Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Sado Estuary Natural Reserve is a natural reserve in Portugal. It is one of the 30 areas which are officially under protection in the country. It includes the municipalities of Setubal, Palmela, Sesimbra, Alcacer, and Grandola. A nature reserve (natural reserve, nature preserve, natural preserve) is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research. Nature reserves may be designated by government institutions in some countries, or by private landowners, such as charities and research institutions, regardless of nationality. Nature reserves fall into different IUCN categories depending on the level of protection afforded by local laws.