Dynamic changes in seagrass assemblages under eutrophication and implications for recovery
Dynamic changes in seagrass assemblages under eutrophication and implications for recovery
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DOI：
10.1016/j.jembe.2003.10.014
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发表时间：
2004-05-12
影响因子：
2
通讯作者：
Marques, JC
中科院分区：
文献类型：
--
作者：
Cardoso, PG;Pardal, MA;Marques, JC
在过去的20年里，海草床的丧失（通常与富营养化加剧有关）已成为世界范围内的一个共同问题。在Mondego河口（葡萄牙），富营养化引发了严重的生物变化，这导致了初级生产力的全面增加，并逐步取代海草Zostera noltii床粗沉积物和机会macroalgae.这种富营养化对底栖生物组合的影响进行了研究沿着在Mondego河口1993年至1995年的空间梯度。在这些短时间和小空间尺度上，观察到大型底栖动物群落结构的明显变化。其中一个主要的结构变化是物种多样性沿着富营养化梯度和随着时间的推移而减少，最受干扰的内部区域明显缩小。其他变化包括在食草动物的增加和减少，以及一个显着增加的小沉积物喂养多毛类动物。在长期的，持续的富营养化的河口，预计将导致完全取代海草栖息地的无植被粗沉积物，偶尔覆盖的绿色大型藻类水华和机会无脊椎动物类群为主。从这种情况中恢复可能不仅需要减少河口的营养负荷，而且还需要积极的海草恢复方案，以扭转目前被认为正在发生的正反馈过程。(C)2003 Elsevier B.V.保留所有权利。
Over the last 20 years, loss of seagrass beds, often related with increased eutrophication, became a common problem worldwide. In the Mondego estuary (Portugal), eutrophication has triggered serious biological changes, which led to an overall increase in primary production and to a progressive replacement of seagrass Zostera noltii beds by coarser sediments and opportunistic macroalgae.The effects of this eutrophication on benthic assemblages were studied along a spatial gradient in the Mondego estuary from 1993 to 1995. Over these short temporal and small spatial scales, distinct changes in the structure of the macrobenthic communities were observed. One of the main structural modifications was the decrease in species diversity along the eutrophication gradient and over time, with a marked impoverishment of the most disturbed inner area. Other changes included an increase in detritivores and a decline in herbivores together with a significant increase in small deposit-feeding polychaetes.In the long term, sustained eutrophication of this estuary is expected to lead to complete replacement of seagrass habitat by unvegetated coarser sediments, occasionally covered by green macroalgal blooms and dominated by opportunistic invertebrate taxa. Recovery from this situation may not only require reduction in nutrient loadings to the estuary, but also active seagrass restoration programmes to reverse the positive feedback processes thought to be presently taking place. (C) 2003 Elsevier B.V. All rights reserved.