Analysis of soil and vegetation patterns in semi-arid Mediterranean landscapes by way of a conceptual water balance model

International audienceThis paper investigates the impact of various vegetation types on water balance variability in semi-arid Mediterranean landscapes, and the different strategies they may have developed to succeed in such water-limited environments. Water balance constraints are assumed to dominate the organization of landscapes and a conceptual bucket approach is adopted to model the temporal water balance dynamics, with vegetation water use efficiency being parameterized through the use of empirically obtained crop coefficients as surrogates of vegetation behavior in various developmental stages. Sensitivity analyses with respect to the root zone depth and soil water holding capacity are carried out with the aim of investigating the existence of preferential soil-vegetation associations and, hence, the spatial distribution of vegetation types within the study region. Based on these sensitivity analyses the degrees of suitability and adaptability of each vegetation type to parts of the study region are explored with respect of the soil water holding capacity, and the model results were found to be able to explain the observed affinity patterns. Finally, the existence of such preferential association between soil water holding capacity and vegetation species is verified through an extensive soil survey available in the study region