GEOGRAPHICAL RESEARCH ›› 2017, Vol. 36 ›› Issue (9): 1755-1772.doi: 10.11821/dlyj201709012

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Wetland and grassland egradation and the response to climate in Dalinor Basin duing 1962-2016

Chao MA1,2(), Weiwei LIU1, Pengfei ZHAO1, Wensi MA1, Wei MA1   

  1. 1. School of Surveying & Land Information Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China;
    2. Key Laboratory of Mine Spatial Information Technologies of SBSM, Henan Polytechnic University, Jiaozuo 454000, Henan, China
  • Received:2017-02-24 Revised:2017-07-19 Online:2017-09-15 Published:2017-12-12

Abstract:

The Dalinor Lake Wetland National Nature Reserve is included on the list of Asia important wetlands. Being an integrated ecosystem composed by lakes, rivers, swamps, wet meadows and sparse grasslands, the Dalinor reserve behaves as the important ecological function region in the eastern basin of Inner Mongolia Plateau, and also a natural eco-barrier of the Beijing-Tianjin region. Based on multi-sourced remote sensing data of Keyhole-1 (1962), Landsat TM/ETM+/OLI (1985-2016) and SRTM/ASTER DEM (2000, 2009), along with field observations of annual temperature and precipitation from 3 meteorological stations around the lake, interpretations and quantification were carried out on the water area of the three main lakes (i.e. Dalinor, Ganggengnor and Duolunor lakes) within Dalinor watershed, typical environmental elements of human activities (i.e., the area of the residential, cultivated and grazing land) and vegetation coverage derived from normalized difference vegetation index (NDVI), especially the variation of the river basin and climate change and their correlation between human activities in this 55-year period (1962-2016) were analyzed. The research reveals that: (1) There have been changes on the ecological, humanistic and geographical indicators of the Dalinor area. In the past 55 years, the water areas of the three lakes shrank by 24.65%, while the inhabitants and cultivated lands increased by 15.32 and 7.86 times, respectively. Focusing on a 32-year period from 1985 to 2016, the average NDVI was reduced by about 38.46% within the whole region, and the grassland (for pasture) reached 1720 km2, accounting for 52.8% of the available area. (2) The variation of the water area of the main lakes presented no significant correlation with the global climate change, however, its strong relationships with typical environmental elements (changes in the area of the residential, cultivated and grazing land) were observed, suggesting that human activities are becoming the dominant factors which lead to the wetland and grassland degradation. (3) The warming rate across the Dalinor basin climbed much higher than the average level of the global and Northeast Asia scale, indicating that a prominent warming-drying trend was performed during this period, to a certain extent, the fragile habitat of the Dalinor reserve acts like an "Ecological magnifier" to the global climate change. The wetland ecology of the Dalinor watershed is extremely sensitive to global climate change.

Key words: Dalinor Basin, wetland, ecological function, normalized difference vegetation index (NDVI), climate change, man-land relationship