The document provides an introduction to the IUCN Red Listing process. It describes the scope and categories of the IUCN Red List, including threatened categories like Critically Endangered, Endangered, and Vulnerable. It also defines key terms used in IUCN criteria like population size, subpopulations, decline, and location. Acceptable data types are discussed, as well as the five criteria used to evaluate taxa for listing: reductions, range size, population size and decline, very small or restricted populations, and quantitative analysis.

1. Introduction to the IUCN Red Listing Process

2. The IUCN Red List assessment estimates risk of extinction What is the likelihood of a species becoming extinct in the near future, given current knowledge about population trends, range, and recent, current or projected threats?

3. The IUCN Red List Categories & Criteria

4. Scope of Application All described taxa (species, subspecies, varieties), except micro-organisms Taxa not yet formally described, but only if they are: A clearly distinct species; Museum/herbarium voucher references are provided; Distribution information is available; There is clear conservation benefit to assessing the species. IUCN Categories and Criteria can be applied to : The IUCN Red List Categories and Criteria are : Used to assess taxa at the global level Can be used at regional levels (but see the Guidelines for Application of IUCN Red List Criteria at Regional Levels ) Used to assess wild populations inside their natural range (including populations resulting from benign introductions)

5. The IUCN Categories Not Evaluated (NE) Near Threatened (NT) Data Deficient (DD) THREATENED Endangered (EN) Critically Endangered (CR) Vulnerable (VU) Extinct in the Wild (EW) Extinct (EX) Least Concern (LC)

6. A taxon is Extinct when there is no reasonable doubt that the last individual has died. Dodo, Raphus cucullatus Extinct (EX) Extinct in the Wild (EW) A taxon is Extinct in the Wild when it is known only to survive in cultivation, in captivity or as a naturalized population (or populations) well outside the past range. Franklinia, Franklinia alatamaha Photo © Craig Hilton-Taylor

7. A taxon is threatened when the best available evidence indicates that it meets any of the criteria A to E for the thresholds stated in one of the three threatened categories: Critically Endangered, Endangered or Vulnerable. Critically Endangered (CR) CR taxa are considered to be facing an extremely high risk of extinction in the wild Mandrinette, Hibiscus fragilis Photo © Wendy Strahm Endangered (EN) EN taxa are considered to be facing a very high risk of extinction in the wild Black-browed Albatross, Thalassarche melanophrys Photo © Tony Palliser Vulnerable (VU) VU taxa are considered to be facing a high risk of extinction in the wild Golden Pagoda, Mimetes chrysanthus Photo © Craig Hilton-Taylor

8. Near Threatened (NT) A taxon is Near Threatened when it has been evaluated against the criteria and does not qualify for CR, EN or VU now, but is close to qualifying for or is likely to qualify for a threatened category in the near future . Macaronesian Laurel, Laurus azorica Photo © H. Fraga Least Concern (LC) A taxon is Least Concern when it has been evaluated against the criteria and does not qualify for CR, EN, VU or NT. Widespread and abundant taxa are included in this category. Olive Baboon, Papio anumbis Photo © Caroline Pollock

9. Data Deficient (DD) A taxon is Data Deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status. Tree Tomato Solanum [Cyphomandra] betacea Not Evaluated (NE) A taxon is Not Evaluated when it has not yet been evaluated against the criteria

10. Although DD and NE are not threatened categories, taxa classed as DD or NE should NOT be treated as not threatened Data Deficient (DD) Not Evaluated (NE)

11. Types of data required for IUCN Red List assessments

12. Dealing with a lack of high quality data The threatened categories use quantitative thresholds BUT a lack of high quality data should not deter assessors from applying the IUCN criteria.

13. Acceptable types of data quality Observed Projected Estimated Inferred Suspected

14. Observed Observed information is directly based on well-documented observations of all known individuals in the population. Estimated Estimated information is based on calculations that may involve assumptions . Projected Projected information is the same as “estimated”, but the variable of interest is extrapolated in time towards the future

15. Inferred Inferred information is based on variables that are indirectly related to the variable of interest, but in the same general type of units (e.g. number of individuals or area or number of subpopulations). Suspected Suspected information is based on circumstantial evidence, or on variables in different types of units. In general, this can be based on any factor related to population abundance or distribution.

16. Concepts and definitions underlying the IUCN Red List Categories and Criteria

17. Key terms used in the IUCN Red List criteria Population and Population Size Subpopulations Mature Individuals Generation Length Reduction Continuing Decline

18. Extreme Fluctuations Severely Fragmented Extent of Occurrence Area of Occupancy Location Quantitative Analysis Key terms used in the IUCN Red List criteria

19. Population is the total number of individuals of a given taxon across its global range. Population size is measured as the number of mature individuals only. Population and Population Size Subpopulations Subpopulations are geographically or otherwise distinct groups in the population between which there is little demographic exchange (e.g., 1 successful migrant individual or gamete per year). Mature Individuals Mature Individuals are individuals that are known, estimated or inferred to be capable of reproduction.

20. Population Population Size (mature individuals only) Subpopulations

21. Greater than the age at first breeding and less than the oldest breeding individual, except in taxa that breed only once . Reflects turnover rate of breeding individuals in a population. Scales all time-based measurements in the criteria to account for different rates at which taxa survive and reproduce. Where generation length varies under threat, use the more natural (i.e. pre-disturbance) generation length. Generation Length Generation Length is the average age of parents of the current cohort (i.e., newborn individuals in the population).

22. Reduction Reduction is a decline in population size of at least the % stated in criterion A over the specified time period. For commercially fished species, may use: Reduction in biomass in place of # mature inds CPUE fisheries data (with care) Fishery-independent surveys (preferable) Time Population Size Continuing Decline Continuing Decline is a recent, current or projected future decline which is liable to continue unless remedial measures are taken.

23. Extreme Fluctuations Extreme Fluctuations occur in a number of taxa where population size or distribution area varies widely, rapidly and frequently, typically with a variation greater than one order of magnitude (i.e., a tenfold increase of decrease ). Severely Fragmented Severely Fragmented refers to the situation in which increased extinction risks to the taxon result from the fact that most of its individuals are found in relatively isolated subpopulations.

24. Extent of Occurrence is the area contained within the shortest continuous imaginary boundary which can be drawn to encompass all known, inferred, or projected sites presently occupied by the taxon. Area of Occupancy is the area within the extent of occurrence which is actually occupied by the taxon (measured by overlaying a grid and counting number of occupied cells ). Extent of Occurrence Area of Occupancy

25. Problems of Scale Area of Occupancy In many cases, a grid size of 2 km (i.e., cell area 4 km² ) is an appropriate scale. AOO = 10 x 1 = 10 units 2 AOO = 3 x 16 = 48 units 2 Grid Cells 16 units² Grid Cell = 1 unit²

26. Location Location is a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon.

27. Location 2 locations Invasive species

28. Location 4 locations Pollution

29. Location 4-5 locations Pollution

30. Quantitative Analysis Quantitative Analysis is any form of analysis which estimates the extinction probability of a taxon based on known life history, habitat requirements, threats and any specified management options (e.g., Population Viability Analysis (PVA)). = oh ohh!

31. The IUCN Red List Criteria

32. CRITERIA Nature of the Criteria A Population reduction B Restricted geographic range C Small population size & decline Very small or restricted population D E Quantitative analysis Quantitative thresholds THREATENED CATEGORIES Critically Endangered (CR) Endangered (EN) Vulnerable (VU)

33. Why use multiple criteria? All taxa being assessed must be evaluated against each criterion. Meeting any one of the criteria qualifies a taxon for listing at that level of threat All criteria met at the highest level of threat should be listed. Not all the criteria are appropriate to all taxa.

35. Criterion A Past, present or future population reduction Time Population Size

36. Based on any of four criteria: A1: Population reduction in past and causes of decline now ceased A2: Population reduction in past and causes of decline ongoing A3: Population reduction expected in future A4: Population reduction in past AND future Criterion A

37. Sub-criterion A4 past & future: “shifting time window” 10 years / 3 generations 6.6 years / 2 generations 3.3 years / 1 generation 6.6 years / 2 generations 3.3 years / 1 generation 10 years / 3 generations Present 5 years / 1.5 generations 5 years / 1.5 generations 10 years / 3 generations

38. For ALL the criteria (A1–A4), rate of population reduction should be based on any of: (a) Direct observation ( not for sub-criterion A3 – future reduction ) (b) An index of abundance appropriate to the taxon. (c) A decline in: area of occupancy; extent of occurrence; and/or quality of habitat. (d) Actual or potential levels of exploitation. (e) The effects of: introduced taxa hybridization pathogens pollutants competitors parasites

39. A. Population reduction Declines measured over the longer of 10 years or 3 generations A1  90%  70%  50% A2, A3 & A4  80%  50%  30% A1 . Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction are clearly reversible AND understood AND have ceased, based on and specifying any of the following: (a) direct observation (b) an index of abundance appropriate to the taxon (c) a decline in area of occupancy (AOO), extent of occurrence (EOO) and/or habitat quality (d) actual or potential levels of exploitation (e) Effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites A2 . Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1. A3 . Population reduction projected or suspected to be met in the future (up to a maximum of 100 years), based on (b) to (e) under A1. A4 . An observed, estimated, inferred, projected or suspected population reduction (up to a maximum of 100 years) where the time period must include both the past and the future, and where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1. Use any of the criteria A-E Critically Endangered Endangered Vulnerable

40. Criterion B Restricted geographic range and fragmentation, continuing decline or extreme fluctuations

41. Criterion B Based on either of two sub-criteria: B1: Estimated extent of occurrence AND / OR B2: Estimated area of occupancy AND at least TWO of a-c: a. Severely fragmented or few locations b. Continuing decline c. Extreme fluctuations

42. Use any of the criteria A-E Critically Endangered Endangered Vulnerable B. Geographic range in the form of either B1 (extent of occurrence) AND/OR B2 (area of occupancy) B1 . Extent of occurrence < 100 km² < 5,000 km² < 20,000 km² B2 . Area of occupancy < 10 km² < 500 km² < 2,000 km² AND at least 2 of the following (a) Severely fragmented, OR Number of locations = 1 ≤ 5 ≤ 10 (b) Continuing decline in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) area, extent and/or quality of habitat; (iv) number of locations or subpopulations; (v) number of mature individuals (c) Extreme fluctuations in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) number of locations or subpopulations; (iv) number of mature individuals

43. Small population size and continuing decline Criterion C Extinct

44. Based on small population size AND either C1 or C2 : Criterion C C1: Continuing decline in population size at a specified rate OR C2: Continuing decline in population size at any, unspecified rate AND either C2a or C2b : C2a: (i) very small subpopulations, OR (ii) most mature individuals are in one subpopulation C2b: extreme fluctuations in number of mature individuals

45. C. Small population size and decline Number of mature individuals < 250 < 2,500 < 10,000 AND either C1 or C2 : C1. An estimated continuing decline of at least: 25% in 3 years or 1 generation 20% in 5 years or 2 generations 10% in 10 years or 3 generations (b) extreme fluctuations in the number of mature individuals (up to a maximum of 100 years in future) C2. A continuing decline AND (a) and/or (b): (a i) number of mature individuals in each subpopulation: < 50 < 250 < 1,000 (a ii) or % individuals in one subpopulation = 90-100% 95-100% 100% Use any of the criteria A-E Critically Endangered Endangered Vulnerable

46. Very small or restricted population Criterion D

47. D. Very small or restricted population Either: Number of mature individuals < 50 < 250 D1. < 1,000 AND / OR Restricted area of occupancy D2. typically: AOO < 20 km² or number of locations ≤ 5 Use any of the criteria A-E Critically Endangered Endangered Vulnerable

48. Quantitative analysis Criterion E = oh ohh!

49. E. Quantitative analysis Indicating the probability of extinction in the wild to be:  50% in 10 years or 3 generations (100 years max)  20% in 20 years or 5 generations (100 years max)  10% in 100 Use any of the criteria A-E Critically Endangered Endangered Vulnerable