Abstract: Cultivated soybeans are derived from Glycine soja Sieb.et Zucc.,which distributes only in the eastern Asia.China is located in the major part of eastern Asia and the germplasm of G.soja is abundant.Because of the human impacts on natural ecosystems,the species is under the threat of extinction and has been ranked as an endangered species.Thus,it is important to study the relationships between G.soja and its habitats for scientific protection.Based on systematic investigation of the G.soja communities in Beijing,niche width and niche overlap of 28 dominant species were analyzed at three different scales of region,habitat,and association group.The results demonstrate that the dominant species with high frequency had a broad niche,while others with low frequency had relatively narrow niches at three scales;there were certain similarities among G.soja communities in three different habitats(e.g.stone-based riverbed,soil-based riverbed,and idle land around reservoir),but the composition patterns of the dominant species were still different;the species with high niche width in their association groups could represent the habitat characteristics because the habitats influenced the distribution of species;species pairs with high niche overlaps were more likely to live in the similar habitats;the species with higher niche width were not likely to have higher niche overlap because different ecological characteristics and resource requirements could result in lower niche overlap.

Key words: Glycine soja Sieb.et Zucc., Niche width, Frequency, Niche overlap

摘要： 野生大豆(Glycine soja Sieb.et Zucc.)属豆科(Leguminosae),为我国二级濒危保护植物。为给野生大豆种群保护提供科学依据,对北京地区野生大豆群落环境进行系统调查,通过对区域、生境和群丛组3种不同尺度下28个优势种生态位宽度和生态位重叠分析,结果表明:在3种尺度下,优势种的生态位宽度同频度有相同的变化趋势,频度越大,生态位宽度越大;在石质河床、土质河床和水库撂荒地3种不同基质生境下分布的野生大豆群落具有一定相似性,但在优势种组成上仍有差异;每个群丛组生态位宽度较大的物种在一定程度上可以代表其群丛组生境特点,生境条件影响物种分布;生态位重叠值较高的各种对,因为具有相似的生物学特征,对生境要求比较相近;生态位宽度较大的种群之间,生态位重叠值并不一定高。

关键词: 野生大豆, 生态位宽度, 频度, 生态位重叠