额济纳绿洲景观邻接特征与生态安全评价

Ejina oasis landscape spatial neighboring characteristic and ecological security evaluate

额济纳绿洲在内陆河流域绿洲中具有典型意义,生态安全研究面临着很大的迫切性。本文以2003年TM影像为数据源,运用Arcview 3.2计算额济纳绿洲景观类型和荒漠景观类型之间的邻接长度和数目比例,据此计算了绿洲生态安全及受胁程度。结果表明,绿洲景观类型与荒漠类型的邻接边长和斑块数目、面积的差异较大;草地和林地与沙地和盐碱地的邻接边长和数目较大,受沙漠化、盐碱化的威胁比较严重。景观类型之间邻接特征分析表明,绿洲景观类型受沙漠化和盐碱化的威胁程度严重。从绿洲整体来看,绿洲受沙化的威胁比盐碱化的要大。

In this paper, we intend to present the urgency for water pollution prevention in the Ejina oasis area as a result of our on-spot investigation in 2003 by taking the TM image as the data source and Arcview 3.2 as a tool for measuring the data of the oasis-surrounding landscape sizes, indexes and desert landscape types. The investigation results of ours have also been used to calculate the ecological security and threatening degree the oasis is suffering now. The data collected indicate that, the oasis proves quite different in its neighboring length radiation, patch numbers and area numbers between its landscape and the surrounding deserts. Furthermore, the grass land and woods prove more widely spreading length to the surrounding deserts and more patches mixed with sandy oils and Salina as a result of severe influence of desertification and salinization. Such a situation can help to reveal the threatening tendency by desertification and salinization, which tends to reduce the environmental security degree.