研究青海湖流域的土地利用/覆被变化,对识别流域人类活动特征和分析区域生态环境演化规律及其成因具有重要意义。文章以1977~2004年4期遥感影像数据为基础,采用土地利用转移矩阵、动态度、利用程度等方法,研究了青海湖流域1977年以来的土地利用变化特征及其空间分异规律。研究结果表明:①近年来流域内生态用地数量逐渐减少,其中水域面积净减少292.70km2;②对草地的开垦占用是流域增加耕地的主要来源,1977~2004年因湖泊水位下降而增加的沙地面积为103.22km2;③1977年以来,流域内除2000~2004年水域面积减少速率显著上升达0.71%外,其他主要类型土地面积变化速率不断减缓;④流域内沙地主要分布在海晏县(70%以上),90%的林地和95%以上的耕地均分布在刚察、共和两县,各县土地利用结构变化特征存在差异;⑤土地利用程度综合指数平均值为186.47,明显低于其他地区,说明人类活动对流域土地利用变化影响较小,区域生态环境问题的研究应当更加注重自然因素的驱动作用。
In the recent years, Qinghai Lake has experienced severe declines in water level and its watershed is in an advanced state of ecological degradation, which resulted from both natural (climatic) and anthropogenic factors. However, information concerning human activities (e.g., land use/cover change) is scarce, therefore, it is necessary to know land use change and its effects on ecological degradation in the lake watershed. This would help us to have a better understanding of the effect of human activity on the processes of land degradation in the past and may enable the improvement of future planning strategies.Based on the multi-temporal remotely sensed data in 1977,1987,2000 and 2004, this study analyzed the land use change characteristics in the Qinghai Lake watershed from 1977 to 2004 and investigated the spatial difference of land use structures between different counties, by the using of transition matrix of land use types and land use dynamic degree. Then land use intensity in the Qinghai Lake watershed was calculated and compared with other typical regions in China. The conclusions of the study can be drawn as follows: (1) Land use change was characterized by constant land decrease for ecological function and land increase for production as well as degraded land from 1977 to 2004, for instance, the water body area decreased 292.70 km2 in the last 30 years. (2) The increase of farmland and sand derived respectively from occupying the grassland and transferring from the lake sand due to the decline of water level in the Qinghai Lake, the sand area increased 103.22km2because of the decline of water level from 1977 to 2004. (3) The changing rate of farmland area,residential area,sand area and forest area has been slowed down since 1977 while the water area decreased obviously from 2000 to 2004 (0.71%)and the grassland area changed slowly all the year round. On the whole watershed, the changing rate of all the land use types had the characteristics of interannual variation. (4) The differences of land use structures between four counties were obvious with most of the sand distributed in Haiyan (more than 70%),at the same time, Gangcha and Gonghe had 90% of forest and more than 95% of farmland of the whole watershed, moreover, changes of land use structures were various between these four counties. (5)The variation of land use intensity in the Qinghai Lake watershed was insignificant from 1977 to 2004 while the average value of integrated index is 186.47. The comparison of land use intensity between the Qinghai Lake watershed and other typical regions showed that human activity had little effect on the land use/cover change in this study region, so the related researches on regional environmental and ecological problems should pay more attention to the driving process of natural factors.
[1] Evans Jason, Geerken Roland. Discrimination between climate and human-induced dryland degradation[J]. Journal of Arid Environments,2004,57:535-554.
[2] Ernest C Njau. Formulation of human-induced variations in global temperature[J]. Renewable Energy,2007,32: 2211-2222.
[3] Alessio Alexiadis. Global warming and human activity: A model for studying the potential instability of the carbon dioxide/temperature feedback mechanism[J]. Ecological Modeling,2007,203:243-256.
[4] Ren Liliang, Wang Meirong, Li Chunhong, et al. Impacts of human activity on river runoff in the northern area of China[J]. Journal of Hydrology,2002,261:204-217.
[5] Navin Ramankutty, Christine Delire, Peter Snyder. Feedbacks between agriculture and climate: An illustration of the potential unintended consequences of human land use activities[J]. Global and Planetary,2006,54: 79-93.
[6] Abdullah Saiful Arif, Nakagoshi Nobukazu. Forest fragmentation and its correlation to human land use change in the state of Selangor, peninsular Malaysia[J]. Forest Ecology and Management,2007,241:39-48.
[7] 李秀彬.全球环境变化研究的核心领域——土地利用/土地覆被变化的国际研究动向[J].地理学报,1996,51(6):553~557.
[8] 葛全胜,赵名茶,郑景云.20世纪中国土地利用变化研究[J].地理学报,2000,55(6):698~706.
[9] 张文忠,王传胜,吕昕,等.珠江三角洲土地利用变化与工业化和城市化的耦合关系[J].地理学报,2003,58(5):677~685.
[10] 周青,黄贤金,濮励杰,等.快速城镇化农村区域土地利用变化及驱动机制研究——以江苏省原锡山市为例[J].资源科学,2004,26(1):22~30.
[11] 蒙吉军,吴秀芹,李正国.河西走廊土地利用/覆被变化的景观生态效应——以肃州绿洲为例[J].生态学报,2004,24(11):2535~2541.
[12] 卢远,华璀,王娟.东北农牧交错带典型区土地利用变化及其生态效应[J].中国人口·资源与环境,2006,16(2):58~62.
[13] 王秀兰,包玉海.土地利用动态变化研究方法探讨[J].地理科学进展,1999,18(1):81~87.
[14] 刘彦随,陈百明.中国可持续发展问题与土地利用/覆被变化研究[J].地理研究,2002,21(3):324~330.
[15] 田彦军,郝晋珉,韩亮,等.县域土地利用程度评估模型构建及应用研究[J].农业工程学报,2003,19(6):293~297.
[16] 倪绍祥,巩爱歧,蒋建军,等.环青海湖地区生态环境问题及其整治[J].资源科学,1999,21(6):43~46.
[17] 朱琰,崔广柏,杨珏.青海湖萎缩干涸原因、发展趋势及对生态环境的影响[J].河海大学学报,2001,29(4):104~108.
[18] 李林,王振宇,秦宁生,等.环青海湖地区气候变化及其对荒漠化的影响[J].高原气象,2002,21(1):59~65.
[19] 马瑞俊,蒋志刚.青海湖流域环境退化对野生陆生脊椎动物的影响[J].生态学报,2006,26(9):3066~3073.
[20] 宋春晖,方小敏,师永民,等.青海湖西岸风成沙丘特征及成因[J].中国沙漠,2000,20(4):443~446.
[21] 俞文政,常庆瑞,王锐,等.青海湖地区耕地演变过程与影响机制分析[J].水土保持通报,2006,26(5):19~22.
[22] 刘小园.青海湖流域水文特征[J].水文,2004,24(2):60~61.
[23] 侯佩玲,沈小京.浅谈青海湖流域草地资源的可持续利用[J].青海环境,2004,14(3):119~122.
[24] 郑丙辉,田自强,王文杰,等.中国西部地区土地利用/土地覆被近期动态分析[J].生态学报,2004,24(5):1078~1085.
[25] 陈述彭,童庆禧,郭华东.遥感信息机理研究[M].北京:科学出版社,1998.
[26] 王力,牛铮,尹君,等.基于遥感技术的小城镇土地利用变化分析——以黄骅镇为例[J].资源科学,2006,28(5):68~75.
[27] 庄大方,刘纪远.中国土地利用程度的区域分异模型研究[J].自然资源学报,1997,12(2):105~111.
[28] 时兴合,李林,汪青春,等.环青海湖地区气候变化及其对湖泊水位的影响[J].气象科技,2005,33(1):58~62.
[29] 李凤霞,李林,沈芳,等.青海湖湖岸形态变化及成因分析[J].资源科学,2004,26(1):38~44.
[30] 陈新海.青海湖地区的人类活动与环境[J].青海民族学院学报(社会科学版),2005,31(1):38~43.
[31] 蔡运龙.中国农村转型与耕地保护机制[J].地理科学,2001,21(1):1~6.
[32] 樊宏,张建平.岷江上游半干旱河谷土地利用/土地覆盖研究[J].中国沙漠,2002,22(3):273~278.
[33] 马安青,陈东景,王建华,等.基于RS与GIS的陇东黄土高原土地景观格局变化研究[J].水土保持学报,2002,16(3):56~59.
[34] 萨仁娜,阿拉腾图雅,包玉海,等.内蒙古农牧交错带中部地区荒漠化与土地利用之关系分析[J].干旱区资源与环境,2004,18(9):69~72.