Dissertation Research: Dynamics and History of Treeline in the Southern Sierra Nevada

论文研究：内华达山脉南部林线的动态和历史

基本信息

批准号：
9411573
负责人：
Lisa Graumlich
金额：
$ 0.7万
依托单位：
University of Arizona
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
1994
资助国家：
美国
起止时间：
1994-08-15 至 1996-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9411573&HistoricalAwards=false
关键词：
Dissertation Research Dynamics History Treeline

项目摘要

9411573 Graumlich Concern of the possible ecological consequences of trace-gas induced climatic change has led to examinations of how past variation in climate has influenced community structure and composition. Of particular interest is the paleoecological history of ecotonal boundaries, where species are expected to respond sensitively and predictably to climate change. The elevational position of alpine treeline in the southern Sierra Nevada has shifted over the past several millennia; dead and sub-fossil wood, up to several thousand years old, remains preserved at elevations of up to 80 m higher than present treeline. Previous research has demonstrated that the wood is dateable using dendrochronological methods, providing a temporarily precise record of ecotonal shifts over the last three millennia. This research will use this wealth of paleoecological information to analyze the role of climate in driving past movements of alpine treeline in the southern Sierra Nevada. Long-term records (1000 yr) of seasonal climate fluctuations will be compared with records of treeline movement. Using the technique of stand reconstructions, this study will also investigate how climate variation over the last millennium has affected rates of recruitment and mortality in subalpine forests. %%% Results from this dissertation research will allow quantification of the time-varying relationship between climate and treeline, and exploration of how this relationship is mediated through climatic effects on rates of population processes in subalpine forests.

9411573 Graumlich对痕量气体诱发气候变化的生态后果的关注导致了对过去气候变化如何影响社区结构和组成的检查。尤其令人感兴趣的是生态界边界的古生态历史，期望物种对气候变化的敏感和可预测的反应。在过去的几千年中，内华达山脉南部的高山林线位置在内华达州发生了变化。死亡和亚化石的木材（最多几千年）仍保留在比目前的绿林高达80 m的海拔高度上。先前的研究表明，木材是使用树突课程学方法可数据的，在过去三千年中，暂时精确的生态转移记录。这项研究将利用大量的古生态信息来分析气候在内华达山脉南部的阿尔卑斯山脉运动中的作用。将季节性气候波动的长期记录（1000年）与Treeline运动的记录进行比较。利用架子重建技术，这项研究还将研究上千年中的气候变化如何影响亚高山森林中的招募和死亡率。这项论文研究的结果%%％将允许量化气候与天线之间的时变关系，并探索如何通过气候对亚高山森林中种群过程率的影响介导的关系。