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Southeast Asia has the highest diversity of seagrass species and habitat types, but basic information on seagrass habitats is still lacking. This review examines the known distribution, extent, species diversity, and research and knowledge gaps of seagrasses in Southeast Asia by biogeographic region of the Marine Ecoregions of the World (MEOW). The extent of seagrass meadows in Southeast Asia is ~36,762.6 km ² but this is likely an underestimate as some ecoregions were not well-represented and updated information was lacking. There is a paucity of information from the Western Coral Triangle Province, with no areal extent data available for the Indonesian regions of Kalimantan, Central and Southeast Sulawesi, the Maluku Islands, and West Papua. Regional research output has increased in the last two decades, with a trend towards more experimental, rather than descriptive research. However, there are knowledge gaps in socio-cultural-economic themed research, despite growing awareness of the importance of seagrass-human relationships in this region. Obstacles to advancing seagrass research, knowledge and conservation are rooted in either lack of expertise and training or the failure of effective management and policies. We propose a roadmap for seagrass conservation, with suggested solutions, including 1) encouraging collaboration between research institutions and scientists in the region to build capacity and share knowledge; 2) engaging with policymakers and governments to encourage science-based policies; 3) engaging with communities to raise awareness and foster stewardship of seagrass in the region.
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Botanica Marina 2018; 61(3): 269–288
Miguel D. Fortes, Jillian Lean Sim Ooi, Yi Mei Tan, Anchana Prathep, Japar Sidik Bujang
and Siti Maryam Yaakub*
Seagrass in Southeast Asia: a review of status and
knowledge gaps, and a road map for conservation
Received 2 February, 2018; accepted 24 April, 2018; online first 29
May, 2018
Abstract: Southeast Asia has the highest diversity of sea-
grass species and habitat types, but basic information on
seagrass habitats is still lacking. This review examines
the known distribution, extent, species diversity, and
research and knowledge gaps of seagrasses in Southeast
Asia by biogeographic region of the Marine Ecoregions
of the World (MEOW). The extent of seagrass meadows in
Southeast Asia is ~36,762.6 km2 but this is likely an under-
estimate as some ecoregions were not well-represented
and updated information was lacking. There is a paucity
of information from the Western Coral Triangle Province,
with no areal extent data available for the Indonesian
regions of Kalimantan, Central and Southeast Sulawesi,
the Maluku Islands, and West Papua. Regional research
output has increased in the last two decades, with a
trend towards more experimental, rather than descrip-
tive research. However, there are knowledge gaps in
socio-cultural-economic themed research, despite grow-
ing awareness of the importance of seagrass-human rela-
tionships in this region. Obstacles to advancing seagrass
research, knowledge and conservation are rooted in either
lack of expertise and training or the failure of effective
management and policies. We propose a roadmap for sea-
grass conservation, with suggested solutions, including 1)
encouraging collaboration between research institutions
and scientists in the region to build capacity and share
knowledge; 2) engaging with policymakers and govern-
ments to encourage science-based policies; 3) engaging
with communities to raise awareness and foster steward-
ship of seagrass in the region.
Keywords: conservation challenges; developing states;
marine ecoregion; research gaps.
Southeast Asia is a biologically, culturally, and ethnically
diverse region, made up of 14 countries, many of which
are archipelagic states (Tangsubkul 1984). The region as a
whole has seen a rapid population expansion of nearly six-
fold between 1900 and 2000 (Jones 2013). The current pop-
ulation stands at approximately 622 million people, with
most of the population concentrated in coastal capital cities
(Figure 1). The region is also a global biodiversity hotspot,
with high numbers of endemic species in both the marine
and terrestrial environments (Sodhi et al. 2010, Tittensor et
al. 2010). The cost of rapid population expansion and eco-
nomic development in the region has resulted in devastat-
ing losses in terms of biodiversity on land (Sodhi et al. 2004),
with similar impacts on marine biodiversity, although the
true extent of this is still likely not fully realised, given the
paucity of information from this region (Chou 2014).
Despite being a key component of marine ecosystems,
seagrass meadows are a prime example of a habitat that is
largely understudied and underdocumented in the South-
east Asian region (Waycott et al. 2009), with only 62 ISI
cited seagrass-related publications between the 1980s and
2010 (Ooi et al. 2011a), most of which are on two specific
sites in Northwest Luzon in the Philippines, and South
Sulawesi in Indonesia. Much of the literature on seagrass
in this region exists as grey literature, stemming from
globally funded initiatives such as the UNEP-GEF South
*Corresponding author: Siti Maryam Yaakub, Environment and
Ecology Department, DHI Water and Environment (Singapore),
2Venture Drive, #18-18, Singapore 608526, Singapore,
Miguel D. Fortes: Marine Science Institute, CS, University of the
Philippines, Diliman, QC 1101, Philippines
Jillian Lean Sim Ooi: Department of Geography, Faculty of Arts
and Social Sciences, University of Malaya, Kuala Lumpur 50603,
Yi Mei Tan: DHI Water and Environment (Singapore), 2 Venture Drive,
#18-18, Singapore 608526, Singapore
Anchana Prathep: Prince of Songkla University, Deparment of
Biology, Faculty of Science, Hat Yai, Thailand
Japar Sidik Bujang: Department of Biology, Faculty of Science,
Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul
Ehsan, Malaysia.
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270M.D. Fortes etal.: A review of seagrass in Southeast Asia
China Sea Project (UNEP 2008), yet these projects focus on
specific areas, while excluding the wider Southeast Asian
region, which is data depauperate. Seagrass meadows
are widely recognised as offering a number of key ecosys-
tem services, such as habitat formation, nutrient cycling,
carbon sequestration, and food provisioning (William and
Heck 2001, McGlathery et al. 2007, Fourqurean et al. 2012,
Cullen-Unsworth and Unsworth 2013), with many coastal
populations within Southeast Asia directly dependent on
these habitats for a living (Unsworth and Cullen 2010).
Seagrasses also continue to decline at a global rate of
approximately 7% (Waycott et al. 2009), and the losses
may be more acute in the Southeast Asian region due to
the pressure from increasing coastal populations and
developments, and the lack of data on seagrass resources.
Perhaps just as important are the socio-economic-cultural
links between seagrass meadows and coastal populations,
which is only now coming to the attention of researchers
(Unsworth and Cullen 2010).
The causes of seagrass loss in Southeast Asia have
been documented in two other reviews (Fortes 1995,
Kirkman and Kirkman 2002), and these threats, and their
associated challenges, still remain relevant today. This
review paper will instead focus on the current state of
knowledge of seagrass in Southeast Asia, focusing on the
the extent of seagrass within the diverse biogeographic
regions of its marine environments. Based on the status
review, we focus on the areal gaps in knowledge within
Southeast Asia, followed by a more general thematic gap
analysis. We also address the conservation and manage-
ment challenges based on these gaps, and propose a
broad roadmap for seagrass conservation and research
in Southeast Asia, in order to develop the adaptive capac-
ity of the coastal environment and its dependent human
Status of seagrass in Southeast
Seagrass distribution and extent by biogeo-
graphic region
There are six seagrass bioregions that encompass all the
oceans of the world, across both tropical and temperate
waters (Short et al. 2007). Southeast Asia lies within the
Figure 1:Total population by country in Southeast Asia.
Population figures derived from
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M.D. Fortes etal.: A review of seagrass in Southeast Asia271
Indo-West Pacific bioregion (Bioregion 5), a vast region
stretching from east Africa to the eastern Pacific Ocean,
notable for being the largest and most biodiverse (24
species). However, Southeast Asia itself is potentially a
distinct biogeographic province within the Indo-West
Pacific, as indicated by the cluster analysis by Fortes
(1988) for the seagrasses of the Indo-West Pacific. The
Philippines and Brunei Darussalam were also shown to
be slightly differentiated from other areas because of high
seagrass species numbers in the former and low species
numbers in the latter (Fortes 1988), which suggests that
even finer-scale regions within Southeast Asia may exist,
if based on updated distribution data.
In this review, we use the Marine Ecoregions of the
World (MEOW) biogeographic scheme to provide the geo-
graphical context for seagrass distribution. The MEOW
biogeographic scheme classifies all coastal and shelf
areas of the world according to benthic and pelagic biota
(Spalding et al. 2007), producing a nested system of 12
realms, 62 provinces, and 232 ecoregions. Based on this
classification, the seas of Southeast Asia consist of seven
provinces and 22 ecoregions (Figure 2), extending from
the Bay of Bengal and the Andaman Sea in the west, to the
Arafura Sea in the east. The provinces vary in size, with
the largest being the Western Coral Triangle Province,
which contains seven ecoregions. The Bay of Bengal Prov-
ince and Sahul Shelf Province are only partly included in
what we define as Southeast Asia in this review, which
explains their relatively small size in Figure 2.
Species richness at the province level is highest in
the Sunda Shelf and Western Coral Triangle (15 species).
Within these provinces, species richness in the individ-
ual ecoregions ranges from 3 to 14 species (Table 1), but
note that we excluded Halophila gaudichaudii and Hal-
ophila tricostata from our dataset because of locational
uncertainty. Low species counts were found in the Cocos-
Keeling/Christmas Island ecoregion (3 species) and the
South China Sea Oceanic Islands ecoregion (4 species).
Both ecoregions are fairly isolated, comprising atolls with
lagoon seagrass meadows. Low species richness here
likely reflects either a limited dispersal pathway between
meadows in the greater Southeast Asian region and these
remote sites, or a lack of suitable ecological drivers for the
majority of species in these lagoons.
Figure 2:Marine provinces and ecoregions of Southeast Asia, based on Spalding etal. (2007).
Provinces are made out of ecoregions with the following codes: 20108Northern Bay of Bengal; 20109 Andaman and Nicobar Islands; 20110
Andaman Sea Coral Coast; 20111 Western Sumatra; 20112 Gulf of Tonkin; 20114 South China Sea Oceanic Islands; 20115 Gulf of Thailand;
20116 Southern Viet Nam; 20117 Sunda Shelf/Java Sea; 20118 Malacca Strait; 20119 Southern Java; 20120 Cocos-Keeling/Christmas Island;
20126 Palawan/North Borneo; 20128 Sulawesi Sea/Makassar Strait; 20129 Halmahera; 20130 Papua; 20131 Banda Sea; 20132 Lesser
Sunda; 20133Northeast Sulawesi; 20139 Arafura Sea.
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272M.D. Fortes etal.: A review of seagrass in Southeast Asia
In contrast, the Malacca Strait emerges as an ecore-
gion of special interest in terms of species richness. It is
amongst the smallest of the ecoregions but supports 14
seagrass species (Table 1). This narrow strait, measuring
926 km in length, is one of the busiest shipping lanes in the
world because it connects the Indian Ocean to the South
China Sea (Mokhzani 2004, Ibrahim and Nazery 2007).
This may partly explain its high seagrass species rich-
ness, as in the case of marine fish (Carpenter and Springer
2005). In an analysis of global shore fish biodiversity, the
location of the strait in an area of overlap between Indian
and Pacific ocean fauna was suggested as a likely expla-
nation for high species richness (Carpenter and Springer
2005). In terms of gene flow, this ecoregion is recognised
as the Indo-Pacific Barrier (Bowen et al. 2016), the equiva-
lent of a marine Wallace line that separates populations
of marine fauna on either side of the strait through shifts
in sea level during periods of glaciation. This insight is
useful in guiding the selection of sampling locations for
seagrass phylogeographic studies that address questions
about biodiversity distributions in Southeast Asia, and
specifically in testing hypotheses about Southeast Asia as
a centre of overlap, refuge, accumulation or centre-of-ori-
gin for seagrass, such as those suggested by Mukai (1993)
and Nguyen et al. (2013), Nguyen et al. (2014). However,
we see the need to draw attention to the fact that devel-
opment in the Malacca Strait due to shipping, port con-
struction, and land reclamation are likely factors that
will determine how rapidly seagrasses, as well as other
marine ecosystems, are likely to change in the near future
(Mokhzani 2004, Ibrahim and Nazery 2007).
The most widespread species in Southeast Asia is
Thalassia hemprichii, which had distribution records in all
ecoregions, even in locations as remote as the South China
Sea Oceanic Islands. Cymodocea serrulata and Cymodo-
cea rotundata are common species as well, occurring in all
ecoregions except for the South China Sea Oceanic Islands
and the Cocos-Keeling/Christmas Islands. Species that
Table 1:Number of seagrass species and extent of known meadows in marine bioregions of Southeast Asia.
Province/ecoregion No. of species/province No. of species/ecoregion Seagrass area (km)
Bay of Bengal 
Northern Bay of Bengal ()  .
Andaman 
Andaman and Nicobar Islands () .
Andaman Sea Coral Coast ()  .
Western Sumatera () ND
South China Sea
Gulf of Tonkin () .
South China Sea Oceanic Islands () ND
Sunda Shelf 
Gulf of Thailand ()  .
Southern Viet Nam ()  .
Sunda Shelf/Java Sea ()  .
Malacca Strait ()  .
Java Transitional 
Southern Java ()  .
Cocos-Keeling/Christmas Island () .
Western Coral Triangle 
Palawan/North Borneo ()  ,.
Eastern Philippines ()  .
Sulawesi Sea/Makassar Strait ()  .
Halmahera () .
Papua () .
Banda Sea ()  .
Lesser Sunda ()  .
Northeast Sulawesi () ND
Sahul Shelf
Arafura Sea () ND
Provinces are in bold; ecoregions are in italics. ND denotes the absence of data. In assessing number of species, Halophila gaudichaudii
and H. tricostata were excluded from this dataset because of locational uncertainty within ecoregions. Seagrass area values were available
for very few sites in comparison to what we know about seagrass extent in the region, and should be regarded as underestimates.
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M.D. Fortes etal.: A review of seagrass in Southeast Asia273
were unique to one ecoregion were Halophila sulawesii
(Kuo 2007), with only one record in Samalona Island of the
Spermonde archipelago (see also: Taxonomic Highlights,
below), and Zostera japonica in the Gulf of Tonkin (Luong
et al. 2012). Halophila major and Halophila ovata are also
limited to single ecoregions in the Northern Bay of Bengal,
and the Andaman and Nicobar Islands, but this may be
because these forms are taxonomically difficult to iden-
tify (addressed in Taxonomic Highlights below), although
recent progress has been made in molecular approaches
(Nguyen et al. 2013, 2014).
The extent of seagrass meadows in Southeast Asia is
currently 36,762.6 km2 (Table 1). The largest areas are in
the Palawan/North Borneo (20,115 km2), Eastern Philip-
pines (7159 km2) and Banda Sea (8246.2 km2) ecoregions,
all of which are part of the Western Coral Triangle Prov-
ince. Not all ecoregions are as well-represented in terms of
seagrass meadow estimates. The South China Sea Oceanic
Islands, Western Sumatera, Northeast Sulawesi, and the
Arafura Sea ecoregions, for example, have obvious infor-
mation gaps. These will be further highlighted in Section
Areal gaps in knowledge and information”.
Seagrass distribution and extent by country
Recent updates now show Southeast Asia to have 21 sea-
grass species in nine genera and four families, which
makes up 29% of the world’s seagrass species (Table 2).
Seagrass species diversity is highest in the Philippines (19
species), and lowest in Brunei (7 species), which is the
country with the most recent additions to its species list
(Lamit et al. 2017).
The nation states of Southeast Asia have a collective
coastline of more than 100,000 km that encompass at least
675,824 km2 of territorial seas (Flanders Marine Institute
Table 2:Seagrass species distribution in Southeast Asia by country/territory.+
Family and species BNID CMMMMYPHSGTH VNAN+
Family Hydrocharitaceae
Enhalus acoroides (L. f.) Royle
Thalassia hemprichii (Ehrenb.) Aschers. in Petermann
Halophila beccarii Aschers.
Halophila decipiens Ostenfeld
Halophila gaudichaudii J. Kuo 
Halophila major (Zoll.) Miq.
Halophila minor (Zoll.) den Hartog
Halophila ovalis (R. Br.) Hook. f.
Halophila ovata Gaudich. and in Freycinet 
Halophila spinulosa (R. Br.) Aschers. 
Halophila sulawesii J. Kuo
Halophila sp.  
Halophila sp.  (Halophila tricostata Greenway) 
Family Cymodoceaceae
Cymodocea rotundata Ehrenb. et Hempr. ex Aschers.
Cymodocea serrulata (R. Br.) Aschers. et Magnus
Halodule pinifolia (Miki) den Hartog
Halodule uninervis (Forssk.) Aschers.
Syringodium isoetifolium (Aschers.) Dandy
Thalassodendron ciliatum (Forssk.) den Hartog 
Family Ruppiaceae
Ruppia maritima L.
Family Zosteraceae
Zostera japonica Aschers. et Graebn.  
Total no. of species     
Country codes and references used to compile this list as follows: BN, Brunei (Fortes 1988, Lamit etal. 2017); ID, Indonesia (Kuo 2007,
Wawan 2011, Tuntiprapas etal. 2015); CM, Cambodia (UNEP 2008, Vibol etal. 2010); MM, Myanmar (Novak etal. 2009, Soe-Htun etal.
2009, Nguyen etal. 2014, BOBLME 2015); MY, Malaysia (Japar Sidik and Muta Harah 2011, Nguyen etal. 2014); PH, Philippines (Fortes 1989,
Waycott etal. 2002, Fortes 2013, Kim etal. 2017); SG, Singapore (Yaakub etal. 2013); TH, Thailand (Nguyen etal. 2014, Tuntiprapas etal.
2015); VN, Viet Nam (Nguyen etal. 2013, 2014); AN, Andaman and Nicobar Islands (Jagtap etal. 2003, Tangaradjou etal. 2010), the “+”
denoting this is a union territory of India.
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274M.D. Fortes etal.: A review of seagrass in Southeast Asia
2016). The Philippines has the largest seagrass extent,
with seagrass meadows constituting at least 24% of its ter-
ritorial waters – the largest proportion in the region (Table
3). In contrast, Myanmar and Malaysia have the lowest
proportion of known seagrass areas relative to the size
of their territorial seas (0.02%), while Timor-Leste has
yet to produce areal estimates of seagrass meadows. This
provides a guide to which countries in particular require
greater capacity-building in developing spatial databases
for seagrass.
Taxonomic notes
The seagrass species list of Southeast Asia (Table 2) shows
21 species, but some of these are still considered taxonom-
ically uncertain. The genus with the greatest number of
unvalidated species is Halophila. This genus has high tax-
onomic diversity, but its constituent forms appear to have
overlapping leaf morphologies that have made validation
problematic. The plasticity of this species in response to
different substratum, salinity, and light regimes has been
demonstrated (Young and Kirkman 1975, Benjamin et al.
1999, Japar Sidik et al. 2010), and is the main reason for
taxonomic uncertainty on the basis of morphological traits
alone. In Table 2, we show Halophila to consist of nine rec-
ognised species and two undescribed species, Halophila
sp. 1 (the Philippines) and Halophila sp. 2 (Malaysia and
Philippines). Amongst those we list as recognised species,
however, we acknowledge that H. major, H. gaudichaudii,
H. minor, and H. ovata, which are regarded as being part
of the H. ovalis complex (Waycott et al. 2004), which may
now include H. sulawesii, are undergoing taxonomic scru-
tiny in this region, which we briefly summarise below.
In Southeast Asia, Halophila major has been studied
in greater detail than other species in its genus, through
a combination of morphological and molecular traits.
As a result, it has become a recent entry into the species
records of Indonesia (Tuntiprapas et al. 2015), Thailand
(Tuntiprapas et al. 2015), Malaysia (Japar Sidik pers. obs;
see Figure 3), Myanmar (Nguyen et al. 2014), Viet Nam
(Nguyen et al. 2013, 2014), and the Philippines (Kim etal.
2017). Halophila minor and Halophila ovata were treated
as synonyms for the seagrass flora of Singapore (Yaakub et
al. 2013) despite being recognised as two distinct species
by Kuo (2000). However, H. ovata was subsequently con-
sidered an illegitimate name and proposed as Halophila
gaudichaudii by Kuo et al. (2006). As a result, all these
Table 3:Extent of known seagrass areas in Southeast Asia, arranged according to seagrass area size for each country.a
extent (km)
area (km)
Proportion of territorial
seas with seagrass (%)a
Philippines ,,. . World Bank 
Indonesia ,. . Neinhuis etal. , de Iongh etal. , Douven etal. ,
Arifin , Kuriandewa and Supriyadi , UNEP , Kamal
etal. , Unsworth , van Katwijk etal. , Torres-
Pulliza etal. , Patty , Kawaroe etal. , Fitrian etal.
, Mintje 
Cambodia . . UNEP 
Thailand . . Poovachiranon etal. , UNEP 
Viet Nam . . Luong etal. 
. Hobbs etal. 
Malaysia . . Japar Sidik and Muta Harah , Jaaman etal. ,
Anscelly , Ooi etal. , Rajamani and Marsh ,
Hossain etal. a,b, Japar Sidik and Muta Harah 
Andaman and Nicobar+. Tangaradjou etal. 
Myanmar . . BOBLME 
Brunei . . Lamit etal. 
Singapore . . Yaakub etal. 
Timor-Leste Unknown Unknown
Total ,,.
Proportion of territorial seas with seagrass was calculated for each country or territory based on territorial sea area values obtained from
Flanders Marine Institute (2016). +Cocos Keeling/Christmas Island and Andaman and Nicobar Islands are territories of Australia and India
respectively. aTerritorial seas are defined as areas of water “enclosed within the maritime delimitations of a coastal state extending 12 nauti-
cal miles seawards from the baselines” (Flanders Marine Institute 2016). Estimates were not made for territories. Seagrass area values were
available for very few sites in comparison to what we know about seagrass extent in the region, and should be regarded as underestimates.
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M.D. Fortes etal.: A review of seagrass in Southeast Asia275
confounding species, i.e. H. minor, H. ovata and H. gau-
dichaudii are present in the species records of this region,
and are reported as such in this review on the grounds of
maintaining the transparency of these species lists until
a taxonomic consensus is reached. We note, however,
that H. major appeared in the records of VietNam (South-
ern VietNam ecoregion) and Myanmar (Northern Bay of
Bengal ecoregion); H. gaudichaudii in the records of the
Philippines (ecoregion undetermined); and H. ovata in
the Andaman and Nicobar Islands, and the Philippines
(ecoregion undetermined).
In Table 2, there are two unidentified Halophila
species, i.e. Halophila sp. 1 from Malita, Davao del Sur,
the Philippines (Fortes 2013) and Halophila sp. 2, from
a mangrove area of Teluk Sepinong, Sandakan, Sabah,
Malaysia (Japar Sidik and Muta Harah 2011). Halophila
sp. 1 needs further verification. However, Halophila sp. 2
(Figure 4), was also reported as an uinidentified Haloph-
ila sp. nov., collected off Molleangan Island, near Banggi
Island, Sabah (Rajamani and Marsh 2015), which has
recently been described and identified as Halophila tricos-
tata using molecular ITS sequence data in the Philippines
(Calumpong et al. 2010, Tiongson 2012). Halophila tricos-
tata is considered endemic to the east coast of Australia
(Greenway 1979) and its presence in the species records
of Southeast Asia indicates its potential for long distance
dispersal from the Great Barrier Reef of Australia to the
Palawan/North Borneo ecoregion.
The genus Halodule is another taxon that has been
a source of uncertainty and confusion in species iden-
tification because of overlapping morphological char-
acters (leaf width, leaf length dimensions) and species
separation through their leaf tips (Phillips 1967, den
Hartog 1970, Japar Sidik et al. 1999). Halodule pinifolia is
considered to be the narrow-leaved form of Halodule unin-
ervis (Waycott et al. 2004), but these have been shown
through genetic analysis on samples in the Philippines to
be separate species that have morphological variations in
leaf width because of site-specific differences, density and
exposure (Wagey and Calumpong 2013). Thus, we have
maintained them as different species in Table 2.
Knowledge gaps
Areal gaps in knowledge and information
Information on seagrass in Southeast Asia is geographi-
cally unbalanced, with hotspots and coldspots of research
effort. Within hotspots, the level of information itself is
variable, with some providing reports of species pres-
ence, while others provide both species presence and
estimates of meadow size. Estimates of meadow size are
rarely reported because of the logistical challenges in
mapping seagrass meadows. It has only been in recent
years that areal estimates for seagrass meadows have
begun to emerge more rapidly as a result of advance-
ments in remote sensing technology and well-funded
regional projects such as the UNEP/GEF South China
Sea Project (UNEP 2008), the Bay of Bengal Large Marine
Ecosystem Project (BOBLME 2015), and the JSPS-Asian
CORE Project. We consider meadow size data to be par-
ticularly critical for moving seagrass conservation and
management forward in the region because these provide
Figure 3:Halophila major from Tanjung Adang Laut, Sungai Pulai
estuary, Johor (refer also to Nguyen etal. 2014 for morphological
and genetic identification of the species).
Photo credit: © Muta Harah.
Figure 4:Halophila sp. 2 collected in 1997 at a mangrove area of
Teluk Sepinong, Sandakan, Sabah, Malaysia.
Photo credit: © Japar Sidik.
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276M.D. Fortes etal.: A review of seagrass in Southeast Asia
baselines for understanding ecosystem trajectories, either
under natural conditions or in response to environmen-
tal change over the long-term, as in the case of the global
analysis of seagrass trajectories by Waycott etal. 2009. In
this review, information gaps by geographic areas are vis-
ualised by plotting locations where data on species pres-
ence, meadow size, or both, are available in the region
(Figure 5).
There is quite an even spread of sampling sites and a
high level of information (species presence and seagrass
areal extent) in the Gulf of Tonkin, the Gulf of Thailand,
the Eastern Philippines, Lesser Sunda and the continental
part of the Andaman Sea Coral Coast ecoregion (see solid
points in Figure 5).
Ecoregions that potentially have seagrass habitats but
which are data depauperate include:
1. The South China Sea Oceanic Islands, with merely
one data point in the Layang-Layang atoll and no
meadow area estimates;
2. The Sulawesi Sea/Makassar Strait, with most of the
data points clustered on the southwestern and north-
eastern coastline of Sulawesi, with no meadow area
3. The Sunda Shelf/Java Sea, especially on the islands of
Borneo and Sumatera;
4. The Arafura Sea, which has just one data point, in the
Aru group of islands.
Accessibility to seagrass sites influences the distribution
of data points in the region, to a certain extent. Some sites
are inaccessible to researchers because they are remote or
are under territorial dispute. The South China Sea Oceanic
Islands, which include the Spratly Islands, have both char-
acteristics: they lie right in the centre of the South China
Sea and have been the subject of multiple overlapping
maritime claims by the Philippines, Malaysia, Viet Nam,
Brunei, Taiwan and the People’s Republic of China for
more than 50 years. Because they are physically iso-
lated, these sites are natural laboratories for testing ideas
about allopatric differentiation in seagrass and seagrass-
associated species, and to elucidate seagrass dispersal
routes in the region. To take the example of fish larvae
in the Spratly Islands, larval drift time and vector current
charts indicate that the western Philippines, Taiwan,
south-eastern China, Brunei, and Malaysia are direct sink
habitats for coral reef fish from the Spratlys (McManus
Figure 5:Level of seagrass information available within the Southeast Asian region.
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M.D. Fortes etal.: A review of seagrass in Southeast Asia277
2017). Long-distance dispersal in seagrasses has also been
shown to be possible through seeds, fruits, viviparous
seedlings and vegetative fragments, all of which have the
capacity to move over hundreds of kilometers in distance
(Kendrick et al. 2012). However, if seagrass scientists in
the region hope to fill in this data gap, rapid action is nec-
essary because of the amount of recent island-building
in this ecoregion as a result of intense territorial claims
(Southerland 2016). Island-building often involves sand-
dredging and land reclamation on shallow coral reefs and
in lagoons. To date, two-thirds of currently occupied atolls
in the Spratlys have been shown to have proportionally
less reef extent than unoccupied atolls, implying the det-
rimental effects of island-building on reef systems (Asner
et al. 2017). Along with these reefs, seagrasses may also
be equally damaged before being recorded and studied for
Google Earth images of the the Sulawesi Sea/Makas-
sar Strait ecoregion show the presence of soft substrate
coastlines, large estuaries, and outlying islands which
are often associated with seagrass. Seagrasses appear
to be widespread in this ecoregion, and the area of
Derawan, east Kalimantan, in particular has been the
subject of study (McKinnon et al. 1996, van der Zon 2010).
However, the available sources mentioned seagrass in
the area in a broad sense, without giving details of loca-
tions, full species list, or meadow extent. Similarly, the
Sunda Shelf/Java Sea ecoregion has sparse datasets on
the Malaysian side of Borneo despite anecdotal evidence
for large areas of seagrass along those coastlines (Japar
Sidik pers. obs.).
An observation that came up in this effort to review
updated seagrass species and meadow information was
that these were often categorised according to countries.
This is certainly useful from a national point of view, but
for seagrass science to be cohesive at the regional level,
we need to ensure that information about species and
meadow estimates are both sea-specific and country-
specific. In this review, we used MEOW bioregions for this
purpose. However, other biogeographic schemes may be
just as useful, and we regard the use of bioregions as a
starting point for scientists in the region to discuss data
and information needs when collaborating on regional-
scale studies.
Thematic gaps in knowledge and information
Seagrass research in Southeast Asia is increasing based on
the number of research papers that have been produced
in the last decade (Ooi et al. 2011a), and an update of the
number of research articles, reports and studies that have
been reported in the region has shown a steady increase
in research output decade by decade for most countries
(Figure 6). However, there are still noticeable gaps in
knowledge in Cambodia, and Myanmar, as well as places
like East Timor, Brunei, and the Cocos (Keeling) Islands.
There is also an increase in the number of research papers,
reports, and theses published by authors originating from
or based in the country or region itself, which indicates an
increase in research interest and capacity of local scien-
tists. There has been an increase in the number of national
Figure 6:Research output per decade by country/territory.
Numbers based on searches on Web of Science and updated from Ooi etal. (2011a).
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278M.D. Fortes etal.: A review of seagrass in Southeast Asia
or regional journals being made available online, which
has increased the visibility of the research being pub-
lished, along with academic sharing and networking sites,
such as ResearchGate™ which allows researchers with a
verified profile to share their research output – both in
journals as well as in other forms, such as reports, posters,
conference proceedings, book chapters, etc. – to be shared
publicly and directly with the platform’s audience.
Taxonomic research continues to be a mainstay of the
research efforts in this region, with new species – par-
ticularly in the Halophila ovalis species complex (Waycott
etal. 2004) – being described (see Kuo 2007, Japar Sidik
and Muta Harah 2011, Fortes 2013). However, there is
an obvious need for traditional morphological seagrass
taxonomy to embrace new methods in the field. There is
currently already a Global Initiative to Barcode Seagrass
(GIBS) based at the State Herbarium of South Australia
and the University of Adelaide (GIBS 2018), and more
participation from researchers in the Southeast Asian
region may be beneficial for the advancement of seagrass
There is an increasing trend of research output for the
region as a whole (Ooi et al. 2011a; Figure 6), and there
are some distinct trends in the intensity of work within
each thematic research area across the decades (Figure 7).
There was a surge in the number of seagrass ecology and
environment related research from the 1990s onwards,
and this is by far the most productive research area in
terms of output. There has also been a progression in this
field moving away from purely descriptive to more experi-
mental studies examining interactions and cumulative
stressors and anthropogenic impacts of the major causes
of seagrass decline such as sedimentation (Cabaço and
Santos 2007, Manzanera et al. 2011, Ooi et al. 2011b, Han et
al. 2012), water quality declines and light reduction (Bite
et al. 2007, Leoni et al. 2008, Baden et al. 2010, Collier
et al. 2011, Yaakub et al. 2014a), changes in temperature
(Campbell et al. 2006, Collier and Waycott 2014, Gao et al.
2017), and competition with macroalgae (Davis and Four-
qurean 2001, Taplin et al. 2005, Martinez-Luscher and
Holmer 2010, Holmer et al. 2011).
New research themes also emerged in the 1990s con-
cerning conservation and management (e.g. Fortes 1991,
Kirkman and Kirkman 2002, Unsworth and Cullen 2010),
and connectivity of seagrass habitats (e.g. Fortes 1988,
Vermaat et al. 2004), likely in response to the trend of
habitat loss from the rapid population expansion across
Southeast Asia between the mid-90s and the present.
There were also some new research areas – such as genet-
ics (e.g. Matsuki et al. 2013, Nakajima et al. 2014, Arries-
gado et al. 2015, Hernawan et al. 2017) and blue carbon
(e.g. Miyajima et al. 2015, Alongi et al. 2016, Rozaimi et
al. 2017) – that have increased in intensity, advancements,
and improvements in protocols and methodology. More
traditional research areas, such as mapping of areal extent
of seagrass habitats, also received a boost in research
output with improvements in remote sensing technology,
and accessibility of satellite imagery. Continued interest
in this field and expansion of research into more remote
areas can help improve and continue to address infor-
mation gaps in areal extent of seagrass meadows in the
region, and also start to expand into examining seasonal
variation and decline.
Despite the continued increase in research, it is plain
to see that a lot of work still needs to be carried out in
order to address the gaps in knowledge and information.
Figure 7:Research output for the Southeast Asian region by thematic area presented as decadal totals.
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M.D. Fortes etal.: A review of seagrass in Southeast Asia279
For example, there is virtually no social science research
examining the social, cultural and economic aspects
of human-seagrass interactions, and there is research
emerging that points to important relationships between
coastal populations and seagrass beds (Cullen-Unsworth
et al. 2014). Furthermore, while the significance of sea-
grass fishery activity has been acknowledged globally
(Nordlund et al. 2017), the lack of information on seagrass
fishery resources and the flow-on benefits from ecosys-
tem services it provides in the Southeast Asian region is
a data gap that needs to be addressed (Unsworth et al.
2009). In Table 4, we suggest the direction for existing and
new thematic research areas, as well as potential areas for
regional research cooperation.
Paving the way: key challenges for
the next decade
There have been previous articles and reviews on chal-
lenges for seagrass conservation in Southeast Asia, and
while we do not wish to revisit them, the obstacles to the
effective management and conservation of seagrass hab-
itats must be addressed. If the experiences of coral reef
and mangrove habitats are any indication, the past half
century has taught us that the future of seagrass meadows
in SE Asia is bleak, their degradation is expected to con-
tinue, despite greater local and region-wide conservation
efforts and the promises of programs and projects being
implemented and planned. Fortes (2013) addressed some
key challenges for seagrass habitats in the context of the
Philippines, but these concepts can be extrapolated and
are widely applicable to the Southeast Asian region as a
whole. We have summarised the six key challenges that
are hampering efforts towards the successful manage-
ment of seagrass habitats in the region in Table 5.
The first three challenges are rooted around the
central problem of lack of knowledge, expertise, and
information. Expertise in seagrass research and infor-
mation on tropical seagrass habitats in the region was
built on collaborations and partnerships with research
partners from outside the region. Actual capacity build-
ing and training of researchers in the region seemed to
be concentrated in some institutions, with little to no
information sharing beyond those institutions (Table
5; Challenge #1). Where seagrass research was carried
out by researchers outside the centers of knowledge,
the work tends to be highly descriptive, which is likely
fuelled by the lack of training, expertise, and resources
(Table 5; Challenge #2). This lack of access to information
and training, especially in basic methods, then exacer-
bates the problem of lack of basic knowledge of seagrass
meadows in Southeast Asia (Table 5; Challenge #3),
which results in a paucity of basic information such as
spatial extent, species composition, and cover. To over-
come these challenges requires a concerted and multi-
pronged approach, and must come from researchers
who are based in Southeast Asia themselves. Forming a
network of scientists working in the region (even infor-
mally) builds a collaborative and supportive research
and knowledge sharing network. Training workshops
for young researchers and inter-institution collabora-
tion and exchanges should be encouraged. Knowledge
sharing can also avoid duplication of work and sharing
of resources and equipment, and the institutional diver-
sity could also put researchers in a better and more com-
petitive position when it comes to funding opportunities.
The next three challenges are related to policy-mak-
ing, and management of natural resources. While man-
agement efforts have been initiated at various sites across
the region, these have largely focused on remedial or
curative measures, and do not address the root problems
(Table 5; Challenge #4). The causes of seagrass decline in
Southeast Asia are well documented, and many of these
are due to anthropogenic impacts related to coastal devel-
opment. These impacts need to be addressed in order to
stem further deterioriation of seagrass meadows across
the region. Although attempts are occasionally made
to undertake seagrass relocation and restoration, these
are often not the most cost-effective solution as success
rates are quite low despite a large input of effort and
funds (van Katwijk et al. 2015). These ineffective solutions
are also often compounded by the lack of effective link-
ages between science, government, and private sectors,
leading to poor management and conservation actions
taken. There is currently a big gap or disconnect between
seagrass science, policy, and practice (Fortes 2018).
In turn, these management and conservation actions,
or environmental laws are not always adequately enforced
or implemented (Table 5; Challenge #5). It is especially dif-
ficult to slow down coastal development in the developing
world, and even more challenging to justify conservation
of natural habitats over economic growth. The prioritisa-
tion of economic growth means that environmental laws
are not always put in place, with no proper safeguards
against habitat degradation and destruction. Where envi-
ronmental laws exists, they are not always effectively
enforced as enforcement agents sometimes lack sufficient
resources or authority to carry out their duties. Designa-
tion of marine parks is also often inadequate, with fishing,
aquaculture, or other anthropogenic activities that impact
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280M.D. Fortes etal.: A review of seagrass in Southeast Asia
Table 4:Suggestions for future direction and potential regional cooperation in the different thematic areas.
Thematic research area Future direction/expansion Potential for regional cooperation?
Climate change/blue
Address knowledge gaps on carbon storage potential of seagrass meadows in SE Asia.
Economic and finance of blue carbon, and challenges in the SE Asian context
Exploratory climate change scenarios for seagrass habitats and increasing resilience to effects
of climate change
Yes. Many sites required for a complete picture of blue
carbon storage potential in SE Asia.
Both blue carbon and climate change research require
concerted effort at wider scales
and management
and ecology and
Research into more effective marine policy and integrated coastal zone management
Review of current marine protected areas and reserves to include more seagrass habitats,
and science-based zoning plans.
Development of decision support tools for natural resource managers.
Data collection on environmental and water quality parameters to understand changes at a regional scale
Yes. Using existing platforms such as the ASEAN Working
Group on Coastal and Marine Environments (AWGCME) can
help coordinate management efforts at the regional scale.
Region-wide monitoring programs to increase rate of data
collection across regions
Genetics Increase population genetics studies to better understand connectivity and gene flow.
Expand number of species that are being studied.
Harness and train local researchers in new techniques e.g. next-gen sequencing techniques, etc
Yes. Genetic work can be costly, and collection is difficult.
Regional cooperation will help ease difficulties in collection
and sharing of samples and associated hurdles (e.g.
collection permits)
Connectivity Studies on various aspects of connectivity of seagrass meadows within ecoregions (see Section
“Thematic gaps in knowledge and information”) need to be conducted. Results from these studies
can (should) be used to inform management and policy decisions
Yes. In most cases, a bioregion encompasses more than one
country, connectivity studies will involve data collection and
sharing across national boundaries
Physiology Plant level physiological interactions and response to anthropogenic stressors. Incorporation of
physiological measures in other research areas
Yes. Cooperation in standardisation of methods and in
experimental studies
Mapping Intensive mapping needs to be carried out across the region. Harness rapid development in mapping
tools – e.g. using UAVs (unmanned aerial vehicles) for obtaining multi-spectral imagery
Yes. Sharing of resources and equipment can aid faster data
generation, especially for remote regions and for groups
that lack funding
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M.D. Fortes etal.: A review of seagrass in Southeast Asia281
Table 5:Table documenting obstacles to seagrass conservation and the possible solutions.
Challenges (adapted from Fortes ) Possible solutions
) Lack of trained researchers
– Knowledge and expertise is concentrated in a few institutions
– Knowledge and expertise is sometimes tied with visiting researchers; little
knowledge and capacity building
Increase knowledge sharing within each country and region.
Form a network of Southeast Asian Seagrass Scientists to foster collaboration and
knowledge exchange
) Limited scope of work
– Early work is largely descriptive, qualitative and does not synthesise knowledge
– Lack of coordination in seagrass research themes
Studies need to be synthesised across regions (and countries) in order for research findings
to be applicable beyond the local context.
Tapping on a network of regional scientists can also help avoid duplication of work and form
working groups on pressing research areas
) Gaps in basic knowledge
– Very little information on extent, status, seasonal trends, uses of seagrass beds
– Very few comprehensive studies and/or experimental work on environmental
and anthropogenic stressors/impacts faced in the region
Increase in funding for basic research to plug knowledge gaps in areal extent and
distributions; use new and freely available techniques.
Engage local communities and citizens in monitoring programs.
Identify regional trends in anthropogenic impacts and seagrass habitat usage (e.g. fisheries)
) Misguided management efforts
– Efforts focused on remedial or curative measures, do not address root problems
– Lack of effective linkage between science, and government (management) and
private sectors (industry)
Increase education and capacity building for natural resource managers.
Build research collaborations between management agencies and research institutes
Increase private sector/industry funding for applied research
) Lack of implementation and enforcement of environmental laws
– Environmental rules and regulations are not effectively enforced and
– Lack of planning and enforcement in protected areas
Increase funding for regulation and enforcement.
Co-opt local communities into regulation and enforcement in remote areas – education and
awareness campaigns.
Re-examine marine reserve zoning plans to include scientific principles
) Socio-economic and cultural disconnect
– Lack of appreciation for seagrass
– Lack of understanding of the usage and socio-economic value of seagrass
Increase presence of seagrass in mainstream social media, news, education curriculum.
Increase research funding on socio-economic and cultural valuation of seagrass
Increase participatory citizen science initiatives to engage the wider public
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282M.D. Fortes etal.: A review of seagrass in Southeast Asia
seagrass meadows continuing to take place (e.g. Guima-
rães et al. 2012).
One of the major difficulties surrounding implenta-
tion and enforcement of enviromental laws is often resist-
ance from the local seafaring communities (Bennett and
Dearden 2014). This social-economic and cultural discon-
nect is the last challenge facing seagrass conservation
(Table 5; Challenge #6). Seagrass ecosystems have been
reported to be one of the least charismatic of coastal eco-
systems, especially when compared to coral reefs, and this
lack of charisma often translates into lack of attention,
research, and conservation action (Duarte et al. 2008). To
counter this, and to bring seagrass into the collective con-
sciousness of society and government, active steps need to
be taken by seagrass scientists to reach across the divide
to educators, managers, and the wider public, in order to
garner support for seagrass science and conservation. One
of the ways of achieving this aim is to introduce natural
heritage education into the school curriculum (Table 5).
The development of natural heritage curriculum could
potentially inculcate greater conservation values from an
early age, leading to greater interest and awareness of sea-
grass ecosystems in the future, as well as participation in
voluntary citizen science programs. The value of citizen
science is widely acknowledged, with the United Nations
Environment Programme emphasising the importance of
public participation towards sustainability (UNEP 1995).
Such initiatives provide long-term monitoring data of sea-
grass meadows at a much lower cost, allowing research
funding to be directed at other research avenues (Theil
et al. 2014). A successful example of a long-term citizen
science monitoring program in Southeast Asia is Team-
SeaGrass (Yaakub et al. 2014b). TeamSeaGrass is part of
the Seagrass-Watch Network and the data collected by
volunteers have contributed towards scientific publica-
tions (Yaakub et al. 2014c, McKenzie et al. 2016), and been
shared with managers from the National Parks Board
(NParks) in Singapore.
Moving forward, a road map for seagrass conservation
and research in Southeast Asia is proposed (Figure 8). The
road map incorporates the main challenges facing seagrass
conservation as identified above (Table 5), and proposes
solutions that have the potential to solve several problems
and provide the proper approach to face these challenges
at the same time. Three main outcomes are proposed for
the conservation and management of seagrass in South-
east Asia – (1) moving towards knowledge-based decision
making, (2) understanding the socio-cultural-economics
of seagrass ecosystems, and (3) increase seagrass aware-
ness and understanding. As already mentioned, several
decision making
Understand socio-
Increase seagrass
industry &
platformsIncrease socio
Training &
Develop natural
curriculum Increase
presence in
mainstream &
social media
Education of
research &
gaps Lack of
Lack of
of scientific
Emphasis on
Figure 8:Roadmap for addressing conservation challenges facing seagrass in the Southeast Asian region.
Challenges can have multiple solutions and these solutions can contribute to a final aim. The challenges are listed at the bottom of the
figure in red ovals and the final aims are at the top of the figure in blue boxes. Intermediate solutions are presented in the middle in green
boxes. Dotted lines represent linkages betweeen the challenges and the intermediate solutions, with each dotted line colour coded specific
to a challenge. Intermediate solutions that contribute to a final aim are joined by dashed and solid lines and colour coded.
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M.D. Fortes etal.: A review of seagrass in Southeast Asia283
challenges impeding seagrass conservation in research
are interconnected. For example, knowledge gaps in the
region is itself a challenge, but is also a result of other
problems such as the lack of funding or lack of interest.
Similarly, the solutions to these challenges are also con-
nected. This interconnectedness allows conservation
managers and other stakeholders to identify the most
appropriate action to take immediately, and to prioritise
conservation and management accordingly based on the
specific needs of each area. This multipronged approach
towards conservation and management of seagrass
meadows in Southeast Asia is illustrated in Figure 8.
A roadmap for seagrass conservation
and research in Southeast Asia
An example of sharing platforms would be the Interna-
tional Seagrasss Biology Workshop (ISBW). The ISBW
series is a meeting of research scientists, students, and
coastal environment managers focusing on global sea-
grass issues, improving seagrass knowledge, developing
networks and advocating seagrass protection or conser-
vation. Twelve ISBWs have been held and each followed
individual themes reflecting both a geographical or insti-
tutional interest, and current trends in seagrass research
as new knowledge and techniques became available
(Coles et al. 2014). The 12th ISBW held in Nant Gwrtheyrn
in North Wales focused on securing a future for seagrass.
The 13th ISBW, to be held in Singapore in June 2018, will
have a theme of “Translating Science into Action”, and
will focus on current developments in seagrass science
and how it can be effectively developed into actions, pro-
grams, and policies that will aid in seagrass conservation
and management. These outcomes are important, not just
for the Southeast Asian region, but globally as well.
Regionally, there is the option of leveraging on exist-
ing platforms to foster sharing and cooperation, such
as the Association of Southeast Asian Nations (ASEAN)
Cooperation on Environment. This regional organisa-
tion holds nature conservation and biodiversity, and
the coastal and marine environment as two of its seven
strategic priorities (ASEAN Cooperation on Environment
2017). Getting seagrass conservation on the ASEAN envi-
ronmental agenda would be a big boost in terms of fos-
tering cooperation, collaboration, and knowledge sharing
in the region. This in itself, will be an uphill task, espe-
cially since there are competing environmental issues,
such as transboundary haze, which are more visible and
seemingly have wider regional urgency. There are also
other ASEAN-related bodies, such as the ASEAN Center
for Biodiversity, which could be a smaller and more man-
ageable platform to launch the seagrass conservation and
management agenda for the region.
It is likely that the degradation of seagrass ecosystems
is expected to continue, despite greater local and region-
wide conservation efforts and the promises of programs
and projects being implemented and planned. At present,
there appear only two likely options left for us: status quo
or “business as usual”, wherein coastal development are
intensified, but with almost complete disregard of rel-
evant scientific knowledge and pertinent laws; or protect
and enhance what remains of the ecosystem, wherein
people are given the opportunity to conserve and enjoy
them for themselves and the future generations. It is easy
to argue in favour of a combination of these approaches,
but as the past years have shown, this has been easier said
than done. To our knowledge, success along this line in
the region has been insignificant – in both temporal and
spatial magnitude and scale – in relation to the total area
of coastal space utilised and the amount of resources
spent. There is an increasing likelihood that coastal envi-
ronmental change will create a need for adjustments of
established ecosystems on spatial and temporal scales
that are unprecedented in SE Asian history. Hopefully,
these adjustments are not compromises to the detriment
of seagrass ecosystems.
Sound conservation and management of our seagrass
ecosystems can be realised. Basic human survival as well
as robust national and global socioeconomic arguments
underline the compelling need for the effort. The specific
interventions in improving seagrass management in the
world have been spelled out even as early as the 1990s
(Fortes 1991, UNEP SCS/SAP 1999) and more recently
by UNEP (2012), but even with these, a secure future for
the region’s seagrass resources seemingly remains out of
sight. Trajectories toward seagrass loss can be reversed if
and when all concerned stakeholders contribute positively
to the effort in reversing current coastal ecosystem degra-
dation trends. In order to sustain the benefits we all derive
from these natural assets, substantial commitments and
investments must collectively be made by communities,
scientists, local government units, national government
agencies, and assisting organisations to effect a change
from the current self-destructive course to one of conser-
vation and sustainable use. Indeed, a transdisciplinary
approach is required, with each proposed step undertaken
in a holistic manner and not separately or compartmental-
ised. There is a great opportunity and compelling grounds
for regional collaboration and cooperation to tackle the
issue of seagrass conservation. It would be a tragedy to
let it slip.
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Miguel D. Fortes
Marine Science Institute, CS, University
of the Philippines, Diliman, QC 1101,
Miguel D. Fortes is a coastal ecologist, biodiversity, ICZM and blue
carbon specialist, focusing on seagrasses and mangroves. His
works are major contributions to seagrass science and policy in the
tropics. These have been making major impacts in relation to their
applications and in the development of coastal resilience in the face
of climate change and other environmental uncertainties.
Download Date | 6/2/18 12:34 PM
288M.D. Fortes etal.: A review of seagrass in Southeast Asia
Jillian Lean Sim Ooi
Department of Geography, Faculty of Arts
and Social Sciences, University of Malaya,
Kuala Lumpur 50603, Malaysia
Jillian Lean Sim Ooi is a teaching and research academic at the
Department of Geography, University of Malaya. Her early training
was in environmental social science but she found talking to human
subjects too difficult, and so shifted to studying plants. She has a
PhD in seagrass biogeography from the University of Western Aus-
tralia for her work on the spatial patterns and processes of seagrass
in Johor, Malaysia. Her current focus is on understanding how these
same meadows function as habitats for fish and as feeding grounds
for dugongs and invertebrates. Her life-long goal is to set up a
community arts centre-cum-marine research station on Siti Maryam
Yaakub’s seagrass island.
Yi Mei Tan
DHI Water and Environment (Singapore), 2
Venture Drive, #18-18, Singapore 608526,
Yi Mei Tan is a marine ecologist trained at the University of Mel-
bourne (BSc) and University of Aberdeen (MSc). She has broad-
based interests in tropical marine ecosystems, but has since discov-
ered a life consuming passion for seagrass. Yi Mei enjoys using GIS
and spatial planning tools to aid in policy and marine conservation
planning. Her life-long dream is to swim with orcas (but not be eaten
alive), and to combine her newfound love of seagrass with her first
love, fisheries research.
Anchana Prathep
Prince of Songkla University, Deparment of
Biology, Faculty of Science, Hat Yai, Thailand
Anchana Prathep leads the Seaweed and Seagrass Research
Unit at Prince of Songkla University, Thailand. Her work focuses
on seaweed and seagrass ecology, and she is recently trying to
understand how much seaweeds and seagrasses contribute to
carbon sequestration and storage, as well as how they respond to a
changing world.
Japar Sidik Bujang
Department of Biology, Faculty of Science,
Universiti Putra Malaysia, 43400 UPM
Serdang, Selangor Darul Ehsan, Malaysia.
Japar Sidik Bujang is Professor of Biology at Universiti Putra
Malaysia (UPM). He was awarded a PhD in biology in 1989 by the
Universiti Sains Malaysia, Penang, Malaysia for work on studies on
leaf litter decomposition of the mangrove, Rhizophora apiculata Bl.
He studied taxonomy, biology, and habitat characteristics of sea-
grasses and mangroves for over 26 years. His team has conducted
studies on distribution, diversity and uses of aquatic macrophytes.
Currently the team’s research focus on identification of seagrass
using morphology and molecular approaches, seagrass monitoring
and adaptability to stressors, as well as techniques for the remote
sensing of seagrass changes in coastal estuaries.
Siti Maryam Yaakub
Environment and Ecology Department,
DHI Water and Environment (Singapore),
2Venture Drive, #18-18,
Singapore 608526, Singapore,
Siti Maryam Yaakub is a marine ecologist with experience working
in the academic, government, and private sectors. A marine biolo-
gist by training with a broad understanding of marine ecosys-
tems from mangroves to coral reefs, Siti specialised in seagrass
ecosystems from an early stage. She has studied various aspects
of seagrass biology and ecology including taxonomy, molecular
genetics, ecology, restoration ecology, and physiology. Her life-long
goal is to buy an island with seagrass and never retire from seagrass
Download Date | 6/2/18 12:34 PM
... Coasts with strong wave action that hindered SCUBA exploration were excluded from the study. The line intercept transects (LIT; English et al., 1997) method was employed for systematically sampling seagrass meadows after locating them intertidally and sub-tidally. We surveyed 18 sites from NMA (25 LITs), 19 sites from RA (44 LITs), 8 from SA (11 LITs), 7 from LA (14 LITs), and 14 from NIC (20 LITs). ...
... Lastly, despite the vast spatial scale of our study, we did not observe H. ovata from the ANI's seagrass checklist (12 species). Genus Halophila, with high taxonomic diversity, overlapping morphology, and phenotypic plasticity at local scales (Japar Sidik et al., 2010), has often led to species misidentification and systematic ambiguity (Fortes et al., 2018). The species was last reported in 2010 from ANI (Thangaradjou et al., 2010a;Thangaradjou et al., 2010b). ...
... A recent study (Ragavan et al., 2016) argued that H. ovata is a misidentified H. minor from all previous assessments in ANI. A similar report from Southeast Asia pointed to taxonomic discrepancies within Halophila spp., where the morphological resemblance between H. ovata and H. minor was "compounding" and has led to species misidentification (Fortes et al., 2018). Since all seagrass assessments in ANI have relied only on morphological traits for species identification, including our study, the possibility of misidentification cannot be ruled out. ...
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The Andaman and Nicobar Islands, India, a geographically remote region, harbor a diverse island ecosystem. Limited exploration has hindered our understanding of marine floral biodiversity in this area. To address this gap, we investigated seagrass meadows in the Andaman and Nicobar Islands to understand their spatial distribution, species composition, and habitat characteristics. We assessed 66 seagrass meadows, including 32 newly discovered ones, filling data gaps in the region’s seagrass coldspots. Seagrasses were found across a wide range of depths, with the majority occurring in shallow subtidal waters (< 8 m). Large-sized species such as Thalassia hemprichii, Enhalus acoroides, Cymodocea rotundata, Cymodocea serrulata, and Syringodium isoetifolium dominated the littoral and shallow subtidal zones, while smaller species such as Halophila spp. and Halodule spp. exhibited broader depth distributions. H. beccarii and H. decipiens were strictly intertidal and subtidal species, respectively. Water depth significantly influenced seagrass occurrence (p < 0.0001), cover (β = -0.2759; SE = 0.02471; p < 0.0001), shoot densities (β = -0.3556; SE = 0.1231; p = 0.005), and biomass (β = -0.3526; SE = 0.1159; p = 0.003). Sand availability emerged as the second significant predictor of seagrass distribution, cover, and biomass (p values < 2e-16, < 2e-16, and 0.01, respectively). Habitat heterogeneity decreased with increasing water depth, and seagrass species exhibited strong preferences for specific substrata, resulting in spatial niche partitioning. Our study provides novel insights into the seagrass spatial diversity, habitat characteristics, and seagrass-environment relationship in the Andaman and Nicobar Islands. Further, it highlights the importance of water depth, habitat characteristics, and substratum heterogeneity in seagrass distribution and growth. Lastly, our findings imply that any change to the benthic profile of the meadows will influence the seagrass species distribution and growth. Understanding these factors is crucial for seagrass conservation and management in the region, aiding the development of targeted strategies to protect these valuable marine habitats and associated biodiversity.
... According to the bioregion classification of seagrass distribution, the Anambas is part of the Indo-Pacific bioregion, specifically in the seas of Southeast Asia. These seas, based on their benthic and pelagic biota characteristics, have been further classified into seven provinces and 22 ecoregions (Fortes et al., 2018). In this more detailed division, Anambas belongs to the Sunda Shelf province and Sunda Shelf/Java Sea ecoregion, which is claimed to have the highest species richness of seagrasses in the Southeast Asia seas (Fortes et al., 2018). ...
... These seas, based on their benthic and pelagic biota characteristics, have been further classified into seven provinces and 22 ecoregions (Fortes et al., 2018). In this more detailed division, Anambas belongs to the Sunda Shelf province and Sunda Shelf/Java Sea ecoregion, which is claimed to have the highest species richness of seagrasses in the Southeast Asia seas (Fortes et al., 2018). ...
... Mapping the distribution of the current seagrass meadows is a mandatory measure to protect their existence (Coles et al., 2011;Fortes et al., 2018;Thalib et al., 2018;Tan et al., 2020). However, in many locations, seagrass habitats are largely uncharted, even at a low spatial resolution and scale; thus, most marine conservation initiatives are difficult to accomplish (Unsworth and Cullen, 2010). ...
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Seagrasses are vital monocotyledonous marine flowering plants that serve as essential food sources for megaherbivores, contribute significantly to organic carbon production, and offer a multitude of crucial ecosystem services. Preserving seagrass habitats is of utmost importance, but the lack of comprehensive spatial data poses challenges to conservation efforts. The Anambas Islands, consisting of 255 small islands in the Natuna Sea, the southern part of the South China Sea, exemplify the scarcity of seagrass data, with the current distribution map only covering the Central and East Siantan region. In this study, our aim was to map the Buan coastal lagoon, where previous visual interpretation of Google Earth imagery suggested the presence of seagrasses. To achieve this, we carried out a drone survey and collected field data to classify and map the substrate types in the study area. The field survey documented four species in the location: T. hemprichii, E. acoroides, H. ovalis and S. isoetifolium, thereby expanding the known seagrass species in Anambas to nine. By employing a pixel-based classification of orthophotos, we achieved a promising overall accuracy of 69.5%. Our findings demonstrated that imageries from the Google Earth platform are viable alternatives for identifying seagrass meadows and can be utilized to support seagrass mapping efforts. This discovery offers valuable support for future seagrass mapping initiatives, especially at a local scale. Ultimately, our study contributes to the broader understanding of seagrass distribution in the Anambas Islands, and emphasizes the importance of further exploration to support conservation efforts in the seagrass ecosystem.
... It modernizes a centuries-old name through improved scientific understanding of genetic relationships between seagrass species. Significant concentrations are visible in the Indo-Pacific region, spanning from East Africa [25], throughout South [26,27] and Southeast Asia [28][29][30][31], to northern Australia [26,32]. Dense stands occur in the Gulf of Thailand [33], around Indonesian islands [26,29], and in the Philippines [34] and Vietnam [28]. ...
... Significant concentrations are visible in the Indo-Pacific region, spanning from East Africa [25], throughout South [26,27] and Southeast Asia [28][29][30][31], to northern Australia [26,32]. Dense stands occur in the Gulf of Thailand [33], around Indonesian islands [26,29], and in the Philippines [34] and Vietnam [28]. Smaller isolated populations are found in Singapore [14]. ...
Full-text available
The seagrass species previously classified as Cymodocea serrulata has been reclassified as Oceana serrulata. This reclassification is based on genetic analysis, which reveals a distinct separation of this species from others within the Cymodocea genus. This change will have implications for future research and taxonomy, highlighting the value of advanced genetic techniques in elucidating the relationships between seagrass species. Nevertheless, further analysis is warranted as new evidence emerges. The transition to the designation Oceana serrulata harmonizes traditional morphological descriptions with modern genetic phylogenetics, enabling a more precise classification. This adjustment will facilitate targeted research on the newly categorized Oceana genus’s biology, ecology, and conservation. We emphasize the importance of disseminating this update to inform the scientific community about these alterations in species classification. Accurate taxonomy serves as the essential foundation for biological research and conservation efforts. Presenting the rationale and process behind taxonomic changes enhances understanding of scientists’ challenges. Furthermore, evaluating name changes encourages scientific discourse and feedback, underscoring the significance of ongoing taxonomic reassessment in advancing seagrass biology and conservation.
... Due to continuing decline of seagrass meadows, fundamental research on seagrass biology, ecology and conservation is needed for future assessment of marine community and restoration planning (Sievers et al., 2019). However, research is few in seagrass and their environment interaction, especially the relationship between morphology and environment parameters (Fortes et al., 2018). ...
Globally, seagrass meadows have declined due to environmental factors and human activities, particularly by limiting light to seagrass in turbid coastal waters. Furthermore, publications of seagrass research findings from the Southeast Asia region are scarce, making understanding these habitats difficult despite their ecological and economic importance. This research aimed to provide mean and standard deviation of seagrass morphology, as well as to examine the morphology structures in response to water depth. Samples of two species of seagrass, Halodule uninervis and Halophila ovalis, were collected by using random sampling in a line transect at Pulau Besar and Pulau Tinggi in Johor, southern Malaysia, in September 2013 and April 2014. Six morphological features of each seagrass species were measured physically using CPCe software and the relationship of water depth to seagrass were evaluated using Pearson's Correlation. The result highlights that the leaf and root morphology is larger in Pulau Tinggi because it is nearer to the Johor mainland, where the introduction of nutrients from economic activity positively influence seagrass growth. The overall morphology structures of both species in both islands are greater in 2013 than 2014. For the relationship with water depth, it had greater positive relationship to H. univervis leaf width (r = 0.7532), internode width (r = 0.6722), leaf length (r = 0.5739); whereas for H. ovalis, water depth was correlated strongly with leaf width (r = 0.6697) and leaf surface area (r = 0.6313). The morphology of seagrass species varies depending on habitat conditions, this study can fill knowledge gaps, but more fundamental research on seagrass meadows is required particularly for the seagrasses in the Southeast Asia marine region.
... However, they are highly susceptible to both natural and human influences, and there has been concern about the global decline in this important ecosystem (e.g., [10][11][12][13]). Studies related to seagrasses and associated herbivores are especially important in the tropical Indo-West Pacific region and southeast Asia, where the highest biodiversity in seagrass species is found [14][15][16][17]. Many seagrass beds, however, have been damaged. ...
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The sea urchin Tripneustes gratilla is a major grazer and is, hence, an excellent key model organism to study to gain a better understanding of responses to changes in its habitat. We investigated whether there are significant variations in the feeding and reproductive phenotypic traits of populations from three seagrass bed sites, with respect to their proximity to fish farms in Bolinao, northwestern Philippines. We established three stations in each of the three sites: the far, the intermediate, and those near the fish farms, and compared the sea urchins’ phenotypic traits and determined whether these were related to seagrass productivity and water parameters. Regardless of the sampling period, adult sea urchins (66.92 ± 0.27 mm test diameter, TD, n = 157) from the areas intermediate and near to the fish farms had significantly lower indices of Aristotle’s lantern, gut contents, gut and gonads, and lower gonad quality (high percentage of unusual black gonads), compared to those from the far stations. Multivariate analysis showed that the smaller feeding structures and gut, lower consumption rates and lower gonad indices and quality of sea urchins in the intermediate and near fish farms were positively related to lower shoot density, leaf production and species diversity, as well as lower water movement in those stations. The larger size of the Aristotle’s lantern in the far stations was not related to food limitations. More importantly, the phenotypic variability in the feeding structures and gonads of sea urchins in the same seagrass bed provides new evidence regarding the sensitivity of this species to environmental factors that may affect variability in food quality.
... The condition of seagrass beds in Indonesia can be categorized into three classes, namely good (43%), moderate (50%), and damaged (7%). Damage to seagrass ecosystems results from changes in environmental conditions mostly due to coastal development, coastal and land reclamation, coral and sea sand mining, and waste disposal (Fortes et al. 2018;Unsworth et al. 2018). However, the real impact of the damage is the decrease in the diversity of marine life due to the decline in the ecological function of the ecosystem (Saraswati et al. 2021). ...
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Seagrass beds are important components of a coastal ecosystem. This ecosystem serves as the primer producers of the water food chain, habitat for marine biota, produces organic carbon, and indirectly contributes to the economic well-being of coastal communities. However, the ecosystem is vulnerable to damage caused by natural factors and human activities. The objectives of this study were, firstly to identify the distribution of seagrass beds in Tanjung Benoa using Sentinel 2B satellite imagery and secondly to compare classification results from two different approaches namely pixel-based image classification and object-based image classification. Accuracy-test was carried out using field data reference of 195 sample points in the form of a 10 m X 10 m transect. The image pre-processing process was conducted with Bottom of Atmosphere (BoA) correction using the Dark Object Subtraction (DOS) method. Furthermore, the water column correction was performed using the Depth Invariant Index (DII) and the Lyzenga algorithm. The mapping results showed that the area of seagrass beds in the shallow waters of Tanjung Benoa reaches 242.99 ha. There were seven seagrass species in the study area, with an average cover of 75%. The accuracy of object-based image classification was higher than that of pixel-based classification with a difference up to 25% for six classes classification and 15% for two classes classification. Excellent results for classifying seagrasses based on cover density can be obtained when high-resolution satellite imagery and OBIA are combined with the SVM or Fuzzy Logic algorithm.
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Tidung Island is one of the small inhabited islands and a tourist destination that allows the degradation of seagrass meadow and requires physical restoration using transplantation techniques. The seagrass species’ preference suitability needs to assess with this island for this case. This study aims to provide information on species that are possible to choose in seagrass transplantation based on their growth zones. The number of seagrass species, depths, and types of substrates was taken using seagrasswatch guideline by line transects along the coast to the reef slope with 10% plot intervals from the total length of the transect. Seagrass growth is divided into three zones: near the coast (back), middle, and near the reef slope (front). Enhalus acoroides , Cymodocea rotundata , and Thalassia hemprichii were found in almost all zones. Halophila ovalis , Halophila minor , and Halodule uninervis were distributed in the middle to front zone, while Syringodium isoetifolium was only in the middle zone. These findings suggest that transplant areas with high anthropogenic disturbances can use Enhalus acoroides and Thalassia hemprichii because they have the persistent trait. Meanwhile, the areas with low anthropogenic disturbance and low nutrients can use Halophila spp. and Halodule spp., because they can grow shoots and recover quickly.
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Seagrasses provide ecosystem services worth USD 2.28 trillion annually. However, their direct threats and our incomplete knowledge hamper our capabilities to protect and manage them. This study aims to evaluate if the NICFI Satellite Data Program basemaps could map Seychelles’ extensive seagrass meadows, directly supporting the country’s ambitions to protect this ecosystem. The Seychelles archipelago was divided into three geographical regions. Half-yearly basemaps from 2015 to 2020 were combined using an interval mean of the 10th percentile and median before land and deep water masking. Additional features were produced using the Depth Invariant Index, Normalised Differences, and segmentation. With 80% of the reference data, an initial Random Forest followed by a variable importance analysis was performed. Only the top ten contributing features were retained for a second classification, which was validated with the remaining 20%. The best overall accuracies across the three regions ranged between 69.7% and 75.7%. The biggest challenges for the NICFI basemaps are its four-band spectral resolution and uncertainties owing to sampling bias. As part of a nationwide seagrass extent and blue carbon mapping project, the estimates herein will be combined with ancillary satellite data and contribute to a full national estimate in a near-future report. However, the numbers reported showcase the broader potential for using NICFI basemaps for seagrass mapping at scale.
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Geopolitical issues pose a challenge to the holistic management of fisheries and associated ecosystems in two Philippine fisheries management areas (FMAs 5&6) encompassing the West Philippine Sea. One way to allay these issues is through a common values approach based on heritage. This paper presents evidence of the heritage value of FMAs 5&6 that could be integrated into an ecosystem approach to fisheries management to manage conflicts. This presupposes a common understanding of their heritage value and the fundamental principle that sustaining this value is good—in fact, essential—for everyone and our planet. Heritage value is assessed as a composite and dynamic unity of human gains and investments in the ecological value, economic value, and value to society of ecosystem services, which create cultural significance and socioeconomic worth for communities and peoples. Ecological value is assessed by way of selected indications of the ecosystem services of the two FMAs; economic value is assessed using published estimates of the monetizable and nonmonetizable value of these services; and value to society is evaluated based on influences on cultural identities, ways of life, and amenities in surrounding lands and contiguous waters. The values are highly significant and beneficial not only to Filipinos but also to others around the South China Sea and beyond. However, the ecosystem services underlying these values—and users’ access to them—are at risk. They need to be protected from climatic and anthropogenic threats, including illegal, unreported, and unregulated fishing, pollution, coastline modifications, island building, and violations of the United Nations Convention on the Law of the Sea provisions on safeguarding the marine environment and fishers’ safety.
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Seagrass beds is one of the most prolific shallow water ecosystems, having ecological function in the life of the various marine organisms and other coastal systems. Data and information of seagrass condition in the waters of Ternate, Tidore and surrounding areas are still hardly unexplored. This study aimed to describe the spatial distribution information of seagrass cover percentage, seagrass conditions and environmental characteristics. The basic data used for mapping of seagrass is Landsat 8 on a path 110 row 59 recordings in July 2015. Analysis of overlaying and the interpretation of the seagrass distribution software using "ERMapper, Image Analysis 1.1 on ArcGIS ArcView 3.2 and 10.1". Field test was conducted on frame 50 x 50 cm squares, each square of the recorded species of seagrasses and cover percentage value. Condition assessment based on seagrass cover by (Rahmawati et al., 2014) and (KMLH, 2004). The results show that there are eight species of seagrass found in the waters of the island of Ternate, Tidore and Hiri Maitara island. The highest percentage in the seagrass cover was found in Maitara islands and Hiri Island, i.e ≥ 50%. Seagrass cover conditions in general are relatively "moderate", but the health conditions are less healthy / less wealthy (30 to 59.9%). Keywords: Seagrass beds, seagrass conditions, mapping, satelite image ABSTRAK Padang lamun merupakan salah satu ekosistem perairan dangkal yang paling produktif, mempunyai fungsi ekologis dalam kehidupan berbagai organisme laut dan sistem pesisir lainnya. Informasi data padang lamun di perairan Ternate, Tidore dan sekitarnya masih belum tereksplorasi dengan baik. Penelitian ini bertujuan mendeskripsikan informasi secara spasial sebaran lamun, persentase tutupan, kondisi lamun dan karakteristik lingkungannya. Data dasar yang digunakan untuk pemetaan padang lamun adalah citra Landsat 8 pada path 110 row 59 rekaman Juli 2015. Analisis tumpang susun dan interpretasi sebaran lamun dengan menngunakan perangkat lunak “Ermapper, Image Analysis 1.1 pada ArcView 3.2 dan “ArcGIS 10.1”. Uji lapangan dilakukan pada frame kuadrat 50 x 50 cm, disetiap kuadrat dicatat jenis lamun dan nilai persentase tutupan. Penilaian kondisi lamun berdasarkan tutupan menurut (Rahmawati dkk., 2014) dan (KMLH, 2004). Hasilnya menunjukkan bahwa terdapat 8 jenis lamun yang ditemukan di perairan pulau Ternate, pulau Tidore, pulau Hiri dan pulau Maitara. Presentase tutupan lamun tertinggi terdapat di pulau Maitara dan pulau Hiri yaitu ≥ 50 %. Kondisi lamun pada umumnya memiliki tutupan tergolong “sedang”, namun kondisinya kurang sehat/kurang kaya (30-59,9%). Kata kunci: Padang lamun, kondisi lamun, pemetaan, citra satelit 1 Proyek Penelitian RHM-COREMAP, 2015 2 UPT. Loka Konservasi Biota Laut Bitung-LIPI
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Community support for a healthy Singapore is high. Good water quality and healthy habitats are seen as key attributes of Singapore’s environments. Seagrass covers over 201 ha of Singapore’s nearshore area, which along with mangroves and coral reefs sustain the country’s high marine biodiversity. The ecological integrity of nearshore habitats, however, is under threat from cumulative human (e.g. coastal development) and natural (e.g. climate) pressures. A successful approach to raising community support and generating much needed environmental data on the condition of nearshore habitats, is to engage local citizens to participate in programs such as Seagrass-Watch. Seagrass-Watch is a global seagrass assessment and monitoring program, which includes an element of citizen science. In Singapore, the monitoring of seagrass habitats has been conducted by TeamSeagrass, in collaboration with the National Biodiversity Centre of the National Parks Board. Quarterly monitoring of three of the largest seagrass meadows in Singapore is carried out by trained TeamSeagrass volunteers using methods developed by Seagrass-Watch HQ since early 2007. Data collected by TeamSeagrass shows that seagrass abundance at Chek Jawa on Pulau Ubin has increased and the dominant species changed from colonising (Halophila ovalis) to foundational (Cymodocea rotundata). Seagrass abundance is stable at Cyrene Reef, but declining at Pulau Semakau. There also appears to be a seasonal trend in seagrass abundance across all sites, with higher abundances between March and June, coinciding with the end of the rainy monsoon season. The data represents the first long-term monitoring dataset for seagrass habitats in the Southeast Asian region, currently spanning seven years. The results of this partnership between scientists and community volunteers shows how ordinary citizens can play an important role in tracking the recovery or decline of habitats and engaging the public in an urban city state like Singapore.
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Seagrass meadows support fisheries through provision of nursery areas and trophic subsidies to adjacent habitats. As shallow coastal habitats, they also provide key fishing grounds; however, the nature and extent of such exploitation are poorly understood. These productive meadows are being degraded globally at rapid rates. For degradation to cease, there needs to be better appreciation for the value of these habitats in supporting global fisheries. Here, we provide the first global scale study demonstrating the extent, importance and nature of fisheries exploitation of seagrass meadows. Due to a paucity of available data, the study used a global expert survey to demonstrate the widespread significance of seagrass-based fishing activity. Our study finds that seagrass-based fisheries are globally important and present virtually wherever seagrass exists, supporting subsistence, commercial and recreational activity. A wide range of fishing methods and gear is used reflecting the spatial distribution patterns of seagrass meadows, and their depth ranges from intertidal (accessible by foot) to relatively deep water (where commercial trawls can operate). Seagrass meadows are multispecies fishing grounds targeted by fishers for any fish or invertebrate species that can be eaten, sold or used as bait. In the coastal communities of developing countries, the importance of the nearshore seagrass fishery for livelihoods and well-being is irrefutable. In developed countries, the seagrass fishery is often recreational and/or more target species specific. Regardless of location, this study is the first to highlight collectively the indiscriminate nature and global scale of seagrass fisheries and the diversity of exploitative methods employed to extract seagrass-associated resources. Evidence presented emphasizes the need for targeted management to support continued viability of seagrass meadows as a global ecosystem service provider.
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The concept of the Social-Ecological System (SES) of the coastal region, can be found in the seagrass ecosystem in the Kotania Bay Waters. Seagrass ecosystem as one of the productive ecosystem is part of an ecological system that can influence and influenced social system, in this case by people living around the seagrass ecosystem. This aim to estimating the socio-ecological vulnerability system of the seagrass ecosystem in the Kotania Bay Waters, the Linkage Matrix is used (de Chazal et al., 2008). This linkage matrix was created to determine the perception and understanding of the community on the ecosystem services provided by the seagrass ecosystem through the appraisal of various stakeholders. The results show that social values are rooted in the public perception of ecosystem goods and services, which are rarely considered. The ecological and economic value of natural resources is increasingly being used to determine the priority areas in the planning and management of coastal areas. The social value that exists in natural resources is highly recognized in conservation.
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Seagrasses in the Air Bangis Archipelago, west coast of Sumatra were found growing in sandy muddy substrates of the shallow coastal waters at depth of 0.3-2.5 m, dominated by degraded coral reefs around the offshore islands. Two species; Enhalus acoroides (L.f) Royle and Thalassia hemprichii (Ehrenb) Aschers were observed at Pulau Unggas, Pulau Pasir Panjang and Teluk Tapang. Halodule uninervis (Forssk) Aschers was observed in two locations; Pasir Panjang and Teluk Tapang. The occurrence of this species is unknown previously and therefore it is a new flora record for Sumatra. With this new record, Sumatra has six species of seagrasses, contributing to half of total number of seagrasses occurring in Indonesia. According to leaf width measurements, two morphological variants (narrow and wide leaved) can be distinguished for Halodule uninervis. In addition, descriptions of the species and their habitat characteristic are provided.
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Offshore coral reefs of the South China Sea are subject to complex overlapping sovereignty claims by up to six regional nations. Escalating tensions have led to widespread structural reinforcement of military outposts on many reefs via dredging and filling. Satellite images indicated at least 160 km² of coral reef damage, including 17 km² of essentially permanent damage from filling and channel/harbour dredging, and 143 km² of decadal-scale damage from dredging for building materials and giant clam harvesting. This damage will exacerbate the growing regional overfishing problem. Options to lessen tensions include (1) the establishment of a Greater Spratly Islands Peace Park, and (2) the collaborative management of fisheries, the environment and mineral resources across the entire Sea. Both options require freezes on extant claims and activities in support of claims. No matter how it is achieved, regional peace would greatly enhance fisheries stability and economic growth among all claimant nations. (freely available at )
Seagrasses are of direct importance in sustaining the integrity and complex nature of Southeast Asian coasts. Multiple stressors, however, cause their declines at scales of square meters to square kilometers. More often, these declines are caused by human activity because the ecosystems are adjacent areas of increasing industrialization. The major driver of this activity, in turn, is the big gap or disconnect between seagrass science, policy and practice. But while the urgent need for scientific research to inform policy and practice directly is well recognized, out of the 1122 articles on seagrass published from 1973 to 2016 in the region (including China), 77% dealt with management and only 23% dealt with science. This status is, however, changing slowly in favor of more conservation oriented research and application of available science in addressing pressing issues. The need is urgent for a focused regional effort to speed up the pace and address this gap, to sustain the ecosystem services of seagrass ecosystems in the face of coastal environmental uncertainties in rapidly developing Southeast Asia. This effort should be functionally coordinated, starting with increased awareness to conserve seagrass, monitoring changes in the ecosystem, and managing their services and users. The challenge of designing effective policies for seagrass conservation in Southeast Asia is rendered even more complex by the urgent need to promote the three preconditions for a stronger science-policy-practice linkage. First, seagrass science has to be relevant. Second, that science has to be considered relevant and third, policy-making has to be open and receptive for scientific advice and public scrutiny. A new truly coordinated and functional regional program is needed aimed at: (a) establishing the principles by which seagrass ecosystems can be protected and their services maintained in the future. (b) regulating practices, which result in the destruction of seagrasses. (c) maintaining and enhancing seagrass ecosystems, and (d) establishing and promoting the interconnections of seagrass with the other coastal ecosystems as a basis of stakeholder integration and cohesion. The social and environmental ‘crisis’ coastal ecosystems face in Southeast Asia is forcing governments to increase awareness of the need for seagrass protection, adaptive management and monitoring.
Borneo is one of the regions expected to have the highest diversity of seagrasses in the world. However, the diversity of seagrasses has scarcely been studied in Brunei Darussalam. The diversity of seagrasses at the intertidal and subtidal zones in Brunei was extensively surveyed in 2016. Six species of seagrasses were found at Pulau Muara Besar and Pulau Bedukang, and this was the first time that three of them (Halophila beccarii, Halodule pinifolia, and Cymodocea rotundata) had been recorded in Brunei. The total area of seagrass distribution around the two islands was approximately 1.5 km 2. The present study extends the distribution of seagrasses on Borneo and suggests that Brunei has a rich seagrass diversity and an aquatic ecosystem supported by the seagrasses.
High temperatures, especially in the summer or during local heat waves, often coincide with high concentrations of herbicides in some estuarine areas during flood plumes. The combined effects of thermal stress (at 26-32 °C) and the herbicide atrazine (at concentrations of 0, 3 and 10 μg L⁻¹) on eelgrass (Zostera marina L.) were studied in a 7-day exposure experiment. The results showed that both atrazine and temperatures above 30 °C inhibited the photosynthetic efficiency and energy conversion potential of the photosystem II (PSII) as indicated by the effective quantum yield (ΔF/F’m) and the maximum yield (Fv/Fm), respectively. High temperatures (31 °C and 32 °C) decreased the Chl a content and stopped the leaf growth of eelgrass. Atrazine concentration had no effect on the photosynthetic pigments at all temperatures; however, decreased leaf growth rate was detected at 30 °C. A high level of agreement between the observed and predicted inhibition of photosynthesis by an Independent Action (IA) model demonstrates that the combined effects of high temperature and atrazine are more harmful to eelgrass than is a single pressure. The present study adds further evidence for seagrass protection and environmental management under the hypothesis that thermal stress combined with herbicides pose a greater threat to seagrasses.