Coastal Biodiversity in Ranong, Thailand
Coastal Biodiversity in Ranong
What is biodiversity?
Biodiversity is a measure of the richness of life, from the habitat down to the gene. Marine systems are particularly rich, with a greater number of different types of organisms than are found on land. Southeast Asia is one of the global marine biodiversity hotspots. Thailand has an amazing wealth of marine species and habitats.
Why is biodiversity important?
Marine biodiversity is important for a number of reasons. Firstly, people rely on life in the seas for food, for medicines and for employment. Secondly, rich marine ecosystems attract tourists who come to dive and wonder at the colour and variety of marine organisms. Thirdly, marine ecosystems provide services such as protection from environmental extremes; for example, mangroves act as a buffer zone in coastal areas, protecting against the worst effects of storms. Finally, diverse and interesting environments add to the quality of life; humans like to live in an interesting world surrounded by a variety of animals and plants.
What happens when biodiversity is lost?
The animals living in the sea have many complex interactions; they all depend to some extent on the presence of other species. When animals or plants are killed, these links are broken and the whole ecosystem becomes less efficient. With further species losses there comes a point when the whole ecosystem breaks down. As yet we are unable to predict what proportion of species can be lost before this point of breakdown is reached.
What are the threats to biodiversity?
Threats fall into three main categories: unsustainable exploitation of various marine resources, loss of habitats and environmental degradation or alteration.
Unsustainable exploitation of natural resources
Unregulated fishing is depleting stocks of fish, prawns and other marine species around the world. Not only does this result in the wiping out of fish populations, it results in the loss of jobs. As one species stocks become uneconomic so fishing targets another species and so on, with increasing effort for a lower return.
Trawling for fish and prawns in coastal habitats also affects the communities of organisms which live in the sand and mud habitats, reducing their diversity. Trawls not only catch unwanted species, the by catch, but they plough up the sediment killing the smaller organisms which live there.
Habitat loss
Increasing pressure on land for development also leads to loss of coastal habitats. Swamps, marshes and mangroves are drained and cleared to provide land for housing, tourism and industrial development. Paradoxically, increasing development changes the living environment making coastal regions less attractive.
The extent of the problem of habitat loss can be seen in the reduction of mangrove forest in countries of the region given in the table below. The figures from the Philippines show that in recent years the rate of mangrove loss has increased dramatically.
| Loss of mangrove habitat in Thailand | ||
|---|---|---|
| Year | Acreage | Per cent loss |
| 1961 | 372,500 | - |
| 1993 | 168,000 | 55 |
| Loss of mangrove habitat in Philippines | ||
| 1918 | 500,000 | - |
| 1984 | 232,000 | 53.6 |
| 1988 | 142,000 | 71.6 |
Source Thailand: Banpot Napompeth & Jittawadee Rodcharoen 1998. Environmental and Biodiversity Issues in Thailand. In Ghazally Ismail & Murtedza Mohamed (eds) Biodiversity conservation in ASEAN. Asean Academic Press, pp.233-246. Philippines: F. G. Claveria & R.D. Cruz Environmental and biodiversity conservation in the Philippines. In Ghazally Ismail & Murtedza Mohamed (eds) Biodiversity conservation in ASEAN. Asean Academic Press, pp.187-213.)
The enormous rise in demand for prawns has resulted in the expansion of prawn culture, which in turn has resulted in a loss of mangrove forest. Ironically, the mangrove forest is the home of the young stages of many species of fish and prawns. Developing aquaculture can have a severe impact on natural fish stocks. Without careful management, such habitat loss ultimately results in the local extinction of many resources.
For more information on conservation issues associated with mangroves look at the Mangrove Action Project.
Environmental degradation
Human activities affect the environment in many ways from changes to the atmosphere and potentially the climate to directly polluting local habitats. In coastal zones several activities pose threats to the marine biodiversity. Activities related to domestic and industrial waste disposal, waste from aquaculture, exploitation of minerals and accidents related to oil exploration and transportation can reduce local marine biodiversity and alter coastal habitats. The International Maritime Organisation also points to the increase in pollution from plastic refuse as being a major problem in coastal marine environments.
Tourism also can change local habitats, often quite unwittingly. Increased pressure from diving can damage the coral reefs that tourists have come to visit. Effluents from tourist resorts can pollute the sea and turn clear water green. On tourist beaches nesting turtles can be disturbed, while the unregulated use of power boats and jet skis can hurt and kill feeding dugong.