Mangroves of the Straits of Malacca
Encyclopedia
The Mangroves of the Straits of Malacca are found along the coast of Singapore
, Thailand
, and Northern Sumatra
. These tropical mangrove forests are highly diverse, and are important wetlands with high conservation values. There are two Ramsar sites along the Strait of Malacca: Pulau Kukup and Tanjung Piai..
, the government and relevant stakeholders have an obligation to ensure the mangrove ecosystem and its values are maintained. Erosion
at the site needs to be minimized to safeguard the ecological integrity of the mangrove ecosystem. The root causes of the erosion need to be eliminated or reduced.
Tanjung Piai is a nationally important icon, being one of only five Ramsar sites in Malaysia. Tanjung Piai is also an important nature site in Johor
, being the 3rd designated park of Johor National Park Corporation. Tanjung Piai has high socio-economic value for fisheries
. The site also has high ecotourism
potential, attracting 32,360 visitors in 2006. The site is located on the southernmost tip of mainland Asia
and is listed as a priority site for national ecotourism.
Tanjung Piai has a good representation of mangroves (22 mangrove tree species). It is also an important habitat for migratory and resident birds. These include the IUCN-listed vulnerable species, such as the Lesser Adjutant Stork
. It is part of the Important Bird Area
(IBA) of southwest Johor, which extends from Parit Jawa to Tanjung Piai. The southwest Johor mangroves are ecologically important as a natural barrier to protect the inland villages and agricultural lands from storm events, including tsunami
s.
s, reptile
s, bird
s, and mammal
s. Mangrove roots hanging in water along creeks and inlets are home a variety of epibionts (those that encrust) such as sponges, barnacle
s, bivalve
s, and algae
. The tree trunks within forest are also a habitat for epibiont
s (small encrusting invertebrate
s) such as barnacles, bivalves, and several species of mobile gastropods including periwinkles. The soft sediment in the mangrove forest is the habitat of polychaete
s, gastropods, crab
s and a sipuncula
(peanut worm).
Mangrove fauna may be grouped into macrofauna (larger than 2mm, gastropods/snails and crabs), meiofauna (0.1 mm to 2mm, mainly free-living nematode
s, harpacticoida
, copepod
s, and foraminfera), and microfauna (less than 0.1 mm, ciliate
s and other protozoa
ns).
s, gastropods, bivalves, hermit crabs, brachyuran crabs and sipuncula. Some species live on the sediment surface or reside in burrow
s, while others live on aerial roots and lower tree trunks or prop roots. Still others burrow in decaying wood
. The burrowing activities of benthic invertebrates have a pronounced effect on sediment properties and biochemical processes. They enhance the porosity of water flow through the sediment and assist in flushing away toxic substances.
Feeding activities of invertebrates on the sediment surface and plant
matter promotes nutrient cycling. Benthic invertebrates are a source of food for vertebrates (for example, reptiles, birds, otter
s, and shallow water fish
that come into the mangrove shore at high tide
).
Macrofauna may be divided into epifauna (living on the surface and not borrowing) and infauna (those burrowing in sediment). Many gastropods, crabs, and bivalve species are typical of epifauna. The infauna consist of few polychaetes, pistol prawns, many crabs, and a sipuncula
. Many sesarmid crabs make extensive burrows beneath the surface, and some fauna
take refuge in them.
In the high shore, the substrate is dry with more leaf litter accumulation; however, deposit feeders are abundant. Frequent inundation of the low shore also favors the presence of filter feeders like barnacles and oyster
s (on tree stems) and abundance of deposit feeders on the substrate.
Very common invertebrates of the mangrove shore are:
Gastropods and Bivalves (low shore)
Littorina spp.
Thais tissoti
Murex capucinus
Nerita articulata
Neritina violacea
Telescopium telescopium
T. mauritsi
Syncera brevicula
Cerithidea cingulata
Enigmonia aenigmatica (bivalve)
Xenostrobus sp. (mytilid bivalve)
Brachyuran crabs (low shore)
Uca mani
U. dussumieri
Metaplax elegans
Metaplax crenulatus, Ilyoplax spp.
Hermit crab
s
Gastropods and a Bivalve (high shore)
Ellobium aurismidae
E. aurisjudae
Cassidula aursifelis, Laemodonta spp. Melampus sp.
Cerithidea obtusa, , C. quadrata,
Nerita articulata, Telescopium telescopium,T. mauritsi Syncera brevicula
Geloina erosa (bivalve)
Brachyuran crabs (high shore)
Grapsid crabs
Episesarma spp.
Perisesarma eumople, P. onychophorum
Clistocoeloma merguiensis
(crabs and gastropods) ingest sediment and food such as bacteria
, microalgae, meiofauna and detritus. They burrow, move through, and modify it in many physical and chemical ways. Crab burrows provide an efficient mechanism for exchanging water between the anoxic substrate and the overlying water. A crab burrow inhabited by a sesarmid crab and a pistol prawn
was completely flushed within one hour by the activities of the crustaceans during a single tidal event.
Crabs and gastropods are the major seed predators in mangrove forests and play an important role in determining plant community structure. There are mutual relationships between sesarmid crabs and mangroves, where mangroves provide a suitable habitat for the crabs, and the crabs reduce competition between mangrove plant species through selective predation on seedlings. High seed predation by crabs can have negative influence on regeneration of mangrove trees. Grapsid crabs dominate in Australia
, Malaysia and Panama
, while gastropods Cerithidea scalariformis and Melampus coeffeus are important seed predators in Florida
mangroves.
Detritus feeding invertebrates dominate the mangrove fauna. Grapsid crabs are major consumers of mangrove leaf litter and therefore produce large amounts of fecal material
rich in nutrient
s and energy. These crabs graze and pick organic material off the surface of sediment, suggesting that they are using microbial resources for their nitrogen
needs.
Fish predation on mangrove invertebrates occurs at high tide when mangrove shore is inundated. Fishes netted within the mangroves at high tide showed the presence of crabs and sipuncula in their stomachs.
Benthic invertebrates in the mangrove forest play an important ecological role by burrowing in the sediment where they assist in flushing toxic substances and modifying the oxidation status of the surrounding sediment.
Feeding on plant matter assists in recycling organic matter and produces animal biomass
. Animal biomass is a source of food for vertebrate predators; e.g. reptiles, birds, otters, and inshore fishes that come in at high tide.
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
, Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, and Northern Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
. These tropical mangrove forests are highly diverse, and are important wetlands with high conservation values. There are two Ramsar sites along the Strait of Malacca: Pulau Kukup and Tanjung Piai..
Tanjung Piai
Tanjung Piai coastal mangrove is an internationally important Ramsar site. Under the Ramsar ConventionRamsar Convention
The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...
, the government and relevant stakeholders have an obligation to ensure the mangrove ecosystem and its values are maintained. Erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
at the site needs to be minimized to safeguard the ecological integrity of the mangrove ecosystem. The root causes of the erosion need to be eliminated or reduced.
Tanjung Piai is a nationally important icon, being one of only five Ramsar sites in Malaysia. Tanjung Piai is also an important nature site in Johor
Johor
Johor is a Malaysian state, located in the southern portion of Peninsular Malaysia. It is one of the most developed states in Malaysia. The state capital city and royal city of Johor is Johor Bahru, formerly known as Tanjung Puteri...
, being the 3rd designated park of Johor National Park Corporation. Tanjung Piai has high socio-economic value for fisheries
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
. The site also has high ecotourism
Ecotourism
Ecotourism is a form of tourism visiting fragile, pristine, and usually protected areas, intended as a low impact and often small scale alternative to standard commercial tourism...
potential, attracting 32,360 visitors in 2006. The site is located on the southernmost tip of mainland Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
and is listed as a priority site for national ecotourism.
Tanjung Piai has a good representation of mangroves (22 mangrove tree species). It is also an important habitat for migratory and resident birds. These include the IUCN-listed vulnerable species, such as the Lesser Adjutant Stork
Lesser Adjutant
The Lesser Adjutant, Leptoptilos javanicus, is a large wading bird in the stork family Ciconiidae. It is a widespread species which is resident breeder in southern Asia from India east to southern China and Java....
. It is part of the Important Bird Area
Important Bird Area
An Important Bird Area is an area recognized as being globally important habitat for the conservation of bird populations. Currently there are about 10,000 IBAs worldwide. The program was developed and sites are identified by BirdLife International...
(IBA) of southwest Johor, which extends from Parit Jawa to Tanjung Piai. The southwest Johor mangroves are ecologically important as a natural barrier to protect the inland villages and agricultural lands from storm events, including tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
s.
Benthic invertebrates
Mangroves are trees that grow in the intertidal zone of sheltered shores in the tropics and subtropics. The tree trunks, aerial roots, and sediment provide suitable habitats for colonization of animals. Above the ground, the trees and canopy provide a habitat for insectInsect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s, bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, and mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. Mangrove roots hanging in water along creeks and inlets are home a variety of epibionts (those that encrust) such as sponges, barnacle
Barnacle
A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
s, bivalve
Bivalvia
Bivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...
s, and algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
. The tree trunks within forest are also a habitat for epibiont
Epibiont
An epibiont is an organism that lives on the surface of another living organism. An epibiont is usually considered harmless to the host; in this sense, the relationship between the two organisms can be considered neutralistic or commensalistic. Typical epibionts are barnacles, remoras, and algae,...
s (small encrusting invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s) such as barnacles, bivalves, and several species of mobile gastropods including periwinkles. The soft sediment in the mangrove forest is the habitat of polychaete
Polychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
s, gastropods, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s and a sipuncula
Sipuncula
The Sipuncula or Sipunculida is a group containing 144-320 species of bilaterally symmetrical, unsegmented marine worms...
(peanut worm).
Mangrove fauna may be grouped into macrofauna (larger than 2mm, gastropods/snails and crabs), meiofauna (0.1 mm to 2mm, mainly free-living nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s, harpacticoida
Harpacticoida
Harpacticoida is an order of copepods, in the Subphylum Crustacea. This order comprises 463 genera and about 3,000 species. Members of it are benthic copepods found throughout the world in the marine environment and in fresh water...
, copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s, and foraminfera), and microfauna (less than 0.1 mm, ciliate
Ciliate
The ciliates are a group of protozoans characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagella but typically shorter and present in much larger numbers with a different undulating pattern than flagella...
s and other protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...
ns).
Macrofauna
Mangroves are inhabited by a variety of benthic invertebrates, such as polychaetePolychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
s, gastropods, bivalves, hermit crabs, brachyuran crabs and sipuncula. Some species live on the sediment surface or reside in burrow
Burrow
A burrow is a hole or tunnel dug into the ground by an animal to create a space suitable for habitation, temporary refuge, or as a byproduct of locomotion. Burrows provide a form of shelter against predation and exposure to the elements, so the burrowing way of life is quite popular among the...
s, while others live on aerial roots and lower tree trunks or prop roots. Still others burrow in decaying wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
. The burrowing activities of benthic invertebrates have a pronounced effect on sediment properties and biochemical processes. They enhance the porosity of water flow through the sediment and assist in flushing away toxic substances.
Feeding activities of invertebrates on the sediment surface and plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
matter promotes nutrient cycling. Benthic invertebrates are a source of food for vertebrates (for example, reptiles, birds, otter
Otter
The Otters are twelve species of semi-aquatic mammals which feed on fish and shellfish, and also other invertebrates, amphibians, birds and small mammals....
s, and shallow water fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
that come into the mangrove shore at high tide
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
).
Macrofauna may be divided into epifauna (living on the surface and not borrowing) and infauna (those burrowing in sediment). Many gastropods, crabs, and bivalve species are typical of epifauna. The infauna consist of few polychaetes, pistol prawns, many crabs, and a sipuncula
Sipuncula
The Sipuncula or Sipunculida is a group containing 144-320 species of bilaterally symmetrical, unsegmented marine worms...
. Many sesarmid crabs make extensive burrows beneath the surface, and some fauna
Fauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...
take refuge in them.
Diversity and distribution of macrofauna
Macrofaunal communities in high and low intertidal mangroves are distinctly different. This relates to prevailing different environmental conditions with different periods of tidal cover. The lower shore is frequently covered by tides, while the upper shore is covered by occasional high tides.In the high shore, the substrate is dry with more leaf litter accumulation; however, deposit feeders are abundant. Frequent inundation of the low shore also favors the presence of filter feeders like barnacles and oyster
Oyster
The word oyster is used as a common name for a number of distinct groups of bivalve molluscs which live in marine or brackish habitats. The valves are highly calcified....
s (on tree stems) and abundance of deposit feeders on the substrate.
Very common invertebrates of the mangrove shore are:
Gastropods and Bivalves (low shore)
Littorina spp.
Thais tissoti
Thais tissoti
Thais tissoti is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails....
Murex capucinus
Nerita articulata
Neritina violacea
Telescopium telescopium
T. mauritsi
Syncera brevicula
Cerithidea cingulata
Cerithidea cingulata
Cerithidea cingulata is a species of medium-sized sea snails or mud snails, marine gastropod mollusks in the family Potamididae, the horn snails.-References:* SeaLifeBase info at:...
Enigmonia aenigmatica (bivalve)
Xenostrobus sp. (mytilid bivalve)
Brachyuran crabs (low shore)
Uca mani
U. dussumieri
Metaplax elegans
Metaplax crenulatus, Ilyoplax spp.
Hermit crab
Hermit crab
Hermit crabs are decapod crustaceans of the superfamily Paguroidea. Most of the 1100 species possess an asymmetrical abdomen which is concealed in an empty gastropod shell that is carried around by the hermit crab.-Description:...
s
Gastropods and a Bivalve (high shore)
Ellobium aurismidae
E. aurisjudae
Cassidula aursifelis, Laemodonta spp. Melampus sp.
Cerithidea obtusa, , C. quadrata,
Nerita articulata, Telescopium telescopium,T. mauritsi Syncera brevicula
Geloina erosa (bivalve)
Brachyuran crabs (high shore)
Grapsid crabs
Grapsidae
Grapsidae is a family of crabs known variously as marsh crabs, shore crabs or talon crabs. It is not confirmed that the family forms a monophyletic group and some taxa may belong in other families...
Episesarma spp.
Perisesarma eumople, P. onychophorum
Clistocoeloma merguiensis
Functional role of macrobenthos
MacrobenthosMacrobenthos
Macrobenthos consists of the organisms that live at the bottom of a water column and are visible to the naked eye. In some classification schemes, these organisms are larger than 1 mm; in another, the smallest dimension must be at least 0.5 mm...
(crabs and gastropods) ingest sediment and food such as bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, microalgae, meiofauna and detritus. They burrow, move through, and modify it in many physical and chemical ways. Crab burrows provide an efficient mechanism for exchanging water between the anoxic substrate and the overlying water. A crab burrow inhabited by a sesarmid crab and a pistol prawn
Prawn
Prawns are decapod crustaceans of the sub-order Dendrobranchiata. There are 540 extant species, in seven families, and a fossil record extending back to the Devonian...
was completely flushed within one hour by the activities of the crustaceans during a single tidal event.
Crabs and gastropods are the major seed predators in mangrove forests and play an important role in determining plant community structure. There are mutual relationships between sesarmid crabs and mangroves, where mangroves provide a suitable habitat for the crabs, and the crabs reduce competition between mangrove plant species through selective predation on seedlings. High seed predation by crabs can have negative influence on regeneration of mangrove trees. Grapsid crabs dominate in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, Malaysia and Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, while gastropods Cerithidea scalariformis and Melampus coeffeus are important seed predators in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
mangroves.
Detritus feeding invertebrates dominate the mangrove fauna. Grapsid crabs are major consumers of mangrove leaf litter and therefore produce large amounts of fecal material
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
rich in nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
s and energy. These crabs graze and pick organic material off the surface of sediment, suggesting that they are using microbial resources for their nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
needs.
Fish predation on mangrove invertebrates occurs at high tide when mangrove shore is inundated. Fishes netted within the mangroves at high tide showed the presence of crabs and sipuncula in their stomachs.
Benthic invertebrates in the mangrove forest play an important ecological role by burrowing in the sediment where they assist in flushing toxic substances and modifying the oxidation status of the surrounding sediment.
Feeding on plant matter assists in recycling organic matter and produces animal biomass
Biomass (ecology)
Biomass, in ecology, is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms,...
. Animal biomass is a source of food for vertebrate predators; e.g. reptiles, birds, otters, and inshore fishes that come in at high tide.