Doctoral Dissertation Research: Calibration and Application of Sedimentary Proxies in Evaluating Spruce Beetle Outbreaks from the High Plateaus of Utah

博士论文研究：沉积物代理在评估犹他州高原云杉甲虫爆发中的校准和应用

• 批准号: 1032099
• 负责人: Andrea Brunelle
• 金额: $ 1.14万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-15 至 2012-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1032099&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Calibration; Application

Bark beetles (Dendroctonus spp.) and wildfire are significant disturbance agents in conifer forests of western North America. Understanding the occurrence, the ecological significance and how these two disturbances interact over long time scales and under different climatic regimes is import to contextualize current forest dynamics. Methodologies exist for reconstructing past fire episodes over the Holocene (last ~10,000 years) using sedimentary charcoal from lake sediments. However, no methodology currently exists for assessing bark beetle disturbances over similar timescales using lake sediments, despite their ecological significance. The ecological response of subalpine forests to a spruce beetle infestation is generally that subalpine fir (Abies lasiocarpa) and other understory components increase in abundance and productivity following mortality of mature spruce. The invigorated growth of the understory is attributed to increased availability of sunlight, moisture and nutrients. The 'release' of the understory component following severe outbreaks is well documented in historic stand inventory data as well as in tree ring records. These changes in stand structure are reflected in the pollen record. Using pollen records obtained from six subalpine basins in Utah, a calibration study was performed emphasizing changes in pollen deposition concurrent with several 20th century spruce beetle (D. rufipennis) outbreaks. These changes generally reflect an exchange of spruce pollen for fir and other understory taxa. The research supported here will apply the calibration set to pollen data from three Holocene-length sediment cores retrieved from the Wasatch Plateau, Markagunt Plateau and Aquarius Plateau, located in central and southern Utah. The Markagunt Plateau site is the most temporally resolved core and will be dated and analyzed at multidecadal resolution to further refine forest dynamics associated with spruce beetle infestations.This project will provide an important step forward in using lake sediments to reconstruct non-fire disturbances, specifically for spruce beetle in subalpine forests. Developing long term records of forest ecology and disturbance are important resources for land managers and their respective agencies. The research conducted here will provide an important baseline of understanding with which to interpret recent bark beetle outbreaks in western conifer forests. The support of this research through a Doctoral Dissertation Research Improvement award will enable a promising student to establish a strong environmental research career.

小蠹（Dendroctonus spp.）和野火是北美西部针叶林的重要干扰因子。 了解的发生，生态意义，以及这两种干扰如何在长时间尺度上，在不同的气候条件下相互作用是进口的背景下，目前的森林动态。 存在使用来自湖泊沉积物的沉积木炭重建全新世（过去~ 10，000年）过去火灾事件的方法。 然而，目前还没有方法来评估树皮甲虫干扰在类似的时间尺度上使用湖泊沉积物，尽管它们的生态意义。亚高山森林的生态响应云杉甲虫的侵扰，一般是亚高山冷杉（毛果冷杉）和其他林下成分的丰富度和生产力的增加后，死亡率的成熟云杉。 林下植被的快速生长归因于阳光、水分和养分的增加。 林下组成部分严重爆发后的'释放'是有据可查的历史立场库存数据，以及在树轮记录。 林分结构的这些变化反映在花粉记录中。利用从犹他州6个亚高山盆地获得的花粉记录，进行了一项校准研究，强调花粉沉积的变化与几个世纪云杉甲虫（D. rufipennis）爆发。这些变化通常反映了云杉花粉与冷杉和其他林下植物的交换。这里支持的研究将应用校准集花粉数据从三个全新世长度的沉积物岩心从瓦萨奇高原，Markagunt高原和宝瓶座高原，位于中部和南部犹他州检索。 Markagunt高原网站是最及时解决的核心，并将在几十年的分辨率，以进一步完善森林动态与云杉甲虫infestations.This项目将提供一个重要的一步，利用湖泊沉积物重建非火灾干扰，特别是云杉甲虫在亚高山森林。 发展森林生态和干扰的长期记录是土地管理者及其各自机构的重要资源。在这里进行的研究将提供一个重要的基线的理解与解释最近树皮甲虫爆发西部针叶林。通过博士论文研究改进奖对这项研究的支持将使有前途的学生能够建立强大的环境研究事业。