email a friend
printable version
Location United Kingdom, South East
Central coordinates 1o 7.63' West  50o 49.61' North
IBA criteria C7
Area 1,246 ha
Altitude 0 - 3m
Year of IBA assessment 2007

Royal Society for the Protection of Birds

Site description A large industrialized estuary that includes one of the four largest expanses of mudflats and tidal creeks on the south coast of Britain. The IBA holds important numbers of wintering wildfowl and waders. Branta bernicla are the bernicla subspecies.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Brent Goose Branta bernicla winter  2001-2006  2,925 individuals  good  C7  Least Concern 
Grey Plover Pluvialis squatarola winter  2001-2006  41 individuals  good  C7  Least Concern 
Black-tailed Godwit Limosa limosa winter  2001-2006  264 individuals  good  C7  Near Threatened 
Dunlin Calidris alpina winter  2001-2006  5,672 individuals  good  C7  Least Concern 

IBA Monitoring

2007 high near favourable medium
Good - based on reliable and complete / representative data

Biological resource use fishing & harvesting aquatic resources - unintentional effects: large scale happening now some of area/population (10-49%) moderate to rapid deterioration high
Climate change and severe weather habitat shifting and alteration happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications dams & water management/use - small dams likely in short term (within 4 years) small area/few individuals (<10%) slow but significant deterioration low
Pollution agricultural & forestry effluents - nutrient loads happening now small area/few individuals (<10%) slow but significant deterioration low
Residential and commercial development tourism and recreation areas likely in short term (within 4 years) some of area/population (10-49%) moderate to rapid deterioration medium

Branta bernicla Brent Goose 2820 2925 individuals 100 favourable
Pluvialis squatarola Grey Plover 52 41 individuals 79 near favourable
Limosa limosa Black-tailed Godwit 21 264 individuals 100 favourable
Calidris alpina Dunlin 4650 5672 individuals 100 favourable

Whole area of site (>90%) covered by appropriate conservation designation  A management plan exists but it is out of date or not comprehensive  Some limited conservation initiatives are in place  medium 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Portsmouth Harbour Site of Special Scientific Interest 1,264 protected area contains site 1,246  
Portsmouth Harbour Wetlands of International Importance (Ramsar) 1,249 is identical to site 1,246  


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Mud flats and sand flats; Rivers and streams; Salt marshes; Tidal rivers and enclosed tidal waters  100%

Land use

Land-use Extent (% of site)
tourism/recreation -

Contribute  Please click here to help BirdLife conserve the world's birds - your data for this IBA and others are vital for helping protect the environment.

Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Portsmouth Harbour. Downloaded from on 25/10/2016

To provide new information to update this factsheet or to correct any errors, please email BirdLife