Department of Ecology and Evolutionary Biology, Yale University, P.O. Box 208106, New Haven, CT 06520-8106, USA.
Oecologia. 2013 Feb;171(2):571-81. doi: 10.1007/s00442-012-2427-4. Epub 2012 Aug 21.
Climate change has the potential to alter the genetic diversity of plant populations with consequences for community dynamics and ecosystem processes. Recent research focused on changes in climatic means has found evidence of decreased precipitation amounts reducing genetic diversity. However, increased variability in climatic regimes is also predicted with climate change, but the effects of this aspect of climate change on genetic diversity have yet to be investigated. After 10 years of experimentally increased intra-annual variability in growing season precipitation regimes, we report that the number of genotypes of the dominant C(4) grass, Andropogon gerardii Vitman, has been significantly reduced in native tallgrass prairie compared with unmanipulated prairie. However, individuals showed a different pattern of genomic similarity with increased precipitation variability resulting in greater genome dissimilarity among individuals when compared to unmanipulated prairie. Further, we found that genomic dissimilarity was positively correlated with aboveground productivity in this system. The increased genomic dissimilarity among individuals in the altered treatment alongside evidence for a positive correlation of genomic dissimilarity with phenotypic variation suggests ecological sorting of genotypes may be occurring via niche differentiation. Overall, we found effects of more variable precipitation regimes on population-level genetic diversity were complex, emphasizing the need to look beyond genotype numbers for understanding the impacts of climate change on genetic diversity. Recognition that future climate change may alter aspects of genetic diversity in different ways suggests possible mechanisms by which plant populations may be able to retain a diversity of traits in the face of declining biodiversity.
气候变化有可能改变植物种群的遗传多样性，从而影响群落动态和生态系统过程。最近的研究集中在气候变化均值的变化上，发现降水减少会降低遗传多样性。然而，气候变化也预计会增加气候制度的可变性，但这方面的气候变化对遗传多样性的影响尚未得到调查。在经历了 10 年的实验性增加生长季节降水变异性后，我们报告说，与未受干扰的草原相比，原生高草草原中占优势的 C(4)草 Andropogon gerardii Vitman 的基因型数量显著减少。然而，与未受干扰的草原相比，个体表现出不同的基因组相似模式，增加的降水变异性导致个体之间的基因组差异更大。此外，我们发现，在这个系统中，基因组差异与地上生产力呈正相关。改变处理后的个体之间的基因组差异增加，以及基因组差异与表型变异的正相关表明，基因型的生态分类可能是通过生态位分化发生的。总的来说，我们发现更具变异性的降水模式对种群水平遗传多样性的影响是复杂的，这强调了需要超越基因型数量来理解气候变化对遗传多样性的影响。认识到未来的气候变化可能以不同的方式改变遗传多样性的某些方面，这表明植物种群在生物多样性下降的情况下可能保留多种特征的可能机制。
