Abstract: The main mechanism and types of the formation and succession and spatial distribution pattern of agricultural ecosystem are discussed in this paper. It suggests that the formation and succession of agricultural ecosystem is co-influenced by the natural environmental conditions, natural resources, economic development level, market background, science and technology, policy systems,and social and cultural customs. But in different areas, the formation mechanism of the agroecosystem is also different. There are some main types such as the closed environment-induced, cultures and customs-induced, economy and technique-induced, resource-restricted, policy-induced types. Because of the interaction of above induced factors, agroecosystems often have following spatial distribution pattern, including gradient distribution, random inlaid distribution, island-like distribution and line or strip distribution.

Key words: Hucho taimen, compensatory growth, starvation and re-feeding, feeding frequency, coefficient of variation.