Environ Geol (2008) 55:1135–1147 DOI 10.1007/s00254-007-1061-7 ORIGINAL ARTICLE Eco-environmental degradation in the northeastern margin of the Qinghai–Tibetan Plateau and comprehensive ecological protection planning Hui Wang Æ Xiaolei Zhou Æ Changgui Wan Æ Hua Fu Æ Feng Zhang Æ Jizhou Ren Received: 27 April 2007 / Accepted: 1 October 2007 / Published online: 18 October 2007 Ó Springer-Verlag 2007 Abstract The regional hydrology and ecosystems of the margin of the Qinghai–Tibetan Plateau has decreased by northeastern margin of the Qinghai–Tibetan Plateau have 20%, and the local ecosystem has become very fragile. changed over the past 40 years driven by intense human Given the relatively stable weather conditions, the north- activity and regional climate changes. Annual mean air eastern margin of the Qinghai–Tibetan Plateau can be temperature has increased in the region. Streamflow from characterized by its three major ecosystems: grassland the northeastern margin of the Qinghai–Tibetan Plateau has ecosystem, forest ecosystem and wetland ecosystem, which decreased significantly. Overall, a number of Alpine step are crucial in maintaining the ecological stability. Changes meadows and Alpine frigid meadows have seriously in these ecosystems could influence sustainable develop- degraded. Degeneration of vegetation and grassland led to ment in the region. To avoid further deterioration of the desertification and frequently induced dust storms. With environment and ecosystems, it is important to establish the continuous increase in cultivated land area, grassland and implement ecosystem protection planning. Some area in the region has dropped significantly since the 1960s. effective measures are essential in this respect, including At present, degraded grassland occupies about 83% of total technical and political considerations. usable grassland area. As the number of livestock increased, range condition deteriorated and the carrying Keywords Climate change Á capacity was reduced. The forest area in the northeastern The Qinghai–Tibetan Plateau Á Grassland Á Source region of Yellow River H. Wang Á X. Zhou Á H. Fu Á F. Zhang Á J. Ren College of Pastoral Agriculture Science and Technology, Introduction Lanzhou University, Lanzhou 730000, People’s Republic of China Environmental changes caused by human activities and X. Zhou Á C. Wan regional climate changes have long been recognized Forest Inventory and Planning Institute of Gansu Province, throughout the world (Chen and Qu 1992; Ye et al. 1998; Lanzhou 730020, People’s Republic of China Wang and Cheng 1999; Chen and Kang 2001; Shi et al. C. Wan 2001; Umar et al. 2001; Feng et al. 2006). During the past Department Natural Resources Management, half-century, drastic environmental changes have occurred, Texas Technical University, Lubbock, TX 79409, USA which have invoked concerns. In the northeastern margin of the Qinghai–Tibetan Plateau, like elsewhere in the H. Wang College of Forestry, Gansu Agricultural University, world, environmental changes can be classified into two Lanzhou City 730070, People’s Republic of China categories, i.e. natural and human factors. The former includes tectonic uplift and a monsoon climate (Zhang & X. Zhou ( ) et al. 2000a). The latter involves population explosion and Duanjiatan Road 1234, Lanzhou 730020, Gansu province, People’s Republic of China human activities (Zhang et al. 2000b). The formation of the e-mail: [email protected] fragile eco-environment in northwestern China is a result 123 1136 Environ Geol (2008) 55:1135–1147 of long-term natural evolution, superimposed by human level, and a mean annual precipitation ranging from activities in recent times. The northeastern margin of the £200 mm in the lower-mountain or foothill zones to Qinghai–Tibetan Plateau is one area severely affected by ‡600 mm in the higher-mountain zone. Macroscopically, these changes. As a part of the Yellow River basin, the the northeastern margin of the Qinghai–Tibetan Plateau is a northeastern margin of the Qinghai–Tibetan Plateau is one fragile ecosystem because of three main factors: (1) severe of the most important inland bodies of water for the Yellow water loss and soil erosion, (2) grassland desertification, River, with about 18.6% of the runoff coming from this and (3) atrophying and extinction of swamp land. region. The source region’s eco-environmental changes and related land degradation have a strong influence on the hydrological conditions and the environments of the mid- Study method and data source dle and lower reaches of the river. The repeated drying up of the Yellow River since 1990s has led to in-depth studies The vegetation, land (soil, land use/land cover), hydrology of eco-environmental problems in the catchment of the (including aquatic ecosystems) are the main aspects Yellow River (Tian 1995; Liu 1996;Xi1997; Yang 1997). reflecting environmental changes (Wang et al. 2003). Previous studies in the upper reaches and the catchment Based on information accumulated from the past 40 years region of the Yellow River are focused mainly on water in the northeastern margin of the Qinghai–Tibetan Plateau, resource utilization and soil erosion, and relatively little including 40 years of hydrological records made by the research has been carried out on the effects or causes of Gansu Hydrology Reconnaissance Bureau, and streamflow regional eco-environmental changes (Tian 1995; Liu data from previous studies, detailed analyses on environ- 1996). Some preliminary results show that eco-environ- ment degradation of the Yellow River resource were mental changes in the source region of the Yellow River conducted. The evaluation of the eco-environmental deg- not only greatly affect the region’s sustainable develop- radation was further aided by Landsat images and the field ment but also aggravate soil erosion (Liu 1996; Chen and investigation. The primary information for this study was Liang 1998; Cheng and Wang 1998). Viewed holistically, obtained from eight counties’ false color composites made as part of the whole river catchment area, the eco-envi- up of bands 4, 3 and 2 (R, G, B) of LandsatTM (Thematic ronmental changes and their significance for hydrology Map) imagery of September 1982 and 2001. The spatial have a strong influence on the hydrological conditions and resolution of the TM images was 30 m· 30 m. The geo- the environments of the middle and lower reaches (Feng metrical correction of the images was made by using the et al. 2006). In this study, we use changes in plant com- Erdas Imagine provided by ERDAS, and its accuracy was munities as indicators of eco-environmental evolution achieved within one pixel (30 m). The details of the caused by climatic changes (Cheng et al. 1997; Cheng and satellite image processing were described by Navas and Wang 1998) and human factors, and to ascertain evolu- Machin (1997), Valle et al. (1998), Bocco et al. (2001) and tionary trend of this fragile ecosystem. We also outline Vasconcelos et al. (2002). In addition, investigations were strategies that could contribute to ecological sustainability carried out to reveal the trend of eco-environmental in the northeastern margin of the Qinghai–Tibetan Plateau. changes in the region over the past 40 years. During 1994, 2000, and 2005, environmental field surveys of the Gannan catchment region were conducted at two levels of detail: Study area (1) the main sampling transects focused on the three river systems to identify and compare plant communities, (2) The region is located between 100°4504500 and 104°4503000 more intense sampling within the main sampling transects E, and 33°0603000 and 35°3400000 N. It covers an area of sought to assess the current and ongoing situation with approximately 97,000 km2. A city and three counties of respect to vegetation types, land desertification, hydrology. Gansu province lie in the region, namely Hezuo City, Some historical records were used in the comparative study Maqu County, Luqu County, and Xiahe County (Fig. 1). of land cover changes in the area. The following indices The region contains three large hydrographic systems, were selected to analyze the features of regional environ- namely, Yellow River, Tao River and Daxia River. ment change for land, vegetation, and water factors, Geographically, the northeastern margin of the Qinghai– respectively. (1) Vegetation: forest and grassland coverage, Tibetan Plateau belongs to stratum drape system of Qin degraded grassland (grass yields, grassland desertification, Moutain, with a downward inclination from south to north. and carrying capacity); (2) landscape: the area of land The southern mountains are characterized by a remarkable desertification and land desertification processes, measured vertical zonality (Wu 2000). The water source area is and analyzed by the field surveys and historical record mainly concentrated on their upper and middle sections data; and (3) water environments were quantified by long- with an elevation ranging from 1,300 to 3,500 m above sea term observation results. 123 Environ Geol (2008) 55:1135–1147 1137 Fig. 1 The location of the northeastern margin of Qinghai–Tibetan Plateau Results addition, the swampland drained away gradually in the northeastern margin of the Qinghai–Tibetan Plateau. Since Changes in regional water resources the 1970s, the swampland vegetation was gradually replaced by meadow species, mesophytes and xerophytes Changes of surface water system (Wang et al. 2001). Swampland was 1,200,000 in 1980s and shrank to a mere 300,000 ha at the end of 2004, a The northeastern margin of the Qinghai–Tibetan Plateau was reduction of 75.0% (Statistics yearbook of Ganan 2005; the most important water reservation area and ecological Gannan recorder 1998). Figures 2 and 3 represent a map shelter for the Yellow River basin, where rivers and showing the spatial distribution of wetland and swampland swampland supply the Yellow River with large quantities of in the study areas, where there were 6.570,000 ha wetland water. About 18.6% of the runoff comes from this region. and 1,340,000 ha swampland in 1982 (Fig.