ORIGINAL ARTICLE Yuanrun Zheng Zhixiao Xie Lianhe Jiang Hideyuki Shimizu Glyn M. Rimmington Guangsheng Zhou Vegetation responses along environmental gradients on the Ordos plateau, China Received: 28 January 2005 / Accepted: 4 October 2005 / Published online: 19 November 2005 Ó The Ecological Society of Japan 2005 Abstract The Ordos plateau is a unique ecotone and is a focal region for the campaign to reduce or reverse desertification in China. This paper explores the rela- tionship between vegetation and environmental gradi- ents on the Ordos plateau based on a field survey of species distribution, vegetation distribution patterns, plant community structure, ecophysiological properties, and soil water content along an environmental gradient. The vegetation on the Ordos plateau may be divided into three types from east to west: steppe (eastern part), desert steppe (middle part) and steppe desert (western part). From east to west, precipitation declines signifi- cantly (from 400 mm to 150 mm). The spatial distribu- tion pattern of vegetation at different sites was random. The density of shrub islands decreased from east to west, and their height and diameter were negatively correlated with precipitation. From east to west, the transpiration rate increased as temperature increased. Stomatal con- ductance was positively correlated with percentage of sunshine hours and negatively correlated with tempera- ture. Water-use efficiency was positively correlated with average annual precipitation but negatively correlated with increasing percentage of sunshine hours. The re- sults suggest that for effective revegetation, highly drought-tolerant species, such as Caragana tibetica and C. stenophylla, should be used and a lower percentage of vegetation cover expected (30–40%) in the western half of the Ordos plateau. In the eastern half, moderately drought-tolerant species, such as Artemisia ordosica and C. korshinskii, could be used and a higher percentage vegetation cover expected (40–50%). Keywords Ecophysiological properties Plant community structure Species distribution Shrub islands Soil water content Temperature Vegetation distribution patterns Introduction As global warming increases, desertification is becoming a global environmental problem. It is a serious challenge in China, especially at the north-central region where the Ordos plateau is located. The Ordos plateau lies in southern Inner Mongolia and is bounded by the Great Wall in the south and the Yellow River from the other three sides (east, north, and west). It contains an ecotone with air circulation changing from continental, temper- ate, high-pressure ridge (Mongolia–Siberian) in the northwest to the influence of the monsoonal trough in the southeast and covers the arid, semiarid and moist climate types. Correspondingly, its representative vege- tation varies from western continental desert, central desert grassland, to eastern grassland, with flora and fauna from the ancient Mediterranean central-Asian zone to the eastern-forest zone. According to Chen (1964), vegetation on the Ordos plateau can be divided into three types (Fig. 1): steppe (eastern part), desert steppe (middle part), and steppe desert (western part). In the eastern steppe zone, the plant community coverage can reach 40–50% and include 20–30 plant species. The Y. Zheng (&) G. Zhou Laboratory of Quantitative Vegetation Ecology, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, 100093 Beijing, China E-mail: zhengyuanrun@hotmail.com Tel.: +86-10-62836508 Fax: +86-10-82590429 Z. Xie Geography and Geology Department, Florida Atlantic University, Boca Raton, FL 33431, USA L. Jiang Institute of Botany, Chinese Academy of Sciences, 100093 Beijing, China Y. Zheng H. Shimizu National Institute for Environmental Studies, Tsukuba 305-8506, Japan G. M. Rimmington Office for Global Learning, Wichita State University, 1845 N Fairmount, Wichita, KS 67206, USA Ecol Res (2006) 21:396–404 DOI 10.1007/s11284-005-0132-z