太行山低山丘陵区景观变化特征分析——以河南省济源市为例

以位于太行山南端的河南省济源市为例 ,在对其内部环境进行区划的基础上 ,利用遥感影像数据对其 1995～ 2 0 0 0年的景观变化特点进行了分析。结果表明 ,济源市的景观基质没有变化 ,均是以耕地占绝对优势 ;在景观类型的绝对面积变化中 ,以耕地面积的减少最大 ,而草地和林地的面积则呈现出明显的增加。从景观斑块类型的区域相对变化速率来看 ,变化最明显的区域主要集中在黄土丘陵区 ,该区域的变化速率高于全市的平均变化速率。从景观斑块类型的变化速率看 ,黄土丘陵区的水域、居民点和未利用土地的平均变化速率也大于全市同一斑块类型的变化速率。从该市主要景观斑块类型的转化方向来看 ,耕地、林地、草地这三者之间相互转化比较频繁 ,在目前的国家环境政策下 ,这容易造成人财物的浪费 ,同时也导致了环境稳定性的下降 ,这是极不合理、也是极不经济的。促使上述变化的驱动力主要表现在环境安全驱动上 ,其中起到至关重要作用的为以政府行为所实施的太行山绿化工程、黄河中游防护林工程、天然林保护工程以及退耕还林工程等。

Characterization of landscape changes in Taihang Mountain in China:a case studies of Jiyuan City, He'nan Province

Landscape dynamics, focused on the process and pattern of changes of landscape structure and functions, is one of the core areas of landscape ecology studies. Issues addressed by landscape dynamics are also important components of the current studies of global environment changes, particularly land-use/land-cover changes. Many achievements in studies of landscape dynamics have been made in the past ten years. However, the inherent environmental differentiation within a given administrative or natural region has not been given adequate consideration in these studies. Consequently, the results of the studies were poorly applicable in local ecological, environmental and economic development at county level. In order to avoid this limitation in this study, we first divided the study region, Jiyuan City into four sub-regions, the mountainous, stony hills, loess hills and alluvial plains, according to the differentiation of the landform and physiognomy identified from the 2000 TM images released by Resources and Environment Center of Chinese Academy of Sciences. Landscape changes during 1995~2000 were analyzed based on the land use maps. The land uses were classified into 6 types: cropland, forested and for-forestry-use land, grassland, water body, residential areas, and unused land. The landscape change indicators such as the relative regional change rate, the land-use preference index (LUPI), the transitional probability matrix and the changing pattern of Jiyuan city from 1995 to 2000 were analyzed. The results showed that cropland area was the largest during 1995 to 2000, larger than all the other land use types, so the cropland is the landscape matrix. Within different land use types, the change was obvious. The cropland decreased from 57.61% to 42.31%, and the forested and for-forestry-use land and grassland increased from 28.28% to 32.42% and from 7.61% to 16.87% respectively in the whole region. The change rate for the loess hilly sub-region was higher than for any other sub-regions and for the total Jiyuan city. The change rates for water body, residential and unused land were higher in the loess hilly sub-region than in the whole region. Regarding the changing direction, the unused land was completely converted into forested land and the water bodies were mainly transformed into other land use types, only 26.07% of the water areas in 1995 were left in 2000. In general, the cropland, forested land and grassland have a high stability in the changing process, of which the unchanged area were respectively 65.09%, 85.8% and 50.4%, but the conversion direction in the changing area was concentrated in these three land use types. The result showed that some manpower, finance and materials were wasted. In order to ameliorate the environment quality, the government has invested a lot of money in planting trees and growing grasses, but the facts that the forested land and grassland being transformed into the cropland indicates that ecological and environmental destruction still exist. It was found that the driving force for land use changes in Jiyuan city is mainly the pursuit of environment benefit in macro-scale, in which the central government has played an important role. Key events include the implement of the Greening Program of Taihang Mountain, the Natural Forest Protection Program and the Mandatory Conversion of Marginal Farmlands to Forest Lands and Grassland Program. In addition, the construction of Xiaolangdi water reservoir is also a driving force on the landscape change during 1995 to 2000.