Philippines
The seagrass flora of Philippines is characterized by a high species richness and mixed meadows are common1. There are 13 seagrass species found in the country, Cymodocea rotundata, Cymodocea serrulata, Enhalus acoroides, Halodule pinifolia, Halodule uninervis, Halophila beccarii, Halophila decipiens, Halophila minor/ovata, Halophila ovalis, Halophila spinulosa, Syringodium isoetifolium, Thalassodendron ciliatum and Thalassia hemprichii1. These species present contrasting growth forms and growth capacities, from the small, fast-growing Halophila species to the large E. acoroides. The contrasting growth strategies have been postulated to confer on them differential capacities to survive disturbance1. Large shoots (E. acoroides) or fast vertical growth (C. serrulata) may allow the plants to get closer to the water surface thereby overcoming light reduction or enhanced sedimentation under high suspended silt loads1. Conversely, species with slow growth (T. hemprichii), will be more sensitive to environmental deterioration1.
There is some confusion regarding the distribution of seagrass in the Philippines. Some estimate only 975 km2, however others based on remote sensing estimate approximately 22,000 km21. Nevertheless, mapping of seagrass distribution is limited and ad-hoc.
Seagrass-Watch in Philippines
To provide an early warning of change, long-term monitoring has been established in Philippines as part of the Seagrass-Watch, Global Seagrass Observing Network (www.seagrasswatch.org). Establishing a network of monitoring sites in Philippines provides valuable information on temporal trends in the health status of seagrass meadows in the region and provides a tool for decision-makers in adopting protective measures. It encourages local communities to become involved in seagrass management and protection. Working with both scientists and local stakeholders, this approach is designed to draw attention to the many local anthropogenic impacts on seagrass meadows which degrade coastal ecosystems and decrease their yield of natural resources.
Location
Bolinao
Monitoring: Suspended
Location: located at the north-westernmost part of Oriental Mindoro, and at the south-western end of the Isla Verde Passage, about 130 kilometers south of Manila
Site code: BS
Comments: The seagrass meadows of Cape Bolinao form the base of fishery resources for 35 barangays (a Philippine political unit). The seagrass of Bolinao are seriously threatened through the direct and indirect effects of human settlement and coastal development leading to intense pressure and anthropogenic disturbances to the said habitat.
There is real need to take initiatives to protect, conserve and maintain the resources. Seagrass plays a very important role in the community since many of their livelihoods rely heavily on the seagrass meadows. At present, most people in the community understand that the existing resource provides their livelihood. But the importance of linkage of seagrass meadows with the other two major components of the marine ecosystem, mangroves and coral reefs, is not seriously considered.
Location
Palawan
Monitoring: Suspended
Location: Palawan is an island province of the Philippines located 600 km southwest of Manila and is flanked by the South China Sea on the west and the Sulu Sea on the east.
Comments: At least 10 species of seagrass are known from Palawan. Enhalus acroides is to be the most common seagrass occurring in Palawan. Since 1997, staff from the Palawan Council for Sustainable Development have conducted coastal resource assessments to generate information on the general condition of Palawan’s Coastal resources. Seagrasses were surveyed at a number of sites using a transect/quadrat technique. They reported that nearly half of Palawan’s seagrass resources or in a “poor” condition.
Data generated from surveys of coral reefs and seagrasses across Palawan is input to coastal resource management planning, Environmentally Critical Areas Network (ECAN) zoning and environmental monitoring.
Under ECAN zoning, identify potential core zones which may include habitat of rare and endangered marine species, fish sanctuaries (declaring certain areas as fish sanctuaries to enhance sustainable fisheries).
The effects of eutrophication and siltation are insignificant due to the lack of urbanization and scarce coastal population especially in Balabac waters. There are several factors that have contributed to this fortunate condition. First, as Palawan houses 232 endemic species, the province was proclaimed as Fish and Wildlife Sanctuary in 1967.
Because of this proclamation, coastal development activities that lead to excessive earthworks are almost absent in Palawan. Secondly, major crops in Palawan such as corn, cashew and coconut have limited use of fertilizers and agrochemicals. These crops are not a major source of agrochemical pollutants in the marine ecosystem.
Furthermore, these types of crops cultivation cause very little soil erosion and alteration of physical terrestrial environment. Lastly, commercial logging has ceased in Palawan with the cancellation of timber license agreements in 1993. Water pollution may still occur in other parts of Palawan. Small operations of illegal logging activities occur in the mountain range especially in Quezon and Rizal have contributed to siltation along the coastal areas. In addition, nickel mining and processing plant in Rio Tuba and quarry activities in Rizal contribute to coastal pollution and sedimentation.
Dugong were commonly found in Palawan waters before they were excessively hunted. The sightings of dugong herds in Palawan are considered rare nowadays. In 1991, dugong conservation took a leap with the issuance of Department of Environment and Natural Resources of the Philippines (DENR) Administrative Order (AO) No. 55, which made the dugong the first marine mammal protected in Philippine waters. As stipulated in this AO, any person who hunts, kills, wounds, takes away, possesses, transports and/or disposes of a dugong, dead or alive, its meat or any of its by-products shall be punished by imprisonment from 6 months to 4 years or fined Php 500 to 5,000 or both (equivalent to RM 35 to 350).
Community-based management plays an important role for a province like Palawan that is isolated from other parts of the country. In 1993, the Provincial government created community police forces such as “bantay Palawan” and “bantay dagat” to protect Palawan’s marine resources.
Philippines’ legislation supports empowerment of the community through its 1990 Republic Act 7160. The Act devolves authority so that “territorial and political subdivisions of the State shall enjoy genuine and meaningful local autonomy to enable them to attain their fullest development as self reliant communities and make them more effective development partners”.
The extent of the 15 km of Palawan’s coastal water as municipal waters by the 1990 Local Government Code has given a major mandate in the implementation of the community based management. Before success in marine resources management can be achieved, the locals especially in the rural areas need to be educated. The UNESCO Commission on Science and Technology and the Department of Environment and Natural Resources plan to initiate such an education campaign in Palawan.
In the Philippines, it is not only dugong, turtle and fish which eat seagrass. The rhizome of Enhalus acoroides is served as delicacy in some coastal villages. The seeds are eaten by children and recently the starch from seeds has been extracted for baking cookies (hoped to be a viable commercial venture). Another species, Halophila ovalis, is pickled and used as salad vegetable. Importantly, dried seagrass leaves are found to cure diarrhea. Seagrass also has other uses apart from a food source. The handicraft and furniture industries have utilized seagrass blades as a component and accent parts of selected furniture, handicrafts and other saleable household items.
Location
Puerto Galera
Monitoring: Suspended
Location: located at the north-westernmost part of Oriental Mindoro, and at the south-western end of the Isla Verde Passage, about 130 kilometers south of Manila
Site code: PU
Status (July 2007):
- Sites are similar in species composition and abundance. Enhalus acoroides, Cymodocea rotundata, Halodule uninervis, Halophila ovalis and Thalassia hemprichii dominated the approximately 500 m seagrass bed in the area.
- At least three species of sea urchins were found in the meadow.
- Each site has only been sampled once.
- From anecdotal reports, seagrass meadows in the Puerto Galera region are in a fair condition, and no major losses are apparent.
- Insufficient data to describe long-term trends.
Ulugan Bay, Palawan
Data collection: ZSL philippines
Map planning, Data Analysis and Map creation: Seagrass-Watch
Location: Ulugan Bay, Palawan
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ulugan bay seagrass mapping results
Seagrass meadows within Ulugan Bay, Palawan, Philippines, were assessed between the 30 October 2020 and 09 May 2023.
Observers walked or used drop-cameras to collect photoquadrats at mapping points, which were positioned using a restricted random sampling design. Visual estimates of above-ground seagrass percent cover, seagrass species and macroalgae percent cover were recorded at each mapping point from 3 quadrats (50cm x50cm), using globally standardised Seagrass-Watch protocols. Substrate type was assessed at each mapping point by hand, and aided by a Van Veen grab at subtidal points. A differential handheld global positioning system (GPS) was used to locate each mapping point (accuracy ±3m).
A total of 692 individual points were examined, of which 445 were collected from drop-camera, 180 in-situ and 69 from Seagrass .
Seagrass was present at 309 of the mapping points, with percentage cover ranging from 0.1 to 100%, and with an average of 20.8%. Eight seagrass species were identified, with the most frequently encountered being Enhalus acoroides, Halophila ovalis and Thalassia hemprichii (36.2%, 15.4% and 10.9% average cover, respectively).
Spatially explicit seagrass maps were created from PlanetScope Dove (3.7 m × 3.7 m pixel) imagery, using the field validation point data and a machine-learning model (random forest). A total of 86.8 to 323 hectares, with an additional 10.2 ha (manually digitized from subtidal and/or turbid area where imagery does not allow for reliable predictions) of seagrass meadows were mapped within Ulugan Bay.
The southern coastal area,around Macarascas, was mainly dominated by Enhalus acoroides (inshore) with some smaller sections of Thalassia hemprichii, Halophila ovalis and Syringodium isoetifolium near the reef crest.
North along the East coast of Ulugan Bay, seagrass meadows changes from Enhalus acoroides dominated meadows to Thalassia hemprichii. There is a change back to Enhalus acoroides dominated meadows with a greater diversity around Buenavista where there are smaller patches of varying seagrass communities some dominated by Halodule uninervis and Cymodocea rotundata.
The west side of Ulugan Bay, there is a decrease in seagrass, which mostly Halophila ovalis and Thalassia hemprichii dominated meadows except for Rita Island which comprised of some Halodule uninervis dominated meadows.
Technical report
Report to Edith Cowen University of activities conducted by Seagrass-Watch for the “Conservation of biodiversity, seagrass ecosystems and their services – safeguarding food security and resilience in vulnerable coastal communities in a changing climate”
How the data was collected
Field validation points were spatially balanced and randomised within the Area of Interest (AOI). All data collected within the AOI was used to ensure mapping of all seagrass meadows present.
At each field validation point, teams conducted a spot-check using either Drop-Cam, in situ observation, or grab.
Photoquadrats were captured (except where only a grab sampler was used) during each spot-check. Photoquadrats were either geotagged or geolocated. Data collected from the photoquadrats (e.g. % cover and species) at each point and the Seagrass Spotter sightings were used to train and validate models for classification of satellite imagery.