景观的空间异质性是景观要素产生能量流、物质流的原因，是景观的根本属性。尺度依赖性和方向依赖性是在研究景观空间异质性中的重要问题，然而各向异性即方向依赖性却未受到足够重视，这主要是因为没有简单有效的定量方法去描述和表达景观要素的各向异性，从而限制了该领域的研究。本文提出以中心发散的放射式角度来确定各向异性的方向，建立一套能表现一维方向上景观斑块特征的指标体系，编写了能自动提取景观类型图各方向景观指标的程序，并结合洪湖湿地恢复前后的水生植被景观及其动态变化，对该方法进行了探索性的应用实例研究，评价“洪湖湿地保护与恢复示范工程”前后对植被的恢复效果。本文所取得的成果和结论如下：

1.以湖心（中心）为基准的各向异性的概念构架可以较好的用于湖泊植被、城市扩张、极地冰川变化等放射性景观类型变化的定量表达。

2.单年高分辨率景观破碎性分析中，洪湖东北部植被覆盖率低，斑块数少，而西南部螺山干渠区域斑块数多，斑块密度大，破碎度高，西南保护区各方向斑块多，但破碎化相对并不严重。多样性最高的在西南三角湖、桐梓湖水域。

3.中低分辨率植被景观多年变化显示，各向植被都呈先减后升趋势，最大斑块距离指数LPDI较好的反映了水生植被向湖岸消退或向湖心推进的过程，反映了水产养殖和拆围等人工活动的正负反馈结果。

 

Spatial heterogeneity is the main reason for landscape energy and mass flux, which is basic attribute of landscape. Scale-dependence and direction-dependence are the two important issues in spatial heterogeneity. However the latter, also called anisotropy, was ignored, due to a lack of simple and effective methods dealing with description and expression of landscape anisotropy. This paper defines a radiate direction system from a central point to detect anisotropy. A one-dimension landscape index system was established displaying paths’ feature and a program was written for automatically extracting directional landscape index. We apply the new method as a exploratory study in Honghu lake aquatic vegetation landscape and its annual dynamic change research, which can also be used in evaluate the Honghu wetland conservation and restoration effect. The main conclusions are as follows:

1. The central-lake (central point) based direction definition concept framework is fit for the quantitative description of divergent landscape types such as lake vegetation, urban expansion and polar glacier.

2. In the single year high-resolution data fragments analysis shows the northeast of Honghu lake with rare aquatic vegetation cover, less path numbers, while southwest ,at the Luoshan main canal, with bigger path numbers, high path density, high fragmentation degree, the southwest conservation area, of large path number, but less fragmentation degree. Diversity analysis shows the highest value exist at Sanjiaohu, Tongzihu water area.

3. In the muti-year mid-low resolution data change detection, vegetation of all direction present first-decline-later-increase trend, the LPDI index shows the progress of aquatic vegetation regression to the lakeshore or expansion to central lake, which reflect the positive and negative feedback of aquaculture and purse seine removal