福建东山岛海岸沙地利用变化及其驱动力分析

受海平面上升和人类活动的双重影响，海岸沙地生态环境日益脆弱；揭示海岛海岸沙地动态变化特征及其驱动机制，对科学制定海岛发展规划，保护海岛自然环境和确保经济社会健康持续发展具有重要的实践意义。东山岛是我国华南海岸典型的海岛沙地分布区，文章基于5次海岸沙地监测成果数据，利用土地转移矩阵、土地利用程度综合指数和土地利用动态度模型等方法，对东山岛1994―2014年间海岸沙地动态变化及其驱动力进行分析。结果表明：1）东山岛海岸沙地总体呈快速减少特点，海岸沙地利用的速度和程度增幅显著。海岸沙地利用结构发生了明显变化，各沙地利用类型转换频繁，沙地利用综合动态度不断升高，沙地整体稳定性显著降低。2）各类型沙地面积总体大幅减少，主要集中在2009―2014年。流动沙地和半固定沙地基本消失，沙化耕地是面积减少最多的类型。3）沙地利用类型转换主要表现为林地、耕地之间的相互转换和林地、耕地向建设用地的转变。4）影响东山岛海岸沙地利用变化的驱动力主要有自然地理因素、政策法规因素和社会经济因素。1994-2014年东山岛旅游产业的快速发展、工业化进程的加速和城镇化大大推动了岛内沙地利用格局的演变，是研究期内海岸沙地利用动态变化的最主要驱动因素。

Coastal Sandy Land Use Change and Its Driving Forces in the Dongshan Island of Fujian Province

The ecological environment of coastal sand is more fragile due to the dual influences of sea level rise and human activities. To reveal the characteristics of dynamic changes and its driving mechanism of the coastal sand of islands, is of great scientific and practical significance for formulating island development plans scientifically, protecting the island's natural environment as well as ensuring the healthy and sustainable development of economic society. By taking the Dongshan Island as the study area, which is a typical distribution area of island sand of South China coastal zone, the dynamic changes and its driving factors of the island coastal sand from 1994 to 2014 were analyzed based on five times monitoring data by the methods of land transfer matrix, land-use comprehensive index and land use dynamical change models and so on. The results indicated that: 1) The area of coastal sand in the Dongshan Island reduced at an ever-increasingly faster speed in the past 20 years. The area reduction decelerated slowly in 1994-1999 and in 2004-2009. The reduction speed of sandy land area in 1999-2004 was basically the same as that in the whole monitoring period and was the fastest in 2009-2014. The development degree and intensive level of coastal sand resources were far higher than the national average, and the speed and degree of sandy land utilization increased obviously. The structure and using types of coastal sand changed apparently. Meanwhile, the comprehensive index and dynamic degree of sandy land use increased constantly and the overall stability of sandy land significantly decreased. 2) The conversion types of coastal sand in the past 20 years were mainly those of outward. The area of mobile sandy land continued to decrease, mainly shifting to fixed and non sandy land. The area of semi-fixed sandy land decreased sharply in 1994-1999, and mainly changed into fixed sandy land. After that, it fluctuated slightly. The area of fixed sandy land showed a trend of increasing first and then decreasing. The main types of roll-out of fixed sandy land were non sandy land and sandy farmland, and the main type of roll-in was semi-fixed sand. 3) A significant adjustment was made in the utilization structure of coastal sand in the past 20 years. The unused land reduced rapidly, the area of woodland and sandy land was relatively stable, and construction land began to appear in 1994-1999. The area of unused land and cultivated land reduced greatly, the area of forest land remained relatively stable and the area of construction land increased substantially in 1999-2004. The area of forest land decreased significantly, the area of cultivated land increased and the area of construction land decreased rapidly in 2004-2009. Forest land and cultivated land reduced greatly, and the area of construction land increased rapidly in 2009-2014. 4) The main driving forces influencing the dynamic change of the Dongshan island coastal sand included natural geographical factors, policy and regulation factors and social and economic factors. The long-term trend of sea level rise and short-term sudden typhoon storm surge caused by climate change and coastline erosion were the important natural reasons for the decrease of coastal sand. The implementation of land compensated use system and urban development planning led to the conversion of woodland and cultivated land into construction land. The policy of returning farmland to forests and the policy of developing agriculture were the important policy drivers for the conversion of woodland and cultivated land. The rapid development of the tourism industry, the acceleration of industrialization process and urbanization, greatly promoted the evolution of the sandy land use pattern in the past 20 years, which were also the main driving factors of the dynamic change of the sandy land use.