Doctoral Dissertation Research: Landscape Level Dynamics in an Endangered Mountain Ecosystem, Northern Rocky Mountains, USA

树枝生态学技术和分析将被用来提供关于濒危白皮松生态系统生态状况的高质量、时间上准确的信息。本论文采用林分动态和树枝生态学的方法，对蒙大拿州西部和爱达荷州中部白皮松群落退化过程中的干扰和林分历史进行研究。白皮松是一种长寿树种，见于北美西部的许多高海拔和亚高山森林群落。白皮松被认为是包括克拉克胡桃夹子、黑熊和灰熊在内的互惠关系中的关键物种。20世纪的灭火，周期性的山松甲虫暴发，以及白松水泡锈病的感染，导致了整个物种原生范围内白皮松群落的急剧下降，对依赖的野生动物物种造成了严重的影响。为了更好地了解这些衰退群落的动态，本项目将调查现在和过去的林分动态，以及泡锈病、防火、山松甲虫和气候对改变白皮松群落结构、组成和活力的协同效应。该项目的独特之处在于它将重点放在落基山脉北部的林分动态、干扰机制和气候-森林健康相互作用上。研究人员将(1)收集所有活的和死亡的直立树木的树心，以获得关于过去五个世纪白皮松干扰状况和演替状况的准确信息，(2)量化亚高山冷杉的年龄结构并评估其演替状况，(3)在景观尺度上评估泡锈病、山松甲虫和灭火对白皮松生态系统的影响。了解白皮松生态系统复杂的林分动态和林分历史，对于长期管理和恢复这一日益衰落的关键物种至关重要。白皮松的恢复工作必须在未来15-20年取得成功，才能避免该物种灭绝，这将极大地影响野生动物物种，并可能破坏高海拔地区脆弱的生态系统的稳定。这项研究的结果将与土地管理机构(如美国农业部林务局和国家公园管理局)和保护组织(如白皮松生态系统基金会)分享。白皮松年轮数据(将提供给世界古气候学数据中心)将为北美的古气候记录增加所需的数据点。从这项研究中收集的信息将被整合到田纳西地理联盟运营的项目中，并将呈现给各种受众，包括幼儿园-12年级的学生、老年人团体和当地夏令营(YMCA)。

Dendroecological techniques and analyses will be used to provide high-quality, temporally precise information on the ecological status of endangered whitebark pine ecosystems. This dissertation research investigates the ecology of whitebark pine communities using methods of stand dynamics and dendroecology to provide a long-term record of disturbance and stand history in diminishing whitebark pine communities in western Montana and central Idaho. Whitebark pine is a long-lived tree species found in many high elevation and subalpine forest communities of western North America. Whitebark pine is considered a keystone species in mutualistic relationships that involve Clark's nutcrackers, black bears, and grizzly bears. Twentieth century fire suppression, periodic mountain pine beetle outbreaks, and infection by white pine blister rust have led to dramatic declines in whitebark pine communities throughout the species' native range, with critical ramifications for dependent wildlife species. To better understand the dynamics of these declining communities, this project will investigate current and past stand dynamics and the synergistic effects of blister rust, fire exclusion, mountain pine beetle, and climate on changing the structure, composition, and vigor of whitebark pine communities. This project is unique for its combined emphasis on stand dynamics, disturbance regimes, and climate-forest health interactions in the northern Rocky Mountains. The researchers will (1) collect tree cores from all living and dead standing trees to obtain precise information on the disturbance regime and successional status of whitebark pine over the past five centuries, (2) quantify the age structure and assess the successional status of subalpine fir, and (3) evaluate the effects of blister rust, mountain pine beetle, and fire suppression in whitebark pine ecosystems on a landscape scale. Knowledge of the complex stand dynamics and stand history of whitebark pine ecosystems is essential to the long-term management and restoration of this declining critical species. Whitebark pine restoration efforts must succeed in the next 15-20 years for this species to avoid extinction, which would dramatically impact wildlife species and likely destabilize fragile ecosystems in the higher elevations. The results from this research will be shared with land management agencies (such as the USDA Forest Service and the National Park Service) and conservation organizations (such as the Whitebark Pine Ecosystem Foundation). Whitebark pine tree-ring data (which will be contributed to the World Data Center for Paleoclimatology) will add needed data points to the paleoclimatic record in North America. Information gathered from this research will be integrated into programs run by the Tennessee Geographic Alliance and will be presented to a variety of audiences, including kindergarten-12th grade students, senior citizen groups, and local summer camps (YMCA).