Mostly they had the function to delimitate the property and guarantee the control of the flock during the pasture. Often there are small portion of walls built in parallel in order to delay the stream of the rainwater when they were strong and avoid the erosion of the ground. Beside the walls can be defined as a microhabitat for many species of plants and animals as they have an high variability of the microclimate during the day. The range of the temperature reach 20 degrees. If follows a short description of the population phases of the walls: from the pioneer organisms, able to resist also the hardest conditions, to the complex organisms.