广西滨海区域景观格局分析及土地利用变化预测

Landscape pattern analysis and prediction of land-use change in the Guangxi coastal area

研究滨海湿地景观动态及其发展趋势对于维持沿海地区可持续发展具有重要意义。利用移动窗口法分析广西滨海湿地景观格局时空变化,同时提取珍珠湾、茅尾海和丹兜海典型区进一步分析景观变化趋势,最后采用土地利用变化模型(Land Change Modeler,LCM)预测区域未来的景观演化趋势。结果表明,2000—2014年间,草地、乔木园地和常绿阔叶灌木林面积减少,而工业用地面积明显增加。研究区总体的景观异质性变化不大,破碎化趋势不明显。比较景观格局指数发现,边缘密度和多样性指数的空间分布特征相似,多样性指数较大的区域,边缘密度也大,并且多集中于珍珠湾、茅尾海和研究区的中东部。3个典型区的格局变化趋势相似,景观多样性指数降低而均匀度增加,其中,湿地斑块数目减少且所占面积比也减少。LCM模型结果表明,至2020年,草本湿地与森林灌丛湿地面积进一步降低,而工业用地和居民区则持续增长;其中,3个典型区土地利用变化均受到了工业发展的影响,以珍珠湾土地利用动态度最高,茅尾海其次,而丹兜海最小。当前,区域景观的变化明显降低了湿地植被的质量,加强湿地植被保护,限制工业区域的无序发展是维持区域生境完整和安全的有效途径。

The determination of landscape patterns of coastal wetlands has great significance in promoting the sustainable development of coastal regions. Spatiotemporal changes in landscape patterns in the coastal wetlands were analyzed using the moving window method. Three typical regions were extracted for variation tendency analysis of landscape patterns, and future trends in landscape evolution were predicted using the Land Change Modeler （LCM）. The results showed that the areas of grassland, arbor plantation, and evergreen broad leaved shrub forest decreased, whereas that of industrial land increased. Changes in landscape heterogeneity and fragmentation were not obvious in the study region from 2000 to 2014. The comparison of landscape indices showed that the spatial distribution patterns of edge density were similar to that of the diversity index, indicating that regions with higher diversity also had higher edge density. Areas with higher diversity and edge density were located in Zhenzhu Bay, Maowei Sea, and the middle eastern portion of the study area. In addition, three typical regions exhibited similar patterns in which the diversity index decreased while the evenness index increased from 2000 to 2014. The number of patches and the area of coastal wetlands declined during this period. Results from the LCM revealed that areas of herbaceous wetland and mixed shrub and forested wetland have a declining tendency until 2020 because of their conversion to industrial land and residential land. Thus, the expansion of industrial land will be the main factor affecting land-use changes for these three typical regions. Zhenzhu Bay will experience the greatest level of land-use change, followed by Maowei Sea and Dandou Sea. In conclusion, changes in the regional landscape patterns resulted in decreased wetland quality ; therefore, enhancing the protection of wetlands and limiting development of industrial land will be an effective way to maintain the integrity and security of the regional environment.