This discussion was first published as part of the 2017 Red List update.
Assessments against criterion B2 require the Area of Occupancy (AOO) to meet a threshold size (<10km2 for Critically Endangered; <500km2 for Endangered; <2,000km2 for Vulnerable; no threshold set by IUCN for Near Threatened but for this analysis one was arbitrarily set at <2,500km2), and at least two further conditions must also be met. These further conditions are a) the species’s range is severely fragmented or restricted to a certain number of locations* (1 for CR; 2-5 for EN; 6-10 for VU), b) continuing decline in i) extent of occurrence, ii) area of occupancy, iii) area/extent/quality of habitat, iv) number of locations/subpopulations or v) number of mature individuals, and c) extreme fluctuations in i) extent of occurrence, ii) area of occupancy, iii) number of locations/subpopulations or iv) number of mature individuals.
Listing as Near Threatened need not only be confined to species with an AOO of 2,000km2-2,500km2, and fulfilling at least two of the further conditions. Species with a far smaller AOO but which do not fully meet the further conditions required for listing as Vulnerable, may also warrant listing as Near Threatened, because they approach the threshold for listing as Vulnerable (e.g. a species with an AOO of 450km2, found at 12 locations which are fragmented but NOT severely fragmented, where the habitat area is declining, but there is no evidence for any extreme fluctuations, would merit listing as Near Threatened).
A total of >350 species reached the threshold for a higher Red List category based on AOO alone, but the vast majority of these did not fulfil the other conditions required for listing under criterion B2. Of these species, 29 potentially warrant uplisting to a higher category based on an assessment against B2. These 29 are the species presented in the pdf below. It should be noted that not all of the species presented are proposed for uplisting. The 29 species represent the species that have the greatest potential for uplisting based on criterion B2. For those where our proposed decision is not to uplist them they have been put forward here because comments/further information may mean that these species end up being proposed for uplisting.
Additionally, not all of the species presented in the pdf are proposed for uplisting under criterion B2 alone. The reassessment against the conditions for criterion B2 also meant that some of the species presented in the pdf will also qualify for uplisting under other criteria, and in fact this may be the most appropriate listing for the species rather than under criterion B2. However, all of the species in this topic do have the potential for uplisting under criterion B2. Species that qualify for uplisting solely under other criteria are not part of this forum topic but will be presented in other topics in the future.
The pdf can be downloaded here: Assessment of species with potential uplisting under criterion B2.
In the pdf we present for each species:
- Its AOO, calculated as the remaining tree area within the species’s range, from (Ł. Tracewski unpublished data), and its EOO.
- Whether the species’s range/habitat and population are deemed to be in decline.
- Whether the species’s range is considered to be (severely) fragmented.
- Whether the number of locations where the species occurs meets the threshold for listing under a Threatened category.
- The highest potential Red List status for the species.
- The Red List status that will be proposed to IUCN in the absence of further information or comments.
- Justification for the difference between the highest RL status and the proposed RL status where applicable.
Comments or further information regarding these proposed Red List statuses are very welcome.
*Note that the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. Gland, Switzerland and Cambridge, UK: IUCN Species Survival Commission.
IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.
Tracewski, Ł.; Butchart, S. H. M.; Di Marco, M.; Ficetola, G. F.; Rondinini, C.; Symes, A.; Wheatley, H.; Beresford, A. E.; Buchanan, G. M. 2016. Toward quantification of the impact of 21st-century deforestation on the extinction risk of terrestrial vertebrates. Conservation Biology 30: 1070-1079.