北京东灵山区景观类型空间邻接与分布规律

景观由斑块实间镶嵌而成。如何从错综复杂的斑块镶嵌中发现景观类型的空间分布规律，是景观格局研究中亟待解决的问题。通过对北京东灵山地区景观类型空间邻接关系的研究，借鉴群落生态学方法对其空间分布规律进行了探讨。结果表明，各个景观类型的空间邻接特征明显差异，可依紧密邻接的类型数目和程度分为３类；决定景观类型邻接多样性的主要因素是邻接类型的数目；采用作者提出的以景观类型空间邻接长度替代群落学数据的群落分类方

Viewpoints on the study of economic thresholds of cotton bollworm

Landscapes are the spatial mosaic of patches.How to find spatial distribution regularity of landscape types in a complicated patch mosaics still remains as a challenge in landscape pattern analysis.The spatial neighboring properties of the landscape types in Donglingshan mountain region,Beijing,China was studied,the spatial distribution regularity of the landscapes types was found by using the classification method adapted from community ecology.The results showed that,the spatial properties of the landscape types were quite different.The main factor determining the spatial neighboring diversity of the landscape types was the number of neighboring types.The spatial distribution of the landscape types was clearly divided into 3 groups by using the adapted TWINSPAN classification:subalpine,middle mountain,and low mountain groups.They were obviously correlated with elevation,and influenced by human disturbance degree.