【作者】 郭碧云；

【导师】 张广军；

【作者基本信息】 西北农林科技大学 ， 水土保持与荒漠化防治， 2010， 博士

【摘要】 为了研究人类活动对农牧交错带土地利用/覆被的空间分布、转化及对生态环境的影响,本研究以内蒙古农牧交错带太仆寺旗为例,运用卫星遥感数据,辅以地理信息系统技术对该区域土地利用/覆被变化、景观格局空间变化及土壤侵蚀情况进行分析研究,并在此基础上运用Markov模型对未来20年土地利用情况进行预测。研究结果如下:1.对土地利用/覆被变化分析表明:在土地利用类型结构构成上,1975~2004年,主要的土地利用类型为草地和农业用地,1990年农业用地占主导地位,其余3个时期(1975年、2000年、2004年),草地面积位居第一位,林地、水域、建设用地和未利用土地所占份额较小。从土地利用类型空间变化来看,草地与农业用地之间发生着明显的相互转化,1975~1990年,农业用地面积转入大于转出,面积增加,草地面积下降,1990~2004年草地面积转入大于转出,面积增加,农业用地面积下降。土地利用程度变化分析表明,1975~2000年土地利用综合指数呈上升趋势,2000年达到最大值,1975年土地利用程度较低,综合指数最小,说明上世纪70年代中期土地资源开发程度较低,人类活动对土地利用类型的变化影响较小,2000年左右影响较大,1975~2000年土地利用程度处于发展期,2000~2004年处于调整期。2.对景观格局变化分析表明:在斑块类型水平上,草地和农业景观在研究区内属于主要景观类型,1975年草地斑块占景观面积比例远远大于其它斑块类型,处于优势地位,2000年农业景观的斑块密度达到最大值,破碎化程度加大,2004年农业景观形状指数最大,边缘地带增加,面积有效性减少。在景观水平上,1975~2000年蔓延度指数和聚集度指数持续减小,Shannon多样性指数和Simpson多样性指数呈增长趋势,说明这一时期景观由多种连接性较差的斑块组成,景观被边界割裂的程度增加,斑块的离散性加大,空间形状复杂性增大,同类型斑块间的连接度降低,景观格局向着破碎、多样化的方向发展;2000~2004年景观受一种或几种占优势景观的控制程度加大,斑块形成了良好的连通性,表现出团聚趋势的特征,整体景观格局破碎化程度减弱,土地利用系统向着有序、均衡的方向发展。3.对土壤侵蚀(水蚀)研究结果表明:在2007年研究区土壤受水力侵蚀影响的程度较小,以微度为主,占水蚀面积的77.2%,轻度水蚀面积为14.4%,中度水蚀面积占8.3%,受强度和极强度水蚀的土地面积很小。微度水蚀中,农业用地面积占19.12%,草地占50.47%,林地占5.74%,未利用地占1.84%;轻度水蚀中草地占11.31%,农业用地占2.51%,林地和未利用地受轻度侵蚀面积很少;中度侵蚀中草地占6.44%,农业用地占1.81%,林地和未利用地占很少部分。研究发现,不同的土地利用方式会导致不同程度的水土流失,研究区水蚀率最高的是农业用地,水蚀率为42.87%,草地的水蚀率为22.96%,林地的水蚀率为6.52%,未利用土地主要以微度水蚀为主,太仆寺旗土地利用方式总体上是有利于水土保持的。4.运用Markov模型对研究区土地利用变化进行预测表明:在今后一段时期内,农业用地、草地、未利用土地每年会有轻微减少,林地面积将会增加,水域面积的变化趋势趋于平稳,随着城镇化进程和经济的发展,建设用地增加趋势显著。总之, 1990年前后人类活动对生态景观的影响程度最大,这主要与这一时期农业用地大幅度扩张有关,1975年草地面积占首要地位,农业用地面积较小,土地利用受人为干扰强度最小。土地利用影响程度主要受国家土地利用政策的影响,实行合理的土地利用政策,利用生态系统自身的修复功能进行生态环境治理是该地区生态恢复的基本途径。更多还原

【Abstract】 In order to study the impact of human activities on spatial distribution, transformation and the ecological environment of land use / cover in agro-pastoral transitional zone, With Taipusi Qi in Inner Mongolia as the case and its satellite remote sensing data, supported by GIS platform technology, this paper has analyzed the change of land use, land cover and spatial landscape pattern in the past 30 years. Based on the above, the Markov Model is applied in the prediction of land use variation in the following 20 years. The results are as follows:Land use / cover change analysis shows that: from 1975 to 2004, the major land-use type consists of grassland and farmland in the structure land use-type. The farmland dominated in coverage in 1990, while in the other three periods, the grass area led the first place, with forest, water, construction land and unused land in relatively small share. In terms of the spatial changes of land-use types, there was a clear transformation between grassland and farmland. Between 1975 and 1990, the farmland area increased with entrance surpassing exit, in contrast, the grassland area decreased. From 1990 to 2004, the grassland area expanded while the farmland shrank. Land-use change analysis shows that: from 1975 to 2000, comprehensive land use index was in an upward trend, reaching the maximum in 2000. Land-use degree in 1975 was low with the smallest index, indicating the small influence of human activities on the change of land-use types with the low exploitation of the land resources in 1970s. But the influence deepened in 2000. In brief, the land-use extent was in the development period in 1975-2000, contrasting a period of adjustment in 2000-2004.Analysis of the change in landscape-pattern shows that: In the patch-type level, grassland and farmland scapes are the main landscape types in the study area. In 1975, the proportion of grassland plaque was in a dominant position, surpassing the other patch types clearly. In 2000, farmland scape patch density reached the maximum degree with the fragmentation increasing. In 2004, the farmlandscape shape index got the highest with the increase of margins and the reduction of the area validity. At the landscape level from 1975 to 2000, spread index and aggregation index continued to decrease, Shannon and Simpson diversity index showed a growth trend, indicating that during this period the landscape was comprised by a variety of plaque with low connectivity, the degree of landscape boundary fragmentation was increased, the seperation of plaques grew, the complexity of space shape rose, the connectivity of same type patches declined, and the landscape developed in the direction fragmentation and diversification. From 2000 to 2004, as the degree of landscape controled by one or more dominating landscapes rose, the plaque got a good connectivity, showing the feature of reunion trend. The overall landscape fragmentation level reduced, and land-use system developed in the orderly and balanced direction.Reasearch results on soil erosion (water erosion) show that: In the study area in 2007, the soil was slightly affected by water erosion, mainly in a micro-degree, accounting for 77.2% of the area erosion, with the mild-degree covering 14.4%, the moderate-degree 8.3%. Land area eroded to the intense or more extent was small. In the area of slight erosion, the farmland accounted for 19.12%, grassland accounting for 50.47%, woodland 5.74%, unused land 1.84%. Of the mild erosion area, grassland occupied 11.31%, farmland 2.51%, forest land and unused land covering the least. In the moderate erosion area, grassland took 6.44%, farmland 1.81%, forest land and unused land accounting for a very small proportion. Different land use patterns led to different levels of soil erosion. In the study area, farmland is in the highest rate of water erosion with the proportion of 42.87%, contrasting grassland 22.96%, forest 6.52%. The unused land was mainly in the micro-degree in water erosion. On the whole, the way of land-use in Taipusi Qi is beneficial to soil and water conservation.Prediction gained by the use of Markov models in the land-use change in the study area indicates that: In the futural period of time, farmland, grassland, unused land will be slightly reduced each year, forest area will increase, and the change trend of water area is getting stabilized. With the process of urbanization and economic development, construction land will increase in a significant tendency.In short, human activities had the largest influence on ecological landscape in 1990s, primarily for the significantly expanding of farmland in this period. In 1975, grassland was in the dominating place, while farmland area was small, so the land-use was least disturbed by human activities. The extent of land-use is mainly affected by the national land-use policy. Implementation of rational land use policy, environmental management by use of restoring function of the ecosystem itself are the basic way of ecological restoration in the region.更多还原