瑞典南部落叶林动物对种子捕食的实验研究

在瑞典南部落叶林,于1985年和1986年秋季分别研究了不同动物对欧洲七叶树、夏栎、山楂和黑刺李等4种种子的捕食作用,即种子释放1周后被动物捕食的情况。实验分以下3种处理:排除小兽和鸟、排除鸟和对照(小兽和鸟均不排除),但昆虫可进入所有处理。在不同落叶林和小型林地共建有16个重复实验,即每个林分类型于每年秋季各设4个重复。在所有林分(包括落叶林和小型林地),不同处理的种子捕食表明:小兽是欧洲七叶树、夏栎和黑刺李等植物种子的主要捕食者,而无脊椎动物则是山楂种子的重要捕食者,但鸟类很少取食上述种子,因而捕食作用极小。在其中1年,动物对种子的总捕食率在落叶林和小型林地存在较大差异,以小型林地较高。

Seed predators in south Swedish deciduous woods: a field experiment

Seeds from oak, horse chestnut, hawthorn, and sloe were exposed to seed predation during one week in autumn and over winter (for 6 months) in two different years. Three different exposure treatments were used and designed to exclude (1) small mammals and birds or (2) birds or (3) none. Insects and slugs had access to all exposures. 16 replicate experiments were set up in different deciduous woods and small woodlots. The pattern of seed loss from the different treatments suggest that small mammals were the quantitatively most important seed predators on chestnut, acorns and sloe nuts. Invertebrates probably had some importance as predators on hawthorn nuts. Birds appeared to be of less importance. This conclusion was valid for both woods and small woodlots. In one year, total predation rates were significantly higher in small woodlots than in large woods.