Population biology of green sea urchins on rocky barrens
Population biology of green sea urchins on rocky barrens
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岩石贫瘠区绿海胆的种群生物学
DOI：
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发表时间：
1986
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影响因子：
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通讯作者：
J. Himmelman
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作者：
J. Himmelman
1968年夏季，对纽芬兰东部轻度放牧的石质荒地上的德巴哈圆心海胆种群进行了定量取样。在极度暴露、中等暴露和受保护地点的种群比较表明，在繁殖和/或幼体生存、死亡率和生长方面的差异可能是由温度、波暴露和食物供应的差异引起的。密集的人口有一种不同寻常的增长模式。幼鱼生长非常缓慢，在某一点上，几乎可以停止生长，从而形成一种固定的模式，由几年一班的幼鱼组成。该砾岩模式在不同位置或深度的测试直径范围为8 ~ 11mm。大于15至20毫米的海胆的生长速度要慢得多。我推测，在密集的种群中，幼小的海胆生长缓慢是由于严重的食物短缺和它们的低出生率。大于15至20毫米的海胆会主动移动，寻找大型藻类食物；据推测，它们的增长速度是由于它们的流动性和由此产生的更多的食物。如果任何一个积极觅食的大型海胆死亡，它们将被数量越来越多的幼崽所取代，从而保证了海胆主导的贫瘠地区的持续存在。
Populations of the sea urchm Strongylocentrotus droebachensis in lughly grazed rocky barrens in eastern Newfoundland were sampled quantitatively in summer 1968. Comparisons among populations at an extremely exposed, a moderately exposed and a protected site show Mferences in recruitment and/or juve~ule survival, mortality and growth which may be caused by dfferences in temperature, wave exposure and food availability. Dense populations have an unusual growth pattern. Juveniles grow very slowly and at a certain point growth can virtually stop causing the formation of a stationary mode composed of several year classes of juveniles. The position of this conglomerate mode varies from 8 to 11 mm in test diameter at different locahons or depths. Urchins larger than 15 to 20 mm have a much lugher growth rate. I hypothesize that the slow growth of juvenlle urchins in dense populations is due to a severe food shortage coupled to their low mobhty. Urchins larger than 15 to 20 mm move actively about searching for macroalgal food; it is postulated that their increased growth rate is due to their mobllity and resultant greater access to food. If any of the larger actively foraging urchins were to die they would be replaced by the ever abundant juveniles, thus assuring the persistence of urchin-dominated barrens.