中文摘要：

食物是多维生态位理论中最重要的一维,食物生态位的分离对群落中物种的稳定共存起到非常重要的作用。对高寒草甸生态系统中常见的7种雀形目鸟类的食性调查表明,它们主要以草籽、昆虫和燕麦等为食,且不同物种对不同食物的取食比例存在较大差异曰不同物种的食物生态位宽度变化较大（0.120~0.752）,除黄嘴朱顶雀（Carduelis flavirostris）和地山雀（Pseudopodoces humilis）的食物生态位重叠较小（0.059）外,其他物种间的重叠都较大（0.334~0.904）。不同物种的肝重、胃重和小肠长度存在较大的差异,比如以草籽为食的黄嘴朱顶雀,其肝重和胃重较小,小肠长度最大；以昆虫为食的地山雀,其胃重和小肠长度最小,肝重较大。随着各物种食性由草籽到昆虫的变化,小肠长度逐渐变小,杂食性物种的相关变化不明显。栖息于相似生境中的雀形目鸟类具有不同的食物资源利用模式,而同域共存物种消化道形态结构的差异是对食物资源利用种间权衡的功能响应。

英文摘要：

Diet is one of the most important dimension in the hypovolume niche, and the separation of di- etary niche plays an important role in the stable coexistence of species within a community. Diet and mor- phological characteristics of digestive tracts of seven passerines in alpine meadow were studied. Grass seeds, insects and oats were the main components of the diets of passerines. The food niche breadth ranged from 0.120 to 0.752, and the overlap from 0.334 to 0.904, except for the overlap of twites （C. flavirostris） and ground tits （P.. humilis）, which was 0.059. The liver weight, stomach weight and the intestine length of the seven stud- ied species were significantly different. Twites, which eat grass seeds only, have the lightest liver and stom- ach, but the longest intestines, while ground tits, mainly eating insects, have the lightest stomach and short- est intestines, but the heaviest liver. Intestines became shorter as the diet was changed from grass seeds to insects, while there was no obvious tendency within omnivorous species. These results support our hypothe- ses that： 1） food selection pattern are different among passerine species in alpine meadow, and 2） the differ- ent features of gut morphology among these species are a functional manifestation of the partitioning of food resource in alpine meadow.