Study On The LUCC And Its Eco-environment Effects Of Longnan Region

LUCC is important because changes in land use and land cover are inputs and consequences of global environmental change, which is related with global change and global warming, and plays a key role in sustainable development research.Longnan region lies in the south of Gansu Province, bordering Shaanxi in the east and Sichuan in the south, covering one urban district and eight counties.In geographical location, it situates on the transition zone between the second and the third terrace in China; and connects the North China craton, Qilian and Qaidam, and the Sonpan-Ganzi block on the north, on the west, and on the south, respectively; and is the Yangtze River Basin, and the transition area of Yangtze River and Yellow River Basin; and places in warm temperate/sub-tropical transition region. In which mountain areas account for above 90 percent, and Hilly Basin less than 10 percent, and its elevation range from 800 to 4200m a.s.l. In a word, Longnan region is a complex terrain and environment zone.In this paper, Longnan region is the study area, mainly because it is the representative of the transition zone of climate, valley, and terrain unit. The objectives of this paper are that to reveal the LUCC and its driving force in Longnan region, and the impact of LUCC on the ecological environment, and to provide the basis for the study of LUCC and its eco-environment effects in the transitional zones.The study used time-series Landsat TM/ETM+images which are acquired in 1989,2000, and 2007 to produce the data of land-cover/use types by using visual on-screen interpretation and verification of fieldwork supervision, then the author used ArcGIS software to extract spatial information by overlaying maps. According to the process of LUCC in the study area, combining with DEM and related statistical data, the author analyzed the driving force of LUCC. Besides, the author used AHP and landscape ecology to bridge the connection between LUCC and ecological environment, and analyzed the process of ecological environment change.The results show that:1) The cropland in Longnan region was the most active type, the change of the cropland in the study area directly leaded into changes of others land-use and land-cover types; 2) During 1989-2000, the cropland increased (about 25314.63hm2), while woodland and grassland decreased (about 9165.48hm2 and 16437.23hm2, respectively); During 2000-2007, the cropland decreased (about 13128.37hm2), while woodland and grassland increased (about 7007.81hm2 and 5933.65hm2, respectively); During 1989-2007, water area still reduced (about 162.35hm2), the built-up land increased (about 637.36hm2), and unused land had not changed.3) During 1989-2000 the cropland increased, while woodland and grassland decreased, the driving factors were human activities, such as population growth, economic growth and the improvement of the average living standards; During 2000-2007 the cropland increased, while woodland and grassland increased, the national land policy played a key role in LUCC; During 2000-2007, the main reason that water area reduced and the built-up land increased were human activities; the change of climate only played background role in the LUCC, and not directly affected LUCC; Elevation and slope factors played a prominent role in LUCC;4) Longnan region's environment underwent the trend of degradation firstly and improved later during the 18-year study period from the viewpoint of ecology and environment.