Assessment Methodology

Which species may be assessed?

  • The Red List Categories and Criteria can be applied to all species, except micro-organisms.
  • The Red List Categories and Criteria may only be applied to wild individuals within their natural range.
  • When no more natural habitat remains, individuals reintroduced for the purposes of conservation in areas outside the natural range may be assessed once the population has proved to be self-sustaining.
  • The Red List Categories and Criteria are typically applied to species, but may also be applied to subspecies and varieties, or biologically isolated subpopulations of species. The national Red List of South African plants contain assessments for a number of subspecies and varieties of South African plants. Therefore Red List statistics often refer to numbers of taxa, rather than species, indicating that subspecies and varieties were also counted, rather than just species.
  • Newly discovered species that are not yet formally described may only be assessed under the following conditions: (1) There must be general agreement that it is clearly a distinct species. (2) The assessment of the species must be of clear conservation benefit. (3) A voucher specimen must be available in a museum or herbarium to allow the species to be traced and identified without confusion. (4) The species must be described within four years of its inclusion in a Red List.
  • No hybrids, cultivars or breeds may be assessed.
  • No domesticated individuals, or feral individuals derived from domesticated sources, may be assessed.
  • Naturalized or introduced individuals may not be assessed, unless the introduction was for the purposes of conservation, as described above.

How are assessments conducted?

Assessments are completed, published and updated in five stages: information collection, assessment workshops, assessment review, publication of assessments and updating of assessments.

1. Information collection
Red List scientists, who can be any biological scientist trained in the application of Red List criteria, will first collect all available information on the species that are to be assessed. Information is gathered from as wide a range of sources as possible, and can include any of the following:

  • Taxonomic, scientific and other literature provides information on the distribution, habitat, ecology and life histories of species.
  • Herbarium and museum specimens provide a historical overview of the location of species' subpopulations, thereby guiding field surveys. In the absence of field data, specimens can help scientists to estimate the number of subpopulations.
  • Electronic spatial data, such as those used in geographic information systems (GIS), can be used to calculate the extent of species' habitats, and maps of land uses can provide information on the threatening processes that may affect species. The extent of occurrence and area of occupancy (used in Criterion B) are calculated in GIS, using geo-referenced point data that indicate the location of existing subpopulations. Electronic spatial data, including climate data, combined with maps of species' distribution ranges have been used to forecast the potential impact of climate change on certain species.
  • Observation data obtained through public contributions to atlassing projects, either via structured surveys or submissions to virtual museums, provide vital information on the current distribution and status of populations of threatened species.
  • Monitoring data of threatened species collected by scientific institutions and national and provincial conservation agencies provide valuable information on population trends.
Once all available information has been collected, Red List scientists may use it as a basis to conduct preliminary Red List assessments.

2. Assessment workshops
Species' Red List assessments are generally conducted through workshops involving persons with expert knowledge on the species that are to be assessed. Experts can be scientists, taxonomists, conservationists, or even amateur scientists with a good knowledge of a particular group of species. Before assessments commence, it is very important that expert contributors to assessments are made aware of the purpose of Red List assessments (namely to determine extinction risk) as well as the supporting data requirements for the criteria. During the workshop, experts provide additional information to that already collected by the Red List scientists; the data are measured against the Red List criteria, and the appropriate Red List category is assigned to each species. Information typically provided by experts include the status of certain populations of the species that they are familiar with, local knowledge of threatening processes affecting the species, and general information on a species' life history, for example how often it reproduces, or its generation length. This type of information is often excluded from published literature.

3. Assessment review
After the workshop, the Red List scientists prepare the supporting documentation, containing the data validating species' Red List status for review. Red List assessments follow a peer-review system, and it is therefore important that all assessments are checked by reviewers who are independent from the assessment process.

4. Publication of assessments
After species' Red List assessments are completed, it is important that they are published in an accessible format so that they can be used to guide the conservation of threatened species. Global assessments conducted by SANBI's Threatened Species Programme are submitted to the IUCN for inclusion in the IUCN's international Red List of Threatened Species. The first complete assessment of the South African flora was published in book format (Raimondo et al. 2009), an updates to the national status of South African plants are published on this website.

5. Updating of assessments
New information about threatened species continually becomes available, and it is therefore important that assessments are updated to keep abreast of the latest available data. Red Lists play an important role in guiding conservation, but if assessments are left to become outdated, the already limited conservation resources might not be channelled to those species requiring the most urgent intervention.

The IUCN recommends the reassessment of species' status every five to ten years. Specific rules are also set to guide the movement of species between categories:

  • If successful conservation attempts improve the status of a species, thereby lowering its extinction risk, that species needs to be moved to a lower category. However, this may only be done after the new status has been maintained for at least five years. This condition is intended to ensure that the conservation measures are indeed effective, and to prevent the premature withdrawal of conservation support for the species.
  • If a species' situation has worsened, however, it should be moved to a higher category without delay.
  • If new information reveals that a species has been classified incorrectly, the species should be reassessed and the correct category applied without delay.

Updates to the Red List of South African plants

Updates to the Red List of South African plants are published every six months. Each update is given a unique version number. A species' status published on this site represents the current valid status for the species, and overrules all previously published statuses. It is therefore important to include the Red List version in citations when using any information published on this site. An assessment history is included in each species report to aid the tracking of status changes for species, and summaries of changes from the previous Red List version are included in the section Summary of recent changes.