Habitat Fragmentation Differentially Affects Genetic Variation, Phenotypic Plasticity and Survival in Populations of a Gypsum Endemic.
Habitat Fragmentation Differentially Affects Genetic Variation, Phenotypic Plasticity and Survival in Populations of a Gypsum Endemic.
复制标题
生境破碎化对石膏特有种群遗传变异、表型可塑性和生存的差异影响
DOI：
10.3389/fpls.2017.00843
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发表时间：
2017
影响因子：
5.6
通讯作者：
Escudero A
中科院分区：
文献类型：
--
作者：
Matesanz S;Rubio Teso ML;García-Fernández A;Escudero A
生境破碎化（即片段大小和隔离程度）可以不同程度地改变植物群体中性和数量遗传变异、适合度和表型可塑性的模式，但很少同时对其影响进行测试。我们评估了大小和连连性对半毛茛（Centaurea hyssopifolia）种群遗传和表型变异这些方面的综合影响，半毛茛是一种狭窄的地方性嗜毒动物，以前显示出与碎片化相关的性能差异。我们从10个不同片段大小和连通性的种群中抽取了111个母系，在一个共同的花园中进行了实验，并对数量遗传变异、关键功能性状对干旱的表型可塑性以及作为种群适应度衡量指标的植物存活率进行了表征。我们还利用8个微卫星标记评估了群体内部和群体之间的中性遗传变异。虽然C. hyssopifolia是一种狭窄的地方性嗜石膏动物，但我们发现了大量的中性遗传变异和关键功能性状的数量变异。遗传变异的分配表明群体内变异比例较高，这与群体在分子标记、功能性状及其可塑性方面分化程度较低是一致的。这一点，再加上生境破碎化的影响一般较小，表明种群间的基因流动并未受到限制，尽管片段大小和隔离程度存在很大差异。重要的是，群体在遗传变异和可塑性方面的相似性并不能反映孤立群体中观察到的较低存活率。总体而言，我们的研究结果表明，尽管物种由能够表达功能可塑性的遗传可变种群组成，但这些适应潜力的方面可能并不总是反映种群的生存。鉴于生境连通性对功能性状、遗传变异和适合度的差异影响，我们的研究强调需要将碎片化研究的重点转移到调节连通性效应的机制上，并呼吁谨慎使用遗传变异和可塑性来预测种群表现。
Habitat fragmentation, i.e., fragment size and isolation, can differentially alter patterns of neutral and quantitative genetic variation, fitness and phenotypic plasticity of plant populations, but their effects have rarely been tested simultaneously. We assessed the combined effects of size and connectivity on these aspects of genetic and phenotypic variation in populations of Centaurea hyssopifolia, a narrow endemic gypsophile that previously showed performance differences associated with fragmentation. We grew 111 maternal families sampled from 10 populations that differed in their fragment size and connectivity in a common garden, and characterized quantitative genetic variation, phenotypic plasticity to drought for key functional traits, and plant survival, as a measure of population fitness. We also assessed neutral genetic variation within and among populations using eight microsatellite markers. Although C. hyssopifolia is a narrow endemic gypsophile, we found substantial neutral genetic variation and quantitative variation for key functional traits. The partition of genetic variance indicated that a higher proportion of variation was found within populations, which is also consistent with low population differentiation in molecular markers, functional traits and their plasticity. This, combined with the generally small effect of habitat fragmentation suggests that gene flow among populations is not restricted, despite large differences in fragment size and isolation. Importantly, population’s similarities in genetic variation and plasticity did not reflect the lower survival observed in isolated populations. Overall, our results indicate that, although the species consists of genetically variable populations able to express functional plasticity, such aspects of adaptive potential may not always reflect populations’ survival. Given the differential effects of habitat connectivity on functional traits, genetic variation and fitness, our study highlights the need to shift the focus of fragmentation studies to the mechanisms that regulate connectivity effects, and call for caution on the use of genetic variation and plasticity to forecast population performance.