Contrasting influence of sea urchins on attached and drift macroalgae
Contrasting influence of sea urchins on attached and drift macroalgae
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海胆对附着和漂浮大型藻类的影响对比
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发表时间：
2005
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影响因子：
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通讯作者：
G. Kendrick
中科院分区：
文献类型：
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作者：
M. Vanderklift;G. Kendrick
海胆可以对温带珊瑚礁产生深远的影响，但它们的影响程度在地理位置上也有很大差异。本文描述了在澳大利亚西南部的一个潮下岩礁上，海胆对附着的大型藻类和漂流的大型植物的影响。在一项实验中，我们对围篱样地的H. ery- throgramma的密度进行了控制；在一秒钟内，我们操纵了在没有围栏的地块上红红弧菌的存在和不存在。对红藻密度的控制没有引起附着大藻生物量的变化，但海胆密度最高的处理对附着大藻生物量有较大的漂移。当从未隔离的样地去除红红胞丝藻时，在南方夏季观察到略高的大藻生物量，但几个月后这种差异就不存在了。然而，未去除海胆的样地的漂流生物量是未去除海胆样地的4倍。在漂流物中占主导地位的大型植物种类很少或没有出现在附着在珊瑚礁上的植物组合中，这表明大部分漂流物起源于其他地方，要么是邻近的海草床，要么是数百米到公里外的珊瑚礁。红胞芽胞杆菌对海带辐射Ecklonia辐射有不成比例的滞留。基于这些结果，我们认为以漂流藻为形式的空间补贴导致红红红囊藻对附着藻的影响较弱。
Sea urchins can exert a profound influence on temperate reefs, but the extent of their influence also varies considerably among geographic locations. Here, we describe the influence of the sea urchin Heliocidaris erythrogramma on attached macroalgae and drift macrophytes at a sub- tidal rocky reef in south-western Australia. In one experiment, we manipulated the density of H. ery- throgramma in fenced plots; in a second, we manipulated the presence and absence of H. erythro- gramma in unfenced plots. The manipulation of H. erythrogramma density did not result in changes in attached macroalgal biomass, but the treatment with the highest density of sea urchins had a greater drift macrophyte biomass. When H. erythrogramma was removed from unfenced plots, a slightly higher macroalgal biomass was observed in the austral summer, but this difference was not present a few months later. However, the drift biomass was 4 times higher in plots where sea urchins were not removed. The dominant macrophyte species in the drift were scarce or absent from the assemblage growing attached to the reef, suggesting that much of the drift originated elsewhere, either in adjacent seagrass beds or on reefs hundreds of metres to kilometres away. There was a disproportionate retention of drift kelp Ecklonia radiata by H. erythrogramma. Based on these results, we propose that spatial subsidies in the form of drift macroalgae result in a weak influence of H. erythrogramma on attached macroalgae.