Abstract: Using Landsat TM imageries (taken in 1987, 1993 and 1999) and GIS method, the spatial and temporal changes in land use of a typical urban lake watershed, Donghu Lake of Wuhan, were analyzed between 1987 and 1999. The satellite images were classified into seven land use/cover categories: water body, broadleaf forest, coniferous forest, shrubgrass land, bare land, cropland and urban land. Overall classification accuracy on satellite imagery for three period was all above 85%. Our results showed that urban land expansion (from 9.1% to 29.6% of study area) and farmland increase (from 7.0% to 13.9%), at the cost of reduction of water body (from 30.4% to 23.8%) and forestland (from 33.6% to 24.3%), are main characteristics of land use change in the watershed. At the same time, landscape diversity of the watershed decreased, as dominance increased during the study period. While degree of fragmentation changed differently between dominant landscape components and others. Because forestland becomes major source of the increment of the urban land and farmland, the ecological impact of urbanization on this urban lake watershed is remarkable. Several physical and economical factors contribute to land use pattern and its change in the study area.

Key words: urban lake, land use change, Donghu Lake, urban expansion