Phase-Shift Dynamics of Sea Urchin Overgrazing on Nutrified Reefs.
Phase-Shift Dynamics of Sea Urchin Overgrazing on Nutrified Reefs.
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DOI：
10.1371/journal.pone.0168333
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Ling SD
中科院分区：
文献类型：
--
作者：
Kriegisch N;Reeves S;Johnson CR;Ling SD
从多产的海带床到贫瘠的海胆贫瘠地的转变在全球范围内发生，代表了潮下温带珊瑚礁生态的大规模变化。虽然在可选稳定状态之间转换的理论很先进，但很少有详细描述这种转换动力学的实地研究。在这项研究中，对海胆草食（一个“自上而下”的生态系统驱动因素）进行了为期12个月的操纵，以估计(1)海胆密度，在此情况下，海胆床会崩塌为海胆贫瘠区；(2)在澳大利亚菲利普湾城市化的实验珊瑚礁上，维持海胆贫瘠区所需的最低海胆密度。与此同时，通过(3)操纵当地的营养水平，从而试图改变实验珊瑚礁的初级生产，研究了生态系统结构的“自下而上”驱动因素之一的作用。研究发现，当海胆密度大于等于8只（≥427 g m-2生物量）时，会导致海带床完全过度放牧，而当海胆密度小于等于4只（≤213 g m-2生物量）时，海带床会恢复。该实验通过探索该系统中可能的临界点（4至8个海胆m-2（分别为213和427 g m-2）），进一步了解了海胆贫瘠地和海带床之间的过渡动力学。局部增加养分负荷不会改变过度放牧或海带床恢复所需的海胆密度，因为藻类的生长不受养分增加的影响。
Shifts from productive kelp beds to impoverished sea urchin barrens occur globally and represent a wholesale change to the ecology of sub-tidal temperate reefs. Although the theory of shifts between alternative stable states is well advanced, there are few field studies detailing the dynamics of these kinds of transitions. In this study, sea urchin herbivory (a ‘top-down’ driver of ecosystems) was manipulated over 12 months to estimate (1) the sea urchin density at which kelp beds collapse to sea urchin barrens, and (2) the minimum sea urchin density required to maintain urchin barrens on experimental reefs in the urbanised Port Phillip Bay, Australia. In parallel, the role of one of the ‘bottom-up’ drivers of ecosystem structure was examined by (3) manipulating local nutrient levels and thus attempting to alter primary production on the experimental reefs. It was found that densities of 8 or more urchins m-2 (≥ 427 g m-2 biomass) lead to complete overgrazing of kelp beds while kelp bed recovery occurred when densities were reduced to ≤ 4 urchins m-2 (≤ 213 g m-2 biomass). This experiment provided further insight into the dynamics of transition between urchin barrens and kelp beds by exploring possible tipping-points which in this system can be found between 4 and 8 urchins m-2 (213 and 427 g m-2 respectively). Local enhancement of nutrient loading did not change the urchin density required for overgrazing or kelp bed recovery, as algal growth was not affected by nutrient enhancement.
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影响因子：
2.5
作者：
Feehan, C.;Scheibling, R. E.;Lauzon-Guay, J. S.
通讯作者：
Lauzon-Guay, J. S.
DOI：
10.1098/rstb.2013.0272
发表时间：
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影响因子：
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影响因子：
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作者：
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影响因子：
2.4
作者：
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通讯作者：
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