Data Zone
The site was identified as internationally important for bird conservation 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 List | Season (year/s of estimate) | Size | IBA criteria |
|---|---|---|---|---|
| African Penguin Spheniscus demersus | CR | resident (-) | 8,000–9,000 pairs | A1, A4ii |
| African Penguin Spheniscus demersus | CR | non-breeding (-) | 30,000 birds | A1, A4ii |
| Crowned Cormorant Microcarbo coronatus | LC | resident (-) | 80–175 pairs | A1, A4i |
| Crowned Cormorant Microcarbo coronatus | LC | non-breeding (-) | 400 birds | A1, A4i |
| Cape Cormorant Phalacrocorax capensis | EN | resident (-) | 13,767–48,000 pairs | A1, A4i |
| Cape Cormorant Phalacrocorax capensis | EN | non-breeding (-) | 30,000–100,000 birds | A1, A4i |
| Bank Cormorant Phalacrocorax neglectus | EN | resident (-) | 30–50 pairs | A1 |
| Bank Cormorant Phalacrocorax neglectus | EN | non-breeding (-) | 50–200 birds | A1, A4i |
| African Oystercatcher Haematopus moquini | LC | resident (-) | 100 pairs | A1, A4i |
| African Oystercatcher Haematopus moquini | LC | non-breeding (-) | 221–436 birds | A1, A4i |
| Ruddy Turnstone Arenaria interpres | NT | winter (-) | 416 birds | A4i |
| Hartlaub's Gull Larus hartlaubii | LC | breeding (-) | 30–100 pairs | A4i |
| Hartlaub's Gull Larus hartlaubii | LC | non-breeding (-) | 250 birds | A4i |
| Kelp Gull Larus dominicanus | LC | breeding (-) | 5,000–7,500 pairs | A4i |
| Kelp Gull Larus dominicanus | LC | non-breeding (-) | 12,000–18,000 birds | A4i |
| Greater Crested Tern Thalasseus bergii | LC | breeding (-) | 3,038 pairs | A4i |
| Greater Crested Tern Thalasseus bergii | LC | non-breeding (-) | 400–7,000 birds | A4i |
| A4iii Species group - seabirds | n/a | non-breeding (-) | 50,000-99,999 birds | A4iii |
| A4iii Species group - seabirds | n/a | resident (-) | 100,000-499,999 birds | A4iii |
| A4iii Species group - waterbirds | n/a | breeding (-) | 20,000-49,999 birds | A4iii |
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.
| IBA conservation assessment | |||
|---|---|---|---|
| Year of assessment | State | Pressure | Response |
| 2013 | good | high | high |
| Whole site assessed? | State assessed by | Accuracy of information | |
| yes | habitat | medium | |
| State (condition of the trigger species' populations) | |||||
|---|---|---|---|---|---|
| Species | Actual vs Reference (units) | % remaining | Result | ||
| African Penguin Spheniscus demersus | 16,000 / 30,000 (birds) | 54 | poor | ||
| Hydrobates leucorhous | 5 / 5 (pairs) | 100 | good | ||
| Great White Pelican Pelecanus onocrotalus | 450 / 550 (pairs) | 82 | moderate | ||
| Crowned Cormorant Microcarbo coronatus | 280 / 175 (pairs) | 100 | good | ||
| Cape Cormorant Phalacrocorax capensis | 765 / 13,767 (pairs) | 6 | very poor | ||
| Bank Cormorant Phalacrocorax neglectus | 70 / 50 (pairs) | 100 | good | ||
| African Oystercatcher Haematopus moquini | 280 / 436 (birds) | 65 | poor | ||
| Hartlaub's Gull Larus hartlaubii | 1,327 / 100 (pairs) | 100 | good | ||
| Kelp Gull Larus dominicanus | 1,739 / 7,500 (pairs) | 24 | very poor | ||
| Greater Crested Tern Thalasseus bergii | 1,477 / 3,038 (pairs) | 49 | poor | ||
| State (condition of the trigger species' habitats) | |||
|---|---|---|---|
| Habitat | Quantity (% remaining) | Quality (% carrying capacity) | Result |
| Marine Coastal/Supratidal | good (>90%) | good (>90%) | good |
| Pressure (threats to the trigger species and/or their habitats) | ||||
|---|---|---|---|---|
| Threat | Timing | Scope | Severity | Result |
| Human intrusions and disturbance | happening now | some of population/area (10–49%) | slow decline (1–10% over 3 generations) | medium |
| Pollution | happening now | some of population/area (10–49%) | slow decline (1–10% over 3 generations) | medium |
| Climate change and severe weather | happening now | some of population/area (10–49%) | slow decline (1–10% over 3 generations) | medium |
| Energy production and mining | likely in short term (<4 years) | some of population/area (10–49%) | moderate decline (10–30% over 3 generations) | medium |
| Natural system modifications | happening now | few individuals/small area (<10%) | slow decline (1–10% over 3 generations) | low |
| Residential and commercial development | happening now | few individuals/small area (<10%) | no or slight decline (<1% over 3 generations) | low |
| Transportation and service corridors | happening now | few individuals/small area (<10%) | no or slight decline (<1% over 3 generations) | low |
| Biological resource use | happening now | few individuals/small area (<10%) | no or slight decline (<1% over 3 generations) | low |
| Invasive and other problematic species and genes | happening now | few individuals/small area (<10%) | no or slight decline (<1% over 3 generations) | low |
| Response (conservation actions taken for the trigger species and/or their habitats) | |||
|---|---|---|---|
| Designation | Planning | Action | Result |
| Whole area (>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 (management category) | % coverage of IBA |
|---|---|---|---|
| 2000 | Cape West Coast Biosphere Reserve | UNESCO-MAB Biosphere Reserve (UA) | 100 |
| Habitat | % of IBA | Habitat detail |
|---|---|---|
| Marine Coastal/Supratidal | major (>10) | |
| Marine Intertidal | major (>10) |
| Land use | % of IBA |
|---|---|
| unknown | - |
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 23/12/2024.