摘要
本文从农业生态系统原理出发选择57个适合于北京郊区农业生态系统分类的特征指标,以村作为类型分类的基本单元,对北京郊区有关县区的77个大队进行不重叠的、内在的等级聚合分类(系统聚类),采用了五种聚类分析方法。结果表明,离差平方和法分类效果较好。除最短距离方法外其它方法均可明显分出低集约化山区、中集约化平原、高度集约化近郊和特殊类型四大类型,阈值更小的划分出现相应的一些亚类型。研究农业生态系统类型将为不同类型的农业生态系统采取相应的控制和管理措施提供依据,从而达到扬长避短,因地制宜地分类指导生产,使农业生态系统获得较高的生态经济效益。
In this paper. 57 specific attributes which arc suitable for the classification of the village level aprofCoSystems are selected according to the principles of agroeccSy-stem. These specific attributes are taken for classifying the agroecosystems of 77 villages (production brigades) in some counties of Beijing suburbs and 5 methods of non-overlapping intrinsic hierarchical agglomerative analysis are adopted4The results are as follow: except the single linking method, the other methods adopted can classifty the villages clearly into \ major types: the less intensive farming mountain areas,the middle intensive farming plain areas, the highly intensive farming environs and the specific type. The Ward's hierarchical classification method is better than the others in this classification. With less threshold values, some subtypes were found. The differences among the units in the plain areas are smaller and the structure of it's units are steady, but the units closed to urban in third type are influenced by the city, the differences are obvious and the structure of it's units is unsteady.
出处
《生态学报》
CAS
CSCD
北大核心
1989年第3期253-258,共6页
Acta Ecologica Sinica
关键词
聚类分析
农业生态系统
北京郊区
cluster analysis, Beijing suburbs, aprroecosvstem.
