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Location Portugal, Lisboa e Vale do Tejo
Central coordinates 9o 2.00' West  38o 52.00' North
IBA criteria B2, C6
Area 218 ha
Altitude 0 - 5m
Year of IBA assessment 2002

Sociedade Portuguesa para o Estudo das Aves

Site description This site is located at north bank of Tejo Estuary. Is formed by two salinas (salt pans) complexes: Salinas de Alverca and Salinas do Forte da Casa, extensive agricultural landscapes that separe them, and the final part of Verdelha river; it represents the only bird refuge in this riverbank. In the surrounding zone, the strongly built up and industrializated area of Alberca contrasts with the Natural Reserve of Tejo Estuary and Portuguese Air-Force installations. Besides the salinas banks and landscapes, there are also drainage trenchs and a stream with an important water fringe vegetation. Now, salinas are abandoned and water lever is conditioned by precipitation. Vegetation inside the banks is mainly constituted by aquatic plant, namely rushes and reeds. In the edges salt-marshes vegetation and rarely tamarisks are found.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Greater Flamingo Phoenicopterus roseus winter  2000  1-100 individuals  good  C6  Least Concern 
Purple Heron Ardea purpurea breeding  2001  common  C6  Least Concern 
Western Marsh-harrier Circus aeruginosus resident  1998  common  C6  Least Concern 
Himantopus himantopus resident  2001  40-300 breeding pairs  good  C6  Not Recognised 
Himantopus himantopus winter  2001  1-50 individuals  good  C6  Not Recognised 
Pied Avocet Recurvirostra avosetta resident  2001  1-2 breeding pairs  good  C6  Least Concern 
Pied Avocet Recurvirostra avosetta winter  2001  10-100 individuals  medium  C6  Least Concern 
Collared Pratincole Glareola pratincola breeding  2001  10-40 breeding pairs  good  B2, C6  Least Concern 
Little Tern Sternula albifrons breeding  2000  frequent  C6  Least Concern 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Estuário do Tejo - PTZPE0010 Birds Directive 44,772 protected area overlaps with site 16  


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Rivers and streams; Standing brackish and salt water; Standing freshwater; Water fringe vegetation  -
Artificial - terrestrial Arable land; Other urban and industrial areas  -
Shrubland Sclerophyllous scrub, garrigue and maquis  -

Land use

Land-use Extent (% of site)
agriculture -
hunting -
military -
tourism/recreation -
urban/industrial/transport -
water management -

Protection status National:NoneInternational:None

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Salinas de Alverca e do Forte da Casa. Downloaded from on 21/10/2014

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