Landscapes of sandy areas along a rainfall gradient of 90-450 mm, average annual rainfall

Dryland areas are regarded as highly sensitive to climatic changes. A positive relationship between average annual rainfall, and environmental factors is often assumed for areas with an average annual rainfall of 100-400 mm. The above assumption disregards the fact that a climate change in some dry-land areas is not limited to climatic factors. In addition, the climatic models, based on average annual rainfall, disregard the rainfall characteristics at the rain-shower level, which greatly influence the degree to which rainwater will percolate, thereby significantly affecting the spatial redistribution of water resources. The present work deals with the complex relationships between average annual rainfall, and environmental variables in sandy areas, along a rainfall gradient of  90-450 mm, in the south eastern Mediterranean area, Israel. Data obtained clearly show that average annual rainfall is not a good indicator of water resources, and ecosystem characteristics. The controlling factors vary from one site to another.