典型喀斯特石漠化地区植被动态监测与土地利用变化的影响分析

基于2001至2014年MOD13Q1数据集、数字地面高程数据以及中梁山地区多期土地覆盖数据，进行植被覆盖度（FVC）估算及其变化趋势模拟、多期土地利用转移矩阵分析，探讨中梁山地区植被覆盖度动态变化特征、土地利用的时空变化特征以及土地利用和地形同植被覆盖度间的响应机制。研究结果表明：中梁山76.69%的区域为植被改善区，退化区面积占总面积的10.12%，存在明显的改善趋势，生态情况得到良好恢复；人类活动对中梁山区域影响方式主要表现为耕地向林地和建设用地转化的特点；植被生长趋势的空间异质性与坡度有关，坡陡区植被改善面积约为退化面积的14倍，缓坡区仅为7倍；植被退化现象受人览活动的影响较大，而人类晃动对植被改善影响较小，植被改善主要与植物的自然生长演替有关。

Dynamic monitoring of vegetation and the impact of land use/cover change in the topical karst rocky desertification areas

The study area is located in the Zhongliang mountains of karst areas in southwestern China. Its mean annual temperature is 18 ℃, average annual rainfall is about 1,100 mm and height is about 500 m to 700 m. The terrain in the north side is higher than the south with steep slopes prone to soil erosion. Taking Zhongliang town for example, its total area is 4.75 km2, of which barren mountains account for 1 km2. As rocky desertification results in soil productivity sharply decline, regional economic develops slowly with hostile survival condition. Based on the dataset of MOD13Q1 from 2001 to 2014, digital terrain elevation data and the multi-period land use data, the Fractional Vegetation Cover (FVC) degree was estimated with the dimidiate pixel model in the topical karst rocky desertification areas. The vegetation cover variation tendency was simulated by the linear regression. We carried out the transformation matrix of land use, made comparison of land use changes before and after management, and analyzed the statistical characteristics of land use changes in vegetation change regions. Then the spatial-temporal variation characteristics of FVC and land use and the response mechanism between FVC and land use, terrain were discussed in detail.The results indicate that the percentage of areas with increasing vegetation cover is 76.69, while the area with decreasing vegetation cover accounts for 10.12% of the total area. There is obvious improvement tendency and the ecological regime also recovers greatly. The transformation matrix between 2005 and 2014 shows that human beings activity is the main driving factor and the cultivated land to woodland and construction land are the main transformation types in Zhongliang mountains. The phenomenon of vegetation degeneration has been affected extremely by human activity. The vegetation improvement, barely influenced by human beings activity, is mainly related to the natural restoration.