基于物元分析的小流域土地利用结构调整及景观格局变化

将土地利用的适宜度、适宜度评价指标及其特征值作为物元,由实测资料和专家系统综合得到模型的经典域、节域、权重及关联度,建立起土地利用适宜性评价的物元分析模型,将模型应用于四川省阆中市岳家沟小流域土地利用结构调整中.结果表明,经调整后,该区的农林牧比例趋于合理,土地的经济效益指数、生态效益指数分别由原来的1529.80、1460.94提升到1719.99、1758.21.此外,调整后,景观格局发生变化：景观多样性指数（H）和景观均匀度指数（E）分别由调整前的1.3028和0.6108增加到调整后的2.0920和0.8463,分别增加了60.58%和38.56%,最大多样性指数上升了18.33%.而景观优势度和蔓延度指数则由调整前的0.6431和0.7467减少到调整后的0.2106和0.7125.说明景观斑块的空间分布趋于均匀,斑块的聚集状况分散化.实例证明,在小流域土地利用结构调整中,物元分析方法能克服土地适宜性评价过程中人为因素的影响,提高评价的精度,而且能落实到山头、地块,具有较强的可操作性.

Structure regulation on land uses and landscape pattern changes based on matter element analysis in small watershed

The agricultural land suitability assessment based on natural characteristics of land blocks is traditionally the basis of agricultural and/or land use planning. However the assessment is static and can not incorporate potential land use changes. A dynamic approach emerging recently, i.e., matter element based analysis, has provided an effective way for land use planning. Taking the suitability grade of land use, assessment indicators and their characteristic values as matter elements, this paper established a matter element analysis model for land use suitability assessment, using of sutra field, controlled field, weight value and relating degree from field survey and expert system. This model was then applied in Yuejiagou small watershed of Langzhong Municipality in Sichuan Province, the results show that the proportion among agriculture, forestry and animal husbandry is tending to appropriateness; the economic and ecological indices of the lands has been increased from 1529.80 and 1460.94 to 1719.99 and 1758.21 respectively after regulation. The regulation also results in changes in the landscape patterns. The indices of diversity and evenness of landscape patterns have increased from 1.3028 and 0.6108 to 2.0920 and 0.8463 respectively, or by 60.58% and 38.56% respectively. However, the indices of dominance and contagion have decreased from 0. 6431 and 0. 7467 to 0. 2106 and 0.7125 respectively. It is indicated that the land use in the small watershed tends to be reasonable; the spatial distribution of patches trends to be uniformed; patch congregation is gradually dispersed. This example has proven that the matter element analysis approach can not only overcome the man-made influences and improve the precision, but also can implement the exact regulation to the specific patches in the structure regulation of land use in small watershed.