Genotypic variation in a foundation tree (Populus tremula L.) explains community structure of associated epiphytes

Community genetics hypothesizes that within a foundation species the genotype of an individual significantly influences the assemblage of dependent organisms. To assess whether these intra-specific genetic effects are ecologically important, it is required to compare their impact on dependent organisms with that attributable to environmental variation experienced over relevant spatial scales. We assessed bark epiphytes on 27 aspen (Populus tremula L.) genotypes grown in a randomized experimental array at two contrasting sites spanning the environmental conditions from which the aspen genotypes were collected. We found that variation in aspen genotype significantly influenced bark epiphyte community composition, and to the same degree as environmental variation between the test sites. We conclude that maintaining genotypic diversity of foundation species may be crucial for conservation of associated biodiversity.

群落遗传学（Community genetics）提出假说：在基础物种（foundation species）内，单个个体的基因型会显著调控其依附生物群落的组成。为评估此类种内遗传效应（intra-specific genetic effects）是否具备生态学重要性，需将其对依附生物的影响，与相关空间尺度下环境变异所产生的影响进行对比。我们以27个颤杨（Populus tremula L.）基因型为研究对象，调查其树皮附生植物（bark epiphytes）群落；这些基因型被栽种于两处环境梯度覆盖该颤杨基因型原生采集环境的对比样地中，且栽种布局采用随机实验阵列设计。研究结果显示，颤杨基因型的变异会显著影响树皮附生植物的群落组成，其影响程度与两处实验样地间的环境变异相当。综上，维持基础物种的基因型多样性，或许对保护其伴生生物多样性至关重要。