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Mangroves
What caused this?
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Picture of Thai coast after Tsunami
Mangrove Protection Would Have
Lessened Tsunami’s Impact
Many of the affected countries
admitted the damage caused was
partially self inflicted
For reasons of tourism much of the
mangrove that would have partially
protected the region has been
removed
Since 1961 50% of Thai mangroves
have been removed
These tourist areas where mangrove
had been removed was area where
5000 people died during the tsunami
In Sri Lanka a tale of contrasts
Wanduruppa an area where Mangroves
are degraded 5-6000 died, in nearby
Kapuhenwala surrounded by 200
hectares of dense mangroves only 2
deaths occurred!
On first appearances- these places
do not look inviting.
Full of sticky mud and biting
insects, they’re smelly and look like
wastelands.
But to an educated intelligent eye,
they are an important habitat for a
diverse range of marine flora and
fauna- manatees, crab eating
monkeys, fishing cats, monitor
lizards, mud skipper fish and
Bengal tigers
They are essential to marine biodiversity- they stabilise
coastlines against erosion, collect sediment and provide a nursery
for coastal fish
Where do we find them?
Areas above 20 degrees
Where shorelines are protected from full force of waves
On shores where deposition occurs
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Grow in inner tidal areas and estuary mouths
Found along tropical and sub-tropical coasts of Africa, Australia, Asia and
the Americas
Greatest diversity of mangrove species is in South East Asia
Found in areas with
• Permanently waterlogged soil
• With high salinity
• Areas which are frequently flooded or
inundated
• Areas with intense sunlight and hot
weather
• Areas with a sometimes limited supply
of fresh water
Sundra Shelf Mangroves (Sundaland wetlands hotspot)
Covers area 2x Wales
Found on the
Island of Borneo
and Sumatra
proboscis monkey
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The spectacular flora and fauna
of the Sundaland Hotspot are
succumbing to the explosive
growth of industrial forestry in
these islands and to the
international animal trade that
claims tigers, monkeys, and
turtle species for food and
medicine in other countries.
Populations of the orangutan,
found only in this hotspot, are
in dramatic decline. Some of
the last refuges of two
Southeast Asia rhino species
are also found on the islands of
Java and Sumatra. Like many
tropical areas, the forests are
being cleared for commercial
uses. Rubber, oil palm, and pulp
production are three of the
most detrimental forces facing
biodiversity in the Sundaland
Hotspot.
Vegetation
Mangroves vary in height
from shrubs to 40 metres
tall
Prop roots- essential for
support in waterlogged
ground
Pneumataphores- erect roots
that protrude from the stem
above water and hang down
They breathe in both water
and air using pores known as
lenticels which allow oxygen
to diffuse into the plant
Vegetation description
They have a Zonation pattern• Red mangroves- closest to coast, taking brunt
of wave action, protect inland areas, can
survive permanent waterlogging
• Black Mangroves- found further inland,
protected behind red mangroves. Have
pneumatophores to obtain oxygen, die if
permanently waterlogged
• White Mangroves- furthest from coast least
able to survive waterlogging
How productive? Service provision?
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Highly productive, nearly as so as Tropical Rainforests
Flora and Fauna important but perhaps more so is their role as nursery
for fish, shrimp larvae
• A teaspoon of mangrove mud holds 10 million bacteria
• Indication of high productivity
Mangrove service provision• High level of fish, algae and invertebrate production
• High production of timber and fuel wood, charcoal, fibre and dyes also
construction materials
• Medium levels of climate regulation- of carbon and greenhouse gas
emissions
• High level of resistance to species invasions
• High level of removal of phosphates and nitrates from soil, regulating
soil pollution
• High level of prevention of shoreline erosion
• Mangroves have high levels of protection of storm surges, floods,
hurricanes and reduce resultant loss of life
• Provide high levels of habitat for tropical fish- 75% rely on mangroves
in some part of life
• Medium influence in storing and accumulating organic matter
• Also medium aid in nutrient recycling
Can we put a value on Mangroves?
• Economic- areas where the mangroves were
intact suffered less economic damage during
Indian Ocean Tsunami
• Intact mangroves can provide locals with timber,
charcoal, education, protection from storms,
fisheries off shore- about $1000 a hectare, in
some places $36,000
• Cleared mangrove ie ones cleared to make a
quick fisheries buck reduced worth of $200
Tasks
Mangrove loss
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Over 50% of Mangrove forests have been lost
Only around 15 million hectares remain
Thailand has lost 50% of mangrves since 1961
Phillipines- 40% lost between 1918 and 1988.
By 1993 only 123,000 hectares left- lost 70% in
70 years
• In Ecuador thought between 20- 50% has been
lost
What is leading the changes?
• Asian loss- 50% due to Aquaculture (38% shrimp
farming 14% fish farming)
• 25% lost to deforestation and another 11% to
upstream freshwater diversion
• In Latin America- due to agriculture and cattle
farming, cutting for fuel wood and building material,
and beginnings of shrimp agriculture
Aquacultureproduction of
aquatic
organisms
under
controlled
conditions
Case Study- impact of shrimp farms on
Thai Mangroves
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Shrimp farming has
been practised in
Thailand for 60 yrs,
originally shrimp were
trapped in natural
environments, but
during 70s and 80s
farms sprung up
Thailand exports nearly
all the shrimp it farms,
it provides ½ million
tonnes pr year to USA
¼ million to France, UK
and Italy
More is now being
consumed actually in
Thailand since 90s
where tourism has
increased dramatically
Dulah Kwankwa used to be a rice farmer
earning $400 a year, now earns 6 times
more
He turned his rice farm into a shrimp
farm- producing 3 crops a year. Dulah has
money for first time in life. But he still has
to pay off his initial loan and has to borrow
more money every year, but he worries a
lot more about the debt.
Impacts of shrimp Farming
• Reduced rural to urban migration from rural Thailand
to the Capital Bangkok
• Increased wealth in local areas
• Money has led to improved infrastructure
• The decaying remains after a cycle of shrimp farming
are toxic and have to be removed
• This residue affects mangrove fauna and flora
negatively
• It can also lead to disease and infections among those
who are paid to remove it
• Biodiversity is lost
Summarise the IMPACTS of shrimp farming on the economy,
environment and the local Thai people, list BOTH positive and
negative impacts
Impact of Climate Change
• Climate change is likely to lead to an increase in sea
levels of between 15 and 95 cm by the end of this
century
• If the rise is 95cm many of the mangroves will be
lost, and these are very important in protecting areas
from coastal erosion
• The loss of mangroves impacts negatively on the level
of greenhouse gases in our air, because mangroves
take in carbon
• Alos the changing mangrove to shrimp farms releases
carbon that is contained in the mangroves soils
Over harvesting, exploiting marine
life
Over harvesting
• Mangrove trees are used for many purposes like for fuel wood,
construction, wood chip and pulp production, charcoal and for animals
feed
• Although this has been happening for centuries, in some areas it has
reached the point where it is becoming unsustainable
Over exploitation of marine life
• This is depleting fish, prawns and other marine species
• As one species becomes uneconomic, they focus on others
• Results in decline in biodiversity
• This can lead to loss of jobs
• Over fishing alters the balance of the food chain/ web and mangrove
fish communities can be altered as a result
• Tourism is spreading along mangrove coasts- previously they have been
viewed as mosquito infested mud swamps and have often been
destroyed for golf courses, cruise shi p ports, apartments and
restaurants.
Tasks
1) Draw a diagram to show links between
mangrove destruction and economic
activity
2) Explain the impacts of mangrove
destruction
3) Which is more important- conserving
mangroves or the benefits of
exploiting and removing them?
Who are the key players involved in the
mangrove debate?
Local organisationsCommunity Mangrove forests Thailand
• Yadfon, small organisation in Thailand, formed in 1985- working
in Chao Mai, it faced 2 main problems• Mangroves were being destroyed to produce charcoal, which
affected the supply of seafood- Yadfon created an 80 hectare
community managed mangrove forest- which did not allow shrimp
farms in its borders
• Destruction of sea grass- by large drag nets and large fishing
boats. Sea grass is am important nursery for species of fish. To
protect the sea grass a publicity campaign was launched which
led to reduced destruction.
• The project also adopted a dugong - an animal that lives in and
feeds from sea grass- it was adopted as a symbol of their
conservation commitment.
EU funded initiativeBiodiversity along coast in Ranong Thailand
• Collaborative project between Natural History
museum London, Wildlife Fund Thailand, Kampaun
Fisheries cooperative
• Main objective is to assess biodiversity and enable
long term environment monitoring. To make info
available to locals
• Developed a number of activities- meeting with locals
• Open days
• Newsletters
• A education officer who liases with local schools
• Youth camps to raise awareness
Wetlands international
• A non profit global NGO dedicated to the conservation and wise
use of all wetlands. It has 4 long term goals• Global goal 1- all those who use and impact on wetlands should be
well informed about their importance
• Global Goal 2- functions and value of wetlands are recognised
and integrated into sustainable development
• Global Goal 3- conservation and sustainable yield of wetlands is
achieved through effective uses of water resources and coasts
• Global Goal 4- large scale strategic initiatives result in improved
conservation status of species, habitats and ecological networks
Sustainable Yield- ways in which ecosystems can be productive,
but at levels which can be maintained and are sustainable,
without causing damage
Some wetland international
initiatives
• Green coast- for nature and people after the
tsunami- provides capital grants and technical support
and advice to support local communities in restoring
and managing mangroves, coral reefs and sand dunes
• Community based mangrove restoration- to reduce
poverty and vulnerability and increase sustainability in
Aceh, Indonesia- enabling communities to restore and
replicate a mangrove aquaculture ecosystem
• Mangrove replanting in Kuala Gula Perak, to
rehabilitate degraded mangrove areas, involving
private companies in funding community projects
Asia’s coastal ecosystemsGreenbelts
• TVE Asia- a not for profit media organisation- make
programs about issues, made series about the
mangroves to inform people of their whereabouts and
importance.
• The programs made to encourage protection and
restoration projects
Had Chao National Park, Thailand- A
Ramsar Site• Thailand has 10 designated Ramsar sites- including
the above
• Located in Trang province and consists of 3 distinct
wetland areas, with a range of habitats including
mangroves, mudflats, sandy beaches and coral reefs.
• It is important in terms of biodiversity
• At least 212 bird species have been recorded in the
area, including vulnerable and endangered species
• Home to at least 22 mammal species including the
endangered Dugong
• At least 75 fish species are found here- critical to
livelihoods
• http://www.seagrasswatch.org/Thailand.html
Reliance on wetlands
• Chao Mai is home to
10,000 people many of
whom make a living
from fisheries either in
canals the trang river
or coast areas
• Locals rely on wetlands
as water source for
agriculture
• 250,000 tourists visit
each year and locals
earn from them
Despite Chao Mai being a
Ramsar site Threats
• Habitat change still
threatens
• Over fishing
• Lack of pollution control
Ramsar Sites- Ramsar Convention on
Wetlands –intergovernmental treaty
established 1971 in Iranian cityRamsar
It’s mission is ‘conservation and wise
use of all wetlands through local,
regional and national actions and
international cooperation as a
contribution towards achieving
sustainable development’
The convention has 158 member
states and 1720 wetland sites
totalling 159 million hectares
Tasks
• Assess the projects in terms of each
one’s costs and benefits
• How effective do you think each will be?
End of sub unit tasks
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3)
Annotate an A3 world map, choose an ecosystem (either coral
reefs (from earlier in unit), Daintree rainforest or mangroves
Identify the locations where your ecosystem is found and
annotate all the goods and services it provides
Annotate the threats to your chosen ecosystem on the map
Show how the different areas are being managed
Exam QuestionAssess the role played by different players in managing areas
where biodiversity is under threat (15 marks)