Trophic cascade in a marine protected area with artificial reefs: Spiny lobster predation mitigates urchin barrens
Trophic cascade in a marine protected area with artificial reefs: Spiny lobster predation mitigates urchin barrens
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DOI：
10.1002/eap.2364
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发表时间：
2021-05-21
影响因子：
5
通讯作者：
Taino, Seiya
中科院分区：
文献类型：
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作者：
Kawamata, Shigeru;Taino, Seiya
海洋保护区 (MPA) 的最终好处是扭转因人类导致的关键生态相互作用崩溃而造成的营养级联。在这里，我们证明，尽管规模较小（0.28 km(2)）并且没有得到充分保护，日本西南部的海洋保护区通过严格的捕捞管理和人工鱼礁（AR）增强栖息地，可以通过捕食者恢复的级联效应，在广泛的海胆贫瘠之地上形成完善的大型藻类群落。海胆密度低的区域出现在白天龙虾（Panulirus japonicus）庇护所内和周围，这些庇护所主要由海洋保护区内的采石场岩石 AR 形成。我们在实验室中证实，龙虾捕食两种优势海胆（Echinometra sp. A 和 Heliocidaris crassispina），其捕食行为与体型和物种有关。海胆很少的区域从有大量龙虾的 AR 延伸到比从龙虾少得多的天然庇护所（斑礁）延伸得更远（大约 65 m）。系留实验证实了这种模式的因果关系，该实验表明，在龙虾庇护所及其附近，对海胆的捕食率同样较高，但在距 AR 约 100 m 处下降到与未受保护地点相似的水平。延时摄影显示，对拴系海胆的捕食主要是由于最大型的龙虾（甲壳长度>100毫米），该类龙虾仅占种群的7%，这凸显了大型龙虾在控制与海胆为主的贫瘠之地邻近的局部地区海胆丰度方面的重要性。尽管海洋保护区允许每年进行一次的捕捞活动，但龙虾数量仍然持续存在，这表明龙虾对海胆和最终大型藻类的级联效应对于捕食者种群规模的暂时减少具有强大的作用。直立的大型藻类覆盖不仅仅由快照海胆密度或生物量来解释，这表明大型藻优势和海胆贫瘠状态之间的相移存在滞后效应。
An ultimate benefit of marine protected areas (MPAs) is to reverse trophic cascades caused by human-driven collapse of critical ecological interactions. Here we demonstrate that, despite a small scale (0.28 km(2)) and not being fully protected, an MPA with strict fishing management and habitat enhancement by artificial reefs (ARs) in southwest Japan can lead to well-established macroalgal communities on widespread sea urchin barrens through cascading effects of predator recovery. Areas with low urchin densities occurred in and around daytime lobster (Panulirus japonicus) shelters primarily formed by quarry-rock ARs inside the MPA. We confirmed in the laboratory that lobsters preyed on two dominant sea urchins (Echinometra sp. A and Heliocidaris crassispina), with size- and species-dependent predation. The area with few urchins extended farther (similar to 65 m) from an AR with numerous lobsters than from a natural shelter (patch reef) with far fewer lobsters. Causation of this pattern was confirmed by a tethering experiment showing that predation on urchins was similarly high at and near lobster shelters but decreased at similar to 100 m from the AR to a similar level as at an unprotected site. Time-lapse photography revealed that predation on tethered urchins was due mostly to the largest size class of lobsters (>100 mm carapace length), which comprised only 7% of the population, highlighting the importance of large-sized lobsters in controlling urchin abundance in localized areas adjacent to urchin-dominated barrens. Despite an ongoing once-a-year fishing event permitted within the MPA, lobster populations were persistent, demonstrating that the cascading effect of the lobsters on urchins and ultimately macroalgae was robust to temporary reductions in predator population size. Erect macroalgal cover was not simply accounted for by snapshot urchin density or biomass, suggesting a hysteresis effect of the phase shifts between macroalgal dominance and urchin barren states.