Doctoral Dissertation Research: Vegetation Dynamics of Endangered Pine Rockland Communities in the Lower Florida Keys

南佛罗里达湿地松(Pinus elliottii var.Densa)是佛罗里达群岛下部松岩地区的主要木本植物和唯一的郁闭树。这些全球濒危的群落支撑着西印度群岛硬木和棕榈树以及各种地方性草本植物的多样性，这些草本植物要么被火鼓励，要么被火抑制。这项博士论文研究项目将使用树状年代学来研究下佛罗里达群岛衰落的松岩群落的结构和干扰历史。对影响南佛罗里达湿地松在其分布区南部分布的生态和气候因素进行研究。此外，重建过去火灾制度的空间和时间变异性将更好地了解火灾如何影响这些社区的结构和范围。该项目还将调查区域气候振荡(例如，厄尔尼诺-南方涛动)与野火活动之间的相互作用。关于湿地松群落历史火灾发生和气候响应的定量信息对松树群落的长期管理和恢复至关重要。该项目将增加对人类相关和自然干扰事件如何减少南佛罗里达湿地松在下佛罗里达群岛的空间分布的基本了解。该项目将在佛罗里达州最南端的亚热带地区应用树木年代学技术，在那里树木年轮科学从未被应用过，它将产生气候代理数据集，这将增加不断增长的全球低纬气候代理数据网络。这项研究的结果将有助于理解气候振荡如何影响该地区，特别是南佛罗里达州，并将促进对松岩地复杂动态的理解，这将有助于旨在保护这些衰落社区的管理努力。该项目产生的植被数据将提供与自然和人类相关干扰制度有关的林龄分布和组成的宝贵信息，而关于定居前野火与气候机制之间的联系的数据将提供更好的理解，了解火灾如何塑造松林地，以及气候振荡对火灾发生的影响程度。作为博士论文研究改进奖，该奖项将为博士生建立强大的独立研究生涯提供支持。

South Florida slash pine (Pinus elliottii var. densa) is the dominant woody species and sole canopy tree in pine rocklands of the Lower Florida Keys. These globally endangered communities support a diverse subcanopy of West Indian hardwoods and palms as well as a variety of endemic herbs that are alternately encouraged or held back by fire. This doctoral dissertation research project will use dendrochronology to investigate the structure and disturbance history of declining pine rockland communities in the Lower Florida Keys. The ecological and climatological factors contributing to the distribution of South Florida slash pine at the southern extent of its range will be examined. In addition, the reconstruction of spatial and temporal variability of past fire regimes will provide a better understanding of how fire affects the structure and extent of these communities. This project also will investigate the interaction between regional climate oscillations (e.g. the El Nino-Southern Oscillation) and wildfire activity. Quantitative information on the historical fire occurrence and climate response of slash pine communities is essential to the long-term management and restoration of pine rockland communities.This project will increase basic understanding of how human-related and natural disturbance events have decreased the spatial distribution of South Florida slash pine in the Lower Florida Keys. This project will apply techniques of dendrochronology in extreme southern Florida, in a subtropical region where tree?]ring science has never been applied, and it will produce climate proxy datasets that will add to the growing global network of low?]latitude climate proxy data. Results from this research will contribute to the understanding of how climate oscillations affect the region, particularly South Florida, and they will advance understanding of the complex dynamics of pine rocklands that will aid management efforts aimed at preserving these declining communities. The vegetation data produced by this project will provide valuable information regarding stand age distribution and composition in relation to natural and human-related disturbance regimes, and data on the association between pre-settlement wildfire and climate mechanisms will provide a better understanding of how fires shaped pine rocklands and the extent to which climate oscillations affected fire occurrence. As a Doctoral Dissertation Research Improvement award, this award will provide support for a doctoral student to establish a strong independent research career.