Mekong Eye - News, analysis and opinion focusing on the environment and sustainability of the Mekong region

17 January 2017 at 4:59
Credit: Ayuwat Jearwattanakanok, BCST
The Mekong Eye
Much attention has been given to damages that are being inflicted on Mekong fish by massive infrastructure development. But little has been said about another of the region’s most valuable ecological assets: the spectacular birds of the Mekong.
A decade and a half ago when China financed the Thai and Lao governments to blast bedrock to widen river channels for navigation, Thailand’s leading ornithologist Philip D. Round from Mahidol University wrote a preliminary assessment of the project’s potential impacts on birds. As Thailand prepares to restart rapid blasting and river channelization along the Mekong River just below its arrival from Myanmar to allow access for larger barges from China, Round says its realization “would be akin to genocide of riverine bird populations”.
Round adds that reversing this loss of biodiversity is about so much more than preserving some birds or fish species because we find them attractive or tasty. “It’s about humanity’s survival now,” he says. Second to climate change, the loss of species represents the most significant destabilizing force on the earth systems that manage the delicately-running natural cycles that help make earth habitable to humans and contribute to our way of life in many ways. Moreover, losses in the Mekong region, which support one the greatest fresh water diversities in the world and where the many new species continue to be discovered, is now seen as a global catastrophe.
Here are 7 key Mekong bird species that our children may not have a chance to see.
Mekong Wagtail
Photo credit: Ayuwat Jearwattanakanok, BCST
The bird’s name suggests that the species is only found along the Mekong and its tributaries, around the fabled Emerald Triangle, where the borders of Thailand, Laos and Cambodia meet. Discovered by science only in 2001 with an estimated small population of 6,000-15,000, the species have already been classified as globally Near Threatened by Birdlife International, a worldwide bird conservation network.
The Mekong wagtail’s habitat is along wide lowland river channels with fast-flowing braided sections of river flowing through a distinctive landscape of rocks, with bushes adapted to prolonged seasonal submersion with sandbars and gravel shoals. This makes it especially vulnerable to extensive alterations to the river channel such as dams and rapid blasting. The fact that this species is only found in the region renders Thailand and its neighbors as the sole global responsibility for their survival.
River Tern
Photo credit: Thanee Wongniwatkajorn
This species is already very scarce due to human disturbance of the sandbanks on which it nests. There are recent records along the Mekong in Thailand from Chiang Saen, Vientiane and from near Khemmaraj. Scientists did not record any on those sections of the upper Lao Mekong in Bokeo and Luang Namtha, reflecting the present extreme scarcity of this species in areas where they were formerly present or reasonably abundant. Most recent records from the Mekong are in southern Laos, in the vicinity of Khone Falls.
Any additional disturbance, such as alterations to riverine hydrology and perhaps also food supply caused by blasting could prevent any possibility of recovery in numbers sufficient to stop the extinction of this species.
Wire-tailed Swallow
Photo credit: Ayuwat Jearwattanakanok, BCST
This swallow is mainly associated with river rapids. Numbers at Pak Mun are believed to have declined due to demolition and submersion of the rapids there resulting from construction of the Pak Mun dam in 1994. Though widely distributed along rocky sections of the Mekong, numbers are small, having presumably declined since “thousands” were reported some 50 years ago. Although this species disperses widely over cultivated land, rivers constitute its core habitat, and dynamiting of bedrock would directly affect numbers.
River Lapwing
Photo credit: Ayuwat Jearwattanakanok, BCST
Found in small numbers throughout all sections of the Thai-Lao Mekong. Scientists recorded a total of 130 on the upper Lao Mekong, but River Lapwing is already scarce, and much less numerous on those sections of the river in Thailand, due mainly to direct and indirect human disturbance of its riverine sandbar and shingle bar nesting habitat, and collection of eggs and young as food by fishermen. Found upstream and downstream of Chiang Saen and Chiang Khong. It would be adversely affected by additional disturbance caused by blasting of rocks and rapids.
Great Thick-knee
Photo credit: Thanee Wongniwatkajorn
This is a scarce and probably overlooked resident. The only records of apparently breeding birds in Thailand or Laos in recent decades have come from the Mekong River, where it has been found on sandbars upstream of Thailand between Chiang Saen and Chiang Khong, near Pakchom in Loei province; more or less opposite Sangthong, where they were recorded in Laos, and in Amnat Charoen province and along the Mekong in the far south of Laos.
The species lives on sandbars and also areas of exposed bedrock with bushes and scrubby growth. The small populations remaining would therefore be directly affected by blasting or bedrock or dredging of sandbars to deepen river channels, which would destroy their habitat.
Jerdon’s Buschchat
Photo credit: Ayuwat Jearwattanakanok, BCST
The largest population of this species known is on the middle Mekong around and upstream of Pakchom District in Thailand. Duckworth, J. W., who studied birds in Laos estimated in 1997 at
100 plus pairs. Birds occur in association with bushes on riverine sand and single bars and exposed bedrock in “braided channel” habitat. Jerdon’s Bushchat apparently does not extend anywhere further downstream along the Mekong. The bird is present around Chiang Saen in very small numbers. However, the area of
scrubby sand and shingle bars and exposed bedrock from Chiang Saen downstream to Chiang Khong, which has never been properly surveyed for this species, almost certainly supports a sizeable population of Jerdon’s Buschchats, as the habitat appears closely similar to that at Pakchom. It is
likely, therefore, that a sizeable population occurs of at least national and probably regional conservation importance and would be directly damaged by blasting or destruction of riverine bedrock. Moreover, the population at Pakchom is already possibly at risk due to dredging of sand for construction.
Small Pratincole
Photo credit: Ayuwat Jearwattanakanok, BCST
This bird nests exclusively on riverine sandbars, and is the most numerous and abundant riverine nesting bird remaining. Though widespread on the Thai-Lao Mekong, the largest single concentrations known are around Chiang Saen, with at least 840km upstream of the town in early 2000 and a further 1,600 between Chiang Saen and Chiang Khong in 2002. Numbers elsewhere are apparently much less. This species would be directly affected by dredging of sandbars and blasting of bedrock, and numbers possibly much reduced.
*The listicle is based on “Likely impact of destruction of rocky rapids and bedrock along the Mekong River in Thailand upon birds” by Philip Round in 2002.
See also: The Bird’s Eye View: What Endangered Birds Tell us About the Risks of Mekong Developmet
Photos courtesy of Ayuwat Jearwattanakanok from the Bird Conservation Society of Thailand and Thanee Wongniwatkajorn