Table 3. IUCN Red List criteria for ecosystems, version 2.0.
| Critically Endangered | Endangered | Vulnerable | |||
| A | Reduction in geographic distribution over ANY of following periods: | ||||
| 1 | Present (over the past 50 years) | ≥80% | ≥50% | ≥30% | |
| 2a | Future (over the next 50 years) | ≥80% | ≥50% | ≥30% | |
| 2b | Future (over any 50 year period including the present and future) | ≥80% | ≥50% | ≥30% | |
| 3 | Historic (since 1750) | ≥90% | ≥70% | ≥50% | |
| B | Restricted geographic distribution indicated by EITHER: | ||||
| 1 | Extent of a minimum convex polygon enclosing all occurrences (Extent ofOccurrence), OR | ≤2,000 km2 | ≤20,000 km2 | ≤50,000 km2 | |
| 2 | The number of 10×10 km grid cells occupied (Area of Occupancy) | ≤2 | ≤20 | ≤50 | |
| AND at least one of the following (a-c): | |||||
| (a) An observed or inferred continuing decline in EITHER: | |||||
| i. a measure of spatial extent appropriate to the ecosystem; OR | |||||
| ii. a measure of environmental quality appropriate to characteristicbiota of the ecosystem; OR | |||||
| iii. a measure of disruption to biotic interactions appropriate to thecharacteristic biota of the ecosystem | |||||
| (b) Observed or inferred threatening processes that are likely to cause continuing declines in either geographic distribution, environmental quality or biotic interactions within the next 20 years | |||||
| (c) Ecosystem exists at … | 1 location | ≤5 locations | ≤10 locations | ||
| 3 | A very small number of locations (generally fewer than 5) AND | ||||
| prone to the effects of human activities or stochastic events within a very short time period in an uncertain future, and thus capable of collapse or becoming Critically Endangered within a very short time period | |||||
| C | 1 | Environmental degradation over the past 50 years based on change in an abiotic variable* affecting… | ≥80% extent with ≥80% relative severity** | ≥50% extent with ≥80% relative severity | ≥50% extent with ≥50% relative severity |
| ≥80% extent with ≥50% relative severity | ≥80% extent with ≥30% relative severity | ||||
| ≥30% extent with ≥80% relative severity | |||||
| 2 | Environmental degradation over the next 50 years, or any 50-year periodincluding the present and future, based on change in an abiotic variable affecting… | ≥80% extent with ≥80% relative severity | ≥50% extent with ≥80% relative severity | ≥50% extent with ≥50% relative severity | |
| ≥80% extent with ≥50% relative severity | ≥80% extent with ≥30% relative severity | ||||
| ≥30% extent with ≥80% relative severity | |||||
| 3 | Environmental degradation since 1750 based on change in an abiotic variable affecting… | ≥90% extent with ≥90% relative severity | ≥70% extent with ≥90% relative severity | ≥70% extent with ≥70% relative severity | |
| ≥90% extent with ≥70% relative severity | ≥90% extent with ≥50% relative severity | ||||
| ≥50% extent with ≥90% relative severity | |||||
| D | 1 | Disruption of biotic processes or interactions over the past 50 years based onchange in a biotic variable* affecting… | ≥80% extent with ≥80% relative severity** | ≥50% extent with ≥80% relative severity | ≥50% extent with ≥50% relative severity |
| ≥80% extent with ≥50% relative severity | ≥80% extent with ≥30% relative severity | ||||
| ≥30% extent with ≥80% relative severity | |||||
| 2 | Disruption of biotic processes or interactions over the next 50 years, or any 50-year period including the present and future, based on change in a biotic variable affecting… | ≥80% extent with ≥80% relative severity | ≥50% extent with ≥80% relative severity | ≥50% extent with ≥50% relative severity | |
| ≥80% extent with ≥50% relative severity | ≥80% extent with ≥30% relative severity | ||||
| ≥30% extent with ≥80% relative severity | |||||
| 3 | Disruption of biotic processes or interactions since 1750 based on change in a biotic variable affecting… | ≥90% extent with ≥90% relative severity | ≥70% extent with ≥90% relative severity | ≥70% extent with ≥70% relative severity | |
| ≥90% extent with ≥70% relative severity | ≥90% extent with ≥50% relative severity | ||||
| ≥50% extent with ≥90% relative severity | |||||
| E | Quantitative analysis that estimates the probability of ecosystem collapse to be… | ≥50% within 50 years | ≥20% within 50 years | ≥10% within 100 years | |
These supercede an earlier set of four criteria [12]. Refer to Appendix S1 for definitions of terms.
*
see text for guidance on selection of variable appropriate to the characteristic native biota of the ecosystem.
**
see text and Fig. 6 for explanation of relative severity of decline.