Study on background effects of urban wetland dynamics
HE Ge1, YU Yun1, WANG Ke2, JIANG Guo-xiang1, ZHOU Wen3
1. China Academy of Urban Planning and Design Shenzhen, Shenzhen 518040, China; 2. Shenzhen Marine and Fisheries Environment Monitoring Station, Shenzhen 518031, China; 3. Jiangsu Institute of Urban Planning and Design, Nanjing 210036, China
Based on the 1991,2001,and 2009 Landsat TM/ETM+images of Zhaoqing,the dynamic changes of the wetland in Zhaoqing from 1991 to 2009 were analyzed using the remote sensing technology,geographic information system technology, landscape pattern and neighborhood analysis.The wetland area increased greatly between 1991 and 2001,while reduced between 2001 and 2009.These changes of wetland area were strongly correlated with the changes of internal restructuring of agricultural sector.During the last two decades,the landscape pattern of wetland changed significantly in the study area.Both landscape fragmentation degree and spatial heterogeneity decreased,and the patches tended to congregate and connect together.The relative amplitudes of the change in wetland percentage coverage(WPC)varied greatly in different WPC zones.It increased in low WPC zones while decreased in high zones and kept stable in other WPC zones.The maximal absolute growth amplitude and the maximal absolute reduction growth amplitude of WPC occurred respectively in 10%zones and 95%zones,while they showed close and nonlinear correlations to WPC in other zones.The results showed that both change rate and change amplitude of the wetland area in the study region were closely related to local WPC,which indicated there existed the background effects in the dynamics of wetland landscape.The wetlands with different WPC should be protected differently.
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