科尔沁沙地生态环境特征分析

Analysis on the Ecological Environment Characteristics in a Farming-Pasture Ecotone in the Horqin Sandland

科尔沁沙地典型地区生态环境特征的分析表明,40年来科尔沁沙地的年均气温呈逐渐增加的趋势,与全球气温升高变化一致。年降水量的变化呈波动式增加,特别是从20世纪70年代中期到90年代中期年降水量的波动幅度增大。气候类型年际间呈半干旱、半湿润和湿润交替出现,其中半干旱气候出现频率为47.5%,半湿润气候为45%,湿润气候为7.5%。沙尘暴的发生日数从1961年以来呈下降趋势,到1984年以后低于平均水平。科尔沁沙地的土壤和植被的异质性决定了该区域的农牧交错特征,特定的风沙环境促进了农牧交错特征的变化。

The Horqin Sandland (42°20′-44°28′N, 113°30′-123°30′E) is located in the western part of northeast China, its total area is 5.06× 104 km2, and Tongliao City in Inner Mongolia Autonomous Region is the core region of the Horqin Sandland. The Horqin Sandland is a transitional zone between the Northeast Plain and the Inner Mongolian Plateau, and in the sandland it belongs to the semi-humid and semi-arid fluctuation climate. The average annual temperature was 6.8℃ during the 40-year period from 1961 to 2000, and the 40-year average annual precipitation was 366.3 mm. However, under the background of global warming, the productivity and biodiversity of the sandland are reduced, and the ecological environment degeneration including land desertification and steppe degeneration becomes more serious. In this paper, the ecological environment characteristics in a typical region of the Horqin Sandland are analyzed. The result shows that the annual temperature in the Horqin Sandland has been increased since recent 40 years, which accords with global warming. The annual precipitation has been increased in a fluctuation way since recent 40 years, and the fluctuation extent of annual precipitation was high during the period from the mid-1970s to the mid-1990s. Interannually, the semiarid, semihumid and humid climates occur alternately, in which the occurring frequencies of semiarid, semihumid and humid climates are 47.5%, 45% and 7.5% respectively. The days of occurring dust storms have been reduced since 1961 and been below the average from 1984. The soil and vegetation heterogeneity determines the features of farming-pasturing ecotone in the Horqin Sandland, and the change of the features of farming-pasturing ecotone is caused by the peculiar sand drift environment in the sandland.