Data from: Fire coral clones demonstrate phenotypic plasticity among reef habitats

Clonal populations are often characterized by reduced levels of genotypic diversity, which can translate into lower numbers of functional phenotypes, both of which impede adaptation. Study of partially clonal animals enables examination of the environmental settings under which clonal reproduction is favoured. Here, we gathered genotypic and phenotypic information from 3,651 georeferenced colonies of the fire coral Millepora platyphylla in five habitats with different hydrodynamic regimes in Moorea, French Polynesia. In the upper slope where waves break, most colonies grew as vertical sheets (“sheet tree”) making them more vulnerable to fragmentation. Nearly all fire corals in the other habitats are encrusting or massive. The M. platyphylla population is highly clonal (80% of the colonies are clones), while characterized by the highest genotype diversity ever documented for terrestrial or marine populations (1,064 genotypes). The proportion of clones varies greatly among habitats (≥58%–97%) and clones (328 clonal lineages) are distributed perpendicularly from the reef crest, perfectly aligned with wave energy. There are six clonal lineages with clones dispersed in at least two adjacent habitats that strongly demonstrate phenotypic plasticity. Eighty per cent of the colonies in these lineages are “sheet tree” on the upper slope, while 80%–100% are encrusting or massive on the mid slope and back reef. This is a unique example of phenotypic plasticity among reef-building coral clones as corals typically have wave-tolerant growth forms in high-energy reef areas.

克隆种群通常表现为基因型多样性水平降低，这往往会导致功能表型数量减少，二者均会阻碍种群的适应性演化。针对部分克隆繁殖生物的研究，可用于探究克隆繁殖受到选择青睐的环境条件。本研究采集了法属波利尼西亚茉莉雅岛5种不同水动力生境下的3651株带有地理坐标的板叶千孔珊瑚（Millepora platyphylla，火珊瑚）群落的基因型与表型信息。在波浪冲击的礁坡上部，多数群落以垂直片状形态生长（被称为"sheet tree"），使其更易发生破碎化；其余所有生境中的火珊瑚几乎均为结壳状或团块状生长形态。该板叶千孔珊瑚种群具有高度克隆性（80%的群落为克隆株），同时拥有迄今在陆生或海洋种群中记录到的最高基因型多样性（共1064个基因型）。不同生境间的克隆株占比差异显著（58%~97%不等）；共328个克隆谱系沿垂直于礁冠的方向分布，其分布格局与波浪能强度完全匹配。其中6个克隆谱系的克隆株分布于至少2个相邻生境，充分体现出表型可塑性（phenotypic plasticity）。这些谱系中，80%的群落在礁坡上部呈"sheet tree"生长形态，而在礁坡中部与礁后生境中，80%~100%的群落为结壳状或团块状生长。这是造礁珊瑚克隆种群中极为罕见的表型可塑性案例，因为造礁珊瑚通常在高能礁区会演化出耐波浪的生长形态。