Land use/land cover evolution in recent wetlands in the modern Yellow River Delta

Based on digital land cover maps of 1986,1996,2001,land use/land cover evolution was studied on macro-scale over ARC/I NFO platform.Of all the land cover types,cultivated land area was the largest in the last 15 years.It implies that agricultural production is at the for efront of all land uses over the last 15-year period.Cultivated land area decrease outweighs increase from 1986 to 1996,while a near equal cultivated land area decrease and increase is observed from 1996 to 2001.This means that cultivated land area equilibrium prevails for the recent 5 years.The area with favorable halophilous vegetation succession is nearly equal to that with inverse succession from 1986 to 1996.Land formation outweighs land degradation in this period.From 1996～2001,favorable land evolvement is stronger than the inverse,but land formation rate is slower while land degradation area is more than that of land formation.During the last 15 years,construction land area has increased greatly.The increasing rate of construction land area for 1996～2001 outweighs that for 1986～1996.Construction land area ranks third in 1996,second in 2001 rising from the sixth place in 1986.