Landscape connectivity changes analysis for monitoring desertification of Minqin county, China.

Landscape connectivity, as an important indicator of regional landscape functional pattern measured by cost-distances model, could both reveal evidence of, and act as an indicator, for desertification. Using Minqin county as a case study, this study was further to test cost-distance connectivity for indicating desertification, and to analyze temporal changes of connectivity in the county from 1977 to 1997. The results further indicate the connectivity interpreted as lower cost-distance and higher risk of desertification. The temporal change analysis of connectivity provides more detail supplement of desertification processes. Landscape connectivity changes in the county had three distinctive phases, the strongest decline of log cost-distance with overwhelming decrease area and decrease amount in the period 1977--1984, and its slight decline with the relative balance between the high decrease amount and high increase amount in the period 1984--1992, then its the slight decline with the relative balance between the low decrease amount and low increase amount in the period 1992--1997. The frequent temporal and spatial transition in source class, grassland, alkali-saline land and irrigated cultivated land caused negative effects on the oasis environment.