Homogenization Applied to Integrate Across Spatial and Temporal Scales in Forest/Insect Ecology

均质化应用于森林/昆虫生态学中时空尺度的整合

• 批准号: 0077663
• 负责人: James Powell
• 金额: $ 32.09万
• 依托单位: Utah State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0077663&HistoricalAwards=false
• 关键词: Homogenization; Applied; Integrate; Across; Spatial

Powell0077663 In one ecological problem of current interest all theelements exist for application and testing of homogenization toresolve the scale issue and simulate climate and human impacts onoutbreak insect species. The investigator and his colleagues havedeveloped a deterministic spatial model of Mountain Pine Beetle(MPB, Dendroctonus ponderosae) dispersal and mass-attack of pinehosts. The model is validated and descriptive on spatial scalesof hectares and time scales of days. In this project they usetechniques of homogenization on the MPB/host system to constructa forest scale ( 100 hectare/years) model reflecting thelarge-scale emergent consequences of current small-scale spatialand temporal models of insect development, dispersal, andresponse to climate. Direct computation on such large scaleswould be prohibitive; similar difficulties face most ecologicalsimulations involving spatio-temporal heterogeneity at realisticscales and life-system/dispersal interactions. The investigatorsdevelop homogenization procedures that make this type ofecological simulation generally tractable, and implement and testthese procedures in the MPB/host system. The homogenizationprocedure generates an integro-difference equation (IDE),operating with year-long clock `ticks' on landscape scales. In avalidation phase, the IDE model is used to classify landscapes.Statistically analyzing misclassifications in comparison toaerial imagery makes the simulation methodology self-correcting.Finally, scenario studies are used to examine consequences ofhypothetical climate and management trajectories on host/insectdynamics. This illustrates the power of homogenizationapproaches in an ecological context, and provides needed examplesto make these techniques accessible to biological andenvironmental researchers. The method of homogenization is a mathematical techniquethat allows deduction of large-scale properties fromdeterministic small-scale models. To the best of our knowledgethe method of homogenization has never been applied to ecologicalproblems, where issues of scale are the focus of much debate. Onepossible angle of attack is joint use of models and simulation,followed by validation with spatially explicit data. Directcomputational approaches to ecological problems with fulldescription of spatial heterogeneity and climatic variation areextremely difficult due to interaction of scales in time andspace. The difficulty is exacerbated on the one hand by thepaucity of validated, deterministic spatial models at anyecological scale, and by the difficulty of extended spatialobservations on the other. In this project the investigators andhis colleagues apply the technique of homogenization to theMountain Pine Beetle/Lodgepole Pine ecosystem to resolve thescale issue and simulate climate and human impacts on populationoutbreaks of insect species.

Powell0077663 在当前感兴趣的一个生态问题中，所有要素都存在用于均质化的应用和测试，以解决规模问题并模拟气候和人类对爆发昆虫物种的影响。 研究人员和他的同事开发了山松甲虫（MPB，Dendroctonus ponderosae）扩散和松树寄主大规模攻击的确定性空间模型。 该模型在公顷的空间尺度和天的时间尺度上进行了验证和描述。 在这个项目中，他们使用 MPB/宿主系统均质化技术构建了森林规模（100 公顷/年）模型，反映了当前昆虫发育、传播和气候响应的小规模时空模型的大规模紧急后果。 如此大规模的直接计算是令人望而却步的；大多数生态模拟都面临着类似的困难，涉及现实尺度的时空异质性和生命系统/扩散相互作用。 研究人员开发了均质化程序，使这种类型的生态模拟总体上易于处理，并在 MPB/主机系统中实施和测试这些程序。 均质化过程生成一个积分差分方程（IDE），在景观尺度上以长达一年的时钟“滴答声”运行。 在验证阶段，IDE 模型用于对景观进行分类。与航空图像相比，对错误分类进行统计分析，使模拟方法能够自我纠正。最后，情景研究用于检查假设气候和管理轨迹对寄主/昆虫动态的影响。 这说明了生态背景下均质化方法的力量，并提供了必要的示例，使生物和环境研究人员能够使用这些技术。 均质化方法是一种数学技术，可以从确定性小规模模型中推导出大规模属性。 据我们所知，均质化方法从未应用于生态问题，其中规模问题是许多争论的焦点。 一个可能的攻角是联合使用模型和模拟，然后用空间明确的数据进行验证。 由于时间和空间尺度的相互作用，对生态问题进行直接计算并充分描述空间异质性和气候变化是极其困难的。 一方面，在任何生态尺度上都缺乏经过验证的、确定性的空间模型，另一方面，扩展空间观测的难度也加剧了这一困难。 在这个项目中，研究人员和他的同事将均质化技术应用于山松甲虫/木松生态系统，以解决规模问题并模拟气候和人类对昆虫物种种群爆发的影响。