Collaborative Research: Plant Community Structure Across Resource Gradients from Grassland to Forest

在不同的环境制度下，约束模式和系统尺度如何在生态系统之间变化的综合将通过数学建模来发展。搜索将围绕三个目标进行组织：(1)综合现有的生态系统数据，这些数据以各种LTER站点为代表，特别是北美大陆上的站点梯度，包括东部的落叶林到中部的Konza LTER站点。草原草地以中部平原ltter遗址短。草草原。这项工作将侧重于关键环境驱动因素（日照、温度、湿度、营养和干扰制度）在构建特定生态系统中的作用。(2)实现一套完整的计算机模拟器，这些模拟器具有足够的通用性，可以应用于整个梯度。(3)对模型进行检验。根据代表未参与模型开发的生态系统的独立数据生成假设和预测。的生态系统。本研究中感兴趣的水平现象包括空间尺度，通常指“景观”或更大的空间尺度，以及十年至百年的时间尺度。强调生态系统类型之间的转换意味着扩展到空间尺度，至少是区域的，最终是大陆的。目前已有的四种模型可作为本研究的起点：(1)CENTURY碳和养分动态模型；(2)土壤和水化学MAGIC模型；(3)森林动力学的forest模型；(4)半干旱草原的STEPPE演替模式。研究的一个主要任务将是在模拟大陆尺度梯度格局的背景下，在这些模式之间建立适当的接口。本研究的意义在于为LTER网络站点间的生态系统比较分析和生态系统理论的发展提供了模型基础。这项研究还将解决如何在空间和时间的小尺度上进行测量的问题。理论的发展和对规模问题的理解对于地球生态系统可持续管理制度的发展至关重要。Drs。Shugart和Lauenroth是生态建模领域的领军人物。他们可以得到的制度支持是优越的。

A general synthesis of how patterns of constraint and system scaling vary among ecosystems within different environmental regimes will be developed through mathematical modeling. The search will be organized around three objectives: (1) To synthesize existing data from a spectrum of ecosystems as represented by various LTER sites, in particular, the gradient of sites across the North American continent that includes the deciduous forest on the east through the Konza LTER site in the tall.grass prairie to the Central Plains LTER site in the short.grass prairie. This work will focus on the role of key environmental drivers (insolation, temperature, moisture, nutrients, and disturbance regimes) in structuring specific ecosystems. (2) To implement an integrated set of computerized simulators which are sufficiently general that they may be applied across this gradient. (3) To test model.generated hypotheses and predictions against independent data representing ecosystems that were not involved in the model development. The ecosystem.level phenomena of interest in this research imply spatial scales as typically connoted by the term"landscape" or larger, and decadal to centennial time scales. The emphasis on transitions between ecosystem types implies anextension to spatial scales that are at least regional, andultimately continental, in extent. Four models, which are already developed and well documented, will serve as the starting point for this research: (1) the CENTURY model of carbon and nutrient dynamics; (2) the MAGIC model of soil and water chemistry; (3) the FORET model of forest dynamics; and (4) the STEPPE model of succession in semiarid grasslands. A principal task in the research will be the development of appropriate interfaces between these models in the context of simulating the pattern in the continental scale gradient. The significance of this research is that it will help us to develop a modeling base in support of comparative ecosystem analysis among sites in the LTER network and the development of ecosystem theory. The research will also address the issue of how measurements made at small scales in space and time can be extrapolated. Both the development of theory and an understanding of issues of scale are essential to the development of sustainable management regimes for the Earth's ecosystems. Drs. Shugart, and Lauenroth are leaders in the field of ecological modeling. The institutional support available to them is superior.