Collaborative Research: Consequences of habitat heterogeneity and seed dormancy for adaptation at the margins of a native plant population

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。该项目的主要目的是了解环境和遗传因素如何影响植物物种范围的局部扩展。尽管近年来已经开发了许多模型来解决这一问题，但很少有经验来检验已开发的理论。本研究结合了野外实验和建模，以了解植物的范围扩展如何受到种群边缘适应、种群边界上环境变异性的变化以及休眠种子在这些边界之外的传播的影响。已知遗传背景的种子将在连续两年内移植到跨越当地种群边界的加利福尼亚一年生植物的多个地点。这一边界发生在具有高度本地植物多样性的蛇形草地和以外来入侵物种为主的非蛇形草地之间的过渡。同时，这些研究人员将开发新的数学模型来阐明扩散、栖息地变异性和适应如何影响局部范围的扩展。这些模型将使用田间试验的数据进行参数化，以估计平均存活率和繁殖率，以及这些重要率在地点、年份和基因型之间的变化。我们的综合方法将促进对扩散、休眠和适应如何随时间改变植物分布的概念和经验理解。该项目的更广泛影响包括保护环境、培养先进学生和公共教育。研究范围扩展的机制对于了解入侵植物如何适应其扩展到新的栖息地以及预测植物物种在快速环境变化下改变其地理分布的条件具有重要意义。这两种情况都与在蛇形土壤等不寻常基质上发现的植物群落特别相关。这些栖息地是一个特殊的保护问题，因为它们的许多本地植物物种是稀有和独特的，因为它们的植物群落受到入侵物种的威胁。该项目将支持和培训来自环境生物学代表性不足群体的大学生和博士后研究员，并将包括对加州当地公立学校1-7年级学生的科学推广和课程开发。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The principal objective of this project is to understand how environmental and genetic factors affect local expansion of plant species' ranges. Although in recent years many models have been developed to address this issue, little has been done empirically to test developed theories. This study combines field experiments and modeling to understand how range expansion in plants may be influenced by adaptation at population margins, by changes in environmental variability across population boundaries, and by dispersal of dormant seeds beyond those boundaries. Seeds of known genetic backgrounds will be transplanted in two successive years into multiple sites spanning the local population boundary of an annual plant native to California. This boundary occurs along a transition between serpentine grassland harboring high native plant diversity and a non-serpentine grassland dominated by invasive, non-native species. Concurrently, these researchers will develop new mathematical models to elucidate how dispersal, habitat variability and adaptation influence local range expansion. The models will be parameterized using data from the field experiments to estimate average survival and reproduction, as well as variation in those vital rates among sites, years and genotypes. Our integrative approach will advance conceptual and empirical understanding of how dispersal, dormancy and adaptation shape plant distributions over time. Broader impacts of this project include conservation, training advanced students, and public education. Studying mechanisms of range expansion is important for understanding how invasive plants adapt as they expand into new habitats and for predicting conditions under which plant species shift their geographic distributions in response to rapid environmental change. Both contexts are especially relevant for plant communities found on unusual substrates, like serpentine soils. Such habitats are a special conservation concern since many of their native plant species are rare and unique, and because their plant communities are threatened by invasive species. The project will support and train university students and post-doctoral fellows from under-represented groups in environmental biology, and will include science-based outreach to, and curriculum development for, local California public school students in grades 1-7.