ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia.
Ecology. 2010 Dec;91(12):3572-83. doi: 10.1890/10-0143.1.
Dispersal influences ecological dynamics, evolution, biogeography, and biodiversity conservation, but models of larval dispersal in marine organisms make simplifying assumptions that are likely to approximate poorly the temporal dynamics of larval survival and capacity for settlement. In particular, larval mortality rates are typically assumed to be constant throughout larval life; and all larvae are frequently assumed to acquire and lose competence at the same time. To improve upon these assumptions, we here develop simple models of dispersal potential that incorporate rates of mortality, and acquisition and loss of settlement competence. We fit these models to empirical competence and survival data for five scleractinian coral species, to test the models' ability to characterize empirical survival and competence patterns, and to estimate the dispersal potential implied by those patterns. The models fit the data well, incorporating qualitative features of competence and survival that traditional approaches to modeling dispersal do not, with important implications for dispersal potential. Most notably, there was high within-cohort variation in the duration of the competent period in all species, and this variation increases both self-recruitment and long-distance dispersal compared with models assuming a fixed competent period. These findings help to explain the seeming paradox of high genetic population structure, coupled with large geographic range size, observed in many coral species. More broadly, our approach offers a way to parsimoniously account for variation in competence dynamics in dispersal models, a phenomenon that our results suggest has important effects on patterns of connectivity in marine metapopulations.
扩散影响生态动态、进化、生物地理学和生物多样性保护，但海洋生物幼虫扩散模型做出了简化假设，这些假设可能无法很好地近似幼虫生存和定居能力的时间动态。特别是，幼虫死亡率通常被假定在整个幼虫期保持不变；而且通常假定所有幼虫同时获得和失去定居能力。为了改进这些假设，我们在这里开发了简单的扩散潜力模型，该模型纳入了死亡率以及获得和失去定居能力的速率。我们将这些模型拟合到五个石珊瑚物种的经验能力和生存数据中，以测试模型表征经验生存和能力模式的能力，并估计这些模式所暗示的扩散潜力。这些模型很好地拟合了数据，纳入了传统扩散建模方法没有的能力和生存的定性特征，对扩散潜力有重要影响。最值得注意的是，所有物种的有能力期持续时间在种群内都有很大的变化，与假设有固定能力期的模型相比，这种变化增加了自我补充和远距离扩散。这些发现有助于解释在许多珊瑚物种中观察到的高遗传种群结构与大地理范围大小相结合的看似悖论。更广泛地说，我们的方法为在扩散模型中合理考虑能力动态变化提供了一种途径，我们的结果表明，这种现象对海洋复合种群的连通性模式有重要影响。
