陕北黄土高原林草景观破碎化时空演变特征分析

以退耕还林还草生态工程重点区域陕北地区为研究区，采用土地利用转移矩阵、FLUS模型、Fragmentation模型分析1980-2015年林草景观破碎化的空间结构特征以及生态演化过程。结果表明:1）研究区域以林地、草地和耕地的景观类型为主，退耕还林还草工程实施后，林草总面积大幅增加，植被覆盖率提高，明显改善了陕北黄土高原的生态环境；2）Kappa系数与FOM系数数值均表明FLUS模型精度较高，可适用于未来土地利用情景模拟，利用FLUS模型预测2030年陕北黄土高原地区各土地利用类型的分布情况，发现研究区2030年耕地将明显减少，林草面积有大幅增加，建设用地持续扩张；3）空间格局上，景观破碎化呈现以“大核心类型为主导，边界类型集中分布”的特点，景观破碎化程度减弱。研究结果为陕北黄土高原地区林草景观结构优化和生态系统服务价值提升提供一定的参考。

Spatiotemporal pattern evolution of forest and grass landscape fragmentation in the Loess Plateau of northern Shaanxi

Fragmentation of forest landscape is one of the major environmental issues that the international community is generally concerned about.In the past 20 years,the overall landscape pattern of the Loess Plateau has changed due to the implementation of the Grain for Green Project (GGP).This study selected northern Shaanxi in the Loess Plateau as the research area.By using land use transfer matrix,FLUS model,and Fragmentation model,the paper analyzed the basic characteristics of the dynamic evolution of the landscape and the degree of forest and grass fragmentation.The results showed that:1) the landscape types of forest land,grassland and cultivated land were the main types in the study area.After implementation of the Grain for Green Project,the total area of forests and grasses has increased significantly,and the vegetation coverage has become widened,which has significantly improved the ecological environment of the Loess Plateau in northern Shaanxi; 2) The Kappa index and FOM index values both indicate the accuracy of the FLUS model High,which can be applied to the simulation of future land use scenarios.The FLUS model predicts the distribution of various land use types in the Loess Plateau of northern Shaanxi in 2030,and finds that the cultivated land in the study area will continue to decrease significantly in 2030,the area of forest and grass will also increase tremendously,and built-up land will continue to expand; 3) In terms of the spatial pattern,the fragmentation of the landscape is characterized by "large core type as the leading factor and concentrated distribution of border type",and the degree of landscape fragmentation is weakened.This study reveals the spatial structure characteristics and ecological evolution process of forest and grass landscape fragmentation in the Loess Plateau of northern Shaanxi from 1980 to 2015,and provides technical support for the planning of landscape structure in ecologically fragile areas and the improvement of forest and grass landscape structure and functions.At the same time,it is of great significance to promote the sustainable development of forestry.