Ecosystem Threat Status

Coastal zone

Linda R. Harris1 , Natasha Besseling2 , Kerry J. Sink2, 1 , Andrew L. Skowno2, 3 , Lara Van Niekerk4, 1

1. Nelson Mandela University

2. South African National Biodiversity Institute

3. University of Cape Town

4. Council for Scientific and Industrial Research

Published

November 11, 2025


71%
of 190 ecosystem types
Threatened
3
times more
Threatened Ecosystem Types
in the coastal zone
46%
of the coast extent
Threatened
8
times more
Threatened Area
in the coastal zone

Introduction

Ecosystem threat status (ETS), also called ecosystem red list status, is one of the headline indicators of the National Biodiversity Assessment. It is an indicator of the degree to which ecosystems are still intact or, alternatively, losing vital aspects of their structure, function or composition.

The IUCN Red List of Ecosystems (RLE) framework uses the concept of ecosystem collapse as the end point for ecosystem decline. The framework comprises a set of quantitative and qualitative criteria (and thresholds) linked to ecosystem extent, ecological condition, and threatening processes.

Each ecosystem type is assessed according to these criteria, and is then placed into one of several categories. Collectively, ecosystem types assessed as Critically Endangered, Endangered, or Vulnerable are called ‘threatened’. Collapsed is the ecosystem equivalent of the species category, Extinct.

  • Collapsed (CO)

  • Critically Endangered (CR)

  • Endangered (EN)

  • Vulnerable (VU)

  • Near Threatened (NT)

  • Least Concern (LC)

  • Not Evaluated (NE)

  • Data deficient (DD)

For NBA 2025, the RLE framework was applied across all realms, and the results are summarised here for the 190 coastal ecosystem types that were assessed. For more details on ETS, see the general introduction to this headline indicator.

Coastal Ecosystem Threat Status

The South African coast is proportionately more threatened than the rest of the country (entire non-coastal territory combined, Figure 2, Table 1). In fact, the coast (71% threatened ecosystem types) proportionately has 3 times more threatened ecosystem types than the rest of the country (22%), which is proportionately 8 times more by extent (coastal: 46%, non-coastal: 6%). Areas where threatened ecosystem types are concentrated are around the Orange River mouth, through most of the Western Cape, in St Francis and Algoa bays, and along virtually the entire East Coast (Figure 1).

Figure 1. Coastal ecosystem threat status, 2025.
Figure 2. Ecosystem threat status of coastal ecosystem types by (A) number of types and (B) extent of types

Of the 190 coastal ecosystem types in the EDCZ, 134 are threatened, comprising 40 Critically Endangered, 56 Endangered, and 38 Vulnerable ecosystem types (Figure 2, Table 1). These threatened types make up 99% of the estuarine realm, 49% of the coastal terrestrial extent, 43% of the coastal marine extent, and 46% of the overall coastal extent.

In comparison, there are 101 (22%) threatened ecosystem types that comprise 6% of the rest of the country (non-coastal land and sea). Proportionately, this means the coast has three times the number of threatened ecosystem types and almost an order of magnitude (eight times) more threatened area than the rest of the South African mainland territory (Figure 2, Table 1).

Table 1. Ecosystem threat status of coastal ecosystem types: number of types per threat category, given per across-shore zone (inland to offshore). Thr = Threatened (CR, EN, VU); CR = Critically Endangered; EN = Endangered; VU = Vulnerable; NT = Near Threatened; LC = Least Concern
Realm Sub-realm Thr CR EN VU NT LC Total
Coastal Terrestrial Total 57 34 22 1 0 26 83
Coastal Terrestrial Semi-coastal vegetation 28 16 12 0 0 8 36
Coastal Terrestrial Coastal vegetation 29 18 10 1 0 18 47
Estuarine Total 20 1 9 10 0 2 22
Coastal Marine Total 57 5 25 27 11 17 85
Coastal Marine Shore 18 0 11 7 10 9 37
Coastal Marine Inner shelf and river influenced 39 5 14 20 1 8 48
Coastal (overall) Total 134 40 56 38 11 45 190
Non-coastal Total 101 30 53 18 8 351 460
Table 2. Ecosystem threat status of coastal ecosystem types: proportion of types per threat category, given per across-shore zone (inland to offshore). Thr = Threatened (CR, EN, VU); CR = Critically Endangered; EN = Endangered; VU = Vulnerable; NT = Near Threatened; LC = Least Concern
Realm Sub-realm Thr CR EN VU NT LC Total
Coastal Terrestrial Total 68.7 41.0 26.5 1.2 0.0 31.3 100
Coastal Terrestrial Semi-coastal vegetation 77.8 44.4 33.3 0.0 0.0 22.2 100
Coastal Terrestrial Coastal vegetation 61.7 38.3 21.3 2.1 0.0 38.3 100
Estuarine Total 90.9 4.5 40.9 45.5 0.0 9.1 100
Coastal Marine Total 67.1 5.9 29.4 31.8 12.9 20.0 100
Coastal Marine Shore 48.6 0.0 29.7 18.9 27.0 24.3 100
Coastal Marine Inner shelf and river influenced 81.2 10.4 29.2 41.7 2.1 16.7 100
Coastal (overall) Total 70.5 21.1 29.5 20.0 5.8 23.7 100
Non-coastal Total 22.0 6.5 11.5 3.9 1.7 76.3 100
Table 3. Ecosystem threat status of coastal ecosystem types: proportion of extent per threat category, given per across-shore zone (inland to offshore). The extent of terrestrial ecosystem types is given as the percentage of remaining natural habitat. Thr = Threatened (CR, EN, VU); CR = Critically Endangered; EN = Endangered; VU = Vulnerable; NT = Near Threatened; LC = Least Concern
Realm Sub-realm Thr CR EN VU NT LC Total
Coastal Terrestrial Total 49.0 13.2 33.3 2.5 0.0 51.0 100
Coastal Terrestrial Semi-coastal vegetation 63.1 17.8 45.3 0.0 0.0 36.9 100
Coastal Terrestrial Coastal vegetation 40.1 10.4 25.7 4.0 0.0 59.9 100
Estuarine Total 99.1 1.4 71.7 26.0 0.0 0.9 100
Coastal Marine Total 43.1 5.5 20.8 16.8 1.7 55.2 100
Coastal Marine Shore 37.5 0.0 16.9 20.7 34.4 28.1 100
Coastal Marine Inner shelf and river influenced 43.2 5.7 20.8 16.7 1.1 55.7 100
Coastal (overall) Total 46.5 8.0 26.2 12.3 1.1 52.4 100
Non-coastal Total 5.7 0.3 2.4 3.0 1.5 92.8 100

Most (34) of the 40 Critically Endangered coastal ecosystem types are within the coastal portion of the terrestrial realm (Figure 1, Figure 2, Table 1), with a slightly higher proportion of types and extent among semi-coastal vegetation types (44% of types; 17.8% of extent) than coastal vegetation types (38% of types; 10.4% of extent). This is because pressures on land act more locally and intensively than they do in the aquatic realms, often causing complete habitat loss (e.g., houses replacing grasslands) rather than degrees of degradation (e.g., different pollution levels in estuaries).

Because the data and/or assessment methodologies have changed in the realm assessments since the NBA 2018, the results are not comparable between the two assessments. However, the latest results do show that the South African coastal zone is more threatened than was previously reported.

Table 4. Threat status of coastal ecosystem types in South Africa. ETS = Ecosystem Threat Status. CR = Critically Endangered. EN = Endangered. VU = Vulnerable. NT = Near Threatened. LC = Least Concern.
Realm Subrealm Ecosystem Type Threat Status
Terrestrial Coastal vegetation Agulhas Limestone Fynbos Critically Endangered
Terrestrial Coastal vegetation Agulhas Sand Fynbos Critically Endangered
Terrestrial Coastal vegetation Alexander Bay Coastal Duneveld Critically Endangered
Terrestrial Coastal vegetation Algoa Sandstone Fynbos Critically Endangered
Terrestrial Coastal vegetation Garden Route Granite Fynbos Critically Endangered
Terrestrial Coastal vegetation Goukamma Dune Thicket Critically Endangered
Terrestrial Coastal vegetation Groot Brak Dune Strandveld Critically Endangered
Terrestrial Coastal vegetation Hangklip Sand Fynbos Critically Endangered
Terrestrial Coastal vegetation Lambert's Bay Strandveld Critically Endangered
Terrestrial Coastal vegetation Namaqualand Seashore Vegetation Critically Endangered
Terrestrial Coastal vegetation Namib Seashore Vegetation Critically Endangered
Terrestrial Coastal vegetation Peninsula Granite Fynbos Critically Endangered
Terrestrial Coastal vegetation Peninsula Shale Renosterveld Critically Endangered
Terrestrial Coastal vegetation Potberg Sandstone Fynbos Critically Endangered
Terrestrial Coastal vegetation Richtersveld Coastal Duneveld Critically Endangered
Terrestrial Coastal vegetation Saldanha Granite Strandveld Critically Endangered
Terrestrial Coastal vegetation Saldanha Limestone Strandveld Critically Endangered
Terrestrial Coastal vegetation Southern Cape Dune Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Cape Flats Sand Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Cape Winelands Shale Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Gouritz Valley Thicket Critically Endangered
Terrestrial Semi-coastal vegetation Grootbos Strandveld Critically Endangered
Terrestrial Semi-coastal vegetation Knysna Sand Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Kogelberg Sandstone Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Lourensford Alluvium Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Mossel Bay Shale Renosterveld Critically Endangered
Terrestrial Semi-coastal vegetation Motherwell Karroid Thicket Critically Endangered
Terrestrial Semi-coastal vegetation Namib Lichen Fields Critically Endangered
Terrestrial Semi-coastal vegetation Peninsula Sandstone Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Peninsula Shale Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Potberg Ferricrete Fynbos Critically Endangered
Terrestrial Semi-coastal vegetation Sardinia Forest Thicket Critically Endangered
Terrestrial Semi-coastal vegetation St Francis Strandveld Critically Endangered
Terrestrial Semi-coastal vegetation Umtiza Forest Thicket Critically Endangered
Terrestrial Coastal vegetation Cape Flats Dune Strandveld Endangered
Terrestrial Coastal vegetation Hartenbos Dune Thicket Endangered
Terrestrial Coastal vegetation KwaZulu-Natal Coastal Belt Grassland Endangered
Terrestrial Coastal vegetation Langebaan Dune Strandveld Endangered
Terrestrial Coastal vegetation Mangrove Forest Endangered
Terrestrial Coastal vegetation Maputaland Coastal Belt Endangered
Terrestrial Coastal vegetation Overberg Dune Strandveld Endangered
Terrestrial Coastal vegetation Saldanha Flats Strandveld Endangered
Terrestrial Coastal vegetation St Francis Dune Thicket Endangered
Terrestrial Coastal vegetation Transkei Coastal Belt Endangered
Terrestrial Semi-coastal vegetation Albertinia Sand Fynbos Endangered
Terrestrial Semi-coastal vegetation Atlantis Sand Fynbos Endangered
Terrestrial Semi-coastal vegetation Eastern Coastal Shale Band Vegetation Endangered
Terrestrial Semi-coastal vegetation Elim Ferricrete Fynbos Endangered
Terrestrial Semi-coastal vegetation Garden Route Shale Fynbos Endangered
Terrestrial Semi-coastal vegetation Hopefield Sand Fynbos Endangered
Terrestrial Semi-coastal vegetation Humansdorp Shale Renosterveld Endangered
Terrestrial Semi-coastal vegetation Maputaland Wooded Grassland Endangered
Terrestrial Semi-coastal vegetation Overberg Sandstone Fynbos Endangered
Terrestrial Semi-coastal vegetation South Eastern Coastal Thornveld Endangered
Terrestrial Semi-coastal vegetation Southeastern Strandveld Endangered
Terrestrial Semi-coastal vegetation Southwestern Strandveld Endangered
Terrestrial Coastal vegetation Pondoland-Ugu Sandstone Coastal Sourveld Vulnerable
Terrestrial Coastal vegetation Canca Limestone Fynbos Least Concern
Terrestrial Coastal vegetation Cape Seashore Vegetation Least Concern
Terrestrial Coastal vegetation Hamburg Dune Thicket Least Concern
Terrestrial Coastal vegetation Kasouga Dune Thicket Least Concern
Terrestrial Coastal vegetation Namaqualand Coastal Duneveld Least Concern
Terrestrial Coastal vegetation Namaqualand Heuweltjie Strandveld Least Concern
Terrestrial Coastal vegetation Namaqualand Inland Duneveld Least Concern
Terrestrial Coastal vegetation Namaqualand Sand Fynbos Least Concern
Terrestrial Coastal vegetation Namaqualand Strandveld Least Concern
Terrestrial Coastal vegetation Northern Coastal Forest Least Concern
Terrestrial Coastal vegetation Northern Richtersveld Yellow Duneveld Least Concern
Terrestrial Coastal vegetation Richtersveld Sandy Coastal Scorpionstailveld Least Concern
Terrestrial Coastal vegetation Southern Coastal Forest Least Concern
Terrestrial Coastal vegetation Southern Richtersveld Yellow Duneveld Least Concern
Terrestrial Coastal vegetation Subtropical Dune Thicket Least Concern
Terrestrial Coastal vegetation Subtropical Seashore Vegetation Least Concern
Terrestrial Coastal vegetation Swamp Forest Least Concern
Terrestrial Coastal vegetation Western Gariep Plains Desert Least Concern
Terrestrial Semi-coastal vegetation Albany Mesic Thicket Least Concern
Terrestrial Semi-coastal vegetation Bethelsdorp Bontveld Least Concern
Terrestrial Semi-coastal vegetation De Hoop Limestone Fynbos Least Concern
Terrestrial Semi-coastal vegetation Elands Forest Thicket Least Concern
Terrestrial Semi-coastal vegetation Goukamma Strandveld Least Concern
Terrestrial Semi-coastal vegetation Grassridge Bontveld Least Concern
Terrestrial Semi-coastal vegetation Southern Afrotemperate Forest Least Concern
Terrestrial Semi-coastal vegetation Tsitsikamma Sandstone Fynbos Least Concern
Estuarine Estuaries Subtropical Estuarine Bay Critically Endangered
Estuarine Estuaries Cool Temperate Arid Predominantly Closed Endangered
Estuarine Estuaries Cool Temperate Estuarine Lagoon Endangered
Estuarine Estuaries Cool Temperate Estuarine Lake Endangered
Estuarine Estuaries Cool Temperate Large Fluvially Dominated Endangered
Estuarine Estuaries Cool Temperate Large Temporarily Closed Endangered
Estuarine Estuaries Cool Temperate Predominantly Open Endangered
Estuarine Estuaries Subtropical Estuarine Lake Endangered
Estuarine Estuaries Subtropical Large Fluvially Dominated Endangered
Estuarine Estuaries Warm Temperate Estuarine Lake Endangered
Estuarine Estuaries Cool Temperate Small Fluvially Dominated Vulnerable
Estuarine Estuaries Cool Temperate Small Temporarily Closed Vulnerable
Estuarine Estuaries Subtropical Large Temporarily Closed Vulnerable
Estuarine Estuaries Subtropical Predominantly Open Vulnerable
Estuarine Estuaries Subtropical Small Temporarily Closed Vulnerable
Estuarine Estuaries Tropical Estuarine Lake Vulnerable
Estuarine Estuaries Warm Temperate Estuarine Bay Vulnerable
Estuarine Estuaries Warm Temperate Large Fluvially Dominated Vulnerable
Estuarine Estuaries Warm Temperate Large Temporarily Closed Vulnerable
Estuarine Estuaries Warm Temperate Predominantly Open Vulnerable
Estuarine Estuaries Warm Temperate Small Fluvially Dominated Least Concern
Estuarine Estuaries Warm Temperate Small Temporarily Closed Least Concern
Marine Inner shelf and river influenced Agulhas Muddy Mid Shelf Critically Endangered
Marine Inner shelf and river influenced Aliwal Shoal Reef Complex Critically Endangered
Marine Inner shelf and river influenced Cape Bay Critically Endangered
Marine Inner shelf and river influenced KZN Bight Muddy Inner Shelf Critically Endangered
Marine Inner shelf and river influenced Orange Cone Inner Shelf Mud Reef Mosaic Critically Endangered
Marine Inner shelf and river influenced Durnford Inner Shelf Reef Complex Endangered
Marine Inner shelf and river influenced Eastern Agulhas Bay Endangered
Marine Inner shelf and river influenced False and Walker Bay Endangered
Marine Inner shelf and river influenced KZN Bight Deep Shelf Edge Endangered
Marine Inner shelf and river influenced KZN Bight Mid Shelf Mosaic Endangered
Marine Inner shelf and river influenced KZN Bight Mid Shelf Reef Complex Endangered
Marine Inner shelf and river influenced KZN Bight Sandy Inner Shelf Endangered
Marine Inner shelf and river influenced Kei Fluvial Fan Endangered
Marine Inner shelf and river influenced Kei Reef Mosaic Endangered
Marine Inner shelf and river influenced Orange Cone Muddy Mid Shelf Endangered
Marine Inner shelf and river influenced Southern KZN Inner Shelf Mosaic Endangered
Marine Inner shelf and river influenced St Helena Bay Endangered
Marine Inner shelf and river influenced Trafalgar Reef Complex Endangered
Marine Inner shelf and river influenced Western Agulhas Bay Endangered
Marine Shore Agulhas Reflective Sandy Shore Endangered
Marine Shore Agulhas Sheltered Rocky Shore Endangered
Marine Shore Cape Island Endangered
Marine Shore Cape Mixed Shore Endangered
Marine Shore Cape Sheltered Rocky Shore Endangered
Marine Shore Namaqua Exposed Rocky Shore Endangered
Marine Shore Namaqua Mixed Shore Endangered
Marine Shore Namaqua Sheltered Rocky Shore Endangered
Marine Shore Namaqua Very Exposed Rocky Shore Endangered
Marine Shore Natal Delagoa Reflective Sandy Shore Endangered
Marine Shore Southern Benguela Reflective Sandy Shore Endangered
Marine Inner shelf and river influenced Agulhas Inner Shelf Mosaic Vulnerable
Marine Inner shelf and river influenced Agulhas Kelp Forest Vulnerable
Marine Inner shelf and river influenced Agulhas Sandy Inner Shelf Vulnerable
Marine Inner shelf and river influenced Cape Kelp Forest Vulnerable
Marine Inner shelf and river influenced Cape Rocky Inner Shelf Vulnerable
Marine Inner shelf and river influenced Durnford Mid Shelf Reef Complex Vulnerable
Marine Inner shelf and river influenced KZN Bight Muddy Shelf Edge Vulnerable
Marine Inner shelf and river influenced KZN Bight Outer Shelf Mosaic Vulnerable
Marine Inner shelf and river influenced Kosi Coral Community Vulnerable
Marine Inner shelf and river influenced Leadsman Coral Community Vulnerable
Marine Inner shelf and river influenced Namaqua Kelp Forest Vulnerable
Marine Inner shelf and river influenced Port St Johns Inner Shelf Mosaic Vulnerable
Marine Inner shelf and river influenced Port St Johns Muddy Mid Shelf Vulnerable
Marine Inner shelf and river influenced Port St Johns Muddy Shelf Edge Vulnerable
Marine Inner shelf and river influenced Sodwana Coral Community Vulnerable
Marine Inner shelf and river influenced St Lucia Sandy Mid Shelf Vulnerable
Marine Inner shelf and river influenced Wild Coast Inner Shelf Mosaic Vulnerable
Marine Inner shelf and river influenced uThukela Mid Shelf Mosaic Vulnerable
Marine Inner shelf and river influenced uThukela Mid Shelf Mud Coarse Sediment Mosaic Vulnerable
Marine Inner shelf and river influenced uThukela Outer Shelf Muddy Reef Mosaic Vulnerable
Marine Shore Agulhas Exposed Rocky Shore Vulnerable
Marine Shore Agulhas Island Vulnerable
Marine Shore Agulhas Stromatolite Mixed Shore Vulnerable
Marine Shore Cape Boulder Shore Vulnerable
Marine Shore Cape Exposed Rocky Shore Vulnerable
Marine Shore Natal Boulder Shore Vulnerable
Marine Shore Natal Mixed Shore Vulnerable
Marine Inner shelf and river influenced Cape Sandy Inner Shelf Near Threatened
Marine Shore Agulhas Boulder Shore Near Threatened
Marine Shore Agulhas Dissipative Sandy Shore Near Threatened
Marine Shore Agulhas Exposed Stromatolite Rocky Shore Near Threatened
Marine Shore Agulhas Mixed Shore Near Threatened
Marine Shore Agulhas Very Exposed Stromatolite Rocky Shore Near Threatened
Marine Shore Natal Delagoa Dissipative Sandy Shore Near Threatened
Marine Shore Natal Delagoa Intermediate Sandy Shore Near Threatened
Marine Shore Natal Exposed Rocky Shore Near Threatened
Marine Shore Natal Very Exposed Rocky Shore Near Threatened
Marine Shore Southern Benguela Intermediate Sandy Shore Near Threatened
Marine Inner shelf and river influenced Agulhas Inner Shelf Reef Least Concern
Marine Inner shelf and river influenced Delagoa Sandy Inner Shelf Least Concern
Marine Inner shelf and river influenced Namaqua Mid Shelf Fossils Least Concern
Marine Inner shelf and river influenced Namaqua Muddy Mid Shelf Mosaic Least Concern
Marine Inner shelf and river influenced Namaqua Muddy Sands Least Concern
Marine Inner shelf and river influenced Namaqua Sandy Inner Shelf Least Concern
Marine Inner shelf and river influenced Namaqua Sandy Mid Shelf Least Concern
Marine Inner shelf and river influenced St Lucia Sandy Inner Shelf Least Concern
Marine Shore Agulhas Dissipative Intermediate Sandy Shore Least Concern
Marine Shore Agulhas Intermediate Sandy Shore Least Concern
Marine Shore Agulhas Very Exposed Rocky Shore Least Concern
Marine Shore Cape Very Exposed Rocky Shore Least Concern
Marine Shore Delagoa Mixed Shore Least Concern
Marine Shore Delagoa Very Exposed Rocky Shore Least Concern
Marine Shore Natal Delagoa Dissipative Intermediate Sandy Shore Least Concern
Marine Shore Southern Benguela Dissipative Intermediate Sandy Shore Least Concern
Marine Shore Southern Benguela Dissipative Sandy Shore Least Concern

Technical documentation

Github repositories

Coastal synthesis: https://github.com/lrharris/nba2025_coast/

Terrestrial RLE assessment: https://github.com/askowno/RLE_terr

Estuarine RLE assessment: https://github.com/askowno/RLE_est

Marine RLE assessment: https://gitlab.com/nba_2025/ecosystem_assessment/threat_status

Data availability

The following datasets are available for download:

  1. Map of ecosystem threat status of South Africa’s coastal ecosystem types

References