The largest wetland and estuary in Portugal, and one of the mainest in Europe, in extension and in natural value. Located in central Portugal, the site includes the upper and central parts of the River Tejo estuary and the valley of a small tributary (Ria Enguias). The site presents large expanses of mudflats and saltmarshes as result of soft slopes at its edges and its wideness of tide. At the edges of the IBA rice-fields are found and also an extensive area for agriculture and cattle-breed. Lisbon is located at the mouth of the River Tejo, and more than two million people live around this IBA.
The site holds 100,000 or more wintering waterbirds on a regular basis, and is the most important locality in Portugal for wintering flamingos, ducks, waders and gulls. The area also holds important numbers of a wide variety of breeding waterbirds. The reedbeds in the upper part of the estuary support large numbers of migrating passerines during autumn. The wintering population of Tetrax tetrax is significant at national level and represents near 1% of wintering european population. 46 of the near 200 species that occur here are included in Anex I of 79/409/CEE directive.
Pressure/threats to key biodiversity
There is a management plan for the Specia Protection Area, and a management plan for the Narure Reserve is in progress. Disturbance to birds can be moderately intense locally, due to the high human population density, and due to the use of aircraft to seed and spray chemicals onto rice-fields during the breeding season. Several construction projects, including a very large bridge across the Tejo, are underway or are proposed for the site or along its edges. The introduced and highly invasive water-hyacinth Eichhornia crassipes is affecting the natural vegetation cover in the network of channels and is reducing the area of open water.
National Nature Reserve (Estuário do Tejo, 14,192 ha covered by Nature Reserve); Special Protection Area (Estuário do Tejo, 45,071 ha covered by Special Protection Area). International Special Protection Area (Estuário do Tejo, 45,071 ha covered by Special Protection Area); Ramsar Site (Estuário do Tejo, 14,563 ha of IBA covered by Ramsar Site ).
BirdLife International (2020) Important Bird Areas factsheet: Tejo estuary. Downloaded from
http://www.birdlife.org on 16/07/2020.