BIRD ACTIVITY AND SEED DISPERSAL OF A TROPICAL WET FOREST TREE
BIRD ACTIVITY AND SEED DISPERSAL OF A TROPICAL WET FOREST TREE
复制标题
热带湿林树的鸟类活动和种子传播
DOI：
--
复制
发表时间：
1977
期刊：
影响因子：
--
通讯作者：
H. Howe
中科院分区：
文献类型：
--
作者：
H. Howe
在整个结实季节，在雨林树冠果树的哥斯达黎加种群中观察到鸟类的觅食群体，以区分有效的传播剂和不散布种子而使用ARILS作为食物的访客。这一系统具有特殊的意义，因为这棵树是在每年果实稀少的时期结出果实的，这片森林的特点是动物分散的植物和专职食果者的比例很高。结果表明，半裂叶金缕梅是一种有效的种子传播剂，因为它：(1)吐出有活力的种子，(2)是季节中常见的常客，(3)取食率高，(4)在加工种子之前从母树附近取出种子，(5)依赖于此而不是同时结果的其他植物。另有21名游客缺乏散布能力，尽管有些游客严重依赖这种树的果实作为食物。两只鹦鹉(秋亚马孙鹦鹉和粉红亚马孙鹦鹉)通过用喙剥翅并在原地撒下所有种子来阻止传播。有14种物种是偶尔的访客。5个访客(硫磺拉姆菲斯托斯、斯文森拉菲斯托斯、翼舌兰、相似Myiozetters和大Myiozetters)处理种子时不受损害，有时在数量上是相邻的，但在季节的一部分不存在，并倾向于在原位反流种子。由于这种树的结实活动发生在每年的稀缺期，所以它是群落中的一个关键物种。三只专职的食果者，包括一名有效的分散者和两名水果窃贼，在2-6周的时间里几乎完全依靠它作为食物。我推测，这种植物在这个地点的灭绝将导致这些鸟类的消失，并且几乎肯定会抑制在一年中的其他时间作为它们的分散剂的其他树种的招募。
Feeding assemblages of birds were observed throughout a fruiting season at a Costa Rican population of the rain forest tree Casearia corymbosa in order to distinguish effective dispersal agents from visitors which used arils for food without dispersing seeds. This system is of special interest because the tree fruits during an annual period of fruit scarcity in a forest characterized by high proportions of animal-dispersed plants and obligate frugivores. Results show that the Masked Tityra (Tityra semifasciata) is an effective dispersal agent of seeds of this tree because it: (1) regurgitates viable seeds, (2) is a common and regular visitor throughout the season, (3) has high feeding rates, (4) removes seeds from the vicinity of the parent tree before processing them, and (5) depends on this rather than other plants fruiting at the same time. Twenty-one other visitors were deficient dispersers, although some depended heavily on fruit of this tree for food. Two parrots (Amazona autumnalis and Amazona farinosa) preclude dispersal by strip- ping arils with their bills and dropping all seeds in situ. Fourteen species are occasional visitors. Five visitors (Ramphastos sulfuratus, Ramphastos swainsonii, Pteroglossus torquatus, Myiozetetes similis, and Myiozetetes granadensis) process seeds undamaged and are sometimes numerically abun- dant, but are absent part of the season and tend to regurgitate seeds in situ. Because fruiting activity of this tree occurs during annual scarcity, it represents a pivotal species in the community. Three obligate frugivores, including one effective disperser and two fruit thieves, depend almost entirely on it for food for periods of 2-6 wk. I hypothesize that extinction of this plant at this site would lead to disappearance of these birds, and would almost certainly depress recruitment of other species of trees for which they serve as dispersal agents at other times of the year.