Grazer removal and nutrient enrichment as recovery enhancers for overexploited rocky subtidal habitats
Grazer removal and nutrient enrichment as recovery enhancers for overexploited rocky subtidal habitats
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DOI：
10.1007/s00442-014-2944-4
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发表时间：
2014-07-01
期刊：
影响因子：
2.7
通讯作者：
Fraschetti, Simonetta
中科院分区：
文献类型：
--
作者：
Guarnieri, Giuseppe;Bevilacqua, Stanislao;Fraschetti, Simonetta
日益增加的人为压力正在造成从高多样性生态系统向低多样性退化生态系统的长期制度转变。了解多种威胁对生态系统的影响，并确定恢复生物多样性的过程，是生态学目前面临的主要挑战。在几个温带海洋区域，由于过度捕捞，包括非法捕捞海枣贻贝，大部分以高度多样性为特征的岩石潮下带生境已完全退化为不毛之地。裸区的特点是海胆占主导地位，它们的放牧使过度捕捞的影响永久化。我们的实验研究的单独和综合效果的营养富集和海胆排除在贫瘠的土地上恢复。我们的研究结果表明，这两个因素有协同作用，导致重建直立的大型藻类冠层，提高潮下带组合的结构复杂性。特别是，在这里考虑的过度捕捞系统中，只有在海胆被移除的情况下，才能恢复受干扰的组合。然而，在富集条件下，直立大型藻类对贫瘠土地的酸化作用进一步增强。这项研究表明，恢复严重枯竭的海洋生境是可能的，并为目前完全缺乏的具体管理行动提供了有用的指示，以恢复人类活动造成的贫瘠土地。
Increasing anthropogenic pressures are causing long-lasting regime shifts from high-diversity ecosystems to low-diversity degraded ones. Understanding the effects of multiple threats on ecosystems, and identifying processes allowing for the recovery of biodiversity, are the current major challenges in ecology. In several temperate marine areas, large parts of rocky subtidal habitats characterised by high diversity have been completely degraded to barren grounds by overfishing, including illegal date mussel fishing. Bare areas are characterized by the dominance of sea urchins whose grazing perpetuates the impact of overfishing. We investigated experimentally the separate and combined effects of nutrient enrichment and sea urchin exclusion on the recovery of barren grounds. Our results indicate that the two factors have a synergistic effect leading to the re-establishment of erect macroalgal canopies, enhancing the structural complexity of subtidal assemblages. In particular, in the overfished system considered here, the recovery of disturbed assemblages could occur only if sea urchins are removed. However, the recolonization of barren grounds by erect macroalgae is further enhanced under enriched conditions. This study demonstrates that the recovery of dramatically depleted marine habitats is possible, and provides useful indications for specific management actions, which at present are totally lacking, to achieve the restoration of barren grounds caused by human activity.