1980-2017年孟加拉国城市扩张的景观格局变化特征及其模式

目的] 对1980—2017年孟加拉国城市扩张的景观格局变化特征及其模式进行研究,为该国及发展中国家的城市土地利用与管理提供差异化发展建议。方法] 以“一带一路”沿线孟加拉国的4个主要城市Dhaka,Chittagong,Khulna和Sylhet为研究对象,分析1980,1990,2000,2010和2017年5期4个城市扩张过程中的景观格局变化特征,识别城市扩张模式。结果] 1980—2017年,孟加拉国4个主要城市的扩张规模表现为：Dhaka > Chittagong > Khulna > Sylhet,扩张速度表现为：Sylhet > Dhaka > Chittagong > Khulna;4个城市扩张的景观格局变化趋势均表现为面积持续增加,优势度加强,破碎化程度波动上升。空间格局向复杂化和不规则化方向发展,空间形态逐渐多样化。1980—1990年,Dhaka,Chittagong和Sylhet这3个城市扩张的主要模式为外部扩张式,Khulna主要为邻接扩张式,1990—2017年,邻接扩张式成为4个城市扩张的主要模式,城市连片度逐渐增高。结论] 1980年以来,孟加拉国城市持续扩张,景观格局发生显著变化,扩张模式总体呈由外部扩张式向邻接扩张式转变的趋势。

Characteristics and Models of Landscape Pattern Changes in Urban Expansion in Bangladesh During 1980-2017

Objective] The characteristics and landscape pattern change of urban expansion in Bangladesh since 1980 were studied in order to provide differentiated development suggestions for urban land use and management in Bangladesh and other developing countries.Methods] Taking Dhaka, Chittagong, Khulna and Sylhet, four major cities of Bangladeshi along the "One Belt and One Road" as the research objects, the characteristics of landscape pattern change in the process of urban expansion in 1980,1990,2000,2010 and 2017 were analyzed, and the pattern of urban expansion was identified.Results] From 1980 to 2017, the expansion scale of the four major cities in Bangladesh was showed as:Dhaka > Chittagong > Khulna > Sylhet, and the expansion speed was showed as:Sylhet > Dhaka > Chittagong > Khulna. The trend of landscape pattern change of the four cities showed that the area continued to increase, the dominance strengthened, the degree of fragmentation fluctuated, the spatial pattern developed toward complexity and irregularity, and the space formation gradually diversified. From 1980 to 1990, external expansion was the main pattern of urban expansion in Dhaka, Chittagong and Sylhet, while adjacent expansion was the main pattern of urban expansion in Khulna. From 1990 to 2017, adjacent expansion became the main pattern of urban expansion in all the four cities, and the degree of urban connectivity increased gradually.Conclusion] During 1980-2017, the city of Bangladesh was expanding continuously, and the landscape pattern changed significantly. The expansion pattern changed from external expansion to adjacent expansion.