Moisture Matters; Climate-proof and process-based relationships between water, oxygen and vegetation

“Climate change has been forecast and has been observed worldwide. This change could have substantial effects on natural ecosystems. As a consequence, it is questionable whether current nature targets, partly obligatory through law, may still be obtained in a future climate. To assess the impact of environmental changes on terrestrial vegetation, scientists apply habitat distribution models, i.e. models that are capable of predicting the future spatial distribution of habitats. These habitat suitability predictions can be converted into maps of potential vegetation. Current models, however, generally use indirect and simple
site factors to characterize habitats, resulting in a highly correlative relationship with the vegetation. Consequently, these models are likely to be inapplicable under changing climatic conditions. In order to improve vegetation predictions for the future climate, process-based and climate-proof relationships between site factors and vegetation are needed. This thesis addresses the development of climate-proof relationships between soil moisture conditions and vegetation. Soil moisture is one of the main site factors that determine terrestrial vegetation composition. Groundwater levels, and the related soil moisture conditions, vary in time due to temporal variations in meteorological conditions, both within and between years. Due to these temporal variations, systematic differences in the relationships between soil moisture conditions and vegetation are found when the relationships are based on too short measurement periods. Chapter 2 shows that data harmonization removes such differences and increases the general applicability of empirically derived relationships.”

(Citaat: Bartholomeus, R.P. – Moisture Matters: Climate-proof and process-based relationships between water, oxygen and vegetation, 2009)