Use of intensity analysis to link patterns with processes of land change from 1986 to 2007 in a coastal watershed of southeast China

This paper characterizes transitions among three land categories during three consecutive time intervals in a subtropical coastal watershed of southeast China that has enormous influence on the region's economic and ecological health. Landsat Thematic Mapper satellite imagery of 1986, 1996, 2002, and 2007 were used to create maps of each time point for three categories: Agriculture, Natural, and Built. Intensity analysis was applied to quantify the annual intensity of the changes at three levels: time interval, category, and transition. The results show that overall land transformation is accelerating across the three time intervals. Agriculture shows net gain in the first time interval, then net losses in the subsequent two time intervals. The swap change is larger than the net change for both Agriculture and Natural during all three time intervals. Nearly all of the changes are exchanges between Agriculture and Natural areas. Agriculture and Built are active categories, whereas Natural is a dormant category during all three time intervals. The changes are stationary for all three time intervals in terms of the intensities of categories and transitions for Natural to Agriculture, Agriculture to Natural, and Agriculture to Built. The transition from Agriculture to Built is intensively systematic. The land-cover change is associated with the overall economic growth and recent agricultural decline of the area. The intensity analysis in the Jiulong River watershed reveals information that links patterns to processes of land-use and land-cover changes that are common in many other urbanizing places in China. (C) 2012 Elsevier Ltd. All rights reserved.