F. López Bermúdez

Topographic control of soil moisture, vegetation cover and land degradation in a moisture stressed mediterranean environment

Abstract An erosion-vegetation competition model (THORNES 1985) assumes that surface litter, soil organic matter and soil moisture are positively correlated and that these in turn are correlated with topographic conditions on a uniform soil in a moisture-stressed environment. These relationships are tested for an experimental site in Mediterranean Spain. The results show that while these relationships are statistically significant, but rather weak, when all the data are used or when they are grouped according to geomorphic position (interfluve, hollow or slope), the correlations become stronger when considered in relationship to transects and when the data are subject to a low level of spatial smoothing. Even then, the relationships are rather complex, reflecting local features, the stage of vegetal development and, perhaps, the status of competition between erosion and vegetation.