Interspecific demographic trade‐offs and soil‐related habitat associations of tree species along resource gradients
Interspecific demographic trade‐offs and soil‐related habitat associations of tree species along resource gradients
复制标题
DOI：
10.1111/j.1365-2745.2007.01330.x
复制
发表时间：
2007-12
影响因子：
5.5
通讯作者：
S. Russo;P. Brown;Sylvester Tan;S. Davies
中科院分区：
文献类型：
--
作者：
S. Russo;P. Brown;Sylvester Tan;S. Davies
1基本人口比率之间的种间关系，通常被称为人口权衡，产生于个体内部与形态、生理和资源分配有关的限制。在强光下生长迅速的植物物种通常在阴凉处死亡率较高，这种良好的关系在一定程度上决定了一个物种的演替生态位。更广泛地说，这种关系代表了一种权衡，一种是物种快速生长以开发丰富资源的能力，另一种是在资源不那么充足的情况下避免死亡，但很少有研究描述这种人口结构与光以外的环境因素之间的权衡。2利用婆罗洲热带雨林中960个树种的人口统计数据，我们检验了快速生长和低死亡率之间存在种间人口平衡的证据，以及由土壤肥力和水分变化定义的生境之间的差异。这种权衡可能有助于对不同栖息地的树种进行分类，并在一定程度上解释了这片森林和其他森林中物种土壤联想的显著模式。3我们发现了这种人口平衡的有力证据，无论是在同一生境中，还是在土壤丰富的生境上的生长与地下资源可获得性较低的生境上的死亡率进行比较时。4不同生境的生长-死亡关系斜率不同，地下资源最低的生境的斜率最大。对于潜在生长速度最快的物种，在这种生境上的死亡率高于在三个土壤丰富的生境上的可比增长率，这提供了一种可能的机制，通过这种机制，快速生长的物种可能会从最差的生境中消失。适应快速增长可能会带来更大的死亡风险，如果固有的快速增长物种在地下资源稀缺的情况下未能保持正的碳平衡。5相反，对于潜在生长速度最慢的物种，最高的物种死亡率出现在地下资源可获得性最大的生境上，这意味着生长缓慢的物种在资源丰富的环境中可能处于竞争劣势。6综合。这种取舍陡峭程度上的生境差异可能会沿着这种土壤梯度将物种分类到不同的栖息地，而在同一土壤上，这种人口平衡可能会促进至少一些物种在这片森林中共存。因此，通过产生随资源梯度变化的新出现的人口权衡，植物生活史策略可以影响物种多样性和分布。
1 Interspecific relationships between fundamental demographic rates, often called demographic trade‐offs, emerge from constraints within individuals related to morphology, physiology and resource allocation. Plant species that grow fast in high light usually have high mortality in shade, and this well‐established relationship in part defines a species’ successional niche. More generally, this relationship represents a trade‐off between a species’ ability to grow quickly to exploit abundant resources vs. avoiding mortality when resources are less plentiful, but few studies have described this demographic trade‐off with respect to environmental factors other than light. 2 Using demographic data from 960 tree species in Bornean rain forest, we examined the evidence for an interspecific demographic trade‐off between fast growth and low mortality and its variation among habitats defined by variation in soil fertility and moisture. Such a trade‐off could contribute to sorting of tree species among habitats and partly explain the striking patterns of species’ edaphic associations in this and other forests. 3 We found strong evidence for this demographic trade‐off, both within the same habitat and when growth on edaphically rich habitats was compared with mortality on a habitat with lower below‐ground resource availability. 4 The slope of the growth‐mortality relationship varied among habitats, being steepest on the habitat lowest in below‐ground resources. For species with the fastest potential growth rates, mortality was higher on this habitat than at comparable growth rates on the three more edaphically rich habitats, providing a possible mechanism by which fast‐growing species may be eliminated from the poorest habitat. Adaptations for fast growth may entail a greater mortality risk, if inherently fast‐growing species fail to maintain a positive C‐balance when below‐ground resources are scarce. 5 Conversely, for species with the slowest potential growth rates, the highest species’ mortality rates occurred on the habitats with greatest below‐ground resource availability, implying that slow‐growing species may have a competitive disadvantage in resource‐rich environments. 6 Synthesis. Differences among habitats in the steepness of this trade‐off may sort species into different habitats along this edaphic gradient, whereas on the same soil, this demographic trade‐off could facilitate coexistence of at least some species in this forest. Thus, by generating emergent demographic trade‐offs that vary along resource gradients, plant life‐history strategies can influence species diversity and distribution.