高原鼠兔冬季的食物选择

Food selection pattern for plateau pika in winter

本文采用胃内容物镜检分析法,对高原鼠兔在矮嵩草草甸、垂穗披碱草草甸和杂类草草甸三种类型栖息地中的主要食物组成进行了比较分析,旨在探讨三类栖息地不同食物资源状况对高原鼠兔食物组成的影响,以及高原鼠兔在食物匮乏的冬季的觅食对策。研究结果表明:高原鼠兔在冬季主要选食弱小火绒草和铺散亚菊,甘肃棘豆、垂穗披碱草和长茎藁本也是冬季食物主要组成部分。在冬季食物资源较为匮乏的情况下,高原鼠兔选食的主要植物种类相对较多,且不同植物比例变化明显,说明高原鼠兔对食物具有一定的选择性。在矮嵩草草甸中,其食物组成依次为铺散亚菊(16.2%)>弱小火绒草(11.5%)>甘肃棘豆(11.3%)>大籽蒿(9.7%)>早熟禾(7.6%)>长茎藁本(7.5%)>垂穗披碱草(5.5%)等7种,占其食物的69.3%;在垂穗披碱草草甸,其主要食物组成依次为垂穗披碱草(15.8%)>甘肃棘豆(14.7%)>弱小火绒草(14.5%)>铺散亚菊(14.2%)>早熟禾(7.8%)>长茎藁本(6.9%)>锥果葶苈(6.2%)等7种,占其食物的80.1%;在杂类草草甸中,其主要食物组成依次为铺散亚菊(20.8%)>长茎藁本(20.6%)>大籽蒿(9.9%)>弱小火绒草(9.8%)>锥果葶苈(6.5%)>圆齿狗娃花(5.5%)等6种,占选食食物的73.1%。不同栖息地之间食物组成比较分析结果表明,在冬季食物资源匮乏的情况下,栖息地类型不同对高原鼠兔食物组成的影响较小,杂类草构成了它们的主要食物,这可能是由食物质量决定的,而不同栖息地中喜食植物可利用量是决定鼠兔食物组成的主要因子,进一步验证了食物可利用量和质量决定植食性小哺乳动物食物选择模式的假设。

We compared diets of pikas （ Ochotona curzoniae） among meadows dominated by Kobresia humilis, Elymus nutans, and forbs, using micro-histological analysis of stomach contents. Our objective was to explain the effects of changing habitats on pikas, and to examine adaptability and foraging strategy for pikas in winter. The results showed that pikas prefer Leontopodium pusillum, Ajania khartensis, Elymus nutans, Oxytropis kansuensis, Ligusticum thomsonii rather than the others, and plant species composition was larger during food shortage winter. In the Kobersia humilis meadow, main food items were A. khartensis of 16. 2% , L. pusillum of 11.5% , O. kansuensis of 11.3% , Artemisia sieversiana of 9.7% , Poa sp. of 7.6% , Ligusticum thomsonii of 7.5% , E. nutans of 5.5% , and total food items of 69. 3%. In the E. nutans meadow, main food items were E. nutans of 15.8%, O. kansuensis of 14.7%, L. pusillum of 14. 5% , A. khartensis of 14. 2% , Poa sp. of 7.8%, Ligusticum thomsonii of 6. 9%, Draba lanceolata of 6.2%, and total food items of 80. 1%. In the forbs meadow, main food items were A. khartensis of 20. 8%, Ligusticum thomsonii of 20. 6%, A. khartensis of 9. 9%, L. pusillum of 9. 8%, D. lanceolata of 6. 5%, Heterpappus crenatifolius of S. 5%, and total food items of 73.1%. the diets with habitats, suggesting that they can adapt to changing habitat conditions. The results, which the food items compared in different habitats, indicated that habitat changing had a little influence on food items in winter, and the forbs were the main food resource, it may be decided by food quality. The food availability in different habitats may be the key factor that influenced food items. These results above support to the hypothesis that the food availability and food quality decide food selection pattern further more.