基于土地利用/覆盖的干旱绿洲区植被覆盖度变化--以新疆生产建设兵团第八师为例

Vegetation change based on land use/cover in arid oasis: A case study of the Eighth Division of Xinjiang Production and Construction Corps

  • 摘要: 为了探讨西北干旱绿洲区土地利用/覆盖类型景观格局特征, 以及不同土地利用/覆盖类型植被覆盖度变化, 本文以干旱典型绿洲区新疆生产建设兵团第八师为研究区, 选取2000年、2005年的Landsat TM和2010年环境一号星CCD遥感影像数据, 采用室内解译与野外核查相结合, 运用RS和GIS技术分析了该区域的土地利用/覆盖和景观格局变化特征, 并基于土地利用/覆盖类型选取3年的MODIS数据进行了植被覆盖度变化分析。结果表明: 1)该研究区主要以耕地、草地和灌丛为主, 占总面积的88.9%。在自然因素和人为因素的综合作用下, 干旱绿洲区土地利用/覆盖类型发生明显变化, 草地和灌丛呈减少趋势, 面积分别由2000年的2 603.2 km2和1 166.2 km2减少至2010年的1 677.3 km2和933.8 km2; 耕地和城镇逐步增加, 面积分别由2000年的2 892.8 km2和209.2 km2增加至2010年的4 038.3 km2和259.1 km2; 耕地主要由草地和灌丛转化而来, 城镇主要由耕地转化而来, 土地利用变化整体处于不平衡发展趋势。2)研究区景观特征趋于简单, 土地利用变化改变了该区域景观格局, 景观多样性、均匀度减少, 优势度明显增大, 破碎化程度降低, 生物多样性也呈向单一方向转变的趋势。3)受气候等主要因素的影响, 2000-2010年植被覆盖度呈先降低后逐步升高的趋势, 不同土地利用/覆盖类型植被覆盖度表现为林地>耕地>草地>灌丛>荒漠, 林地、灌丛、草地和耕地植被覆盖度分别增加6.7%、38.2%、15.6%和12.3%; 较高和高等级植被覆盖面积增加, 中、较低和低等级植被覆盖度面积减少。4)温度一定的条件下, 降雨量是影响干旱绿洲区植被覆盖变化的关键因素。该研究结果可为新疆生产建设兵团生态环境保护管理以及合理规划生产模式提供科学的参考依据。

     

    Abstract: Xinjiang Production and Construction Corps (XPCC) is in the transition zone of the Xinjiang oasis and desert. In the diverse natural environment, agriculture is the main stay in XPCC and the intensity of agriculture in XPCC is higher than in other areas of Xinjiang. Land use/cover types in XPCC have changed markedly with socio-economic development. The Eighth Division of XPCC was investigated in this study. Aided by field verification, the changes in land use/cover in the study region were determined in RS and GIS environments. The study used Landsat TM satellite imagery for 2000 and 2005 in combination with environment first satellite CCD imagery for 2010 to explore the dynamics of land use/cover and landscape patterns. The changes were analyzed for vegetation cover degree for different land use/cover types using MODIS data for 2000, 2005 and 2010. The results showed that: 1) the study area mainly composed of cultivated land, brush land and grassland, accounting for 88.9% of the study area. The changes in land use/cover in the region were mainly driven by natural and human factors. The areas of grassland and brush land decreased respectively from 2 603.2 km2 and 1 166.2 km2 in 2000 to 1 677.3 km2 and 933.8 km2 in 2010. On the contrary, the areas of cultivated land and urban land increased respectively from 2 892.8 km2 and 209.2 km2 in 2000 to 4 038.3 km2 and 259.1 km2 in 2010. Grassland and brush land were mainly converted into cultivated land and cultivated land converted into urban land. The overall state of land use/cover change in the study area was in unbalanced. 2) An increasing simplification was noted in the characteristics of the landscape in the study area. Land use/cover change had changed regional landscape pattern in the region. Landscape pattern analysis showed obvious increasing dominance with decreasing landscape diversity and evenness. While patchy fragmentation decreased, biodiversity appeared to shift in a single direction. 3) The order of vegetation cover degree for different land use/cover types was forest land > cultivated land > grassland > brush land > desert land. Vegetation cover degrees of forest land, brush land, grassland and cultivated land increased respectively by 6.7%, 38.2%, 15.6% and 12.3% from 2000 to 2010. While the areas of land under high vegetation increased, that under low vegetation decreased. 4) Rainfall was the key factor influencing vegetation change in the arid oasis. The findings of this study provided the scientific basis for the protection and management of the ecological environment and planning reasonable production modes in the XPCC region.

     

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