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 Songkhram River Basin, Thailand
 
Main threats to wetland biodiversity in the Lower Songkhram River Basin

A brief description of the threats to the biodiversity of the Lower Songkhram River is presented below in order of threats to systems, habitats and species. An analysis of the root causes is presented in Table 1.
Permanent inundation of the site. A proposal exists to construct a dam for flood control and irrigation on the Songkhram River, 8 kilometres upstream from its confluence with the Mekong. It would inundate about 14,000 ha of the demonstration site permanently and reduce the total area flooded annually by about 30,000 ha.. If this development proceeds the possibilities for the implementation of the proposed activities would need to be reviewed carefully.
Infrastructure development – water control systems including weirs. Numerous, dykes, weirs and reservoirs on tributaries of the Songkhram River support irrigation systems. However these structures have modified the natural hydrology and obstruct fish migrations to and from the Mekong River.
Unsustainable management of natural resources. Eucalyptus plantations and cattle grazing in inundated forests disturbs the structure of the wetland habitats. The clearing of inundated forest continues today for more extensive and intensive agriculture. The loss in habitat will continue to reduce wetland biodiversity values.
Reduction in water quality. Pollution levels are locally high in the Songkhram River from the use of chemicals for agriculture. In addition, growing villages, industrial, and commercial operations contribute increasingly to pollution levels. Herbicides may alter the wetland vegetation, pesticides and industrial waste may build up to toxic levels in higher order species, and fertilizers and domestic human waste may cause eutrophication. While not a threat presently to global biodiversity, pollution may become so if pollution sources are not addressed.
Focus of management on terrestrial components of river basin. The management of the demonstration site has been focussed on the terrestrial components of the ecosystem to date. Little attention has been paid to the benefits provided by wetland habitats, thus enabling continuing degradation of their biodiversity values.
Introduction of potentially invasive alien fish species. Over 1 million alien, potentially invasive, fish species are currently being cultured in the Lower Songkhram River. If these species escape they may out compete local species and change the structure of the fish community.
Inappropriate fisheries’ activities resulting in a decrease in fish stocks and related fish biodiversity. Over-fishing and destructive fishing practices pose a major threat to Mekong fish species. Fishing pressure, with modern gears, is increasing and the practice of “fishing concessions” where streams are totally blocked with fine-mesh nylon net is common. Conflicts are occurring between small and large-scale fishers.

Table 1: Threats in Lower Songkhram River, Thailand

ThreatImmediate causeRoot cause
Permanent inundation of the site through the construction of a dam at the mouth of Songkhram RiverInfrastructure development
Irrigation for agriculture
• Unco-ordinated sectoral approaches to wetland planning at national and regional level
• Weak policy framework and unsupportive economic environment for wetland biodiversity conservation and sustainable use
Infrastructure development – water control systems including weirsEffort to increase agricultural production, government policy to increase cash-crop production• Weak policy framework and unsupportive economic environment for wetland biodiversity conservation and sustainable use
• Unco-ordinated sectoral approaches to wetland planning at national and regional level
• Inadequate information and awareness base on which to base wetland policy, planning and management decisions.
Unsustainable management of natural resourcesUnsustainable use of wetlands:
Wood harvesting
Grazing
Harvesting wildlife
• Weak policy framework and unsupportive economic environment for wetland biodiversity conservation and sustainable use
• Unco-ordinated sectoral approaches to wetland planning at national and regional level
• Lack of options over resource use by local people
• Inadequate human and technical resources available for wetland biodiversity conservation
Reduction in water qualityIndustrial and agro-industrial pollution • Inadequate human and technical resources available for wetland biodiversity conservation
• Weak policy framework and unsupportive economic environment for wetland biodiversity conservation and sustainable use
• Unco-ordinated sectoral approaches to wetland planning at national and regional level
 Domestic waste• Weak policy framework and unsupportive economic environment for wetland biodiversity conservation and sustainable use
Focus of management on terrestrial components of river basin. Management focus on forest systems• Unco-ordinated sectoral approaches to wetland planning at national and regional level
• Weak policy framework and unsupportive economic environment for wetland biodiversity conservation and sustainable use
 Education activities focused on forest environments• Inadequate human and technical resources available for wetland biodiversity conservation
• Unco-ordinated sectoral approaches to wetland planning at national and regional level
Introduction of potentially invasive alien fish species Extensive culture of exotic fish species• Unco-ordinated sectoral approaches to wetland planning at national and regional level
• Lack of options over resource use by local people
• Inadequate human and technical resources available for wetland biodiversity conservation
Inappropriate fisheries activities resulting in a decrease in fish stocks and related fish biodiversityOver harvesting of fisheries resources and unsustainable harvesting practices• Inadequate information and awareness base on which to base wetland policy, planning and management decisions.
• Inadequate human and technical resources available for wetland biodiversity conservation
• Lack of options over resource use by local people