Old data are a gold standard in climate change research, and much more use should be made of these data sets to document changes in wetlands in recent decades. Key data sets for the study of climate or land use change effects on wetlands may include historical field studies. Old data sets such as those from Iowa State University in the 1980s have immense value for assessing long term vegetation change over time. These data sets include classic studies of biomass production, decomposition, vegetation composition, water level tolerances, and seed bank structure.