DISSERTATION RESEARCH: Drivers and Consequences of Intraspecific Trait Variation: Ecology of a Forest-Stream Community

许多栖息在河流中的水生昆虫以周围森林中树木脱落的叶子为食。 使用桤木的实验表明，这些溪流生物可以适应以沿着其特定河岸生长的单个桤木为最佳饲料;即，它们以当地产的桤木叶子为食，速度快于以生长在不同河流旁的桤木叶子为食。 进一步的研究表明，水生生物根据树叶化学成分的差异来适应不同的桤木。 陆生昆虫取食树叶时，往往诱导植物产生化学阻遏物以抵御进一步取食，这表明个体间化学防御系统的差异影响水生生物取食率的假说。 该项目将通过化学分析来测试这一假设，以确定导致当地适应的叶片性状，并通过实验揭示水生微生物和昆虫在推动这种适应中的作用。 这项研究将增加我们对生物多样性在个体水平上塑造生态系统功能的作用的理解，说明一个生态系统中的生态相互作用如何通过跨边界的通量间接塑造其他生态系统的结构，并阐明河流生态系统的恢复机制。这项研究为华盛顿奥林匹克半岛的两大经济支柱，林业和渔业，通过推进我们对树木之间的变异如何影响维持该地区渔业的河流的理解。 该项目的成果将分发给当地森林和渔业管理人员，包括Elwha和Makah美洲土著部落以及公众。 了解个体变异的生态影响对于预测遗传多样性如何改变生态系统的功能至关重要，遗传多样性由于栖息地丧失和破碎化而迅速下降。 本计画将提供研究经验给本科生，并支援博士生的论文研究。

Numerous aquatic insect species inhabiting rivers feed on leaves shed from trees in the surrounding forest. Experiments using alder trees showed that these stream organisms can adapt to feed optimally on individual alder trees growing along their specific river banks; i.e., they feed on locally derived alder leaves faster than on leaves from alder trees growing alongside different rivers. Further studies suggest that aquatic organisms adapt to individual alder trees based on differences in the chemical composition of the leaves. Terrestrial insects feeding on leaves often induces plants to produce chemical deterrents to defend against further feeding, which suggests the hypothesis that variation in the chemical defense system among individual trees influences feeding rate by aquatic organisms. This project will test that hypothesis through chemical analyses to determine the leaf traits causing local adaptation, and by experimentally unraveling the roles of aquatic microbes and insects in driving this adaptation. This research will increase our understanding of the role of biodiversity at the individual level in shaping ecosystem function, illustrate how the ecological interactions in one ecosystem can indirectly shape the structure of other ecosystems through fluxes across boundaries, and illuminate the mechanisms of resilience in river ecosystems.This research informs two economic pillars of the Olympic Peninsula of Washington, forestry and fisheries, by advancing our understanding of how variation among trees may affect rivers that sustain the region's fisheries. Results from this project will be disseminated to local forest and fisheries managers, including the Elwha and Makah Native American tribes, as well as to the general public. Understanding the ecological effects of individual variation is essential to efforts to predict how genetic diversity, which is rapidly declining due to habitat loss and fragmentation, can alter the functioning of ecosystems. This project will provide research experiences for undergraduates and supports the dissertation research of a doctoral student.