AMUR-HEILONG RIVER BASIN

 

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Introduction

Climate

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Ecosystems and ecoregions

Species diversity and use of biological resources

Nature conservation: econet and protected areas

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International policy

Species diversity and use of biological resources
Lotus
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Nelumbonaceae is a family of aquatic plants with a long evolutionary history.  They appeared some 135 million years ago.  Only two species now survive, lotus (Nelumbo nucifera or Nelumbium komarovii in Russian sources) and American lotus (Nelumbo lutea).  Lotus is an important economic crop and ornamental plant widely distributed in Asia and northern Oceania.  The wild lotus is the source of cultivated lotus and the gene pool for new cultivar breeding.  In China it is frequently cultivated for ornamental, food, or medicinal purposes.  
Researchers from Daqing and Beijing recently analyzed the genetic structure of the remaining wild lotus populations in Heilongjiang Province and adjacent areas of Russia.  The Amur-Heilong River valley is one of the cradles of wild lotus.  Leaf fossils unearthed at Yilan County of Heilongjiang province dated to the Tertiary, which began some 65 million years ago.  The wild lotus is distributed mainly along the Ussuri-Wusuli, Songhua, and the Amur-Heilong River valleys.  In Heilongjiang Province Chinese researchers discovered 60 sites colonized by wild lotus.  A similar number of sites was documented in adjacent areas of Russia.  Although the evolutionary history of lotus in the Amur-Heilong basin is long, individual populations may be short-lived.  Lotus is found in river valleys where rivers meander and lotus habitats are fragmented and isolated yet simultaneously recreated.  Fluctuations of the wild lotus populations are consistent with climate changes.  Wetlands are enlarged in years when precipitation is abundant and under these conditions lotus proliferates.  When wetlands shrink during drought, wild lotus is restricted to only a few localities.  Lotus grows in colonies that can expand through rhizome growth.  Increases in the number of populations depends on dispersal of genets (rhizomes or fruits) that are dispersed by mainly rivers.  Lotus fruit is also be dispersed by birds which feed on the lotus fruit.  Lotus fruits have an extremely long life, enabling plants to reappear in some ponds after apparently disappearing for hundreds of years.
The wild lotus populations of the middle reaches of the Songhua River appear to be the center from which the species spread to the Ussuri-Wusuli and Amur-Heilong River valleys.  The limited genetic diversity of wild lotus suggests that it experienced a severe bottleneck. 
Populations of wild lotus in the Amur-Heilong basin are declining due to loss of wetland habitat and the genetic integrity of wild lotus is threatened by genetic invasion from cultivars.  Conservation of wild lotus is urgent and important not only scientifically but also for economic, cultural and religious reasons.  Conservation efforts should be focused on the middle reaches of the Songhua River, where several local extinctions were recently reported.

Map collections:

Species richness

Distribution of charismatic species

 

Map:

Detailed hydrography of Amur River basin

Wetlands of Amur

Upper Ussury –Lake Khanka

 

Photo:

Lotus (Photo by V.Solkin)

Also look:

Species richness in Amur-Heilong River Basin

Plants of life

Korean pine

Asian ginseng

 

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