SCS/80/WP/94e (Revised) The Present State of Mangrove Ecosystems in Southeast Asia and the Impact of Pollution |
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
UNITED NATIONS ENVIRONMENT PROGRAMME
by
Twesukdi Piyakarnchana
Department of Marine Science
Chulalongkorn University
Bangkok 5, Thailand
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The copyright in this book is vested in the Food and Agriculture Organization of the United Nations and in the United Nations Environment Programme. Applications for permission to reproduce this book, in whole or in part, by any method or process, should be addressed, with a statement of the purpose and extent of the reproduction desired, to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme di Caracalla, 00100 Rome, Italy.
PREPARATION OF THE REPORT
The FAO/UNEP project on “Impact of Pollution on the Mangrove Ecosystem and its Productivity in Southeast Asia - Preparatory Phase”, Project No. 0503-79-04, called for the preparation of country status reports on the impact of pollution on mangrove ecosystem and its productivity in Southeast Asia. Selected specialists from the ASEAN countries were then commissioned to prepare these country reports, which were subsequently discussed in an Expert's Consultation Meeting, sponsored by the Project, and held in Manila on 4 to 8 February 1980. It was necessary to consolidate the data accumulated from the reports into a regional synopsis for the area.
The synoptical report (SCS/80/WP/94) is supplemented by five country reports for Indonesia, Malaysia, the Philippines, Singapore, and Thailand (SCS/80/WP/94a to SCS/80/WP/94e), which were presented at the above meeting. The presented paper is based on the work of Dr. T. Piyakarnchana, with editorial reviewing by Dr. W. W. Kühnhold of SCSP.
SOUTH CHINA SEA FISHERIES DEVELOPMENT AND COORDINATING PROGRAMME
Manila, March 1980
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1.1 Extent and location of mangrove in the country
1.1.1 Floral and flora associations in the mangrove forest of Thailand
1.1.2 Algae in mangrove swamps
1.1.3 Mangrove forest production
1.1.4 Faunal communities in the mangrove swamps
1.2 Chemical and physical environment
1.2.2 Water properties in mangrove swamps
1.2.4 Current systems in Thai waters
1.2.5 Salinity and temperature
1.3 Agriculture, fishery, industry, and human population
1.3.1 Types and distribution of agricultural land
1.3.2 Fishing areas and known spawning grounds
1.3.3 Mariculture and nearshore fisheries
1.3.4 Areas of reclamation of mangrove forests for other uses
1.4.1 Type and distribution of industrial centres
1.4.2 Mining in the mangrove forests and near shore area
1.5 Pollution of coastal waters
1.5.1 Sedimentation in the Upper Gulf of Thailand
1.5.4.2 Gulf of Thailand - water
1.5.4.3 Gulf of Thailand - sediments
1.5.4.4 Gulf of Thailand - biota
2.1 Abundance of mangrove species
2.2 Soil - species relationship
2.3 Effects from mangrove utilization on the aquatic ecosystem
2.3.3 From illegal and uncontrolled uses
2.4 Effects from land-based riverine pollution on the aquatic mangrove ecosystem
2.5 Effects from coast and sea-based pollution on the aquatic mangrove ecosystem
3.1 Identification of the most important pollutants
3.2 Problem areas (most polluted areas interfering with high productive mangrove zones)
3.3 Gaps in understanding of aquatic ecological relationships
3.4 Some selected topics of present research activities
3.6 Present international cooperation with countries in the sub-region
3.7 Needs for international support of national research programmes
LIST OF TABLES
Tables
1 Total area of the mangrove forest in Thailand
2 Distribution of main mangrove species in Thailand
3 Nine species of the family Rhizophoraceae and described by Sripen and Thamathaworn, 1976
4 Epiphytic flowering plants in the mangrove forest
5 Red algae in the mangrove forests in Thailand
6 Marine algae commonly found on the mudflats near the mangrove forests
7 Macrofauna found on the mangrove shore at Ao Nam Bor, Phuket, Thailand
8 Production of green mussel, horse mussel, and cockles in Samut Songkram province
9 The number total area of cockle farms in four provinces from 1973–1977
10 Area of cockle farms and production of cockles at Samut Songkram, Petchaburi and Satul provinces
11 Population and number of households in the provinces bordering the coastline of Thailand
12 Tin mines and mangrove forest of four provinces on Andaman Sea coastline
13 The area of salt farms in 1927–1973
14 Factories producing large amount of waste water
15 Industrial wastes (BOD t/d) discharged into the six large rivers and east coast waters
16 Data of imported pesticides in Thailand in 1977 and 1978
18 Amount of DDT and its derivatives in some rivers in Thailand
21 DDT and its metabolites in dry sediments (ug/kg) of Upper Gulf from 1974–1976
22 DDT and its metabolites in dry sediments (ug/kg) of Andaman Sea coast, March 22–29, 1976
24 Concentrations of heavy metals in water samples from Gulf of Thailand
25 Concentrations of heavy metals in sediment samples from Gulf of Thailand
26 Concentrations of heavy metals in marine animals from Gulf of Thailand
LIST OF FIGURES
Figures
1 Distribution of mangrove forests and extended mudflats in Thailand
3 Geographical distribution of tidal types in Southeast Asia
5a Current observations in the Gulf of Thailand, 2–14 August 1959, southwest monsoon
6a-6b Tidal current characteristics in the Upper Gulf of Thailand
6c-6f Tidal current pattern for one day cycle at one hour intervals
8 Distribution of present horse mussel farms (300 ha) and potential culture areas (4 600 ha)
9 Distribution of present oyster farms (630 ha), and potential culture areas (13 190 ha)
10 Distribution of present cockle farms (500 ha), and potential culture areas (11 300 ha)
11 Distribution of present green mussel farms (2 626 ha) and potential culture areas (34 994 ha)
12 Locations of selected industries along Chao Phraya River
13 Locations of various industries along the Bang Pakong River
14 Locations of various industries along the Ta-Chin River
15 Locations of various industries along the Mae Klong River
17 Amount of dissolved oxygen in lower layer of water at Chao Phraya River from 1970–1978
18 Total agricultural areas where pesticides are applied
19 Locations of sampling stations for pollution analyses
20 Beach tar survey locations in Thailand
21 Beach tar survey locations on Phuket Island, Thailand
THE PRESENT STATE OF MANGROVE ECOSYSTEMS IN SOUTHEAST ASIA AND THE IMPACT OF POLLUTION - THAILAND -
by
Twesukdi Piyakarnchana Department of Marine Science Chulalongkorn University Bangkok 5, Thailand
This report is an overview over the present distribution of mangrove swamps in Thailand, and describes the kinds and extent of aquatic pollution. It reviews the recent studies of mangrove composition and occurrence of fauna and secondary flora in some mangrove forests and adjacent tidal flats. The mangrove areas are further characterized by physical and chemical data of the waters, tides, currents, temperature, and further by the types of land use. The findings of aquatic pollution from various industries are described, but concentrate naturally on the more industrialized areas around the Upper Gulf of Thailand and the Upper Gulf itself. The discussion on pollution effects on mangrove ecosystem considers riverine and sea-based pollution. There are, however, not many studies made although some drastic cases have shown the pollution threat and damaging potential. The report finally identifies the gaps in understanding of the mangrove ecosystem and the impact of human activities, lists priority research needs on national basis as well as for international - regional - cooperation.