BEE: Consequences of phenotypic plasticity for gene-to-ecosystem linkages: Multi-stress experiments across the climatic range of a foundation species

预测生态系统将如何应对环境变化是环境科学家面临的主要挑战。一种策略是关注在生态系统中扮演最关键角色的生物的特征。沿着河流，主要的树种，如棉杨树，为许多其他物种提供了树荫、栖息地和食物。许多种类的昆虫以树叶和落在河里的垃圾为食。树叶的特性会影响这些昆虫的生存，进而影响到食物链上游的鸟类和鱼类。过去的研究表明，叶子的大小和化学成分等特征在一定程度上是由树木的基因决定的。然而，随着环境的变化，这些特征会发生什么变化，我们知之甚少。利用来自亚利桑那州各地的弗里蒙特棉杨树，这项研究将评估树木如何进化以适应过去的环境压力，包括温度变化和昆虫的攻击。这些关于树木的压力历史的信息将被用来预测它在未来的环境压力下所扮演的角色。研究结果将通过帮助确定应该种植的树木类型来支持健康的生态系统，从而帮助整个西南部正在进行的河流恢复项目。基础种内部的遗传变异是功能性状多样性的主要来源，而功能性状的多样性又决定了群落结构和生态系统过程。然而，个体基因型在暴露于环境变化时可能表达不同的性状值。这种表型可塑性在基因型之间是不同的，作为对气候变化或草食动物活动的进化反应，产生基因型与环境（G x E）的相互作用。本研究将验证这样一个假设，即了解局部适应基因型的可塑性进化将有助于在更大的景观尺度上预测遗传变异的影响。首先，该研究将使用三个现有的普通花园来研究西南树种的基因型在炎热和寒冷条件下如何表达不同的叶片特征。在所有花园中，草食损害的实验操作将用于研究非生物和生物胁迫对多种叶片性状的相互作用。其次，该项目将测试如何从每个基因型所在位置的环境过去的变化来预测性状的变化。最后，将利用凋落物移植实验和调查来量化叶片性状变化对依赖这些树木的陆生和水生昆虫群落的影响。研究物种表型可塑性的进化原因和生态后果之间的反馈，将极大地提高我们在快速变化的景观中预测生态系统持久性的能力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Predicting how ecosystems will respond to environmental change is a major challenge for environmental scientists. One strategy is to focus on the traits (characteristics) of organisms that play the most critical roles in their ecosystems. Along rivers, key tree species such as cottonwoods provide shade, habitat, and food for a wide range of other species. Many types of insects feed on the leaves and on the litter that falls in the river. The traits of the leaves impact the survival of these insects, which then impacts birds and fish higher up the food chain. Past research shows that leaf traits like leaf size and chemistry are partly determined by a tree's genes. However, little is known about what will happen to these traits as the environment changes. Using Fremont cottonwood trees from across Arizona, this research will assess how trees have evolved to tolerate environmental stresses in the past, including both changing temperatures and attacks from insects. This information about a tree's history of stress will then be used to predict the role it will play under future environmental stress. The results will aid ongoing river restoration projects across the Southwest by helping identify the types of trees that should be planted to support healthy ecosystems.Genetic variation within foundation species is a major source of diversity in functional traits, which in turn shape community structure and ecosystem processes. However, individual genotypes may express different trait values when exposed to environmental change. This phenotypic plasticity can differ among genotypes as an evolved response to climatic variability or herbivore activity, producing genotype x environment (G x E) interactions. This research will test the hypothesis that understanding the evolution of plasticity in locally adapted genotypes will enhance prediction of the impacts of genetic variation at a broad landscape scale. First, the research will use three existing common gardens to investigate how genotypes of a southwestern tree species express different leaf traits in hot vs. cold conditions. Across all gardens, experimental manipulation of herbivore damage will be used to investigate interactive effects of abiotic and biotic stress on multiple leaf traits. Second, the project will test how variation in traits can be predicted from past variation in the environment at each genotype's home location. Finally, litter transplant experiments and surveys will be used to quantify the impacts of changing leaf traits on whole communities of terrestrial and aquatic insects dependent on these trees. Investigating feedbacks between the evolutionary causes and ecological consequences of phenotypic plasticity across a species' range should greatly improve our ability to predict ecosystem persistence across a rapidly changing landscape.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.