Hu Yuanman

Landscape Changes from 1974 to 1995 in the Upper Minjiang River Basin, China

Landscape changes were traced over the 20 years from 1974 to 1995 in the upper Minjiang River basin, one of the most important forest regions in China, based on satellite image interpretation to provide basic data for local decision-making as well as sustainable landscape use and management. Results revealed that landscape from 1974 to 1995 changed at the regional scale as the area of forestland decreased, while cropland, shrubland, economic forest, grassland, and built-up land increased. Landscape changes mainly occurred in forestland, shrubland, grassland, economic forest, and built-up land. Moreover, the changes among forestland, shrubland, and grassland were the largest, influencing the whole characteristics of the changes in the basin. Analysis of the changes between 1974 and 1995 in the study area indicated that landscape heterogeneity and fragmentation increased, whereas landscape connectivity decreased. There were multiple reasons for landscape changes. A principal component analysis (PCA) was used to quantitatively study driving forces of landscape changes. The PCA results showed that economic and population factors were the principal driving forces of landscape changes from 1974 to 1995 in the upper Minjiang River basin, and that PCA was a suitable method for investigating driving forces of landscape changes.

Land Use Change Modeling and Predicting of Xinzhuang Town Based on CLUE-S Model

Land use change models are the important tools in researching regional landscape dynamics and its driving mechanisms. Researchers have aimed at exploring land use/cover change (LUCC) and predicting future land use pattern in order to improve our understanding of the causes and effects. With the application of CLUE-S (Conversion of Land Use and Its Effects at Small Regional Extent) model and under the support of high-resolution remotely sensed data(1980, 1991, 2001 and 2009 high-resolution remote sensing images: spatial resolution is not more than 1m), this study analyzed landscape change from 1980 to 2009, simulated the land use of 2009 from 1980, 1991 and 2001, respectively, and predicted the land use changes of Xinzhuang town in the south of Jianhsu province for current trend scenario from 2010 to 2027. Results showed that paddy field decreased dramatically from 1980 to 2009, while construction land and fish pond increased largely. With the modeling time’s decreasing, the modeling accuracy was increasing (67%: from 1980, 75%: from 1991, 80%: from 2001), and we identified 18 years were the appropriate temporal scale based on the kappa coefficient wasn’t less than 75%. The predicted results of CLUE-S shows that the paddy field would keep on decreasing in future, most of which were invaded and occupied by construction land and fish pond, the construction land and fish pond would increase dramatically in 2027, the changes of other types weren’t obvious.

Landscape pattern change in the upper valley of Min River

The upper valley of Min River (102°59′–104°14′E, 31°26′–33°16′N), which is consisted of the counties Wenchuan, Maoxian, Lixian, Heishui, and Songpan, refers to the part up to Dujiangyan City, and locates on the transition zone from the Tibetan Plateau to the Sichuan Basin. It is one of the most important forest areas in China, especially in Sichuan Province. Over past two decades, the landscape changed remarkably in the region. The 3S techniques (Remote Sensing (RS), Geographic Information System (GIS) and Global Position System (GPS)) were used to classify the images and analyze the landscape change. The remotely sensed data of Landsat TM 1986 and Landsat ETM+2000 were used to analyze the landscape change of the region. The landscape were classified into 10 types of cropland, forest, shrub land, economic forest, grassland, build up land, river, lake, swamp, and unused land. The results showed that: 1) the woodland and grassland were dominating landscape types in the upper valley of Min River, which is more than 91% of the study area; 2) the alteration of the landscape was mainly happened among forest, shrub land, grassland, economic forest, cropland, and build up land, where forest decreased from 51.17% to 47.56%; 3) the landscape fragmentation in the upper valley of Min River was aggravated from 1986 to 2000.