4.10.7Additional lessons
Restoring Ecosystems — IB Biology SL Revision Notes & Topical Questions
5 min read 4 parts Lesson 141 of 142
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 4Restoration Strategies
Ecosystem restoration aims to repair processes that human activities have disrupted.
Rewilding
- Rewilding Restoring natural ecosystem processes so that a damaged area can recover with as little continued management as possible.
Species reintroduction
- Species reintroduction Returning apex predators or keystone species that were lost can control herbivores and restore vegetation and biodiversity.
Habitat connectivity
- Habitat connectivity Corridors such as hedgerows link isolated habitat patches, allowing larger home ranges and larger populations.
Limiting human influence
- Limiting human influence Stopping logging, fishing or farming lets natural processes such as succession recover.
Ecological management
- Ecological management Techniques like controlled grazing or burning may be used to restore particular habitats.
Monitoring
- Monitoring Progress is checked regularly so that methods can be adjusted if the ecosystem does not recover as expected.
| Strategy | Intended result |
|---|---|
| Reintroduce apex predator | Control herbivores and restore vegetation |
| Build corridors | Connect small populations |
| Limit harvesting | Allow natural recovery |
Section 2 of 4Case Study: Hinewai Reserve
Hinewai shows how limited early action followed by minimal management can allow natural recovery over former farmland.
1
Hinewai Reserve in New Zealand was formerly farmland, with non-native plants present.
2
Early human intervention removed the non-native species that were out-competing the native plants.
3
The reserve is now managed with minimal intervention, allowing native plants to return.
4
Ecological succession replaces the scrub with native forest, increasing the habitat available to native species.
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The public may walk in the reserve, but harmful activities are limited.
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The reserve is widely regarded as a successful example of rewilding, with native forest expanding over former farmland.
Section 3 of 4Why Restoration Helps
Restoration benefits both wildlife and people, but it has costs and limits that should be weighed.
Why Restoration Helps
Biodiversity
- Biodiversity More species and more habitats make the ecosystem more resilient to change.
Nutrient cycling
- Nutrient cycling Recovering vegetation and soils restore recycling of nutrients and stabilise the land.
Carbon storage
- Carbon storage Regrowing forests, peat and wetlands take up carbon dioxide, helping to reduce climate change.
Limitations
- Limitations Restoration takes a long time, needs funding and cooperation from landowners, and may not return the exact original community.
Evaluation
- Evaluation Success is judged by measures such as species richness, vegetation cover and the return of ecosystem functions.
Section 4 of 4Exam Checklist & Tips
4.10.7 – Key Points for the Exam
- Rewilding Restoring ecosystems to a more natural state by reducing human control.
- Wildlife corridor A strip of habitat linking otherwise isolated habitats.
- Succession The gradual change in species composition as a community develops over time.
- Reintroduction Returning a species to an area where it has been lost.
- Habitat connectivity The degree to which habitat patches are linked so that organisms can move between them.
- Apex predator A top predator whose return can restore control over herbivore numbers.
Common Mistakes
- Saying rewilding means doing nothing;
- some management such as removing invasive species is often needed first.
- Assuming restored ecosystems are identical to the original ecosystem.
- Forgetting that connectivity, not just area, matters for populations.
- Treating restoration as quick; communities take decades to recover.
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