Within-Year Soil Legacies Contribute to Strong Priority Effects of Exotics on Native California Grassland Communities
Within-Year Soil Legacies Contribute to Strong Priority Effects of Exotics on Native California Grassland Communities
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DOI：
10.1111/j.1526-100x.2008.00497.x
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发表时间：
2010-09-01
影响因子：
3.2
通讯作者：
Suding, Katharine N.
中科院分区：
文献类型：
--
作者：
Grman, Emily;Suding, Katharine N.
了解优先效应（即栖息地中的一个物种会降低后来物种的成功）对于恢复本地群落可能至关重要。优先效应可以通过两种方式发挥作用：规模不对称竞争和“土壤遗产”的创造，即对土壤的影响在竞争效应之后可能持续很长时间。我们研究了竞争和土壤遗产这两种优先效应如何驱动本地和外来加州草原植物幼苗之间的相互作用。我们在中宇宙实验中建立了本土和外来的社区。 5周后，我们从一半的处理（土壤遗留处理）中移除植物，并保留另一半的植物（优先效应处理，我们将其解释为包括竞争和土壤遗留）。然后我们添加本地或外来种子作为殖民群落。两个月后，我们测量了定殖群落的生物量。当首先发芽时，本地植物和外来植物都产生了优先效应，分别减少了殖民生物量 86% 和 92%。这些优先效应主要是由于规模不对称竞争造成的。只有外来物种才会创造土壤遗产，而这些遗产只会影响本土殖民者，导致生物量减少 74%。这些结果意味着外来物种的优先效应可以影响原生草原的恢复。尽管大多数修复工作的重点是清除外来幼苗，但改良土壤以解决土壤遗留问题也可能至关重要。此外，由于本地物种如果先发制人，可以排除外来物种，因此确保本地物种首先发芽可能是一种具有成本效益的恢复技术。
Understanding priority effects, in which one species in a habitat decreases the success of later species, may be essential for restoring native communities. Priority effects can operate in two ways: size-asymmetric competition and creation of "soil legacies," effects on soil that may last long after the competitive effect. We examined how these two types of priority effects, competition and soil legacies, drive interactions between seedlings of native and exotic California grassland plants. We established native and exotic communities in a mesocosm experiment. After 5 weeks, we removed the plants from half the treatments (soil legacy treatment) and retained the plants in the other half (priority effect treatment, which we interpret to include both competition and soil legacies). We then added native or exotic seed as the colonizing community. After 2 months, we measured the biomass of the colonizing community. When germinating first, both natives and exotics established priority effects, reducing colonist biomass by 86 and 92%, respectively. These priority effects were predominantly due to size-asymmetric competition. Only exotics created soil legacies, and these legacies only affected native colonizers, reducing biomass by 74%. These results imply that exotic species priority effects can affect native grassland restorations. Although most restorations focus on removing exotic seedlings, amending soil to address soil legacies may also be critical. Additionally, because native species can exclude exotics if given a head start, ensuring that natives germinate first may be a cost-effective restoration technique.