The relationship between larval supply and settlement is an integral part of the demographic processes of benthic marine organisms that determine their distribution at subsequent life stages. In ascidians, a strong positive relationship between larval supply and settlement has been previously documented, but only at small spatial scales (one location) and short time scales (less than one day). We investigated how this relationship might scale up by sampling larval abundance and settlement of a colonial ascidian (Botryllus schlosseri) across mesoscales (100 s of m) of the anthropogenic seascape of a 1.5-ha marina. Settlement varied vertically with a linear decrease in settlement with increasing depth. This pattern corresponded to the vertical distribution of larvae in the morning, when they were most abundant. However, larval abundance explained only 26% of the variation in settlement at the meso-spatial scale (i.e. the combined effect of the horizontal and vertical dimensions). This weakening of the relationship between larval supply and settlement suggests that the two processes may become decoupled at larger spatial and temporal scales. Our study underscores how changing the scales of sampling may affect our understanding of larval dispersal and settlement processes.

中文翻译：

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幼虫供应是人为海洋景观中尺度沉降的有限决定因素

幼虫供应和定居之间的关系是底栖海洋生物人口统计过程的一个组成部分，决定了它们在随后的生命阶段的分布。在海鞘中，幼虫供应和定居之间存在强烈的正相关关系，但仅在小空间尺度（一个位置）和短时间尺度（不到一天）中被记录下来。我们通过在 1.5 公顷码头的人为海景的中尺度（100 秒的米）上对殖民地海鞘 (Botryllus schlosseri) 的幼虫丰度和定居点进行采样，研究了这种关系如何扩大。沉降垂直变化，随着深度的增加，沉降呈线性下降。这种模式对应于早晨幼虫的垂直分布，此时幼虫数量最多。然而，幼虫丰度仅解释了中空间尺度（即水平和垂直维度的综合影响）的沉降变化的 26%。幼虫供应和定居之间关系的减弱表明这两个过程可能会在更大的空间和时间尺度上脱钩。我们的研究强调了改变采样规模可能会影响我们对幼虫扩散和定居过程的理解。