北方农牧交错带界线变迁及其生态效应研究
文献类型：学位论文
| 作者 | 刘军会 |
| 学位类别 | 博士 |
| 答辩日期 | 2008 |
| 授予单位 | 中国科学院水利部成都山地灾害与环境研究所 |
| 授予地点 | 成都 |
| 导师 | 高吉喜 |
| 关键词 | 生态效应 界线变迁 景观格局 生态系统服务价值 北方农牧交错带 |
| 其他题名 | Study on the Spatial Change of Boundary and Its Ecological Effect in the Farming-pastoral Ecotone of Northern China |
| 学位专业 | 自然地理学 |
| 中文摘要 | 北方农牧交错带地处农田和草地的生态过渡带，对外界扰动反应迅速、敏感性强、变化幅度大。在气候暖干化的影响下，北方农牧交错带的气候界线向东南移；在草地开垦等人类活动影响下，交错带土地利用界线向西北移。两者的反向变迁必将对北方农牧交错带的生态环境产生重要影响。在20世纪末期的十几年，北方农牧交错带生态环境质量基本上处于“整体恶化、局部改善”的状况，其退化趋势主要表现在生态系统内部结构的不稳定以及外部胁迫下的生态功能降低。北方农牧交错带不仅未能起到防风固沙的屏障作用，反而成为向下风向地区外摊环境成本的源头。论文以北方农牧交错带为研究区域，分析其在全球变化影响下的界线变迁及其生态效应，以期为北方农牧交错带的生态保护和应对全球变化提供理论基础和科学依据。论文研究的主要内容：（1）针对以往研究对北方农牧交错带地理位置分布存在的较大分歧问题，原因在于界定指标的选取争论较大。论文从气候和土地利用格局空间分布两方面重新界定了北方农牧交错带的地理位置。其中，基于气候界定的界线称为气候界线，基于草地、耕地空间分布特征界定的界线称为土地利用界线。（2）在区域干旱化影响下，气候界线向东南方向变迁，与其相适应的农业生产活动也应保持与气候变化的一致性，同向移动。但在20世纪末期的十几年，农业生产活动并未遵守气候规律，而是迫于人口增加压力、广种薄收的耕作方式和“以粮为纲”的政策鼓励下，促使耕地不断向西北扩张，这也使得土地利用界线也随之向西北方向变迁。气候和土地利用界线的变迁幅度存在明显的区域差异，变迁幅度大的区域主要集中于交错带的东北段、华北段，西北段变迁幅度很小。（3）通过利用景观格局变化的指数模型定量分析了研究区的景观格局变化状况。景观类型之间的转换主要集中于耕地、草地之间的相互转化。景观格局变化速率变化较快的地区主要分布在东北段；在华北段和西北段，西北界附近区域的土地利用变化速度明显快于东南界，人类活动北移的趋势明显。草地不断被北开垦，促使耕地重心北移；受交错带西北部草地退化、密度减小、南部耕地撂荒影响，草地重心南移。景观异质性增强、稳定性加强，人类活动对研究区景观变化的干扰程度也在加剧。（4）北方农牧交错带生态系统服务总价值构成中，草地、农田和森林的服务价值所占比例都最大。从单位面积价值看，森林和灌丛服务功能的价值最高。从空间分布来看，在水平方向上，生态系统服务价值由东南向西北递减，区域差异明显，其分布受气候变化和人类活动影响较大；在垂直方向上，生态系统服务价值大小主要受自然因素影响，人类活动影响微弱。受区域降水减少和人类活动的影响，北方农牧交错带各类生态系统服务的单位面积价值都在下降。（5）北方农牧交错带植被NPP总价值和高盖度植被的面积都在下降。植被NPP和覆盖度变化的区域差异显著，植被NPP升高区位于华北段的中西部和西北段的西南部，其它地区植被NPP明显降低；植被覆盖提高区位于东北段东部、华北段西部和西北段西部，植被覆盖明显退化。植被NPP和覆盖度变化同降水变化、干燥度指数变化成正比、与温度变化成反比。在不同地类覆盖下，植被NPP和覆盖度变化的方向和程度不同。 |
| 英文摘要 | The farming-pastoral ecotone of northern China was located in the ecological transitional zone between farmland and grassland, which has a rapid response to the external disturbance, with great sensitivity and large extent. Under the impacts of warmer climate change and the aridity of human activities, climate boundary changes to southeastward and land useboundary changes to northwestward. The reverse change between climate boundary and land useboundary will exert far-reaching influence on the eco-environment of farming-pastoral ecotone of northern China. In recent twenty years, the eco-environment is in the state of getting worse and worse with the exception of some small areas being improved. The tendency of ecosystem degradation is that the structure was instable and the function was decreasing. It does not become the shield to protect against the wind and to keep out the sand, nor become the origin of added environmental cost to the catchment area. This paper takes the farming-pastoral ecotone of northern China as the study area, and analyzes the boundary change and its ecological effects. The research will provide the theoretical foundation and scientific basis for the eco-environment protection and deal with the impacts of the global environmental changes. The content including:(1)Different people have different views about the definition of the farming-pastoral ecotone of northern China, and the basic reason for this is the different selection of defined indices. The definite indices can be classified into two types, one takes the agricultural climate factors as the definite indices, and the other takes the land use spatial pattern distributing as the definite indices. The location which was defined by meteorological indices was influenced greatly and easily by the climate change, so its boundary can be called climate boundary. The location which was defined by the spatial pattern of farmland and grassland was affected greatly by the human activities, and its boundary can be called land useboundary.(2) Under the impact of regional aridification, climate boundary changes to southeastward, and the agriculture should change with the climate change accordingly. However, in fact, agricultural production activity don’t abide by the order of nature, with population increasing, cultivation extending and the encouragement of the “grain is the key link” policy, farmland expands to northward continually, which lead the land useboundary change to northwestward in recent twenty years. The distance of boundary change has obvious regional differences. The maximum distances of climate boundary and land useboundary change are all distributed in northeast section and north section, however, the boundary change of northwest section is not obvious.(3) According to the basic data of land use, the landscape pattern change is quantified by computing the index models of regional landscape pattern change. The farmland transformed into grassland and the grassland transformed into farmland are the chief transformation of landscape pattern changes. The area with high changing rate was located in north section. The speed of land use change is faster in the area round the northwest boundary than in the area round the southeast boundary, it is obvious that the human activities changes to northern. The grassland was reclaimed to the northern part, which makes the zonal centroid of farmland change accordingly. However, the zonal centroid of grassland changed to southern part under the impact of the decrease of grassland density for grassland degradation in the area around northwest boundary and the farmland desertus in the area round the southeast boundary. The heterogeneity of landscape is increased, the landscape stability enhanced. And the interference degree of landscape change by people is being aggravated.(4) The value of grassland, farmland and forestland is the most important in all the ecosystem services. The per-pixel value of forest and shrub is higher than that of other ecosystems. In horizontal distribution, the value of ecosystem services has obvious regional difference, and its distribution was greatly impacted by climate and human activities; in vertical distribution, the topographic factors affect the value of ecosystem services more evidently than human activities. Under the impact of climate change and land use change, the per-pixel value of every ecosystem service are decreasing during 1986~2000.(5) The total value of NPP and the area of the regions with higher vegetation cover were decreasing. The changes of NPP and vegetation cover show a notable regional difference. NPP has increased in the Mid-west of East section and the Southwest of northwest section, and the vegetation cover increased in the east of northeast section, the west of north section and the west of northwest section, while they have obviously decreased in the other areas in the farming-pastoral ecotone of northern China. The changes of NPP and vegetation cover and the changes of precipitation as well as aridity index are in direct proportion, while they are inversely proportional to temperature change. The direction and the extent of changes of vegetation cover and NPP were different according to the spatial distribution of land cover. |
| 学科主题 | 生态学 |
| 语种 | 中文 |
| 公开日期 | 2010-10-15 |
| 分类号 | P53;Q91 |
| 源URL | [http://ir.imde.ac.cn/handle/131551/2212]  |
| 专题 | 成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前） |
| 推荐引用方式 GB/T 7714 | 刘军会. 北方农牧交错带界线变迁及其生态效应研究[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2008. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。