[Changes of land use and landscape pattern in Taihu Lake Basin]

Based on three sets of land use data (1985, 1995 and 2000), and by means of the techniques of remote sensing, geographical information system (GIS), and landscape ecology, this paper studied the changes of land use and landscape pattern from 1985 to 2000 in Taihu Lake Basin located at Yangtse River Delta. The results showed that in past 15 years, the farmland in this Basin decreased, while the built-up areas, woodland, grassland and water body increased. The decrease of the farmland occupied 89.64% of total decrement, while the increase of the built-up areas accounted for 79.21% of total increment. Under the disturbance of human activities, the landscape structure and landscape heterogeneity in Taihu Lake Basin changed greatly. The patches density decreased from 0.996 to 0.930, diversity indices decreased from 1.127 to 1.113, evenness indices decreased from 62.891% to 62.109%; while the edge density increased from 4.408 to 4.459, dominance indices increased from 0.665 to 0.679, and shape indices increased from 1.540 to 2.796. The landscape heterogeneity varied with different kinds of landscape, indicating the complexity of landscape ecosystem. In all kinds of landscapes, farmland and grassland had the highest values of diversity indices. The diversity indices of water bodies decreased firstly and then increased, while those of built-up areas were in adverse. The evenness index was decreased in the order of woodland > farmland > grassland > water body > built-up areas. Population, economy and policies were the driving forces of the dynamic changes of landscape pattern in Lake Taihu Basin during past 15 years, and land use change in the Basin caused distinct landscape effects, such as landscape fragmenting, edge effects intensification, and environmental quality declining. The mode of land use should be adjusted in landscape scale to rehabilitate and reconstruct the landscape ecosystems in Taihu Lake Basin.