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| BIRD OF THE DAY!!! - Cinnamon Bittern |
From Wikipedia -
Prek Toal is a bird sanctuary and Ramsar site located within the Tonlé Sap Biosphere Reserve, at the north-west corner of the Tonlé Sap. It is a popular area for ecotourism and birdwatching given the area's rich biodiversity and rare waterbirds, particularly abundant during the dry season. |
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From our itinerary -
Prek Toal is unmatched in South East Asia for the number and population of endangered water birds it supports during the dry season. Large numbers of cormorants, storks and pelicans are virtually guaranteed from January to May along with herons, egrets and terns.The sanctuary harbors seven species of global conservation significance: Spot-billed Pelican, Milky and Painted Storks, Lesser Adjutant, Greater Adjutant, Black-headed Ibis and Oriental Darter and has a globally significant population of Grey-headed Fish Eagle.
Since the Core Reserve was declared in 2002 and came under the protection of Ministry of Environment as advised by WCS, the numbers of all the above species have increased dramatically.
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Specifically our visit started at a small canal directly south of Siem Reap. Here we boarded a large vessel to cross the lake so we could access the Prek Toal sanctuary. Just before the edge of teh lake we transferred from our large vessel to a fleet of three smaller, sleeker, thinner and fast boats for the trip through a variety of channels to a vast flood plain.
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The variety of species and the number of birds present certainly was impressive.
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Spot-billed Pelican, Milky and Painted Storks, Lesser Adjutant, Greater Adjutant, Black-headed Ibis and Oriental Darter and has a globally significant population of Grey-headed Fish Eagle were teh key species and all were seen by our group.
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Other highlights included three species of Bittern - Yellow, Cinnamon and Black. Cinnamon was our [surprise] choice for bird of the day. But like most days it is surprising to find true consensus; given the variety of birds seen and the potential for a huge variety of criteria in selecting our birds. BTW It was Vince's birthday today and he chose Cinnamon Bittern so that is good enough for me!!
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Our small boats eventually allowed us to get on some semi dry land to try to spot some birds there and again we got some good birds.
Another great day in Cambodia!!!
From Wikipedia -
Tonlé Sap (Khmer: ទន្លេសាប IPA: [tunleː saːp], literally large river (tonle); fresh, not salty (sap), commonly translated to 'great lake') refers to a seasonally inundated freshwater lake, the Tonlé Sap Lake and an attached river, the 120 km long Tonlé Sap River, that connects the lake to the Mekong River. They form the central part of a complex hydrological system, in the 12,876 km2 Cambodian floodplain covered with a mosaic of natural and agricultural habitats that the Mekong replenishes with water and sediments annually. The central plain formation is the result of millions of years of Mekong alluvial deposition and discharge. From a geological perspective, the Tonlé Sap Lake and Tonlé Sap River are a current freeze-frame representation of the slowly, but ever shifting lower Mekong basin. Annual fluctuation of the Mekong's water volume, supplemented by the Asian monsoon regime causes a unique[citation needed] flow reversal of the Tonle Sap River.
The Tonlé Sap Lake occupies a geological depression of the vast alluvial and lacustrine floodplain in the lower Mekong basin, which had been induced by the collision of the Indian Plate with the Eurasian Plate. The lake's size, length and water volume varies considerably over the course of a year from an area of around 2,500 km2, a volume of 1 km3 and a length of 160 km at the end of the dry season in late-April to an area of up to 16,000 km2 a volume of 80 km3 and a length of 250 km as the Mekong maximum and the peak of the southwest monsoon's precipitation culminate in September and early-October.
As one of the world's most varied and productive ecosystems the region has always been of central importance for Cambodia's food supply. It proved capable of largely maintaining the Angkorean civilization, the largest pre-industrial settlement complex in world history. Directly and indirectly it affects the livelihood of large numbers of a predominantly rural population. Due to ineffective administration and widespread indifference towards environmental issues, the lake and its surrounding ecosystem is coming under increasing pressure from over-exploitation and habitat degradation, fragmentation, and loss. All Mekong riparian states have either announced or already implemented plans to increasingly exploit the river's hydroelectric potential. A succession of international facilities that dam the river's mainstream is likely to be the gravest danger yet for the entire Tonle Sap eco-region.
The Great Lake ecosystem
Cambodian floodplain
The Cambodian floodplain or the Mekong Plain is a vast low-lying area traversed by the Mekong River. Only a relatively small portion of the plain consists of fluviatile deposits of the young Mekong. The plain encompasses most of lowland Cambodia and the Mekong delta of Vietnam, a small part of southern Laos, and a small part of eastern Thailand in Chantaburi and Prachinburi Provinces. It is bordered by the Dangrek Mountains on the north, the Elephant and Cardomom mountains on the south, and the southern Annamite Range on the east. The plain is about 800 kilometers from north to south and 600 kilometers from east to west. It is mostly less than 100 meters in elevation, but a few higher outcroppings are scattered throughout the plain and much of northern Cambodia is characterized by rolling and dissected plains between 100 and 200 meters elevation. The plain is the result of erosion and sedimentation. The sediments vary in depth from at least 500 meters near the mouth of the Mekong to only about 30 meters at Phnom Penh, with bedrock outcroppings in isolated hills above the plain in several places.[13]
The Tonle Sap is the largest freshwater lake in Southeast Asia and one of the richest inland fishing grounds in the world. The lake functions as a natural flood water reservoir for the Mekong system as a whole by regulating the floods downstream from Phnom Penh during the wet season and makes an important supplement to the dry season flow to the Mekong delta.[14]
Wetlands, flooded forests, and deciduous forests
A belt of freshwater mangroves known as the "flooded forest" surrounds the lake. The floodplains in turn are surrounded by low hills, covered with evergreen or deciduous seasonal tropical forest dominated by species of Dipterocarpaceae, Leguminosae, Lythraceae, Fagaceae and in some places Pinaceae, Podocarpaceae, or bamboo.[15] The eco-region consists of a mosaic of habitats for a great number of species.[16] The forest gradually yields to bushes and finally grassland with increasing distance from the lake. On higher quality soils or at higher elevation, areas of mixed deciduous forest and semi-evergreen forests occur.[17] This variety of vegetation types accounts for the quantity and diversity of species of the Great Lake ecosystem. Interlocking forest, grassland, and marshland patches provide refuge for the local wildlife.[18][19]
The lake's flooded forest and the surrounding floodplains are of utmost importance for Cambodia's agriculture as the region represents the cultural heart of Cambodia, the center of the national freshwater fishery industry, the nation's primary protein source.[20]
Threats to the lake include widespread pollution, stress through growth of the local population which is dependent on the lake for subsistence and livelihood, over-harvesting of fish and other aquatic, often endangered, species, habitat destruction, and potential changes in the hydrology, such as the construction and operation of dams, that disrupt the lake's natural flood cycle. However, concerns that the lake is rapidly filling with sediment seem[21] to be unfounded at the present time.[22]
Volume fluctuation and flow reversal
Tonle Sap Lake over the course of one year
Inflow starts in May or June with maximum rates of flow of around 10,000 m3/s by late-August and ends in October or November, amplified by precipitation of the annual monsoon. In November the lake reaches its maximum size. The annual monsoon coincides to cease around this time of the year. As the Mekong River is at its minimum flow around this time of the year and its water level falls deeper than the Tonle Sap Lake, the Tonle Sap River and surrounding wetlands, waters of the lake's basin drains via the Tonle Sap River into the Mekong. As a result the Tonle Sap River (length around 115 km/71 mi) flows six months a year southeast (Mekong) to northwest (lake) and six months a year in the opposite direction. The mean annual reverse flow volume in the Tonle Sap is 30 km3 (7.2 cu mi), or about half of the maximum lake volume. A further 10 percent is estimated to enter the system by overland flow from the Mekong.[23][24] The Mekong branches off into several arms near Phnom Penh and reaches Vietnamese territory south of Koh Thom and Loek Daek Districts of Kandal Province.
There is extreme hydrodynamic complexity in both time and space and it becomes impossible to measure channel discharge. Water levels, not flow rates and volumes, determine the movement of water across the landscape.
