Trophic control of cryptic coralline algal diversity
Trophic control of cryptic coralline algal diversity
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DOI：
10.1073/pnas.1900506116
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发表时间：
2019-07-23
影响因子：
11.1
通讯作者：
Martone, Patrick T.
中科院分区：
文献类型：
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作者：
Hind, Katharine R.;Starko, Samuel;Martone, Patrick T.
了解营养动力学如何驱动生物多样性的变化是至关重要的预测全球生态系统的营养降级的结果。然而，评估生物多样性的形态隐蔽的谱系可能是有问题的，但可能是至关重要的理解生态模式。有利于食草动物丰度增加的关键捕食的变化往往对初级生产者的生物多样性产生负面影响。然而，在近岸生态系统中，珊瑚藻类覆盖增加时，草食动物是激烈的，这表明珊瑚可能会独特地受益于营养降级。由于许多珊瑚藻类物种在形态上是神秘的，它们的多样性在全球范围内被低估了，提高我们区分物种的分辨率可能会大大改变我们对这一群体营养动力学后果的结论。在这项研究中，我们使用DNA条形码比较的多样性和组成的隐藏的珊瑚藻组合在不同的海胆生物量和基石捕食海獭的网站。我们表明，虽然在海胆为主的地点（或“贫瘠之地”）中，珊瑚覆盖率更高，这些地点受到强烈的放牧，但这些海胆贫瘠之地的珊瑚群落的多样性明显低于海带森林，并且仅由1或2个物种占主导地位。这些研究结果澄清了食物网结构与珊瑚群落组成的关系，并调和了珊瑚总覆盖模式与广泛记录的模式，即基石捕食促进生物多样性。珊瑚多样性和分布的变化与从海带森林到海胆贫瘠地的过渡有关，可能会产生生态系统层面的影响，而忽视神秘物种的身份会错过这些影响。
Understanding how trophic dynamics drive variation in biodiversity is essential for predicting the outcomes of trophic downgrading across the world's ecosystems. However, assessing the biodiversity of morphologically cryptic lineages can be problematic, yet may be crucial to understanding ecological patterns. Shifts in keystone predation that favor increases in herbivore abundance tend to have negative consequences for the biodiversity of primary producers. However, in nearshore ecosystems, coralline algal cover increases when herbivory is intense, suggesting that corallines may uniquely benefit from trophic downgrading. Because many coralline algal species are morphologically cryptic and their diversity has been globally underestimated, increasing the resolution at which we distinguish species could dramatically alter our conclusions about the consequences of trophic dynamics for this group. In this study, we used DNA barcoding to compare the diversity and composition of cryptic coralline algal assemblages at sites that differ in urchin biomass and keystone predation by sea otters. We show that while coralline cover is greater in urchin-dominated sites (or "barrens"), which are subject to intense grazing, coralline assemblages in these urchin barrens are significantly less diverse than in kelp forests and are dominated by only 1 or 2 species. These findings clarify how food web structure relates to coralline community composition and reconcile patterns of total coralline cover with the widely documented pattern that keystone predation promotes biodiversity. Shifts in coralline diversity and distribution associated with transitions from kelp forests to urchin barrens could have ecosystem-level effects that would be missed by ignoring cryptic species' identities.