Risk Analysis on the Wetland Shrinkage of the Yellow River Estuary Wetland Based on the Land Use Planning

With the rapid urban expansion in recent decades,the wetlands and farmlands of China's eastern coastal areas were increasingly destroyed.Many researchers have paid extensive attention to the phenomenon that wetland shrinkage and the landscape patterns change were the results of land-use and urban expansion.Kenli County of Dongying City in Shandong Province is located in the forefront of China's national development strategy named as efficient ecological economic zone development in Yellow River Delta.As about 60% of the area of International Wetland Nature Reserve is located in the Yellow River Delta,Kenli County has plentiful of wetland resources.In order to know the effects of long-term land use planning on wetland changes,to clarify the threats of construction land expansion to wetland,to discover the potential risk of wetland loss and to develop positive wetland protection strategy,in this study,based on the TM Imagery of Kenli County in 2005 and the land-use planning data from 2005 to 2020,we analyse the threats of construction land expansion to wetland during the planning period by spatial analysis method and evaluate the potential risk of shrinkage wetland.The results showed that: 1) The present wetlands are distributed widely and the types are abundant;the area is 107497.8 hm2,which is 46.32% of the total study area.2) According to the plan,the construction land will increase 542.5 hm2 per year,of which 29.54% will be converted from the wetland,that is to say wetland occupation and encroachment by construction land is very serious.3) During the planning period,the wetland area tends to decrease and about 5057.53 hm2 of wetlands will be converted into built-up lands.The rate and extent of wetlands reduction of each village and town are different in Kenli County.In which,greater changes take place in Dongji Village and Haojia Town while changes in Kenli community office,Shengtuo and Yongan towns are above the average level.As for the wetlands type,the reed lands are the fastest in decline with a reduction of 43.87% in 15 years and the area decrease of irrigation fields is the largest,a reduction of approximately 2211.75 hm2.4) Through the analysis,the high-risk wetland area is 17024.45 hm2,the low-risk is about 29846.89 hm2,while the non-risk is 60626.46 hm2;the overall loss of the wetland has high potential risk.