Ontogenetic shifts in interactions among annual plants
Ontogenetic shifts in interactions among annual plants
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DOI：
10.1111/j.1365-2745.2006.01097.x
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发表时间：
2006-03
影响因子：
5.5
通讯作者：
K. Schiffers;K. Tielbörger
中科院分区：
文献类型：
--
作者：
K. Schiffers;K. Tielbörger
1植物之间的相互作用强烈地影响着植物种群和群落的结构和动态。然而，大多数关于植物-植物相互作用的实证研究未能对邻近个体的反应进行重复测量，从而忽视了植物生活史上相互作用可能发生的变化。2我们通过在以色列沿降雨梯度的三个研究地点连续测量邻居移除实验中的相互作用，检验了一年生物种之间的竞争从生活史早期到晚期加剧的假设。3两种一年生植物--木瓜和卷叶膜果在其自然栖息地中生长，有邻居生长和无邻居生长。在整个生长季中，记录了代表连续生活史阶段的5个响应变量(苗木存活、幼虫生物量、成虫存活、种子数和最终生物量)。4相互作用的方向和强度在环境和生命阶段之间有很大的差异。平均而言，与生长相关的响应变量表明气候梯度生产端的竞争强度较高，而生存表明要么在干端促进竞争，要么沿梯度没有趋势。5发生了时间上的变化，萌发后不久，适度的促进作用转变为生长季末的强烈竞争。6我们的结果表明，植物-植物相互作用的实验研究结果可能不仅取决于环境生产力，而且更取决于研究目标植物的生命阶段。
1 Interactions among plants strongly influence the structure and dynamics of plant populations and communities. However, most empirical studies of plant–plant interactions failed to make repeated measures of responses to neighbouring individuals and thereby neglected possible changes in interactions throughout the life history of the plants. 2 We tested the hypothesis that competition between annual species intensifies from early to late life‐history stages, by sequentially measuring interactions in neighbour‐removal experiments at three study sites located along a rainfall gradient in Israel. 3 Two annual species, Biscutella didyma and Hymenocarpos circinnatus, grew with and without neighbours in their natural habitats. Five response variables representing consecutive life‐history stages (seedling survival, juvenile biomass, adult survival, number of seeds and final biomass) were recorded throughout the whole growing season. 4 The direction and intensity of interactions varied considerably between environments and life stages. On average, growth‐related response variables indicated higher competition intensity at the productive end of the climatic gradient, while survival indicated either facilitation at the dry end or no trend along the gradient. 5 Temporal changes occurred, with moderate facilitation soon after germination shifting to strong competition at the end of the growing season. 6 Our results demonstrate that the outcome of experimental studies on plant–plant interactions may depend not only on the environmental productivity but more so on the life stage at which the target plant is studied.