Survival dynamics of scleractinian coral larvae and implications for dispersal
Survival dynamics of scleractinian coral larvae and implications for dispersal
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DOI：
10.1007/s00338-008-0361-z
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发表时间：
2008-09-01
期刊：
影响因子：
3.5
通讯作者：
Connolly, S. R.
中科院分区：
文献类型：
--
作者：
Graham, E. M.;Baird, A. H.;Connolly, S. R.
远洋海生幼体的生存是决定其扩散潜力的重要因素。尽管如此，很少有关于幼虫存活率的估计。对于硬核珊瑚，很少有关于幼虫存活的研究能够提供准确的寿命估计。此外，根据理论根据所预期的幼虫期死亡率的变化，对珊瑚礁之间的连通性程度有影响，而且没有对任何珊瑚物种进行量化。本研究量化了五种广播产卵的硬核珊瑚（Acropora latistella, Favia pallida, Pectinia paeonia， Goniastrea aspera和Montastraea magnistellata）的幼虫的存活率，以估计幼虫的寿命，并测试随着幼虫年龄的变化死亡率。最长寿命从195天到244天不等。这些寿命大大超过了以前记录的缺乏虫黄藻的珊瑚幼虫的寿命，也超过了基于幼虫早期代谢率的预测。此外，幼虫死亡率在整个幼虫期表现出强烈的变化模式。在四个物种中确定了三个时期：高初始死亡率；其次是低的、几乎恒定的死亡率；最后，在大约100天后，死亡率逐渐增加。本研究中观察到的寿命表明，远距离扩散的可能性可能比以前认为的要大得多。事实上，在生命后期发现的死亡率上升表明，能量储备直到产卵后大约100天才达到极低的水平。相反，生命早期死亡率的增加降低了从出生珊瑚礁转移到附近珊瑚礁的幼虫存活的可能性，从而降低了区域尺度上的连通性。这些结果表明，随着年龄的增长，幼虫存活率的变化可能有助于解释在超种群尺度上高度遗传结构的悖论，以及在许多珊瑚物种中观察到的广泛地理范围的维持。
Survival of pelagic marine larvae is an important determinant of dispersal potential. Despite this, few estimates of larval survival are available. For scleractinian corals, few studies of larval survival are long enough to provide accurate estimates of longevity. Moreover, changes in mortality rates during larval life, expected on theoretical grounds, have implications for the degree of connectivity among reefs and have not been quantified for any coral species. This study quantified the survival of larvae from five broadcast-spawning scleractinian corals (Acropora latistella, Favia pallida, Pectinia paeonia, Goniastrea aspera, and Montastraea magnistellata) to estimate larval longevity, and to test for changes in mortality rates as larvae age. Maximum lifespans ranged from 195 to 244 d. These longevities substantially exceed those documented previously for coral larvae that lack zooxanthellae, and they exceed predictions based on metabolic rates prevailing early in larval life. In addition, larval mortality rates exhibited strong patterns of variation throughout the larval stage. Three periods were identified in four species: high initial rates of mortality; followed by a low, approximately constant rate of mortality; and finally, progressively increasing mortality after approximately 100 d. The lifetimes observed in this study suggest that the potential for long-distance dispersal may be substantially greater than previously thought. Indeed, detection of increasing mortality rates late in life suggests that energy reserves do not reach critically low levels until approximately 100 d after spawning. Conversely, increased mortality rates early in life decrease the likelihood that larvae transported away from their natal reef will survive to reach nearby reefs, and thus decrease connectivity at regional scales. These results show how variation in larval survivorship with age may help to explain the seeming paradox of high genetic structure at metapopulation scales, coupled with the maintenance of extensive geographic ranges observed in many coral species.