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Year of most recent IBA criteria assessment: 2007

Populations of IBA trigger species

Species	Current IUCN Red List Category	Season	Year(s) of estimate	Population estimate	IBA Criteria Triggered
Gadwall Mareca strepera	LC	winter	2001-2006	357 individuals	B1i, C3
Pied Avocet Recurvirostra avosetta	LC	passage	2001-2006	649 individuals	B2
Pied Avocet Recurvirostra avosetta	LC	winter	2001-2006	628 individuals	B2, C6
Pied Avocet Recurvirostra avosetta	LC	breeding	1995	33 breeding pairs	C6
Common Ringed Plover Charadrius hiaticula	LC	passage	2001-2006	737 individuals	B1i, C3
Eurasian Curlew Numenius arquata	NT	passage	2001-2006	1,412 individuals	B2
Eurasian Curlew Numenius arquata	NT	winter	2001-2006	1,495 individuals	B2
Black-tailed Godwit Limosa limosa	NT	passage	2001-2006	3,299 individuals	B1i, C3
Black-tailed Godwit Limosa limosa	NT	winter	2001-2006	1,247 individuals	B1i, C3
Dunlin Calidris alpina	LC	passage	2001-2006	5,541 individuals	B2
Dunlin Calidris alpina	LC	winter	2001-2006	15,181 individuals	B1i, B2, C3
Common Redshank Tringa totanus	LC	winter	2001-2006	1,720 individuals	B1i, C3
A4iii Species group - waterbirds	n/a	passage	2001-2006	24,702 individuals	A4iii, C4
A4iii Species group - waterbirds	n/a	winter	2001-2006	47,805 individuals	A4iii, C4

Note: This table presents the IBA criteria triggered and the species that triggered then at the time of assessment, the current IUCN Red List category may vary from that which was in place at that time.

For more information about the IBA assessment process and criteria please click here

Threats to the site (pressure)
Threat Level 1	Threat Level 2	Timing	Scope	Severity	Result
Climate change and severe weather	habitat shifting and alteration	happening now	small area/few individuals (<10%)	slow but significant deterioration	low
Energy production and mining	renewable energy	likely in short term (within 4 years)	small area/few individuals (<10%)	moderate to rapid deterioration	low
Natural system modifications	dams & water management/use - small dams	likely in short term (within 4 years)	some of area/population (10-49%)	slow but significant deterioration	medium
Natural system modifications	other ecosystem modifications	happening now	small area/few individuals (<10%)	slow but significant deterioration	low
Pollution	garbage & solid waste	likely in short term (within 4 years)	small area/few individuals (<10%)	moderate to rapid deterioration	low
Residential and commercial development	commercial and industrial development	likely in short term (within 4 years)	small area/few individuals (<10%)	moderate to rapid deterioration	low
Transportation and service corridors	roads and railroads	likely in short term (within 4 years)	small area/few individuals (<10%)	moderate to rapid deterioration	low
Transportation and service corridors	shipping lanes	likely in short term (within 4 years)	small area/few individuals (<10%)	moderate to rapid deterioration	low

Condition of key/trigger populations (state)
Scientific	Common	TargetPop	ActualPop	Units	Remaining	Result
Mareca strepera	Gadwall	130	357	individuals	100	favourable
Recurvirostra avosetta	Pied Avocet	205	628	individuals	100	favourable
Charadrius hiaticula	Common Ringed Plover	585	737	individuals	100	favourable
Numenius arquata	Eurasian Curlew	1110	1495	individuals	100	favourable
Numenius arquata	Eurasian Curlew	1160	1412	individuals	100	favourable
Limosa limosa	Black-tailed Godwit	255	1247	individuals	100	favourable
Limosa limosa	Black-tailed Godwit	515	3299	individuals	100	favourable
Calidris alpina	Dunlin	12900	15181	individuals	100	favourable
Calidris alpina	Dunlin	5650	5541	individuals	99	favourable
Tringa totanus	Common Redshank	1890	1720	individuals	92	favourable
Tringa totanus	Common Redshank	1680	1285	individuals	77	not assessed
Species group - waterbirds	A4iii	36027	47805	individuals	100	favourable

Conservation actions taken at site (response)
Conservation Designation	Management Planning	Conservation Action	Result
Most of site (50-90%) covered (including the most critical parts for important bird species)	A management plan exists but it is out of date or not comprehensive	Some limited conservation initiatives are in place	low

For more information about IBA monitoring please click here

Protected Area	Designation	Area (ha)	Relationship with IBA	Overlap with IBA (ha)
West Thurrock Lagoon & Marshes	Site of Special Scientific Interest (UK)	67	protected area overlaps with site	0
Vange & Fobbing Marshes	Site of Special Scientific Interest (UK)	167	protected area is adjacent to site	0
Thames Estuary and Marshes	Marine Protected Area (OSPAR)	0	protected area overlaps with site	0
Thames Estuary and Marshes	Special Protection Area (Birds Directive)	4,802	protected area contained by site	4,839
Thames Estuary and Marshes	Ramsar Site, Wetland of International Importance	5,589	protected area overlaps with site	5,589
South Thames Estuary and Marshes	Site of Special Scientific Interest (UK)	5,289	protected area overlaps with site	5,355
South Essex Marshes	Nature Reserve	736	protected area is adjacent to site	0
Shorne Marshes	Nature Reserve	391	protected area overlaps with site	0
Rainham Marshes	Nature Reserve	409	protected area contained by site	0
Rainham Marshes	Local Nature Reserve	79	protected area overlaps with site	0
Northward Hill	Nature Reserve	364	protected area overlaps with site	0
Mucking Flats and Marshes	Site of Special Scientific Interest (UK)	313	protected area overlaps with site	0
Medway Estuary and Marshes	Marine Protected Area (OSPAR)	0	protected area is adjacent to site	0
Medway Estuary and Marshes	Special Protection Area (Birds Directive)	4,686	protected area is adjacent to site	0
Medway Estuary and Marshes	Site of Special Scientific Interest (UK)	4,748	protected area is adjacent to site	0
Medway Estuary & Marshes	Ramsar Site, Wetland of International Importance	4,697	protected area is adjacent to site	0
Medway Estuary	Marine Conservation Zone	6,000	protected area overlaps with site	0
Medway Estuary	Marine Protected Area (OSPAR)	5,800	protected area overlaps with site	0
Inner Thames Marshes	Site of Special Scientific Interest (UK)	486	protected area overlaps with site	487
Holehaven Creek	Site of Special Scientific Interest (UK)	273	protected area overlaps with site	0
Crossness	Local Nature Reserve	26	protected area is adjacent to site	0
Cliffe Pools	Nature Reserve	238	protected area overlaps with site	0
Canvey Wick	Site of Special Scientific Interest (UK)	93	protected area is adjacent to site	0

IUCN Habitat	Habitat detail	Extent (% of site)
Marine Intertidal		-
Forest	Broadleaved deciduous woodland, Mixed woodland	-
Shrubland	Scrub	-
Grassland	Humid grasslands	-
Wetlands (inland)	Water fringe vegetation	-
Artificial/Terrestrial	Arable land	-
Marine Neritic		-
Marine Coastal/Supratidal		-

For further information about the habitat classification please click here.

Land-use	Extent (% of site)
agriculture	-
nature conservation and research	-
urban/industrial/transport	-

For further information about the land use classification please click here.

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Recommended citation
BirdLife International (2023) Important Bird Areas factsheet: Thames Estuary and Marshes. Downloaded from http://www.birdlife.org on 29/01/2023.