Cross-Site: Analysis of Past and Current Changes in Grassland Ecosystem Dynamics in Asia and North America

跨站点：亚洲和北美草原生态系统动态过去和现在的变化分析

• 批准号: 9527303
• 负责人: Dennis Ojima
• 金额: $ 20万
• 依托单位: Augustana University Association
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-10-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527303&HistoricalAwards=false
• 关键词: Cross; Site; Analysis; Past; Current

We propose a three year project to investigate the role and consequences of changes in climate, land use, vegetation, and soils of the temperate grassland ecosystems of Asia and North America. The objective of this study is to characterize the factors controlling ecosystem integrity relative to changes in climate and land use of North American and Asian grasslands, and to understand these changes relative to the presence and distribution of C3 and C4 species in these two regions. Although plant productivity tends to be greater for the same amount of rainfall in the Asian continent, the occurrence of C4 species in the Asian grasslands is greatly reduced compared to the North American grasslands. They will incorporate isotopic analysis of soils and vegetation across a gradient of rainfall and temperature in Asia and compare these to similar analyses collected in North America. This information will be integrated using the CENTURY ecosystem model to investigate climate-soil-land use interactions on soil and vegetation dynamics. Isotopic signature 813C will be compared across sim ilar topo-edaphic positions of plant communities in different regions of the two continents. Remote sensing will provide the land cover template to evaluate the degree of changes from natural vegetation. These differences will be used in conjunction with the CENTURY model to evaluate net changes in ecosystem properties at the regional scale and the susceptibility of these grasslands to climate change and human activities.

我们提出了一个为期三年的项目，以调查气候、土地利用、植被和土壤变化在亚洲和北美温带草原生态系统中的作用和后果。本研究的目的是描述北美和亚洲草原气候和土地利用变化对生态系统完整性的控制因素，并了解这些变化与C3和C4物种在这两个地区的存在和分布有关。尽管相同降雨量的亚洲大陆的植物生产力往往更高，但与北美草原相比，亚洲草原上C4物种的出现大大减少。他们将纳入对亚洲不同降雨和温度梯度的土壤和植被的同位素分析，并将这些分析与北美收集的类似分析进行比较。这些信息将利用CENTURY生态系统模型进行整合，以研究气候-土壤-土地利用相互作用对土壤和植被动态的影响。同位素标记813C将在两大洲不同地区植物群落的相似地形土壤位置上进行比较。遥感将提供土地覆盖模板，以评估自然植被的变化程度。这些差异将与世纪模型结合使用，以评估区域范围内生态系统性质的净变化以及这些草原对气候变化和人类活动的敏感性。