DOI: 10.15493/sarva.quartets.10000002
title: National Biodiversity Assessment (NBA) Ecosystem Threat Status

description: Ecosystem threat status is a headline indicator for the National Biodiversity Assessment 2011. The threatened terrestrial ecosystems identified in the NBA 2011 are the same as those listed as threatened ecosystems in December 2011

Ecosystem threat status tells us about the degree to which ecosystems are still intact or alternatively losing vital aspects of their structure, function and composition, on which their ability to provide ecosystem services ultimately depends. Ecosystem types are categorized as critically endangered (CR), endangered (EN), vulnerable (VU) or least threatened (LT), based on the proportion of each ecosystem type that remains in good ecological condition relative to a series of thresholds.

Threatened ecosystems make up 9.5% of the country, with critically endangered and endangered ecosystems together accounting for 2.7% and vulnerable ecosystems a further 6.8%.

The mapping of terrestrial ecosystems was based on the South African vegetation map, national forest types or high irreplaceability forest patches or clusters systematically identified by recognized by DWAF. In addition some priority areas identified in a provincial systematic biodiversity plan in Gauteng, KwaZulu Natal and Mpumalanga provincial conservation authorities were also included.

This shapefile uses the South African Vegetation Map as a base file. Most of the original attributes of the original vegetation map are retained. For the purpose of the NBA all vegetation types are classified as ecosystems. The “map code” column and vegmap avl can be used to view the South African vegetation map. To view the threatened ecosystems the Eco_Status field together with the “Vegmap_with_threatened_ecosystems” layer file to display threat status. The “TE name” field shows the name of the Threatened ecosystem. Names for the threatened ecosystems come from the South African vegetation map, the DAFF forest types or a provincial conservation plan. The “TE_SOURCE” column will indicate where the ecosystem name and description is from.

Six criteria were developed for identifying threatened terrestrial ecosystems. Of these six criteria, four (A, C, D1 and F) were used and the remaining two (B and E) are dormant owing to lack of data. Two of the criteria (A and D) were split into sub-criteria. The six criteria for threatened terrestrial ecosystems are:
Criterion A1: Irreversible loss of natural habitat
Criterion A2: Ecosystem degradation and loss of integrity
Criterion B: Rate of loss of natural habitat
Criterion C: Limited extent and imminent threat
Criterion D1: Threatened plant species associations
Criterion D2: Threatened animal species associations
Criterion E: Habitat Fragmentation
Criterion F: Priority areas for meeting explicit biodiversity targets as defined in a systematic biodiversity plan

The criteria and thresholds for critically endangered, endangered and vulnerable ecosystems and explained in more detail in the document on Threatened Ecosystems in South Africa: General Information.
Note: the data represents the original extent of listed ecosystems; in other words, natural areas which have been converted to agriculture, mining and urban areas have been included. It is important to note that while the original extent of each listed ecosystem has been mapped, a basic assessment report in terms of the
EIA regulations is only triggered in remaining natural habitat within each ecosystem and not in portions of the ecosystem where natural habitat has already been irreversibly lost.

See and refer to the following reports for more information:
Threatened Ecosystems in South Africa: General Information (available on BGIS website)
Threatened Ecosystems in South Africa: Descriptions and Maps (available on BGIS website)
National Biodiversity Assessment 2011 Terrestrial Report. (available on BGIS website)
Mucina, L & Rutherford, M.C.(eds) 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute. Pretoria