关键词: 海岸沙地, 土地利用变化, 驱动力, 东山岛

Abstract:

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.

Key words: coastal sandy land, land use change, driving force, the Dongshan Island