Relationships between climate and soil hydrological and erosional characteristics along climatic gradients in Mediterranean limestone areas

An investigation was undertaken to determine the relationships between climate and soil hydrological and erosional characteristics. Rainfall simulation experiments were carried out along three climatological gradients on similar limestone lithologies in the Mediterranean region. Standard experiments were used to characterize each site so that an objective comparison could be made. At each of the eleven south-facing slopes three experiments were carried out. A total of 33 plots were selected for the experiments; located in the Galilee and Carmel Mountains (Israel), Crete (Greece) and Alicante (Spain). Simulated rainfall was used in order to measure time to ponding and runoff, steady-state infiltration rate, runoff coefficient, runoff sediment concentration and the erosion rate at each of the 33 selected plots. The mean annual rainfall is not directly correlated with soil erodibility, infiltration and runoff. The effect of climate on geomorphological processes does not have a great impact on runoff and infiltration at pedon scale. During the wet seasons studied the local thunderstorms discourage any kind of soil moisture trends along the climatic gradients and thus on hydrological processes. Human impacts, mainly grazing and fires seem to be the most relevant factors for soil hydrological and erosional response in the Mediterranean Region.