Geo-informatic spectrum analysis of land use change in the Manas River Basin, China during 1975-2015.

Abstract

Geo-informatic spectrum analysis method was used to understand the complex geogra-phical phenomena concisely in graphic language. It is important for the integration research on spatial pattern and temporal process of land use change over multiple temporal and space scales. Based on remote sensing images in 1975, 1990, 1995, 2000, 2005, 2010 and 2015, we built the geo-spectrum of land use/cover change (LUCC) and quantitatively analyzed both the process and rend of LUCC in Manas River Basin. Results showed that the range of land use change in this basin was gradually decreasing, and land use structure tended to be simplistic, then tended to stable in later stage during 1975-1990. At the same period, the area of grassland increased greatly, which was mainly derived from unused land. The area of cultivated land expanded from 1990 to 2015, which mainly converted from unused land, forestland, and grassland. The geo-spectrum of land use change model showed that prophase change type, anaphase change type and continuous change type accounted for 1.3% of the total basin area. The overall characteristics of geo-spectrum unit were dominated by unused land converted to cultivated land, forestland and grassland. The land use change process was relatively stable. The Manas River Basin was covered 61.2% by region with comparatively stable spatial pattern. The most frequent way of land use change was increasingly expanding of cultivated land, which was displayed as: Liumaowan Bay Town of Shawan County and Liuhudi Town of Manas County were the center, then expanded to the two sides and spread to the Gurbantunggut Desert. The construct geo-spectrum of LUCC enriched the LUCC spatial-temporal analysis method system and provided an effective approach for the future research of LUCC under multiple temporal and spatial scales.