Using the methods of remote sensing

geographical information system(GIS)

landscape ecology and analytic hierarchy process(AHP)

this paper analyzed the change of landuse pattern and its ecological and environmental effects in arid area of central Ningxia Hui Autonomous Region from 1978 to 2007 based on the MSS image in 1978 and Landsat TM/ETM images in 1987

1996

2007.The results showed that areas of farmland and construction areas increased in the past 30 years.The newly-increased farmlands mainly came from unused land and grassland

while the newly-increased lands for construction mainly came from farmland and unused lands.At the same time

the forest land and grassland decreased from 1978 to 1987

and increased from since 1987.The sources of increased area were primary farmland and unused land.These changes caused great changes in landscape such as landscape fragmenting and heterogeneity and declining of environmental quality from 1978 to 1987.The index of environmental effect was only 0.118 in 1987.After that

with implementation of the regulating and controlling measures

prohibiting graze policy and hydraulic engineering

more farmland and unused land have been converted to trees and grasses

the vegetation cover increased

and the landuse structure was adjusted.This led to the gradual improvement of environmental quality since the middle and late 1990s by environmetal strategies.