Table 1.
The IUCN Red List categories and criteria for Critically endangered, Endangered, Vulnerable. n.a., not applicable.
| critically endangered | endangered | vulnerable | |
|---|---|---|---|
| (A) population reduction | |||
| declines measured over the longer of 10 years or 3 generations | |||
| A1 (%) | ≥90 | ≥70 | ≥50 |
| A2, A3 and A4 (%) | ≥80 | ≥50 | ≥30 |
| (B) geographical range either EOO or AOO | |||
| (B1) extent of occurrence (EOO; km2) | <100 | <5000 | <20 000 |
| (B2) area of occupancy (A00; km2) | <10 | <500 | <2000 |
| and 2 of the following: | |||
| (a) severely fragmented or no. of locations | = 1 | ≤5 | ≤10 |
| (b) continuing decline in (i) EOO; (ii) AOO; (iii) area, extent and/or quality of habitat; (iv) no. of locations or subpopulations; and (v) no. of mature individuals | |||
| (c) extreme fluctuations in (i) EOO; (ii) AOO; (iii) no. of locations or subpopulations; and (iv) no. of mature individuals | |||
| (C) small population size and decline | |||
| no. of mature individuals | <250 | <2500 | <10 000 |
| and either C1 or C2: | |||
| (C1) estimated continuing decline: up to a maximum of 100 years | 25% in 3 years or 1 generation | 20% in 5 years or 2 generations | 10% in 10 years or 3 generations |
| (C2) continuing decline and (a) and/or (b): | |||
| (a) (i) no. of mature individuals in all subpopulations: | ≤50 | ≤250 | ≤1000 |
| (ii) % individuals in one subpopulation | >90–100% | 95–100% | 100% |
| (b) extreme fluctuations in the number of mature individuals | |||
| (D) very small or restricted population | |||
| (1) no. mature individuals | <50 | <250 | <1000 |
| or | |||
| (2) restricted AOO | n.a. | n.a. | AOO <20 km2 or no. of locations ≤ 5 |
| (E) quantitative analysis | |||
| indicating probability of extinction in the wild: | ≥50% in 10 years or 3 generations (100 years max.) | ≥20% in 20 years or 5 generations (100 years max.) | ≥10% in 100 years |