Internaional Research Fellowship Program: Understanding the Role of Plasticity and Genetic Variation in Parallel Invasion Fronts: Range Expansion of Erodium Circutarium

[853094 . baythavong]该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。国际研究奖学金项目使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Brooke S. Baythavong博士与智利康塞普西翁大学（universsidad de Concepcion）的Ernesto Gianoli博士开展为期24个月的研究。入侵物种在快速扩张的过程中会经历各种各样的新环境。在一个新的范围内成功建立很可能是由群体内世系之间的遗传变异和表型可塑性的某种组合所促进的。本研究的重点是了解数量遗传变异和表型可塑性在决定一年生入侵植物黄花Erodium cicutarium种群的相对成功中的相对重要性，黄花Erodium cicutarium最近在加利福尼亚和智利进行了范围扩张。该项目利用实地调查、温室实验和贝叶斯建模技术来解决几个问题，包括：1)性状表达如何通过表型可塑性响应环境变化？2)来自环境异质性较大的生境的基因型是否比来自相对同质环境的基因型表现出更大的可塑性？3)在智利和加利福尼亚的入侵前线之间，性状值的遗传和可塑性变异在决定种群相对成功方面的作用是否不同？PI将为表型可塑性和数量遗传变异在重复入侵前沿快速范围扩张过程中决定种群相对成功的作用提供新的见解。虽然环境异质性的空间尺度长期以来一直被假设在决定表型可塑性表达的选择模式中发挥重要作用，但没有全面的测试。以往研究入侵物种范围扩展中遗传变异或表型可塑性的重要性，缺乏对类似于自然栖息地经历的环境变化的可塑性响应的全面分析。这项研究提供了迄今为止第一个全面的分析。入侵物种在世界范围内对地方和国家经济、生态系统完整性和本地物种多样性构成严重威胁。在过去的250年里，加州大部分地区？美国的草原已经被入侵的欧亚一年生植物所统治，包括一年生草本植物镰刀草。尽管入侵的欧亚植物也对智利草原的原生生态系统构成威胁，但入侵植物群落组成和种间相互作用在智利和加利福尼亚之间存在显著差异。由于这项研究结合了在复制入侵前线收集的谱系，它提供了在同一植物物种的两个地理上遥远范围边缘收集的种群之间的新颖比较。

0853094BaythavongThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Brooke S. Baythavong to work with Dr. Ernesto Gianoli at Universidad de Concepcion in Chile.Invasive species undergoing rapid range expansions experience a variety of novel environments. Successful establishment in a novel range is likely to be facilitated by some combination of genetic variation among lineages within a population and phenotypic plasticity. This research is focused on understanding the relative importance of quantitative genetic variation and phenotypic plasticity in determining the relative success of populations of an invasive annual plant species, Erodium cicutarium, undergoing a recent range expansion in California and Chile. The project utilizes field surveys, greenhouse experiments, and Bayesian modeling techniques to address several questions including: 1) How does trait expression respond via phenotypic plasticity to environmental variation?, 2) Do genotypes from habitats with greater environmental heterogeneity express greater plasticity than genotypes from relatively homogeneous environments?, and 3) Do the roles of genetic and plastic variation in trait values in determining the relative success of a population differ between invasion fronts in Chile and California? The PI will provide novel insight into the role of phenotypic plasticity and quantitative genetic variation in determining the relative success of populations in the process of rapid range expansion in replicate invasion fronts. Although the spatial scale of environmental heterogeneity has long been hypothesized to play an important role in determining patterns of selection on the expression of phenotypic plasticity no comprehensive tests exist. Previous studies examining the importance of genetic variation or phenotypic plasticity in the range expansions of invasive species have lacked comprehensive analyses of plasticity in response to environmental variation similar to that experienced in natural habitats. This research provides the first comprehensive analysis to date.Invasive species pose a serious threat worldwide both to local and national economies, and to the integrity of ecosystems and native species diversity. Over the past 250 years, most of California?s grasslands have become dominated by invasive Eurasian annual plants, including the annual forb E. cicutarium. Although invasive Eurasian forbs also pose a threat to native ecosystems in Chilean grasslands, invasive plant community composition and interspecific interactions differ significantly between Chile and California. Because this research incorporates lineages collected across replicate invasion fronts it provides a novel comparison between populations collected in two geographically distant range edges of the same plant species.