Biodiversity is the result of 3 billion 800 million years of evolution, and it is essential for the survival of mankind. In fact we depend on nature for many fundamental resources, among which food, building materials, heating, textile fibres and the active ingredients of medicinal products. Furthermore nature provides for other vital functions such as the pollination of plants, purification of the air, water and soil, etc. Today human activities are a severe threat for biodiversity, and they jeopardize the existence of numerous species.