Collaborative research: Restricted plasticity of canopy stomatal conductance: A conceptual basis for simpler models of forest transpiration

[405306]我们提出的项目具有重大的智力价值，因为它明确地解决了水文学面临的两个关键问题。第一个问题涉及气孔控制水通量的对立观点，一种观点认为是碳同化控制，另一种观点认为是环境控制。我们的概念模型将这两种观点结合在一个统一的机制框架中，该框架结合了同化和水势控制蒸腾。我们的概念模型解决的第二个问题是，比起简单的、可验证的模型，人们更倾向于采用复杂的、通常在数学上不合理的树冠模型。我们通过使用一种新的、面向对象的树冠模型明确地解决了水文建模中的这个基本问题，该模型可以根据所提供的数据灵活地调整其结构和机制。通过在空间上调整模型的复杂性，我们将深入了解物种的可塑性及其在空间梯度上的限制，从而为在威斯康星州北部的研究地点测试我们的概念模型提供了一种严格的方法。从我们提出的研究中获得的知识对寻求产生全球变化对水循环影响的准确预测的陆地表面模拟工作具有广泛的意义。通过发展我们的概念模型，我们将能够提供一个相对简单，但可运输和科学防御的模型。这些模型是制定和实施可信的州、联邦和国际政策的必要基础，这些政策旨在减轻或以其他方式调整预期的全球变化的后果。这个项目的教育重点是多方面的。首先，我们将寻求额外的资金和其他方式来支持、建议和培训一个由来自威斯康星州北部经济弱势地区的本科生组成的综合团队，并将该项目作为他们在威斯康星大学麦迪逊分校森林生态学教育的主要背景。此外，在国家科学基金会研究合作网络项目“契卡梅贡生态系统-大气研究”中，我们将举办一个关于多尺度冠层通量测量和建模的全国宣传研讨会，Mackay是该项目的核心参与者。私立学院将继续在各自的领域招收和雇用少数族裔和其他代表性不足的学生。

0405306MacKayOur proposed project has significant intellectual merit because it explicitly addresses two keyproblems facing hydrology. The first problem concerns the opposing views of stomatal control ofwater fluxes, with one perspective assuming carbon assimilation control, and the other assumingan environmental control. Our conceptual model combines both of these perspectives in a unifiedmechanistic framework that combines both assimilation and water potential controls ontranspiration. The second problem addressed by our conceptual model is the tendency towardsfavoring complex and often mathematically ill-posed canopy models over simpler, verifiableones. We explicitly address this fundamental issue in hydrologic modeling by using a novel,object-oriented canopy model that can flexibly adjust its structure and mechanisms to the data itis provided. By adjusting model complexity spatially we will gain deep insights on speciesplasticity and restrictions thereof across spatial gradients, thus providing a rigorous approach totesting our conceptual model within our study site in northern Wisconsin.The knowledge gained from our proposed research has broad implications for land surfacemodeling efforts seeking to generate accurate predictions of global change effects on watercycling. By developing our conceptual model we will be able to provide a relatively simple, buttransportable and scientifically defensible model. Such models are essential foundations for thecreation and implementation of credible state, federal and international policies aimed atmitigating or otherwise adjusting to the consequences of anticipated global change. Theeducational emphasis of this project is multi-faceted. First, we will seek additional funding andother means of supporting, advising and training an integrated team of undergraduate studentsfrom the economically disadvantaged region of Northern Wisconsin, using this project as theprincipal context for their education in Forest Ecology at UW-Madison. Also, in connection withthe NSF Research Collaboration Network project entitled "Chequamegon Ecosystem-Atmosphere Study," for which Mackay is a core project participant, we will hold a nationallyadvertised workshop on multi-scale canopy flux measurements and modeling. The PIs willcontinue to recruit and hire minorities and other underrepresented students in our respectivefields.