Doctoral Dissertation Research: The Role of Community Boundaries, Environmental Gradients, and Disturbance in a Serpentine Soil Ecosystem: The Darlingtonia Fens of Southern Oregon

食肉植物沼泽是一种罕见的植物群落，仅在美国东海岸和北方加州和南俄勒冈州的蛇形土壤生态系统中发现。 这些社区的一个重要的生态方面是他们的边界，表现出高物种丰度，多样性，初级生产力，并在沼泽的空间特征的高变异性。 这些群落的大小和形状每年都会因一系列环境因素而发生巨大变化，特别是火灾和养分供应。 然而，这些动态和复杂的边界交错带的具体性质知之甚少。 这个博士论文的研究项目旨在确定这些植被边界的性质，在南俄勒冈州的Darlingtonia沼泽，并解释他们的动态演替。 该项目的重点将是测试的假设，随着时间的推移，在没有火，Darlingtonia沼泽社区变得更小，更少的多样性，由于增加了营养物质的可用性。 具体的研究目标是（1）确定存在的生态地球化学梯度的社区的边界，（2）确定干扰和土壤性质的影响，边界组成和结构，（3）检查历史和短期的影响，火灾对西部沼泽社区。 三个Darlingtonia蛇纹土壤生态系统具有不同的燃烧历史将被用作测试网站。 进行这项研究的博士生将分析火灾和灭火对这些社区中发现的生态交错区的历史作用;描述生态交错区植被的群落组成和结构;分析土壤和水的物理和化学特性。（例如pH、N矿化、%P、%K、Mg：Ca比率和重金属浓度）;并分析了蛇纹岩土壤生态系统交错带群落对常见干扰火的短期和长期响应。 该项目的成果具有理论和管理意义。 该项目将评估西部Darlingtonia fens的演替模式，并将为这些和其他独特的适应生态系统的未来研究提供概念基础。 沼泽群落交错带的作用，其动态，其对多样性的影响需要确定，以确保有效的现在和未来的管理。 该研究还将通过描述群落结构和生态系统动态，为美国林务局和大自然保护协会制定管理战略提供生态基础，因为它们与演替和干扰有关。 作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

Carnivorous plant fens are rare and diverse plant communities found only on the eastern seaboard of the United States and in the serpentine soil ecosystems of northern California and southern Oregon. An important ecological aspect of these communities is their boundaries, which exhibit high species abundance, diversity, primary productivity, and high variability in the spatial characteristics of the fens. Size and shape of these communities can change dramatically from one year to the next in response to an array of environmental factors, especially fire and nutrient availability. The specific qualities of these dynamic and complex boundary ecotones are poorly understood, however. This doctoral dissertation research project seeks to determine the nature of these vegetation boundaries in the Darlingtonia fens of southern Oregon and to explain their dynamics in terms of succession. The focus of the project will be on testing the hypothesis that, over time and in the absence of fire, the Darlingtonia fen communities become smaller and less diverse due to an increase in availability of nutrients. Specific research objectives are (1) to determine the presence of biogeochemical gradients across the boundaries of the communities, (2) to identify the effects of disturbance and soil properties on boundary composition and structure, and (3) to examine the historical and short-term effects of fire on western fen communities. Three Darlingtonia serpentine soil ecosystems with different burn histories will be used as test sites. The doctoral candidate conducting this study will analyze the historical role of fire and fire suppression on the ecotones found in these communities; describe the community composition and structure of ecotone vegetation; analyze physical and chemical characteristics of the soil and water (such as pH, N mineralization, %P, %K, Mg:Ca ratio, and heavy metal concentration); and analyze short- and long-term community responses of a serpentine soil ecosystem ecotones to fire, which is a common disturbance. The outcomes of this project have both theoretical and management implications. This project will evaluate a successional model for western Darlingtonia fens and will provide a conceptual basis for future studies in these and other uniquely adapted ecosystems. The role of fen ecotones, their dynamics, and their impacts on diversity need to be identified to ensure effective present and future management. The research also will provide an ecological basis for developing management strategies by the U.S. Forest Service and The Nature Conservancy by describing community structure and ecosystem dynamics as they relate to succession and disturbance. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.