甘肃鼠兔贮草越冬及其生物学意义

对采自草甸、灌丛和弃耕地3 种类型栖息地共27 个甘肃鼠兔草堆的研究结果表明, 每个草堆干重在23.8～984.2 g 之间, 平均184.2 g , 总计含有26 种双子叶植物和一些禾本科单子叶植物。分析显示, 草堆大小(食物重量) 与栖息地植被类型无关。在贮存干草堆时, 甘肃鼠兔对不同植物成分具有强烈的选择性, 其中, 单子叶植物和双子叶植物分别占总重量的8.06 %和84.61 % , 与它们各自在栖息地中的生物量百分比51.76 %和39.57 %形成鲜明对照。甘肃鼠兔对植物种类的选择性在一定程度上受栖息地植被类型的影响, 但最喜食的几种植物却基本不变, 它们是美丽风毛菊、棘豆、麻花艽、禾草、线叶龙胆。人工去除栖息地中的干草堆后, 甘肃鼠兔种群越冬存活率从对照样地的51.84 %下降到21.33 % , 表明草堆食物对其成功越冬有一定正效应。野外观察证实, 甘肃鼠兔的鸣声不及同域分布的高原鼠兔发达, 但前者具有贮存食物越冬的习性, 而后者却不贮存越冬食物, 此结果不支持“鼠兔类动物建立草堆的行为与鸣声行为平行发育”的观点。

Hay-pile Caches as Winter Food by Gansu Pikas and Its Biological Significance

Composition of haypile caches as winter food by Gansu pikas ( Ochotona cansus) and it's relationships to habitat vegetation type were studied based on the 27 hay-piles collected in late fall of 1999 from meadow , shrub , and old fields at the Haibei Research Station of Alpine Meadow Ecosystem , the Chinese Academy of Sciences. The results showed that each hay-pile had a dried weight of 23.8 - 984.2 g with average of 184.2 g , and no significant difference was detected between samples collected from meadow , shrub , and old fields. There were 26 species of dicotyledons and some unidentified monocotyledons in Gramineae in the hay-pile materials. The proportion of dicotyledons in dried weight was 84.61 % , much higher than that of monocotyledons (8.06 %). Compared to their proportions in the environment (39.57 % for dicotyledons and 51.76 % for monocotyledons) , this meant that Gansu pikas preferred dicotyledons to monocotyledons when they cached their winter food. Preferences of plant materials were relatively stable , even though their availability in habitats affected their proportions in hay-piles. The most preferring plants were Saussurea superba , Oxytropis spp. , Gentiana straminea , some grasses in Gramineae , and Gentiana farreri. Overwinter survival of Gansu pikas reduced from 51.84 % for control plot ( 1 hm2) to 21133 %for treatment plot ( 1 hm²) by removing hay-piles , implying that cached food was critical for the animal to live over the winter. Field observations indicated that vocal behavior of Gansu pikas developed poor than that of sympatric plateau pika ( Ochotona curzoniae) without the habit of caching winter food. This disagreed with Kawamichi's (1976 , 1985) opinion that the development of calling parallels the occurrence of harvesting behavior.