干旱区内陆河流域土地利用程度变化与生态安全评价——以新疆玛纳斯河流域为例

以天山北坡玛纳斯河流域为例，在遥感与GIS支持下揭示了流域1989-2002年间土地利用程度变化状况，并进一步对流域生态安全进行了综合评价，最后分析了土地利用程度变化与生态安全的关系。结果表明：①玛纳斯河流域土地利用程度稳定上升，土地利用总体处于发展时期；②1989-2002年，流域生态安全状况整体有所好转，但局部生态环境出现恶化趋势；③流域土地利用程度综合指数在18~100间的区域生态安全等级有所提高，由1989年主体属于中警状态提高到2002年的预警状态；④不同土地利用程度下流域在较安全和预警状态面积之和有以下顺序：Ⅴ＞Ⅳ＞Ⅰ＞Ⅵ＞Ⅲ＞Ⅱ，表明Ⅴ级土地利用程度区即林草地是流域生态恢复和重建的首选和重要组成部分，而沙地则是生态环境治理的难题和关键。最后，提出了通过提高低利用程度区的土地利用程度来确保生态安全的观点。

Change of Land-Use Degree and Ecological Security Assessment of Inland River Basins in the Arid Area-A Case Study on Manas River Basin in Xinjiang

Ecological security can be defined as the maintenance and guarantee of the sustainable development of human society, an ecosystem state of no damage and threat to the health and integrity of the ecosystem itself. It is a kind of highly harmonious situation of human and natural eco-environment. The evaluation of ecological security is conductive to provide decision reference to regional sustainable development and eco-environmental rehabilitation. The Manas River Basin as a typical inland river of arid land in Xinjiang, the evaluation of its ecological security is of especially importance. The change in land-use degree between 1989 and 2002 was revealed in the Manas River Basin by using GIS and remote sensing and building a mathematical model, based on which the ecological security of the river basin was assessed further. The relationship between the change of land-use degree and ecological security was analyzed. The results show that: 1) The comprehensive index of land-use degree kept increasing in the Manas River Basin, an increase from 0.44 to 0.51. 2) During 1989-2002, the general ecological security of the basin was improved. The area in severe-warning and moderate-warning status decreased from 60.78% in 1989 to 39.51% of the total area in 2002 and the area in safer status increased 1.4%. But part regions of the basin were in the opposite situation and the area in severe-warning status increased 2.15% compared to the year of 1989. 3) For the regions, the comprehensive index of land-use degree of which was between 18 and 100, the grade of the ecological security was improved from the moderate-warning status in 1989 to the pre-warning status in 2002. 4) The sum of the area for different land-use degrees under safer and pre-warning status ranked as following: Ⅴ>Ⅳ>Ⅰ>Ⅵ>Ⅲ>Ⅱ. It indicates that the land-use degree of V which is forest-grass land is the first choice for ecological restoration and reconstruction of the basin, while eco-environmental treatment of sandy areas is difficult. Therefore, suitable land-use degree promotes the ecological security and new requirements were put forward to the land use in the aspect of ecological security. To ensure the regional ecological security, a method of increasing land-use degree of the regions with lower land-use degree was proposed.