Data from: Genotypic covariance between the performance of a resident species and community assembly in the field

1.Genetic variation in resident species can influence the assembly and dynamics of communities, but the potential for these genetic effects to persist across generations is largely unresolved. In principle, persistent, directional changes in communities are only predicted when community properties covary genetically with the fitness of resident species. 2.Estimates of genetic covariance between the fitness of a resident species and its community are therefore necessary to ‘close the eco-evolutionary loop’ in studies of community genetics, but such estimates are rare. Emulating community genetics experiments in plants, we used clonal replicates of 21 genotypes of a resident species (the encrusting bryozoan, Hippopodina) to investigate the magnitude of genotypic variance contributing to assembly of a marine benthic community. 3.Genotypes explained up to 35% of variation in community assembly. Critically, the performance of Hippopodina genotypes covaried both with the evenness of communities, and with the abundances of some individual species, representing an indirect genetic effect that creates the potential for multigenerational interactions between Hippopodina and co-existing species. Our results suggest that different genotypes will associate with different community members consistently across generations, and such non-random associations can give rise to specialization. Further interactions between species other than Hippopodina itself may also be altered by effects of genetic variation in the focal species. 4.Furthermore, species in the community other than Hippopodina itself will interact more commonly in the presence of some genotypes over others. 5.Our results support the potential for genetic variation in one species to have deterministic effects on the dynamics of ecological communities.1. 定居物种（resident species）的遗传变异可影响群落组装（community assembly）与群落动态（community dynamics），但这类遗传效应能否跨世代延续，目前尚未得到充分阐明。理论上，仅当群落属性与定居物种的适合度（fitness）存在遗传共变关系时，才会预测到群落出现持续性的定向变化。 2. 因此，要在群落遗传学（community genetics）研究中闭合‘生态进化闭环’，需要估算定居物种适合度与其群落之间的遗传协方差（genetic covariance），但此类估算目前较为匮乏。本研究效仿植物群落遗传学实验，利用某定居物种——结壳苔藓虫（encrusting bryozoan，*Hippopodina*属）的21个基因型（genotype）的克隆重复株（clonal replicates），探究了驱动海洋底栖群落（marine benthic community）组装的基因型方差大小。 3. 基因型可解释高达35%的群落组装变异。尤为关键的是，*Hippopodina*属物种的基因型表现，既与群落均匀度（community evenness）存在共变关系，也与部分物种的多度（species abundance）存在共变，这代表了一种间接遗传效应（indirect genetic effect），为*Hippopodina*属与共存物种（co-existing species）之间的跨世代互作（multigenerational interactions）创造了可能。本研究结果表明，不同基因型会在跨世代过程中持续与不同群落成员形成关联，这类非随机关联可催生生态位特化（specialization）。除*Hippopodina*属自身外的其他物种间的进一步互作，也可能因目标物种（focal species）的遗传变异效应而发生改变。 4. 此外，相较于其他基因型，当存在特定基因型时，群落中非*Hippopodina*属的物种间会更频繁地发生互作。 5. 本研究结果证实，单一物种的遗传变异有可能对生态群落动态产生决定性影响。