江西省公路网规划对景观格局的影响分析

公路网作为廊道网络,对于景观格局的破碎化影响巨大.景观格局的破碎化会缩小景观斑块的尺寸,增加斑块之间的分离度,提高外界对斑块的干扰机率,最终导致生态系统生物多样性的降低,危害生态安全.提出了基于GIS的公路网景观格局影响分析的叠图法,并将其应用到江西省公路网规划环境影响评价中.该方法包括绘制景观图件、景观分类、景观指数计算以及景观影响分析4个步骤.

Analysis Method of impact of road network plan to landscape pattern

The present paper aims to introduce the author's study on the ecosystem fragmentation and the relation between such fragmentation and the impact of the road network on the isolation of such ecosystem patches. As is known, fragmentation refers to the break-up of natural areas into smaller and more isolated units. Our understanding of the insidiousness of habitat fragmentation has increased dramatically in the past few years and this effect is currently considered as one of the greatest threats to biodiversity world-wide. As a matter of fact, ecosystem fragmentation can be described by three main effects: (1) the increase in isolation of the ecosystem patches; (2) decrease in their size; and (3) increase in their exposure to external disturbances, such as the invasion by alien species or the changes in the physical conditions (shadow, wind, etc.). Such negative effects can potentially lead to a decline in the ecosystem biodiversity as well as in its stability and ability to recover from disturbances. We also know that road is acknowledged to be a major cause of fragmentation. The landscape fragmentation has been aggravated by the main transport infrastructure network bit by bit and day by day. Seeing the serious situation, we have put forward a method based on GIS, including 4 steps, namely drawing landscape picture, classing landscape, calculating landscape index and analyzing the impact of the road network. The suggested method can be applied to the strategic environmental assessment for road network plan of Jiangxi province.