关键词: 景观指数； , 油气管道； , 荒漠草地； , 小尺度； , 缓冲区

Abstract: As a key part of landscape ecology，analysis of landscape pattern is frequently used to reflect landscape ecological functions and processes，and the influence of the human disturbance on environment as well. In this paper，the key point is focused on the pipeline construction in the arid desert area. Through statistics and buffer analysis，we investigate the selected landscape patterns changes in different period of the construction. These landscape metrics are used to analyze the landscape pattern and its dynamic change in the different construction stages，so as to reveal the influence of the oil and gas pipeline construction. Based on the land use types interpreted by the years of 2002，2006 and 2010 QuickBird image of oasis-desert ecotone in Xinjiang，the buffers are divided with the width in 50-100 meters，and selected landscape metrics are calculated by using ArcGIS and fragstats. The result shows that grassland area gradually decreased while shrub land and construction land gradually increased. Total 1.96 hm² increased area of shrub land was transformed from grassland. The area of construction land was changed greatly，since there was only 0.03 hm² area remaining the same from 2006 to 2010. At the class level，the grassland that was dominant in the landscape pattern in 2002 had more patch numbers （NP） than the other years. Its pattern got complex and its area was decreased step by step. On the other hand，both shrub land and construction land had [LPI] and [LSI] risen，indicating that although they became complex，their got better function and took more important roles. Above the pipeline，the landscape metrics of each class was varied greatly. Percentage of Landscape （PLAND） of grassland decreased by 90%，and Patch Density （PD） got higher rapidly. On the converse，shrub land was the dominate landscape element in the construction area. [PLAND] of construction land were 13.35%，7.13%，4.36%，3.81% and 1.81% respectively from pipeline to 200-300 m buffer in 2010，as the same with its Aggregation Index （AI）. That meant the influence of the pipeline construction was gradually weakened in the other buffers. At the landscape level，a large increase of fragmentation，heterogeneity and reduction of connectedness was found through the selected landscape metrics. PD and Perimeter-Area Fractal Dimension （PAFRAC） increased，while Largest Patch Index （LPI），AI，CONNECT and Simpson's Diversity Index （SIDI） reduced in the whole study area. It demonstrated that the Integrity of the landscape dropped off，and fragmentation degree heightened. Human disturbances brought by pipeline construction reduced the stability in this area. Moreover，the proportion of each landscape types became more balanced. There were significant differences between the year of 2002 and 2010，as well as construction area and other buffers. In conclusion，pipeline construction influences observably the landscape pattern and its function. The original structure has changed and functions have declined. The main affected area is construction area. Although all the buffers are influenced by the pipeline construction in landscape pattern，the buffer which is farther from the pipeline gets less impact. This study could provide theoretical basis and reference for environment conservation and further study on pipeline construction in arid desert area.

Key words: landscape indexes, oil and gas pipeline, desert steppe, small scale, buffer