Abstract: Since the Ili River delta of Kazakhstan has experienced less human direct disturbances during 1975-2007, it is suitably regarded as a case to analyze landscape pattern changes and its driving mechanism for understanding the importance of spatial ecological dynamics and maintaining sustainable development in unique wetland ecosystems of arid Central Asia. In the study,  two types of data were used: (1) hydrological data, fluvial runoff volume from Ili River (1953-2007) and water levels of Lake Balkhash in the last 54 years (1953-2006), and (2) land cover maps extracted from Landsat images in 1975, 1990, 2000, and 2007. Arid area in Central Asia, the classification system of landscape was established based on the landcover maps of River Ili delta. Using the methods of landscape structure gradient of analysis, landscape disturbance index and Kappa index, the change of landscape structure from 1975 to 2007 was analyzed and the driving mechanism of landscape structure was discussed.  River Ili delta displays special characteristics of landscape in the horizontal structure, vertical structure and internal structure along the topographic gradient and hydrological gradient in the watershed, particularly the landscape types related to water, such as lake, swamp, and flood land. Under the influence of human activities and climatic change, the spatial change in the landscape structure show a certain periodicity and instability in the late 32 years. The spatial change in vertical structure of landscape is generally influenced by corridor width and length as well as the change in landscape types; the spatial change in horizontal structure is characterized by landscape fragmentation, which results in reduction in landscape connectivity. Effect of disturbance on landscape structure shows the distinct differences and temporalspatial variability with different landscape types, in which lake and marsh are most easy to be disturbed. The change in spatial distribution and area of high, medium and low disturbance intensity presents periodicity and instability. Natural factors generally influence the complexity of inner structure of landscape, and anthropogenic factors affect the connectivity in the vertical and horizontal structure of landscape and diversity of inner landscape structure. The dominant driving forces of landscape structure in River Ili delta include a huge reservoir construction in the upstream of river and natural conditions. The interception of reservoir to River Ili has a profound impact on landscape structure and directly changes hydrological condition and landscape structure in the delta. Due to inherent characteristics of the lakes and river, the water level changes in Lake Balkhash and the wetland landscape patterns in Ili River delta were inconsistent, the former generally lagged behind the latter. This also influences the wetland landscape structure, which will be a research topic in the future.

Key words: influence mechanism, River Ili delta, landscape structure, wetland, remotely sensed image, landscape index