Doctoral Dissertation Research: A Multi-Scale Analysis of Disturbance, Dynamics, and Climate-Growth Relationships in Mountain Longleaf Pine Forests, USA

博士论文研究：美国山地长叶松林的干扰、动态和气候-生长关系的多尺度分析

• 批准号: 0927687
• 负责人: Lisa Kennedy
• 金额: $ 0.83万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0927687&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Multi; Scale

This research integrates geospatial and ecological approaches to examine the roles of climate, competition, disturbance, and human activities in regulating the composition and structure of old-growth and second-growth mountain longleaf pine forests of the southeastern United States. Mountain longleaf pine forests are relatively understudied components of the imperiled and highly diverse longleaf pine ecosystems that historically dominated the Coastal Plains and parts of the Piedmont, Ridge and Valley, and Southwestern Appalachians. These mountain forests are at the northern latitudinal and altitudinal range margin for longleaf pine ecosystems. Doctoral student Arvind Bhuta, under the supervision of Dr. Lisa Kennedy at Virginia Tech will produce a high-resolution (temporal and spatial) reconstruction of competition and disturbance at multiple mountain longleaf pine sites. Randomly placed study plots in mountain longleaf pine forest sites will be surveyed for forest structure and composition. All canopy trees within the plots will be identified, measured, referenced with a global positioning system, and cored. Analysis of forest metrics in a geographic information system will document forest processes and patterns at multiple spatial scales ranging from individual tree species and communities to the broader ecosystem. Annual rings from each tree will be measured, standardized, and statistically analyzed. Tree rings provide an annual-resolution record of tree growth, forest composition and structure, and proxy records of climate, disturbance, and competition through time. Historical tree growth will be linked with current forest metrics, land-use history, and climate records to provide detailed information on long-term forest dynamics and the drivers of change in this ecosystem. The investigation of the relationship between climate and longleaf pine radial growth will allow for comparisons to be made between sites at the range margin and others throughout its range to better understand the geographic variation in the climate response of this species. Mountain longleaf pine forests are economically and biologically valuable. They are high in biodiversity and rich with endemic herbaceous and vertebrate species some of which are now rare and endangered due to intense land-use patterns, fragmentation, and the disruption of the natural fire regime. Long-term records of forest dynamics across multiple sites will provide context for sound decisions on the restoration and management of these forests and its vulnerable species, such as the red-cockaded woodpecker and the Cumberland azalea. This research will fill a critical gap in the knowledge of mountain longleaf pine forests by providing new information on the ecological drivers of ecosystem and community processes and patterns which could be influenced by climate change. Land managers of mountain longleaf pine forests have based management and restoration practices on studies that focused on individual stands and short time scales, many at lowland sites that may differ in ecological function. In contrast, this research will account for pattern and processes over large temporal and spatial scales.

本研究结合地理空间和生态方法，探讨了气候、竞争、干扰和人类活动在调节美国东南部山地长叶松原生林和次生林组成和结构中的作用。历史上，长叶松生态系统在沿海平原、山前、山脊和山谷的部分地区以及阿巴拉契亚山脉西南部占主导地位，而山地长叶松林是这种濒危和高度多样化的长叶松生态系统中相对较少研究的组成部分。这些山林位于长叶松生态系统的北纬和高程边缘。在弗吉尼亚理工大学Lisa Kennedy博士的指导下，博士生Arvind Bhuta将对多个山地长叶松基地的竞争和干扰进行高分辨率（时间和空间）重建。在山地长叶松林样地随机设置研究样地，调查森林结构和组成。地块内的所有冠层树木都将被识别、测量，并通过全球定位系统进行参考，并进行核心化。在地理信息系统中对森林指标的分析将记录从单个树种和群落到更广泛的生态系统等多个空间尺度上的森林过程和模式。每棵树的年轮都将被测量、标准化并进行统计分析。树木年轮提供了树木生长、森林组成和结构的年分辨率记录，以及随时间变化的气候、干扰和竞争的代用记录。历史树木生长将与当前的森林指标、土地利用历史和气候记录联系起来，以提供关于长期森林动态和该生态系统变化驱动因素的详细信息。研究气候与长叶松径向生长之间的关系，将有助于对长叶松分布范围边缘和整个长叶松分布范围内的其他地点进行比较，从而更好地了解该物种气候响应的地理差异。山地长叶松林具有经济和生物价值。它们具有丰富的生物多样性和丰富的特有草本和脊椎动物物种，其中一些物种由于强烈的土地利用模式、破碎化和自然火灾制度的破坏而变得稀有和濒危。对多个地点的森林动态的长期记录将为这些森林及其脆弱物种（如红冠啄木鸟和坎伯兰杜鹃花）的恢复和管理提供合理的决策背景。该研究将为气候变化可能影响的生态系统和群落过程和模式的生态驱动因素提供新的信息，从而填补山地长叶松林知识的关键空白。山地长叶松林的土地管理者将管理和恢复措施建立在集中于单个林分和短时间尺度的研究上，其中许多是在生态功能可能不同的低地地点进行的。相比之下，本研究将在大的时间和空间尺度上解释模式和过程。