The Lake Chad basin has a wealth of flora and fauna, especially numerous species of fish and migratory birds of diverse origin that are mostly to be found in and on Lake Chad. Geology is one of the reason for this wealth. It comprises sedimentary formations from the Tertiary and Quaternary periods. The entire basin is encircled by sizeable uplands that hem it in and make Lake Chad, located in the centre of the basin, an endorheic feature, since its waters have no outlet. The water is however fresh and the lake is therefore favourable to fauna and flora. Protected areas of international importance have been created to make it possible to protect these species, but they are often poorly managed by state-run services that lack sufficient means.