid among the spatial and temporal investigation limits. A method is developed to define plant functional groups (PFG) according the studied habitat types. With a fourth corner analysis the occurrence probability of these PFGs in different hydrological regimes is analyzed. Finally, the storage traits of these PFGs could be described. Among other local human made impacts, the analysis of the simulations results asserts the impact of climate (evaporation and precipitation) on habitat qualities of wetlands. The developed method is subsequently used to predict shifts in future plant functional type composition due to climate change.