Tejo estuary (370)
Portugal, Europe

Site overview

KBA status: confirmed

Global KBA criteria: D1a

Year of last assessment: 2002

National site name: Estuário do Tejo

Central coordinates: Latitude: 38.8167, Longitude: -8.9333

System: marine, terrestrial

Elevation (m): 0 to 43

Area of KBA (km²): 447.62763

Protected area coverage (%): 98.04

KBA classification: Global

Legacy site: Yes

Site details

Site description: 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.

Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs.

Additional biodiversity: 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.

Habitats

IUCN Habitat	Coverage %	Habitat detail
Forest	15
Marine Coastal/Supratidal	22
Artificial - Terrestrial	20
Marine Intertidal	22
Marine Neritic	22

Threats

Summary of threats to biodiversity at KBA: 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.

Threat level 1	Threat level 2	Threat level 3	Timing
Pollution	Agricultural & forestry effluents	Herbicides and pesticides	Ongoing
Pollution	Agricultural & forestry effluents	Nutrient loads	Ongoing
Invasive & other problematic species, genes & diseases	Invasive non-native/alien species/diseases	Named species	Ongoing
Invasive & other problematic species, genes & diseases	Problematic native species/diseases	Named species	Ongoing
Biological resource use	Hunting & collecting terrestrial animals	Intentional use (species being assessed is the target)	Ongoing
Biological resource use	Fishing & harvesting aquatic resources	Unintentional effects: subsistence/small scale (species being assessed is not the target) [harvest]	Ongoing
Agriculture & aquaculture	Marine & freshwater aquaculture	Subsistence/artisinal aquaculture	Ongoing
Agriculture & aquaculture	Annual & perennial non-timber crops	Shifting agriculture	Only in the future
Natural system modifications	Dams & water management/use	Abstraction of surface water (agricultural use)	Ongoing
Transportation & service corridors	Utility & service lines		Ongoing
Transportation & service corridors	Roads & railroads		Only in the future
Residential & commercial development	Housing & urban areas		Ongoing
Pollution	Garbage & solid waste		Ongoing
Residential & commercial development	Commercial & industrial areas		Ongoing
Human intrusions & disturbance	Recreational activities		Ongoing
Human intrusions & disturbance	Work & other activities		Ongoing
Climate change & severe weather	Habitat shifting & alteration		Ongoing
Transportation & service corridors	Flight paths		Ongoing

Additional information