SEED AND SEEDLING ECOLOGY OF NEOTROPICAL MELASTOMATACEAE
SEED AND SEEDLING ECOLOGY OF NEOTROPICAL MELASTOMATACEAE
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新热带牡丹科种子及幼苗生态学
DOI：
10.2307/1939932
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发表时间：
1993
期刊：
影响因子：
4.8
通讯作者：
Bette A. Loiselle
中科院分区：
文献类型：
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作者：
A. Ellison;J. Denslow;Bette A. Loiselle
热带潮湿森林的林隙阶段更新模型主要是基于树冠树木的研究。这些范例来自于对少数物种的研究，这些物种的生活史特征使它们很容易成为“先锋”或“顶极”物种。木本植物的森林林下，亚冠层的树木和灌木，是众所周知的影响显着更新动态的树落间隙，但我们缺乏基本的信息林下植物的生活史特征，可以允许他们纳入间隙更新模型。我们调查了内和种间的变化，在早期生活史特征的林下不同的生长形式和成年人的分布，从低地热带雨林在拉塞尔瓦生物站，哥斯达黎加。我们研究了发芽模式在体外（22种），发芽的影响，通过鸟类（5种），幼苗建立在外地（3种），并在不同的光环境（8种）的增长。建立幼苗显着更丰富的差距比附近的林下网站。这种模式是普遍适用于所有melastomes研究，无论栖息地的成年人通常是最丰富的。幼苗更常见的根坑和根丘连根拔起的树木，即使有较少的光提供给幼苗在这些微网站比其他地方的差距。在一系列的离体萌发试验中，大多数种子在1-2周内容易萌发。从鸟粪中收集的种子和从水果中手工提取的种子的发芽率的比较给出了不同的结果。除了一个例外，耐荫物种的种子在通过鸟类后发芽较慢，而高光需求物种的种子在通过鸟类后发芽更快。三种常见的种子直接播种到不同的microsites内的差距和林下对照网站。与发芽试验相反，田间出苗率从林下点的4%到林隙中心的21%不等。1年后的生存率较低（0.1%- /0.4%）。1年后，这些幼苗很小（<2厘米高），产生很少的叶子。在类似的光环境中的荫蔽房子，melastome幼苗的存活率在80%和100%之间，增长增加，从2%（对应于林下网站）到20%（小间隙中心）的全阳光的光照水平。除了两个物种常见的废弃牧场和河岸，在荫棚生长实验中使用的物种没有显示出显着的增长与增加的光从20%到40%。套房的热带树种描述的早期生活史特征是不一致的变化模式内看到这一个家庭的林下物种。
Models of gap-phase regeneration in tropical wet forests are based primarily on studies of canopy trees. These paradigms are derived from studies of a small number of species whose life history traits place them easily into "pioneer" or "climax" species. Woody plants of the forest understory, subcanopy trees and shrubs, are known to affect significantly regeneration dynamics in treefall gaps, yet we lack fundamental information on life history characteristics of understory plants that could permit their incorporation into gap regeneration models. We investigated intra- and interspecific variability in early life history characteristics of understory Melastomataceae species of different growth forms and adult distributions from the lowland tropical rain forest at La Selva Biological Station, Costa Rica. We examined germination patterns in vitro (22 species), effects on germination of passage through birds (5 species), seedling establishment in the field (3 species), and growth in different light environments (8 species). Established seedlings were significantly more abundant in gaps than in nearby under- story sites. This pattern was generally applicable to all melastomes studied, regardless of the habitat where adults were normally most abundant. Seedlings were more common in the root pits and on the root mounds of uprooted trees, even though there was less light available to the seedlings in these microsites than elsewhere in the gaps. In a series of germination trials in vitro, most seeds germinated readily within 1-2 wk. Comparisons of germination rates between seeds collected from bird droppings and seeds extracted from fruits by hand gave varied results. With one exception, seeds of shade-tolerant species germinated more slowly following passage through birds, while seeds from high-light- demanding species germinated more rapidly after passing through birds. Seeds of three common species were sown directly into different microsites within gaps and understory control sites. In contrast to the germination trials, emergence percentages in the field ranged from 4% in understory sites to 21 % in gap centers. Survival after 1 yr was low (0.1%- /0.4%). After 1 yr, these seedlings were small (<2 cm tall) and produced few leaves. In similar light environments in the shade-house, melastome seedling survival was between 80% and 100%, and growth increased with increasing light levels from 2% (corresponding to understory sites) to 20% (small gap centers) of full sun. With the exception of two species common to abandoned pastures and river banks, the species used in the shade-house growth experiments did not show significant increases in growth with increases in light from 20% to 40%. Suites of early life history traits described for tropical tree species are not consistent with the variation in pattern seen within this one family of understory species.