Plant-soil feedbacks promote negative frequency dependence in the coexistence of two aridland grasses
Plant-soil feedbacks promote negative frequency dependence in the coexistence of two aridland grasses
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DOI：
10.1098/rspb.2016.0608
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发表时间：
2016-07-27
影响因子：
4.7
通讯作者：
Rudgers, Jennifer A.
中科院分区：
文献类型：
--
作者：
Chung, Y. Anny;Rudgers, Jennifer A.
了解物种共存的机制是预测物种多样性模式的关键。从历史上看，生态范式一直是物种通过划分资源而共存：随着物种数量的增加，自我限制开始发挥作用，因为特定物种的资源减少。然而，对于资源需求高度重叠的定居生物，如植物，确定共存机制一直是一个特别的难题。最近的证据表明，与植物相关的微生物可以产生物种共存所需的稳定的自我限制(负频率依赖性)。在这里，我们测试了植物微生物反馈导致这种自我限制的关键假设。我们使用竞争实验和模型来评估两种常见的土壤微生物(根际微生物和生物土壤结皮)如何影响两种竞争的荒漠草物种的自我限制。优势植物竞争对手与其根际微生物之间的负反馈放大了自我限制，而植物物种与生物土壤结皮之间的有益相互作用部分抵消了这种稳定作用。在旱地生态系统中，植物微生物相互作用作为植被动态的驱动因素受到的关注相对较少。我们的结果表明，微生物机制可能有助于干旱草原上植物共存的模式。
Understanding the mechanisms of species coexistence is key to predicting patterns of species diversity. Historically, the ecological paradigm has been that species coexist by partitioning resources: as a species increases in abundance, self-limitation kicks in, because species-specific resources decline. However, determining coexistence mechanisms has been a particular puzzle for sedentary organisms with high overlap in their resource requirements, such as plants. Recent evidence suggests that plant-associated microbes could generate the stabilizing self-limitation (negative frequency dependence) that is required for species coexistence. Here, we test the key assumption that plant microbe feedbacks cause such self-limitation. We used competition experiments and modelling to evaluate how two common groups of soil microbes (rhizospheric microbes and biological soil crusts) influenced the self-limitation of two competing desert grass species. Negative feedbacks between the dominant plant competitor and its rhizospheric microbes magnified self-limitation, whereas beneficial interactions between both plant species and biological soil crusts partly counteracted this stabilizing effect. Plant microbe interactions have received relatively little attention as drivers of vegetation dynamics in dry land ecosystems. Our results suggest that microbial mechanisms can contribute to patterns of plant coexistence in arid grasslands.