Habitat fragmentation and the demographic structure of an Amazonian understory herb (Heliconia acuminata)
Habitat fragmentation and the demographic structure of an Amazonian understory herb (Heliconia acuminata)
复制标题
DOI：
10.1046/j.1523-1739.2002.99494.x
复制
发表时间：
2002-10-01
影响因子：
6.3
通讯作者：
Kress, WJ
中科院分区：
文献类型：
--
作者：
Bruna, EM;Kress, WJ
人们对植物种群破碎化的人口后果知之甚少。通过评估一种常见的草本植物（Heliconia acuminata）在亚马逊河中部的实验碎片化景观的人口结构，我们测试了碎片化可以降低人口密度，改变人口结构，减少生殖努力的预测。在连续森林的人口密度变化六倍，一些地区有高密度和其他低密度。小碎片和大碎片边缘的种群密度通常较低，但在连续森林中发现的密度范围内，并且位置之间的差异不显著。然而，在森林片段的蝎尾蕉种群偏向于较小的人口规模类。因为H. acuminata与植物大小正相关，预测这些变化会导致森林片断中开花植物较少。种群开花的比例在森林碎片和连续森林没有显着差异，虽然有一个趋势，比例更大的开花在连续森林。对于开花的植物，每个个体的繁殖成功率（以发育中的坐果率衡量）在森林碎片和连续森林中是相同的。我们的研究结果表明，每一个人和种群水平的繁殖林下草本植物在热带森林片段可能会抵抗片段隔离的有害后果。我们的研究还强调了需要考虑碎片化如何影响人口结构和人口统计学方面的丰富和水果生产，因为这些替代措施的人口结构可以修改森林片段在微妙的，意想不到的方式。
Little is known about the demographic consequences of fragmentation for plant populations. By assessing the population structure of a common herb (Heliconia acuminata) in an experimentally fragmented landscape in the central Amazon, we tested the predictions that fragmentation could reduce population density, alter population structure, and reduce reproductive effort. Population density in continuous forest varied six-fold, some areas having high density and others low density. Population density in small fragments and on the edges of large fragments was often low, but it was within the range of densities found in continuous forest, and the difference between locations was not significant. Heliconia populations in forest fragments were skewed toward smaller demographic size classes, however. Because reproduction in H. acuminata is positively correlated with plant size, these shifts were predicted to result in fewer flowering plants in forest fragments. The proportion of the population flowering in forest fragments and continuous forest was not significantly different, although there was a trend toward proportionately greater flowering in continuous forest. For plants that did flower, per-individual reproductive success (measured as developing fruit set) was the same in forest fragments and continuous forests. Our results suggest that per-individual and population-level reproduction by understory herbs in tropical forest fragments may be resistant to the detrimental consequences of fragment isolation. Our study also highlights the need to consider how fragmentation influences aspects of population structure and demography beyond abundance and fruit production, because these alternative measures of population structure can be modified in forest fragments in subtle, unexpected ways.