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The site was identified as important in 1998 because it was regularly supporting significant populations of the species listed below, meeting ('triggering') IBA criteria.

Populations meeting IBA criteria ('trigger species') at the site:

Species	Red List1	Season	Year(s)	Size	IBA criteria
African Penguin Spheniscus demersus	CR	resident	-	8,000-9,000 breeding pairs	A1, A4ii
African Penguin Spheniscus demersus	CR	non-breeding	-	30,000 individuals	A1, A4ii
Crowned Cormorant Microcarbo coronatus	LC	resident	-	80-175 breeding pairs	A1, A4i
Crowned Cormorant Microcarbo coronatus	LC	non-breeding	-	400 individuals	A1, A4i
Cape Cormorant Phalacrocorax capensis	EN	resident	-	13,767-48,000 breeding pairs	A1, A4i
Cape Cormorant Phalacrocorax capensis	EN	non-breeding	-	30,000-100,000 individuals	A1, A4i
Bank Cormorant Phalacrocorax neglectus	EN	resident	-	30-50 breeding pairs	A1
Bank Cormorant Phalacrocorax neglectus	EN	non-breeding	-	50-200 individuals	A1, A4i
African Oystercatcher Haematopus moquini	LC	resident	-	100 breeding pairs	A1, A4i
African Oystercatcher Haematopus moquini	LC	non-breeding	-	221-436 individuals	A1, A4i
Ruddy Turnstone Arenaria interpres	NT	winter	-	416 individuals	A4i
Hartlaub's Gull Larus hartlaubii	LC	breeding	-	30-100 breeding pairs	A4i
Hartlaub's Gull Larus hartlaubii	LC	non-breeding	-	250 individuals	A4i
Kelp Gull Larus dominicanus	LC	breeding	-	5,000-7,500 breeding pairs	A4i
Kelp Gull Larus dominicanus	LC	non-breeding	-	12,000-18,000 individuals	A4i
Greater Crested Tern Thalasseus bergii	LC	breeding	-	3,038 breeding pairs	A4i
Greater Crested Tern Thalasseus bergii	LC	non-breeding	-	400-7,000 individuals	A4i
A4iii Species group - seabirds	n/a	non-breeding	-	50,000-99,999 individuals	A4iii
A4iii Species group - seabirds	n/a	resident	-	100,000-499,999 individuals	A4iii
A4iii Species group - waterbirds	n/a	breeding	-	20,000-49,999 individuals	A4iii

1. The current IUCN Red List category. The category at the time of the IBA criteria assessment (1998) may differ.

Ideally the conservation status of the IBA will have been checked regularly since the site was first identified in 1998. The most recent assessment (2013) is shown below.

State (condition of the trigger species' populations)
Species	Reference	Actual	Units	% remaining	Result
African Penguin Spheniscus demersus	30,000	16,000	individuals	54	unfavourable
Hydrobates leucorhous	5	5	breeding pairs	100	favourable
Great White Pelican Pelecanus onocrotalus	550	450	breeding pairs	82	near favourable
Crowned Cormorant Microcarbo coronatus	175	280	breeding pairs	100	favourable
Cape Cormorant Phalacrocorax capensis	13,767	765	breeding pairs	6	very unfavourable
Bank Cormorant Phalacrocorax neglectus	50	70	breeding pairs	100	favourable
African Oystercatcher Haematopus moquini	436	280	individuals	65	unfavourable
Hartlaub's Gull Larus hartlaubii	100	1,327	breeding pairs	100	favourable
Kelp Gull Larus dominicanus	7,500	1,739	breeding pairs	24	very unfavourable
Greater Crested Tern Thalasseus bergii	3,038	1,477	breeding pairs	49	unfavourable

State (condition of the trigger species' habitats)
Habitat	Quantity (% remaining)	Quality (% carrying capacity)	Result
Marine Coastal/Supratidal	good (> 90%)	good (> 90%)	favourable

Pressure (threats to the trigger species and/or their habitats)
Threat	Timing	Scope	Severity	Result
Transportation and service corridors	happening now	some of area/population (10-49%)	moderate to rapid deterioration	high
Energy production and mining	likely in short term (within 4 years)	some of area/population (10-49%)	moderate to rapid deterioration	medium
Pollution	likely in short term (within 4 years)	some of area/population (10-49%)	moderate to rapid deterioration	medium
Biological resource use	happening now	some of area/population (10-49%)	slow but significant deterioration	medium
Human intrusions and disturbance	happening now	some of area/population (10-49%)	slow but significant deterioration	medium
Invasive and other problematic species and genes	happening now	some of area/population (10-49%)	slow but significant deterioration	medium
Climate change and severe weather	happening now	some of area/population (10-49%)	slow but significant deterioration	medium
Natural system modifications	happening now	small area/few individuals (<10%)	slow but significant deterioration	low
Residential and commercial development	happening now	small area/few individuals (<10%)	no or imperceptible deterioration	low

Response (conservation actions taken for the trigger species and/or their habitats)
Protected areas	Management plan	Other action	Result
Whole area of site (>90%) covered by appropriate conservation designation	A comprehensive and appropriate management plan exists that aims to maintain or improve the populations of qualifying bird species	Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity	high

Year	Protected Area	Designation	% overlap with IBA
1988	Dassen Island Provincial Nature Reserve	Nature Reserve	37
2000	Cape West Coast Biosphere Reserve	UNESCO-MAB Biosphere Reserve	100

Habitat1	Habitat detail	% of IBA
Marine Coastal/Supratidal		major (>10)
Marine Intertidal		major (>10)

1. IUCN Habitat classification.

Land use	% of IBA
unknown	-

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Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Dassen Island (South Africa). Downloaded from https://datazone.birdlife.org/site/factsheet/dassen-island-iba-south-africa on 23/11/2024.