Coasts GW3 - mangroves

Question 1

mangrove ecosystems

intro (3)

Answer 1

• salt-tolerant tropical or sub-tropical plants
• habitat to many plant and animals
• found on sheltered coasts muds

Question 2

distribution of mangroves

Answer 2

• found on coasts of countries
• between the Tropic of Cancer and Tropic of Capricorn
  (Malay Peninsula, northern Australia, the Sundarbans in India and Bangladesh)

Question 3

mangrove

environmental conditions affecting growth (3)

Answer 3

1. sheltered coastline resulting in low energy wave environment
2. Saline environment -> high salt content
3. Muddy waterlogged

Question 4

Mangrove adaptations (3)

Answer 4

1. types of roots:
   Knee-like roots -> Bruguiera trees – trap soil, essential for growth
   Aerial roots -> Avicennia trees — during high tides, get oxygen
   Prop roots - Rhizophora trees – anchor firmly
2. fruit shape
   javelin-shaped – pierce through, germination
   buoyant – float
   increase chance of survival
3. salt-tolerant, secrete excess salt

Question 5

value of mangroves (4)

Answer 5

1. Breeding grounds and habitat for marine creatures
   Eg 693 species of wildlife live in the Sundarbans mangrove forest, Bangladesh
2. Stabilise shorelines by trapping sediments – Filters sediments washed down by rivers onto coasts – so coral reefs don’t get suffocated
   Eg In Australia, Mangrove ecosystems provide a buffer between land and reef, as they filter land runoff and improve the quality of water entering the Great Barrier Reef lagoon.
3. Protect coastal area from erosion by strong waves – filter/buffer against typhoons, hurricanes, tsunamis – absorbing force of storms
   ○ Acts as a buffer between land and sea, buffer energy waves coming to land
   Eg mangroves reduced impacts of tsunami of the Indian Ocean in 2004 by reducing the destructive energy of water flowing inland.
4. Wood for fuel and construction
   Eg In Brazil, mangroves have been exploited fuel-wood for cooking and heating and construction.

Question 6

Pressure on mangrove (4)

Answer 6

1. Clearing of mangroves for fuel wood and charcoal (environmental impact)
   E: for fuel and charcoal, particularly regions low technology income economics -> breeding grounds reduced, more open to sea waves
   Eg: In Indonesia, mangroves were cleared for fuel and charcoal, affected coasts without mangrove, experiencing rapid erosion
2. Conversion to other land uses (paddy fields, shrimp farms) (environmental impact)
   E: hectares, flat, well-watered mangroves, converted into -> more vulnerable
   Eg: The clearing of mangroves for shrimp farms has left Vietnam’s coastline more vulnerable to erosion from storms and pollution waste
3. Coastal development (environmental impact) (economic – tourism)
   E: reclaimed for housing, industry, recreational uses –> disappear, polluted from human activity
   Eg: At the Caribbean Islands in the U.S. Virgin Islands. The Coastal Program in the Caribbean recognizes the need to balance residential, tourist, commercial, and industrial needs with conservation of coastal habitats and species.
   Impact: Erosion and resultant sedimentation has been identified as a leading threat to near­shore water quality
4. Rising sea level rise (environmental impact)
   E: rise sea level + storm activity, if climate change accelerates -> trouble colonising, further inland despite sea level rise, competition human activities, sea defences
   Eg: In Thailand, coastal flooding of the mangroves caused Thailand to lose land over the years, one third affected – economic impact: less land to build economy