Amur Freshwater Ecosystem
It is important to delineate this eco-region to recognize the integrity and unique conservation value of the mighty Amur-Heilong River system and the necessity of developing special approaches for conservation of its aquatic biodiversity. Wetlands must be simultaneously considered both in terrestrial and freshwater conservation strategies at once. This Global 200 eco-region was given a misleading name. The ecosystem actually extends into China and North Korea. It also includes the Lower Amur wetlands , the middle reach of the Amur-Heilong and its major tributaries, the Ussuri-Wusuli River and Lake Khanka-Xingkai Lowlands, as well as many adjacent rivers independently draining into the Pacific Ocean (Uda, Siphon, Tumen, all streams draining the Eastern Slope of the Sikhote –Alin range and others). Given the basin-wide range of Kaluga sturgeon and some other important species, the freshwater ecosystems of the Daurian steppe are also often considered part of this overwhelming global eco-region.
Wetlands other than rivers and lakes are also valuable components of the Amur-Heilong ecosystem. They regulate and mitigate floods, improve water quality, and provide food, habitat, and breeding sites for many animals, especially fish and waterfowl. Wetland formation is determined by uneven seasonal distribution of precipitation, permafrost, heavy and poorly drained clay soils, and well-developed floodplains. The distribution of wetlands across the Amur-Heilong basin is patchy given variations in topography and climate. Most are inseparable parts of the larger river and lake systems described above.
Lacustrine wetlands are located around lakes and include lake valleys. These wetlands form around permanent and temporary fresh and saltwater lakes. The largest wetlands of this type are located near lakes Khanka-Xingkai, Buir, Torey, Dalai, and lakes of the lower Amur floodplain.
Palustrine and swamp-meadow wetlands of the basin are mainly found in low-lying lands on the Song-Nen plain, Sanjiang plain, along the Orshun and Argun rivers, Zeya-Bureya plains, plains of the Lower Amur-Heilong, and Khanka lowlands. Most of those are sustained by flood regimes of large river systems.
Forest swamps in boreal larch forests are prominent features of the northern part of the basin. These occupy the largest areas in Amurskaya and Khabarovsky Provinces, but are also abundant in mountainous headwaters of most tributaries, especially in the eastern half of the basin. They often form along sedge hummock meadows in floodplains of mountain streams. Small peat bogs are found in headwaters of minor streams throughout the northern part of the basin and in all mountain ridges. However, these forest swamps typically are not inventoried as wetlands due to their small size.
Permanent and seasonal pools, often brackish or alkaline, are prominent features of steppe areas in the western part of the Amur-Heilong basin.
Unfortunately, no consistent comparative data are available on wetland types and their distribution in the transboundary basin given the different approaches to land inventories that are used in the three countries. Drought cycles also complicate the picture, since any given wetland will differ dramatically in area depending on water abundance in a given period. Due to legal requirements in China to protect all wetlands, China currently has more comprehensive inventories than the other two basin countries. Results of our own preliminary inventory of wetland distribution (based on available maps and databases) following very general wetland classification prescribed by Ramsar Convention is presented on Map of Amur-Heilong River Basin Wetlands.
Given the immense importance of wetland ecosystems of Amur-Heilong Basin, a detailed inventory of wetland types and of the current status of wetland complexes in all major sub-basins is a necessary and urgent task.
Wetlands and associated grasslands of Eastern Amur Basin can be divided in at least three distinctive eco-regions:
Suifen-Khanka meadows and forest meadows
Amur meadow steppe
Wetlands of lower Amur mountain valley eco-region
Bolon Lake (Photo by Yury Darman)