Explain how the IUCN Red List criteria are used to assess the conservation status of a species and how this information can guide conservation prioritisation.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
The IUCN Red List uses quantitative criteria to place species into threat categories such as Critically Endangered, Endangered, Vulnerable and Least Concern.
1. Criteria are based on measurable factors: the rate of population decline, the size and restriction of geographic range, the number of mature individuals and the probability of extinction within a set time.
2. A species is assessed against these criteria and given a category that reflects its risk of extinction.
3. The resulting status shows which species are most at risk, so conservationists can prioritise limited resources (funding, management) for those in the highest‑risk categories.
4. Red List information also informs legal protection, such as national legislation and international agreements (e.g. CITES), and guides actions like habitat protection or restoration where threatened species are concentrated.
1. Criteria are based on measurable factors: the rate of population decline, the size and restriction of geographic range, the number of mature individuals and the probability of extinction within a set time.
2. A species is assessed against these criteria and given a category that reflects its risk of extinction.
3. The resulting status shows which species are most at risk, so conservationists can prioritise limited resources (funding, management) for those in the highest‑risk categories.
4. Red List information also informs legal protection, such as national legislation and international agreements (e.g. CITES), and guides actions like habitat protection or restoration where threatened species are concentrated.
Examiner tips
- Use the word ‘criteria’ and list the four main quantitative factors; link each to the category system.
- Show how the status leads to prioritisation and legal/management actions; include examples such as CITES.
Common mistakes
- Confusing the Red List with other conservation status lists; not naming the quantitative criteria; omitting the link between status and prioritisation.
Mark scheme (4 marks)
- The IUCN Red List uses quantitative criteria to categorise species into threat categories (e.g. Critically Endangered, Endangered, Vulnerable, Least Concern).
- Assessment criteria include rate of population decline, geographic range size / restriction, small or declining population size, and quantitative probability of extinction within a defined time frame.
- Red List status identifies species most at risk of extinction, allowing conservationists to direct limited resources (funding, management effort) towards the most threatened taxa first.
- Red List data can also inform legal protection decisions (e.g. national legislation, international agreements such as CITES) and guide habitat protection or restoration in areas with high concentrations of threatened species.
Key terms in this question
IUCN Red List · conservation status · conservation prioritisation
Related
- All IB DP Biology Higher Level (2023 syllabus) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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