【作者】 彭月；

【导师】 王建力；

【作者基本信息】 西南大学 ， 自然地理学， 2010， 博士

【摘要】 长期以来,人类改造自然的脚步从未停止过,而地表系统的土地利用／覆被格局正被这些人类活动不停的改变着,这种改变一方面导致自然环境发生变化,另一方面直接作用于人类社会、经济的发展。土地利用／覆被变化已成为全球变化研究的一个重要内容。三峡库区自然地理条件复杂,是我水土流失严重的生态脆弱区之一。在经济加速发展、快速城市化进程的大背景下,随着重庆市的直辖、三峡工程的实施,区内人类活动持续的干扰着土地利用／覆被格局,影响着区域生态环境变化。土地利用／覆被研究是区域生态环境变化研究的基础,通过监测三峡库区土地利用／覆被的动态变化,研究土地利用／覆被变化过程和机理,可以为了解区域生态环境的演替过程、掌握区内自然和社会环境变化、提高三峡库区的生态环境质量及区域土地资源的可持续利用提供参考。三峡库区面积巨大,主要分布在重庆市和湖北省两个地区,其中绝大部分在重庆市境内,这里也是土地利用／覆被变化较明显的地区。同时,为了便于收据资料的收集,我们选择三峡库区(重庆)为主要研究区域,结合不同的自然地理条件与社会经济差异,选择了江津区、忠县、巫溪县和奉节县4个典型区县作对比。以1986年、1995年、2000年和2007年4期土地利用数据为基础,结合遥感影像、自然地理和社会经济数据建立地理信息数据库,分别对区内土地利用／覆被格局、动态机制进行分析；对土地利用／覆被变化趋势进行模拟；从自然和社会两方面对比土地利用／覆被变化的驱动因素差异；从生物多样性、土壤侵蚀、景观生态变化、生态系统服务价值以及生态风险等方面探讨了三峡库区(重庆)土地利用／覆被变化的生态环境效应。结果表明：1.耕地和林地始终是三峡库区(重庆)主要的土地利用／覆被类型。其中,耕地以旱地居多：林地以有林地和稀疏林地为主。研究区幅原辽阔,区域差异明显：下游地区的巫溪县和奉节县林地最多；中游地区的忠县以耕地为主：上游的江津区内耕地和林地都较多。从土地利用类型的多样化程度来看,下游地区的土地利用类型多样化更高,理论上这里的土地利用景观稳定性更高。在上游地区和中游长江周边立地条件较好的地区,土地利用程度较高,下游地区的土地利用程度相对较低,特别是周边高海拔的山区上地利用程度更低。2.1986年以来,三峡库区(重庆)的耕地先增后减,林地先减少后增加,草地和未利用地的面积持续减少,水体与建设用地面积持续的增加。上游的江津区和中游的忠县土地利用变化趋势同三峡库区(重庆)较一致,下游的奉节县和巫溪县同三峡库区(重庆)土地利用变化差异明显。从土地利用／覆被类型变化速率来看,耕地、林地和草地的相对变化率更高,空间分布较分散,水体和建设用地变化的区域则更集中。利用不同的卫星影像,直观的展示了研究区内森林景观演替、耕地与草地转化、城区快速扩张和新城镇的兴起等4种土地景观变化过程。对未来土地利用／覆被变化趋势的模拟表明：三峡库区(重庆)的耕地和草地面积减少,林地、水体和建设用地面积增加。江津区和忠县的变化趋势同三峡库区(重庆)的相似,下游的奉节县和巫溪县的明显不同。奉节县的耕地、林地和草地面积持续减少,水体和建设用地面积增加；巫溪县的耕地、林地、水体和建设用地增加,草地大幅度减少。通过垦殖指数来定量耕地的变化,从1986-1995年,耕地变化不明显：1995-2007年,垦殖指数明显增加,在空间上的差别明显,在库区上游的重庆市主城区负增长强烈,而在开县、武隆县和巫山县等地正增长较强。4个典型区县中,江津区和忠县的耕地变化数量和速率都比奉节县和巫溪县更强；林地变化集中研究区东部、南部和西北部,在地势较高的山地,林地正向变化明显,逆向变化在库区上游、中游和下游地区都有集中分布。3.对土地利用／覆被变化自然驱动因素分析发现：海拔与坡度制约着土地利用／覆被类型分布,耕地多在中低海拔的缓坡区,林地和草地与之相反,水体与建设用地的海拔较低,坡度较小。1995年来,低海拔平坦地区的耕地减少明显,陡坡耕地有所增加；高海拔区的林地大幅度增加、草地减少、水体和建设用地有所增加。从地貌类型上看,耕地多在低山、丘陵、和喀斯特平原等,林地在中低山分布最多,草地在丘陵与中低山分布明显,而建设用地多集中分布在丘陵与喀斯特平原。从土壤类型上看,紫色土、黄壤、水稻土等面积较大。1986年至1995年,不同地貌类型与土壤类型上的土地利用／覆被变化不明显,1995年以后,变化明显加快,在丘陵与中低山的土地利用变化最快。紫色土与水稻土分布面积最广,立地条件相对较好,人为干扰较重,土地利用变化强烈。对比三峡库区(重庆)4个典型区县耕地变化的主要驱动差异发现：江津区位于库区上游、其经济发展最快,非农业人口快速增长带来的压力是其耕地变化的主要驱动因子；库区下游奉节县的耕地变化主要受科技进步因素与以三峡移民活动为主的人口流动影响：巫溪县耕地变化第一驱动因素是总人口数,其次是人为政策因素(如：农业产业结构调整)；忠县位于库区中游,人为政策因素的影响最强。4.三峡库区是我国生物多样性较高区域之一,生物多样性受土地利用／覆被变化影响明显。①20世纪80年代末以前,森林植被破坏严重使得其生物多样性降低,20世纪90年代以来,虽然森林面积有所恢复,但是生物多样性并未见明显恢复。②草地面积减少,质量下降,草地内生物多样性减少。③研究区内的工程施工、移民、城市扩张等人为活动都影响着区内的生物多样性。④三峡工程蓄水形成的消落区对水体中的藻类、维管植物会有所冲击,但为水生生物也提供了多样的生存环境。不同土地利用方式对土壤侵蚀的影响差异明显,三峡库区(重庆)境内,耕地上土地侵蚀最高、其次是草地、林地上较低。不同地区来看,库区下游的巫溪县和奉节县耕地上的土壤侵蚀最强,其次是草地和林地；上游的江津区草地上土壤侵蚀最高；中游忠县的林地上土壤侵蚀较高。根据土地利用类型破碎化情况对三峡库区(重庆)内的22个区县进行分类,空间上分属东、中和西3个地区,土壤侵蚀由东向西减弱,分别对应着农草地破碎区、林地破碎区和建水破碎区。较强的土壤侵蚀(强度侵蚀、极强度侵蚀和剧烈侵蚀)会增加土地利用破碎程度,但是其加剧土地利用景观破碎化的速率同土壤侵蚀级别相反。5.景观上看,三峡库区(重庆)景观异质性增加,稳定性增强,抗干扰能力增加。1986年-1995年生态系统服务价值变化速率较低,1995年-2007年,区域生态系统服务价值明显加快。模拟发现,2007年后,研究区生态系统服务价值不同程度的增加,区域土地利用具有明显的可持性。从生态风险上看,库区上游和中游地区的生态风险高于库区下游地区。1986年至2007年,三峡库区(重庆)生态风险整体上有所增加,但是高风险区域分布更为破碎,库区下游地区生态风险增加明显。本研究特色：从不同空间和时间尺度对比了三峡库区(重庆)土地利用／覆被格局、动态过程、驱动因素以及其生态环境效应,研究内容较全面。综合使用了多种地学的土地利用／覆被变化的指标、模型、统计等方法,同时应用生态学中的分类排序的方法,定量评价了三峡库区(重庆)土地利用类型破碎化同土壤侵蚀等级的关系,表明较强的土壤侵蚀会增加土地利用景观的破碎度,但其加剧的程度同土壤侵蚀等级相反。将生物学的研究方法同地理学研究结合,具有一定特色。更多还原

【Abstract】 For a long time, the Human have never stop the step to transform the nature world, the surface land use/cover pattern had suffered the disturb at the same time. The disturb come from the human act not only on the nature environment but also on the society and economic development. The LUCC has been a part of the Global changed research. Complicated Geography conditions and The loss of water and soil was most serious in the Three gorge reservoir region. Meanwhile, at the background of economic development and quickly urbanization, with the Chongqing’s direct ruled by the central authorities and the Three Gorge Project’s executed, the human’s activity has non-stop to impact the land use/cover pattern and local Eco-Environment level. LUCC research is the base of the local eco-environment change research. It can help us to find out the succession process of the environment and the nature society changed, improve the eco-environment and the sustainable use of the land resource. The Three Gorge reservoir region was distributed in Chongqing City and HuBei Province, mostl of them in Chongqing city, also, it had the fast LUCC with the quickly urbanization and industrialization. In order to facilitate the recipt of data collection, we choose the The Three Gorge reservoir region in Chongqing city as the whole study area. According to the Great nature geography and economic difference, we chose the Jiangjin District, Zhong District, Wuxi District and FengJie District as the typical region of the study areas. This paper included four parts (The land use/cover changed pattern, dynamic of the land use and land cover change, the drive force of the LUCC, Simulated the trend of the LUCC in the future and the Eco-Environment effect of the LUCC).The result showed:1. Cultivated area and wood land has always been the main types of the study areas, the dry land is the most cultivated types. Because of the difference in the region of space, the situation was differed in the 4 typical districts. The WuXi and FengJie had a maximum area of woodland, there were the more cultivated areas in Zhong district and more cultivated areas and wood land in JiangJin district. Diversification of the land use types of view, the Diversity of the land use types in the lower reaches area were higher than the other areas, it has the stronger land use landscape stability in theoretically. It had the more land use degree In the upper reaches and the place near the Yangzhi River. In the middle reaches, the high elevation areas in the lower reaches had the lowest land use degree.2. Since 1986, the cultivated land areas increased in the first phase and reduced in the second phase, it revered on the wood land. The grass land and the un-use land reduced, water body and the built-up area continued to increase in the land areas. Jiangjin district and the Three gorges reservoir area (Chongqing) had the same trend of the land use change, but it differed in Fengjie district and Wuxi district. From the land use and land cover changed in the types of view, the ralative variety ratio of the cultivated land, wood land and grass land were more than the others, it dispersed on the study areas, but the water body and built-up areas are more concentrated. We can find out the land use and land cover types change (forest landscape succession, the transform between the grass land and the cultivated land, the quickly expand of the old urban areas, the new town come into being) by the RS imagine. We use the model to predict the trend of the land use and land cover change in the future. The cultivated land and the grass land will be reduced, and the wood land, water body and built-up area will increased in the future. It distinguished in the 4 typical districts, Jiangjin district and zhong district had the same LUCC trend of land use and land cover changed with the Three Gorge reservoir region; but in the Fengjie district, the cultivated land, wood land and grass land keep lost, the water body, built-up area increased; in the Wuxi district, the cultivated land, wood land, water body and the built-up area continued to increase, the grass land reduced. By the cultivated index, we study on the cultivated land’s area change, from 1986 to 1995, it had tiny transformation, from 1995 to 2007, it increased so fast, also it distinguished in the spatial area, the index in the chongqing main city zone upriver of the study area increased on the negative, but it rose on the downstream region of the study area. The trend of the cultivated area changed on the 4 typical district were same with the Three Gorge reservoir region, the variety extent of cultivated landm in Jiangjin district and Zhong district were more than it on the Fengjie district and Wuxi district. To the wood land, because of the high elevation, the positive change focus on the east, south and northwest of the study area, and the negative change distributed in somewhere of the study areas.3. The result of the drive force of the land use and land cover change of the study area show: The land use and land cover types distributed in different elevation and slop area, the cultivated land were distributed throughout the middle high and even place, it reversed in the wood land and the grass land, the water body and built-up areas distributed in the low and even place. From 1995, the cultivated area in the low and even place reduced in evidence, but it increased in steep slope areas; in high altitude areas, a plenty of wood land had been increased, the grass land reduced, the water body and the built-up area had increased, From a geomorphological point of view type, Cultivated area were more in the low mountains, hills, and karst plains, wood land were distributed in the low mountain district with the largest areas, grassland in the knap and low mountains in the distribution of apparent, the more concentrated the distribution of built-up area in the karst hills and plains. From the soil types, the area of Purple soil, Yellow soil, Paddy soil were lager than others. From 1986 to 1995, the land use/cover change in different soil and physiognomy types were not obvious. Since 1995, change had accelerated noticeably, in the hills and low mountains had the fastest land-use change. Purple soil and paddy soil area were the most widely distributed, it had a better eco-environ-ment, with heavier human disturbance and a strong land use changed. From cultivated land changes of typical districts in the Three Gorges reservoir area (Chongqing), we find out the Jiangjin district is located in the upper reaches of the reservoir area and it’s fastest growing economy and the rapid growth pressure of Non-agricultural population were the main driving factors of the cultivated land changed; The main driving factors of the cultivated land changed were the scientific and technological advancement factors and the impact of population movements by theThree Gorges Reservoir migrants; The first driving force of cultivated land changed in Wuxi district were the total population, and followed by the man-made policy factors (eg, agriculture, industrial structure adjustment); Zhong district is located in middle reaches of the reservoir area, which suffered the most strong impact of human policy factors.4. Here is one of the regions in China with high biodiversity, where the land use and land cover change impact the biodiversity obviously.①Before the 1980’s, widespread destruction of forest vegetation makes it a decrease in biodiversity, from the 1990’s, although the forest area had been restored, but here’s biological diversity there was no obvious increased.②Grassland area was reduced, the quality of the grass was decreased, the diversity reduced.③The bio-diversity had suffered the disturb come from the human activity of the engineering project, migration and the urban expand, and so on.④The Three Gorges Project reservoir formed some water-fluctuation-zone, it would impact the the algae, vascular plants in the water-fluctuation-zone, on the other hand, on the other side; it could provides a variety of living environment for aquatic organisms. Land-use types affect the level of soil erosion, in the Three Gorges reservoir area (Chongqing), the highest soil erosion was on the cultivated land, and wood land was on the lowest soil erosion. In different regions, in the reservoir area downstream (Wuxi district and Fengjie district) soil erosion on cultivated land was strongest, followed by grassland and woodland; in upstream (Jiangjin District), the the higest soil erosion was on the grass land; The middle region (Zhongxian) had a higher soil erosion in the wood land.According to the fragmentation of land-use type situation, we had classified the 22 districts of the Three Gorges reservoir area (Chongqing), They belong to the eastern, central and western regions, Soil erosion decreased from east to west, They correspond to the fragmentation zone of agricultural-grassland, woodland area and the construction-water. Strong soil erosion (erosion intensity, very intensity of erosion and severe erosion) will increase the extent of land-use fragmentation, But the land-use landscape fragmentation increased the rate of soil erosion with the level was on the opposite side.5. From the landscape ecology, The Three Gorges reservoir area (Chongqing) Landscape heterogeneity was increased, the landscape was more stable, and it resisting ten days bounded disturbances capacity greatly increased, and it can resistant to the disturb of the outside more. From 1986 to 1995, the ’EVI’changed was every slow, but from 1995 to 2007, it increased so fast. by the model, we can find that the value of "EVI" index would increased in varying degrees, after 2007. The regional land use had a obvious sustainability. From the ecological risk, The upper and middle reaches of the reservoir area of ecological risk were more higher than the reservoir downstream. From 1986 to 2007, The Three Gorges reservoir area (Chongqing) had been to increased the overall ecological risk, but the high ecological risk areas will be more dispersed, and Reservoir downstream areas of ecological risk hasd increased.更多还原