TROPHIC NICHES OF FOUR SPECIES OF COMMON SMALL MAMMALS IN INNER MONGOLIA GRASSLAND AND THEIR RELATIONSHIPS
内蒙古典型草原4种常见小哺乳动物的营养生态位及相互关系

In this paper, the realized trophic niche overlaps and breadths were calculated a mong Microtus brandti, Ochotona daurica, Citeilus dauricus and Lepus capensis respectively,according to the diet compositions under free-ling circumstances. Fundamental trophic niche breadths and overlaps of Microtus brandti, Ochotona daurica and Citellus dauricus were also measured based on the results of food selection tirals. Owing to the restriction of food availabil ity in the habitats, the realized trophic niche breadths of Microtus brandti Ochotona daurica and Citellus dauncus were more narrow than their fondamental ones, respectively. The overlap of local distribution spaces between Microtus brandti and Ochotona daurica might be lead t6 quite larger overlap of their realized trophic niches. The results of this paper supported MacArthur and Wilson' s compression hypothesis.