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)提供资金的。这个项目的主要目标是了解环境和遗传因素如何影响当地植物物种范围的扩大。尽管近年来已经开发了许多模型来解决这一问题，但很少有实证研究来检验已开发的理论。这项研究结合了田间试验和模型，以了解种群边缘的适应、跨越种群边界的环境变异性的变化以及休眠种子在这些边界之外的传播如何影响植物范围的扩大。已知遗传背景的种子将连续两年移植到跨越当地种群边界的多个地点，该植物原产于加利福尼亚州。这一边界发生在拥有高度本土植物多样性的蛇形草原和以入侵的非本土物种为主的非蛇形草原之间的过渡阶段。与此同时，这些研究人员将开发新的数学模型，以阐明扩散、栖息地变化和适应如何影响局部活动范围的扩大。这些模型将使用来自野外实验的数据进行参数化，以估计平均存活和繁殖，以及这些生命率在地点、年份和基因类型之间的差异。我们的综合方法将促进对分散、休眠和适应如何随着时间的推移塑造植物分布的概念性和经验性理解。该项目的更广泛影响包括保护、培训高级学生和公共教育。研究范围扩展的机制对于了解入侵植物在扩展到新的生境时如何适应以及预测植物物种在何种条件下改变其地理分布以响应快速环境变化具有重要意义。这两种情况对于在不寻常的底物上发现的植物群落特别相关，比如蛇纹石土壤。这样的栖息地是一个特别的保护问题，因为他们的许多本土植物物种是稀有和独特的，因为他们的植物群落受到入侵物种的威胁。该项目将支持和培训环境生物学方面代表性不足群体的大学生和博士后研究员，并将包括以科学为基础的外联活动，以及为加州当地公立学校1-7年级的学生制定课程。

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.