Trade-offs between seedling growth and survival in deciduous broadleaved trees in a temperate forest
Trade-offs between seedling growth and survival in deciduous broadleaved trees in a temperate forest
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DOI：
10.1093/aob/mcl283
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发表时间：
2007-03-01
期刊：
影响因子：
4.2
通讯作者：
Seiwa, Kenji
中科院分区：
文献类型：
--
作者：
Seiwa, Kenji
在空间异质性环境中，幼苗存活率和相对生长率之间的权衡可能会促进植物物种的共存。然而，在温带森林中，在野外条件下，与荫棚实验相比，几乎没有发现对这一假设的支持。方法在3个林冠覆盖度水平下，研究了苗木质量相对生长率（RGR（M））和高度相对生长率（RGR（H））与苗木存活率的关系（林下植被，FU;小林隙，SG;和大的差距，LG）和两个微型网站内的每个层次的冠层覆盖（有无落叶层）。关键结果在每一个物种中，RCRm（M）和RGR（H）通常随光照水平的增加而增加（按FU < SG < LG的顺序），而基于有无凋落物观察到的差异很小。FU的幼苗存活率与LG和SG的RGR（M）和RCRH均呈负相关。与SG相比，在与LG的关系中高光生长和低光存活之间的权衡更明显。沿着环境梯度观察到种内存活率和RGR之间的权衡，而白桦幼苗的RGR。结论研究结果支持了温带森林光环境空间异质性的光梯度划分（即物种共存）的观点，并进一步说明了空间异质性的增加将促进物种多样性的提高。种内权衡生存和RGR在宏基表明，它有广泛的栖息地的要求，而桦木有狭窄的栖息地的要求，并专门在高光环境。
Background and Aims In spatially heterogeneous environments, a trade-off between seedling survival and relative growth rate may promote the coexistence of plant species. In temperate forests, however, little support for this hypothesis has been found under field conditions, as compared with shade-house experiments. Performance trade-offs were examined over a large resource gradient in a temperate hardwood forest.Methods The relationship between seedling Survival and seedling relative growth rate in mass (RGR(M)) or height (RGR(H)) was examined at three levels of canopy cover (forest understorey, FU; small gap, SG; and large gap, LG) and at two microsites within each level of canopy cover (presence or absence of leaf litter) for five deciduous broad-leaved tree species with different seed sizes.Key Results Within each species, both RCRm(M) and RGR(H) usually increased with increasing light levels (in the order FU < SG < LG), whereas little difference was observed based on the presence or absence of litter. Seedling survival in FU was negatively correlated with both RGR(M) and RCRH in both LG and SG. The trade-off between high-light growth and low-light survival was more evident in the relationship with LG as compared with SG. An intraspecific trade-off between survival and RGR was observed along environmental gradients in Acer mono, whereas seedlings of Betula platyphylla var. japonica survived and grew better in LG.Conclusions The results presented here strongly support the idea of light gradient partitioning (i.e. species coexistence) in spatially heterogeneous light environments in temperate forests, and that further species diversity would be promoted by increased spatial heterogeneity. The intraspecific trade-off between survival and RGR in Acer suggests that it has broad habitat requirements, whereas Betula has narrow habitat requirements and specializes in high-light environments.