基于Markov-CLUES耦合模型的杭州湾湿地多情景模拟研究

Simulating Coastal Wetland Changes in Hangzhou Bay Using Markov-CLUES Coupling Model

杭州湾湿地是中国南北湿地的分界线,也是环杭州湾地区重要的区域生态安全屏障。由于全球气候变化和当地经济发展,杭州湾湿地资源锐减,湿地生态功能退化。因此,对杭州湾湿地未来发展趋势的模拟预测,可为资源合理开发、政府政策规划等提供科学依据。以杭州湾湿地为研究对象,利用2006年、2011年、2016年3期遥感影像提取湿地空间分布信息,对杭州湾湿地现状进行分析;构建Markov-CLUES耦合模型,运用耦合模型模拟了多情景下的杭州湾湿地未来演变趋势。研究结果表明,(1)杭州湾滨海湿地主要历史演变特征为:海岸带区域不断向浅海水域方向延伸;淤泥质海滩受到来自内陆方向的围垦;处于极不稳定状态;稻田类型极易转变为建筑等非湿地类型;非湿地面积呈不断上升趋势。(2)以2011年的湿地空间分布格局图为模拟年份初始图,运用Markov-CLUES耦合模型模拟了2016年的湿地空间分布格局模拟图,并以2016年的实际湿地分布现状图进行验证,结果表明,Markov-CLUES耦合模型的总体精度为86%,Kappa系数为0.81,说明Markov-CLUES耦合模型可用于模拟杭州湾湿地演变趋势。(3)通过对杭州湾湿地未来多情景模拟结果分析发现:淤泥质海滩在经济增长情境下围垦速率加快,与自然情景相比,面积下降速率增加3.46%;在滩涂资源保护情境下,面积几乎不变,得到了有效保护。稻田是除浅海水域外的主要湿地类型,在经济建设情景下,稻田向非湿地的转变速率增加5.31%,稻田面积下降;在粮食安全情景下,面积增加了3 470.76 hm^2,在数量上和空间分布上都得到了良好的保护。非湿地在稻田保护的情景下,由于来源的减少,面积增长受到抑制;在其他3个情景下均呈上升趋势;在经济建设的情景下,非湿地增加速度最快。

Coastal wetlands are sources of abundant biodiversity and valuable ecological services,and contribute to the long-term prosperity in Hangzhou Bay.However,the rapid growth of both the human population and the economy has dramatically increased the environmental pressure on coastal ecosystems and caused serious losses and degradation of coastal habitats.Therefore,simulating the changes of coastal wetlands is of great significance for protecting the wetland resources in Hangzhou Bay.In this paper,multitemporal Landsat images between 2006 and 2016 are used to monitor the changes in the coastal wetlands of Hangzhou Bay using a human-computer interaction classification method,and a modified Markov-CLUES coupling model is used to simulate land use maps for 2026 in different scenarios.The results show that,(1)from 2006 to 2016,the coastline slowly expanded toward the sea,rivers and croplands exhibited statistically significant shrinking trends and the area of non-wetlands rapidly increased.(2)The simulation results were validated by the actual spatial distribution of wetlands in 2016.The result shows that the overall accuracy and the kappa coefficient were 86%and 0.81,respectively.The precision is high,and the simulation results are credible,which indicates that the CLUE-S model could be used to simulate the future spatial pattern of the coastal wetlands in Hangzhou Bay.And(3)the maps simulated for 2026 are significantly different in the four scenarios.In the general change scenario,the change trends of the various wetland types were similar to the evolution trends from 2006 to 2016.In the economic development scenario when there was rapid economic development and urbanization,the fish pond and non-wetland areas increased while the cropland areas further decreased.In the agriculture protection scenario,the cropland areas were protected,and little of the area changed to other wetland types.The beach areas increased because the rate of beach transformation to cropland was inhibited.In the mudflat resources protection scenario,the beach area was protected,and little of the area changed to other wetland types when the change rate declined by half.The rates of increases in fish pond and non-wetland areas declined,and the cropland areas further decreased.The results of this work provide baseline information for wetland changes in Hangzhou Bay,which could be used in the future for restoration purposes in the Hangzhou Bay ecosystem.This study contributes to the understanding of the development of Hangzhou Bay,which may lead to improved coastal wetland planning and protection strategies.