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Coastal
Vegetation
Lecture 10 Dr Amy Choong
SSS 1207 — The Natural Heritage of Singapore Lecture Topics
• References
• Coastal vegetation
– Mangrove forest
– Beach vegetation
• The future
• Summary
References
• Chapter 5 of main textbook
• Sivasothi, S. and P.K.L. Ng (editors), 1999. A Guide to the Mangroves of Singapore, Vols. 1 and 2. Singapore Science Centre, Singapore. QH541.5 Man.Gu 1 and QH541.5 Man.Gu 2
Singapore s Coastal Vegetation
• Coastal vegetation
• Types of coastal vegetation
• Animals of coastal vegetation
• Economic value
Coastal Vegetation • Coastal vegetation = Vegetation that grows on land at the edge of the sea
Sandy beach vegetation and mangrove forest
at Chek Jawa, Pulau Ubin, at high tide
Types of Coastal Vegetation
in Singapore
• Mangrove forest
• Sandy beach vegetation
• Rocky shore or cliff vegetation
Mangrove Forest • Mangrove forest is one of the most dangerous of habitats!
Mangrove Forest
• Mangrove forest = mangal = Tropical or subtropical, intertidal
saltwater community dominated by tree and shrub species, especially
such as bakau (Rhizophora species)
• Community = The interacting populations of species (single-species
groupings) of all the animal and plant species at a specific area
Tropic of
Cancer
Tropic of
Capricorn
Mangrove Forest Areas of the World
Mangrove Forest at Chek Jawa Mangrove Forest at Pulau Tekong
Mangrove Forest at Lim Chu Kang Mangrove Forest at Sungei Khatib Bongsu
Sungei Khatib Bongsu
Status of Singapore s Mangrove Forests 1 • Coasts in primeval Singapore
– Mostly fringed by mangrove forest (13% of Singapore Island; 7,500 ha)
– Beaches with beach vegetation
– Cliffs and rocky headlands and their vegetation
– Mouths of sluggish streams and rivers
Status of Singapore s Mangrove Forests 2
• Present-day mangrove forest
– Only about 659 ha presently (see: Yee, A.T.K., W.F. Ang, S. Teo, S.C. Liew and H.T.W. Tan., 2010. The present extent of mangrove forests in Singapore. Nature in Singapore, 3: 139–145. http://rmbr.nus.edu.sg/nis/bulletin2010/2010nis139-145.pdf)
– Isolated patches and narrow strips
Status of Singapore s Mangrove Forests 3
• Room for optimism
– Sungei Buloh Wetland Reserve set up in 1989 (131.4
ha) = Nature Reserve (new extension totals 202 ha)
– Mangrove patch in Pasir Ris Park (20 ha of mangrove
forest) = Park
Pasir Ris
Park
Mangrove
Patch
Status of Singapore s Mangrove Forests 4 • Room for optimism (continued)
– Malaysians not building crooked bridge to replace causeway so no water currents to wash away sediments of mangrove forest patches protruding into Straits of Johore
– Public awareness of value of mangrove forest
Kranji
mangrove
forest
Sungei Buloh mangrove forest
International Coastal Cleanup, Singapore
celebrated its 20th year on 17 Sep 2011!
http://coastalcleanup.nus.edu.sg/
Mangrove Forest Environment 1
• Intertidal zone = Between the high-tide to low-tide levels of the
shore
• Mangrove forest zone = Between the high-tide to the mid-tide
levels on sheltered, muddy shores or rivermouths where there is
fine sediment deposits What do you think will happen to
mangrove forest with sea level
rise through climate change?
high tide level
mid-tide level
low tide level
intertidal zone
mangrove
forest zone
Mangrove Forest Environment 2 • Salinity varies with time of day, depending on
the tides (from 35‰ to less) ― seawater is physiologically dry
• Substrate is anaerobic, unstable
• Wave action and strong winds during storms
• Rainfall, humidity, insolation, temperatures, etc., like other tropical forest types
unstable substrate low tide
high tide
Mangrove Plant Adaptations • To cope with high salinity
• To cope with unstable substrate
• To cope with anaerobic substrate
NUS undergraduates stuck in
mangrove mud!
NUS professor looking cool
in mangrove forest
Adaptations for High Salinity • Salt secretion
– Uptake salt
– Pump out
through glands
– api api, sea
holly
• Salt
ultrafiltration – Exclude salt at
point of uptake
– bakau,
Bruguiera,
Lumnitzera,
perepat
salt
crystals
Adaptations for Unstable Substrate 1
• Modified
roots – Prop or
stilt roots • bakau
– Plank root • nyireh,
dungun
plank root of nyireh
prop roots stilt roots
Adaptations for Unstable Substrate 2
• Vivipary – Ordinary
• bakau family
members
– Cryptovivipary • api api,
kacang-
kacang, nipah
palm
Nyireh (Xylocarpus)
Adaptations for Anaerobic Substrate
• Breathing roots – Pencil/cone roots
• api api, perepat
– Kneed roots • Bruguiera
species, tengar
– Plank roots • nyireh, dungun
– Prop or stilt
roots • bakau
wavy plank
root of nyireh
straight plank
root of non-
mangrove
plant
Singapore Mangrove Plant Types
Major component
species
Minor component
species
Mangrove
associates
Occur only in mangrove forest May occur outside mangrove
forest in other habitats
Occur outside mangrove forest
in other habitats
Play a major role in the
mangrove ecosystem
Play a more minor role in the
mangrove ecosystem
Play a minor role in the
mangrove ecosystem
Often form pure stands* in
mangrove forest
Rarely form pure stands* in
mangrove forest
Rarely form pure stands* in
mangrove forest
Possess morphological and
physiological adaptations for
the mangrove environment
May not possess
morphological and
physiological adaptations for
the mangrove environment
May not possess
morphological and
physiological adaptations for
the mangrove environment
Taxonomically isolated from
their closest relatives
Less taxonomically isolated Not taxonomically isolated
21 species 9 species Several species
* Pure stand = Group of trees at a site consisting of only one species
Seashore
Pandanus
Singapore Mangrove Plant Types
bakau (major
component) sea hibiscus
(mangrove associate)
piai raya (minor
component)
• Bruguiera hainesii
• rare in Singapore, with only a few known
specimens; one at Pasir Ris, one at Kranji
Nature Trail and two at Pulau Ubin.
• Bruguiera sexangula
• two on Pulau Tekong, and two at Sungei
Buloh and it is being replanted at Chek Jawa,
Pulau Ubin and at Pasir Ris Park.
Sandy Beach 1 • Sandy beach ― the world s most enjoyable holiday habitat!
Ipanema Beach, Rio de Janeiro, Brazil
Sandy Beach 1 • Sandy beach = Coast which consists of sands (such as quartz grains),
usually between two rocky headlands
rocky headlands
sandy beach
headland headland
beach
sea
sea sea current current
Sandy Beach 2 • Sandy beaches undergo
– Erosion
– Accretion
– Continual cycle of erosion-accretion, depending on prevailing sea currents
Sep 1994
Sep 1995
Key concepts
• Know the different forest types, their
characteristics,
• Key flora and fauna, often repeated during
lectures
• Videos
Sandy Beaches in Singapore
present day sandy beach
• Sandy beaches in primeval Singapore
– Longest from Tanjong Ru to Changi Point
– Southern side of Sentosa
• Present day natural beaches
– Few left, mostly reclaimed
– Pulau Ubin, Pulau Tekong, Changi Beach, etc.
• Present day artificial beaches
– East Coast Park, Pasir Ris, etc.
– Pulau Seletar, Pulau Serangoon, etc. primeval sandy beach
sandy beach of past and present
Sandy Beaches of Singapore’s Past
Pasir Panjang, 1911 (now reclaimed)
Pasir Ris Beach, 1940
Tanjong Rhu, 1900
Changi Beach, 1962
Present Day Natural Sandy Beaches
Kampong Wak Hassan Beach,
Sembawang Park
Changi Beach
Kampong Noordin Beach, Pulau
Ubin
Present Day Natural Sandy Beaches
Sandy Beach Environmental Conditions • Like reclaimed
land s conditions,
since reclamation
is at the coastline • High light
intensity
• High wind speeds
• High maximum
temperatures
• Low relative
humidity
• Salt spray ―
physiological
dryness
Flag trees
Beach Vegetation Succession
• Ecological succession = Process of
continuous, uni-directional change in the
vegetation (Revision)
• 2 stages – Pes-caprae association (after the seashore
morning glory, Ipomoea pes-caprae) • Starts on bare ground (on accreting beaches)
• Non-woody (herbaceous) plants (herbs, trailers)
– Barringtonia association (after the sea putat,
Barringtonia asiatica) • Succeeds pes-caprae association
• Woody plants (shrubs, trees, epiphytes)
Seashore Morning Glory • Ipomoea pes-caprae; pes-caprae = goat s foot
water-
dispersed
seeds
explosive fruit
Sea Putat
fruit
water-dispersed
fruit
bat-pollinated flower
Singapore’s Rocky Shore or Cliff Vegetation
• Cliffs and rocky shores were rare in primeval Singapore
• Even rarer today through reclamation or development
• More extreme than
those for the sandy
beach – Hot rocks day and
night
– Little or no soil
– Strong wave action
– Landslides
• High light intensity
• High wind speeds
• High maximum
temperatures
• Low relative humidity
• Salt spray ―
Physiological dryness
Cliff or Rocky Shore Environmental Conditions
Cliffs and rocky shore at
Pulau Tekukor
Cliffs and Rocky Shores of Singapore
St. John s Island
Below Fort
Siloso, Sentosa Pulau Biola
Lazarus Island
Cliffs and Rocky Shore at Pulau Tekukor
Cliffs and Rocky Shores at Pulau Salu Cliff or Rocky Shore Plants • Have to be species that can tolerate these harsh conditions
• Thus a very small subset of Singapore s flora
• Some examples – mentigi
– superb fig
– sea purselane
– pelir musang
– sea teak
Animals of Coastal Vegetation
• Have to be able to cope with the
harsh conditions, salinity
• Similar animals in mangrove forest,
sandy beaches and rocky shores or
cliffs
• Dependant on plants for food and
shelter
• Types – Molluscs
– Crabs
– Mud lobster
– Fishes
– Reptiles
Molluscs
• telescope shell
• red berry snail
• mangrove slug
• mangrove periwinkle
• common nerite
Crabs
• face-banded sesarmine
• tree-climbing crab
• fiddler crab
Mud Lobster
• Makes mud lobster mounds in mangrove forest that changes
the habitat significantly ― a keystone species
• Animals which live in or forage in and round the mud
lobster mounds – ant
– mound crab
– mud shrimp
– file snake
Fishes • Adapted to changing salinity of the
habitat
• Examples – Archer fish
– Mudskipper
Reptiles
• Versatile, terrestrial
and aquatic habits
• Examples – water monitor
– dog-faced water
snake
– estuarine crocodile
Dugong
Carcass found in June 2006,
Pulau Tekong
Economic Values of Coastal Vegetation 1 • Direct values (products which are consumed by their use;
Singapore s earlier days) – Timber – Fuelwood and charcoal (especially from bakau) – Wood for chipboard – Tannins and dyes
Charcoal kiln
Bakau piles
Economic Values of Coastal Vegetation 2
• Direct values (products
which are consumed by
their use; Singapore s
earlier days) – Nipah palm products
(attap chee, gula Melaka,
roofing thatch, salt, etc.)
Economic Values of Coastal Vegetation 3
• Direct values
(products which are
consumed by their
use; Singapore s
earlier days) – Seafood (cockles,
oysters, mussels,
crabs, prawns, fish)
– Commercial honey
– Seaweed
– Live pet food (crab-
eating frog for
arrowanas)
– Land
Economic Values of Coastal Vegetation 4
• Indirect values (services which are not consumed by their utilization; present day Singapore) – Food for marine organisms from
the detritus food chain starting with the fallen mangrove tree leaves (food webs more realistic)
– Nurseries for juvenile fish, prawns, crabs, etc.
shark
snapper
crab
fallen leaves
Economic Values of Coastal Vegetation 5
• Indirect values (services which
are not consumed by their
utilization; present day
Singapore)
– Natural sewage treatment
– Protection and stabilization of
the coastline (within limits;
tsunamis can wipe out
mangrove forests!)
– Carbon sequestration
– Deforestation also release
Carbon into atmosphere
Toilet in mangrove
Mangrove forest can protect
inshore areas even in hurricanes
as here in Honduras
Economic Values of Coastal Vegetation 5a
Acheh, 13 Dec 2004 (before tsunami) Acheh, 29 Dec 2004 (after tsunami)
Economic Values of Coastal Vegetation 6
• Indirect values (services
which are not consumed
by their utilization;
present day Singapore) – Ecotourism (mangrove
forests are interesting;
beaches for swimming or
recreation; cliffs and
rocky shores for their
rugged and wild beauty)
– Education
Economic Values of Coastal Vegetation 7
• Indirect values (services which are not consumed by their utilization; present day Singapore) – Potential sources for
industrial chemicals, pharmaceuticals and other products and their corresponding genes for producing such
– Ornamental plants for use on roadsides, parks and gardens
Factor C extracted from the blood of the
horseshoe crab which binds to bacterial
endotoxins; gene isolated to
manufacture this at DBS, NUS
Yellow flame Pong pong
Sea almond
The Future • Natural coastal habitats
are now very rare in Singapore so must be well protected
• Propagation and replanting of coastal plant species
• Setting up Labrador Nature Reserve in 1 Jan 2002 – Good move by government – Developments (restaurant
inside; spa and hotel just outside) nearby should be monitored
• Threat of oil or chemical spills from shipping traffic by accidents or terrorist attack
restaurant
Development is just across the Straits
Coastal debris
Summary • Coastal vegetation occurred on all coastlines in primeval
Singapore and covered about 13% of Singapore Island
• Natural coastal vegetation is now extremely rare
• Coastal vegetation is quite complex and diverse with
almost no exotic species, so conservation value is the
second highest of all habitats after primary forest (ties for
second with secondary vegetation)
• Coastal vegetation provides numerous economic products
and services to Singapore and the rest of the world
• If undisturbed, coastal vegetation should persist but
development, pollution and global warming are real
threats