Explain how the establishment of marine protected areas (MPAs) contributes to the conservation of biodiversity in ocean ecosystems.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
MPAs restrict or prohibit extractive activities such as fishing or mining, thereby reducing direct anthropogenic pressure on species and habitats.
They protect critical habitats—coral reefs, seagrass beds, mangroves—allowing species populations to recover and maintaining the structural complexity that supports high species richness.
MPAs act as spill‑over reservoirs; populations of fish and invertebrates grow inside the protected area and replenish adjacent exploited zones through larval dispersal or adult migration.
By maintaining larger, less disturbed populations within MPAs, genetic diversity is preserved, improving the long‑term adaptive potential of species to environmental change such as ocean warming or acidification.
They protect critical habitats—coral reefs, seagrass beds, mangroves—allowing species populations to recover and maintaining the structural complexity that supports high species richness.
MPAs act as spill‑over reservoirs; populations of fish and invertebrates grow inside the protected area and replenish adjacent exploited zones through larval dispersal or adult migration.
By maintaining larger, less disturbed populations within MPAs, genetic diversity is preserved, improving the long‑term adaptive potential of species to environmental change such as ocean warming or acidification.
Examiner tips
- Use the exact phrases from the mark scheme; each point counts as one mark.
- Show the causal link between protection and biodiversity outcomes.
- Keep sentences short and to the point.
Mark scheme (4 marks)
- MPAs restrict or prohibit extractive activities such as fishing or mining, reducing direct anthropogenic pressure on species and habitats
- Protecting critical habitats such as coral reefs, seagrass beds or mangroves allows species populations to recover and maintain structural complexity that supports high species richness
- MPAs act as 'spillover' reservoirs, allowing populations of fish and invertebrates to grow inside the protected area and replenish adjacent exploited areas through larval dispersal or adult migration
- By maintaining larger, less disturbed populations within MPAs, genetic diversity is preserved, improving the long-term adaptive potential of species to environmental change such as ocean warming or acidification
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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