A montane "island in the sky," the Helan Mountains separate the semi-arid Ordos Plateau and the Yellow River Valley from the desert regions of the Alxa Plateau to the west. Like mountain ranges in the Great Basin of western North America, the Helan Range isolates conifer forests and may support endemic communities of plants and animals. Although the region has not been well-studied, blue sheep, and blue-eared pheasant and the endemic Helanshan pika are known to be residents here. Commercial logging is responsible for destruction of habitat, and continues to be a major threat to this biologically diverse ecoregion.
Location and General Description
The Helan Mountain Range, about 180 kilometers (km) long with a maximum elevation of 3,556 meters (m), extends north as a fingerlike extension of the Tibet-Qinghai Plateau. These mountains lie to the west of the Huang He (Yellow River) where the river flows north across the Yinchuan Plain and separates the semi-arid Ordos and Alashan Plateaus. Evidence suggests that the Helan Mountains were glaciated during the late Pleistocene at elevations above 3,000 m.
The lower slopes of the range support semi-arid valleys where shrubby Siberian elm (Ulmus pumila) grows near the sandy beds of intermittent streams. Exposed hillsides support a xerophytic (drought-adapted) scrub of rose (Rosa xanthia), Caragana spp., elm (Ulmus glaucescens), Ostryopsis davidiana, Xanthoceras sorbifolia, and juniper (Juniperus rigida). Upland areas support conifer forests of dragon spruce (Picea asperata) growing through a lower story of birch (Betula spp.) and poplar (Populus spp.). Valleys at lower elevation support stands of Chinese red pine (Pinus tabulaeformis), a conifer adapted to warmer, drier summer conditions.
During an expedition in spring 1996, more than 800 blue sheep (Pseudois nayaur) were observed in herds of up to 30 individuals. Other rare mammals that have been reported from these mountains include argali (Ovis ammon) and moose (Alces alces). If confirmed, this population of moose may be the most southerly moose populations in all of Eurasia. The Helanshan pika (Ochotona argentata) is a critically endangered, endemic species that has been placed on the IUCN Red List for lagomorphs.
The Helan Shan Nature Reserve (1,570 square kilometers (km2)) protects the Qinghai spruce (Picea crassifolia) and blue-eared pheasant (Crossoptilon auritum), a species restricted to the mountains and deserts at the eastern margins of the Tibet-Qinghai Plateau, and black stork (Ciconia nigra). The reserve also includes large areas of Picea asperata forest (though much has been logged) and rare plants such as the legume, Ammopiptanthus mongolicus, and the lilac, Syringa pinnatifolia.
Forests have been logged extensively, especially the spruce forests.
Types and Severity of Threats
Hunting pressure was reported to be the major threat to the survival of the blue sheep in the Helan Mountains.
Justification of Ecoregion Delineation
Located between the Yinchuan Plain and the Alashan Plateau, the forests of the Helanshan separate temperate steppe from desert regions. The boundary was derived from the spruce class according to the CVMCC Vegetation Map of China.
Additional Information on this Ecoregion
- For a shorter summary of this entry, see the WWF WildWorld profile of this ecoregion.
- To see the species that live in this ecoregion, including images and threat levels, see the WWF Wildfinder description of this ecoregion.
- World Wildlife Fund Homepage
- Chinese Vegetation Map Compilation Committee. 1979. Vegetation map of China. Map (1:10,000,000). Science Press, Beijing, China. ISBN: 7030089561
- Mackinnon, J., M. Sha, C. Cheung, G. Carey, Z. Xiang, and D. Melville. 1996. A biodiversity review of China. World Wide Fund for Nature, Hong Kong.
- Rost, K.T. 2000. Geomorphilogical and Paleoclimatic investigations in the high-mountain ranges of Central China and adjacent areas. Institute of Geography, University of Goettingen, 37077 Goetingen, Germany.
- Wang Xiaoming, Li Ming, Tang Shaoxiang, Liu Zhixiao. 1998. A preliminary study of some characters of blue sheep population ecology in spring. Acta Theriologica Sinica 18(1): 27-33 (in Chinese).
- Zhao, J. editor. Zheng Guangmei, Wang Huadong, Xu Jialin. 1990. The Natural History of China. McGraw Hill Publishing Company, New York. ISBN: 0070107521
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