Edexcel IGCSE Geography 复习笔记 2.2.3 Threats to Coastal Ecosystems
Edexcel IGCSE Geography 复习笔记 2.2.3 Threats to Coastal Ecosystems
Industrialisation
The Value of Coastal Ecosystems
- All ecosystems offer people a range of opportunities – goods and services
- Goods – a material resource that can be extracted and used
- Services – general benefits and advantages
- Coastal ecosystems can provide the following:
| Goods | Services |
| Fish
Shellfish Salt |
Protection from:
Storms Coastal flooding Rising sea levels |
| Fishmeal
Animal feed |
Harbours
Natural Shelter |
| Seaweed for:
Food Industrial Use Medicines |
Recreation
Leisure opportunities |
| Land for:
Building Farming |
Biodiversity
Wildlife habitats |
| Construction Materials:
Sand Timber (Mangrove) |
Natural waste treatment |
Worked Example
Explain the value of a named coastal ecosystem. (4)
- Coral reefs have a large range of biodiversity. For instance, the Great Barrier Reef in Australia has over 700 species of coral, 1500 species of fish and 4000 species of mollusc (1)
- Coral reefs also protect a low lying coast from the impact of tropical storms (1)
- Coral reefs have a rich fish stock that can supply basic food requirements to many developing countries (1)
- However, its main value lies in its recreational opportunities, such as tourism, snorkelling, and scuba diving (1)
- As a tourist destination as over 150 million people each year take holidays in areas with coral reefs (1)
Industrial Threats
- Threats to Coral Reefs
- Coral reefs are easily stressed by human action, if the stress persists, then the death of the reef soon follows
- Pollution, overfishing and quarrying of coral for building stone
- Industrialisation is responsible for rising sea temperatures and sea-level rise, putting coral reefs under threat
- Rising sea temperatures increase levels of coral bleaching
- Threats to Mangroves
- Pollution, overfishing and deforestation for aquaculture
- Clearance for land development particularly in developing countries
- Threats to Sand Dunes
- Least threatened at a global level due to value being mainly tourism and leisure
- Local level the biggest threat is sand mining
- Threats to Salt Marsh
- Industrial pollution
- Ideal sites for nuclear power stations
- Clearance for development - commercial and private
- Development can lead to increased noise and light pollution which may affect wildlife behaviour and nesting
Agricultural Practices
- Threats to Coral Reefs
- Overfishing reduces the number of grazing fish that keep coral clear of algae
- Fishing using explosives damage coral reefs
- Commercial farming
- Fertiliser runoff
- Pesticide overspray
- Threats to Mangroves
- Aquaculture - intense fish and shrimp farms
- Pesticide use
- Antibiotics used in aquaculture practices
- Clearance for farm development particularly in developing countries
- Threats to Sand Dunes
- Destabilisation due to grazing animals on dunes
- Threats to Salt Marsh
- Drained and cleared for farming
- Eutrophication through heavy use of fertilisers
- Pollution from pesticides and herbicides
- Slurry run-off from cattle
Tourism
- Threats to Coral Reefs
- Tourism is the biggest threat globally and locally to coral reefs
- 58% of all coral reefs are at threat from human activity
- Any contact with the human body is likely to kill coral immediately around the point of contact
- Propellers and anchors directly damaging corals from boat tours
- Pollution through diesel spills
- Threats to Mangroves
- Clearance of mangroves to build hotels and other tourist attractions
- Diversion of fresh water to hotels etc
- Disturbance of habitats
- Collection of souvenirs by tourist
- Tours in waterways and pollution through spills of boat fuel
- Threats to Sand Dunes
- Largest threat to sand dunes due to trampling of delicate, unfixed dunes
- Driving using 4x4 or quadbikes over sand dunes
- Sporting events - sand surfing etc
- Collecting shells and driftwood
- Pollution from rubbish left by tourists
- Car parks
- Sand mining for building hotels
- Development of seaside towns
- Threats to Salt Marshes
- Tourism is limited to the local level and nature reserves
- Roads have divided salt marshes cutting off parts of it
- Trampling by visitors
- Dog walkers letting dogs roam and disturb the wildlife
- Noise from local tourist areas may disturb the wildlife
Deforestation
- Threats to Coral Reefs
- Clearance of coastal forests and mangroves disturbs natural flows of water and nutrients leading to stress and coral bleaching
- Removal of coral reef for stone building or tourist sales
- Any destruction of coral reef leaves the coastline open to coastal flooding and storm surges
- Threats to Mangroves
- Removal of the trees leads to the collapse of the ecosystem
- Leaves the coast open to storms, flooding and coastal retreat
- Mangrove wood is used for timber and fuel
- Cleared to reduce malaria - unsupported evidence that this works
- Threats to Sand Dunes
- Removal of trees destroys the mature dunes and allows for dune migration
- Leaves coast open to storms and flooding
- Threats to Salt Marshes
- Real threat is through industrialisation and agriculture
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