Slope Aspect Effect on Soil and Vegetation in a Mediterranean Ecosystem

Differences in soil properties were found between north- and south-facing slopes located in a Mediterranean region with an average annual rainfall of 690 mm. In general, the differences are small, and in some cases even insignificant. The amount of organic matter, Na, Cl, and K, and available nitrogen (N-NH₄and N-NO₃) are higher in the northern aspect than in the southern one. However, pH, CaCO₃, and available P are significantly higher in the southern than the northern aspect. The differences between the aspects in plant species diversity are very great and are expressed mainly in relatively dry winters. The higher species diversity in the south-facing slope is due to the presence of herbaceous, mainly annual, plants. The importance of such differences in the Mediterranean region is discussed.