Genotype variation in bark texture drives lichen community assembly across multiple environments.
Genotype variation in bark texture drives lichen community assembly across multiple environments.
复制标题
树皮纹理的基因型变异驱动地衣群落在多种环境中的组装。
作者：
L. J. Lamit;Matthew K. Lau;R. R. Næsborg;T. Wojtowicz;T. Whitham;C. Gehring
群落遗传学的一个主要目标是了解物种内遗传变异对生态群落的影响。虽然对一些生物有很好的记录，但需要更多的研究来了解基因型和环境对生物多样性的相对和相互作用的影响，确定树木基因型影响群落的机制，并将这一新兴领域与生态学中现有的主题联系起来。我们采用了一个未充分利用，但具有生态意义的一组生物，附生树皮地衣，了解相关的生物群落组装和主机个体发育的背景下，杨树angustifolia（窄叶棉白杨）基因型和环境的相对重要性。出现了几个关键的调查结果。(1)在一个单一的共同花园，树木基因型解释地衣群落变量和粗糙树皮覆盖的变化，分别为18-33%和51%。(2)在复制常见的花园，树的基因型影响地衣物种丰富度，总地衣覆盖，地衣物种组成，和粗糙的树皮覆盖，而环境只影响组成，没有基因型与环境的相互作用。(3)粗糙树皮覆盖与地衣总覆盖和丰富度呈正相关，并与物种组成的转变有关;在一般园林中，同一年龄的树木基因型间粗皮覆盖率的变化以及在自然河岸林中粗皮覆盖率沿沿着-40年的年龄梯度的增加都表现出这种模式。（4）在一般园林中，20岁的父母树与光滑的树皮有不发达的地衣群落，类似于他们的10岁的分株（根吸盘）生长在附近，而父母树与高粗糙的树皮覆盖有更发达的社区比他们的分株。这些研究结果表明，附生地衣受宿主基因型的影响，这种影响在不同的环境中是强大的。此外，对树木基因型的反应可能是个体发育从光滑树皮向粗糙树皮转变的时间遗传变异的结果，使某些基因型上的群落比其他基因型上的群落聚集得更快。在典型的群落遗传学领域之外的生物，如地衣，可以帮助解决关键问题，并将植物基因型效应与生物学研究的长期发展联系起来，如个体发育和群落组装。
A major goal of community genetics is to understand the influence of genetic variation within a species on ecological communities. Although well-documented for some organisms, additional research is necessary to understand the relative and interactive effects of genotype and environment on biodiversity, identify mechanisms through which tree genotype influences communities, and connect this emerging field with existing themes in ecology. We employ an underutilized but ecologically significant group of organisms, epiphytic bark lichens, to understand the relative importance of Populus angustifolia (narrowleaf cottonwood) genotype and environment on associated organisms within the context of community assembly and host ontogeny. Several key findings emerged. (1) In a single common garden, tree genotype explained 18-33% and 51% of the variation in lichen community variables and rough bark cover, respectively. (2) Across replicated common gardens, tree genotype affected lichen species richness, total lichen cover, lichen species composition, and rough bark cover, whereas environment only influenced composition and there were no genotype by environment interactions. (3) Rough bark cover was positively correlated with total lichen cover and richness, and was associated with a shift in species composition; these patterns occurred with variation in rough bark cover among tree genotypes of the same age in common gardens and with increasing rough bark cover along a -40 year tree age gradient in a natural riparian stand. (4) In a common garden, 20-year-old parent trees with smooth bark had poorly developed lichen communities, similar to their 10-year-old ramets (root suckers) growing in close proximity, while parent trees with high rough bark cover had more developed communities than their ramets. These findings indicate that epiphytic lichens are influenced by host genotype, an effect that is robust across divergent environments. Furthermore, the response to tree genotype is likely the result of genetic variation in the timing of the ontogenetic shift from smooth to rough bark allowing communities on some genotypes to assemble faster than those on other genotypes. Organisms outside the typical sphere of community genetics, such as lichens, can help address critical issues and connect plant genotype effects to long-established streams of biological research, such as ontogeny and community assembly.