Mangroves

Question 1

What are they?

Answer 1

Depositional coastal features found on tidal mudflats in tropical and sub-tropical areas.

Question 2

Why are they important?

Answer 2

• Roots stabilise coast from erosion
• Protection from hurricanes
• Nursery for fish
• Slows water and sediment which reduces erosion
• Bird watching, fishing, boating etc

Question 3

Give some general info on where mangroves are found

Answer 3

Tropical and sub-tropical areas, mainly between 5 degrees N and S.
Greatest diversity of mangrove species are in SE Asia.

Question 4

What conditions do mangroves need to form?

Answer 4

• Gently sloped coastlines with mudflats, ie estuary mouth
• Permanently waterlogged soil with high salinity - mangroves are halophytic
• Areas with intense sunlight and hot weather
• Limited supply of fresh water

Question 5

What are the different types of mangroves?

Answer 5

1. Red mangroves - Closest to coast, take brunt of wave action, can survive permanent water logging, grows downwards, secrete salt.
2. Black mangroves - Behind red mangroves, have snorkel roots as they cannot be permanently water logged.
3. White mangroves - Mostly submerged in water, furthest from coast, least able to survive water logging.

Question 6

What are some threats to mangroves?
* How much of global mangroves do the UN estimate have been lost since 1980?

Answer 6

• 20%
  ! Human clearance, for agricultural land, human settlements and infrastructure.
  ! Overfishing
  ! Coral reef destruction, reefs usually provide protection
  ! Pollution, from both oil and pesticides/fertilisers. Oil can submerge/suffocate mangroves, fertilisers can cause imbalance.
  ! Climate change, sea levels rising

Question 7

Give an example of a mangrove. Include:
* How much of the area was originally occupied by mangroves
* How much lost
* An example of how this has negatively affected the area

Answer 7

Grand Cayman;
* Originally 36% of Grand Cayman was occupied by mangroves
* Since 1997, over 10% lost as island began to develop
* Hurricane Ivan in 2004 left 75% of homes damaged

Question 8

Give an example of an Asian mangrove. Include:
* Location
* “Cool Facts”

Answer 8

• The Sundarbans, India/Bangladesh - Bay of Bengal
• Home to the endangered “Indian Python”, covers 10,000km2, only mangrove forest with tigers