Dissertation Research: Effects of Fires on Population Dynamics and Viability of Chamaecrista keyensis (Caesalpinioideae), An Endemic Herb of the Lower Florida Keys

在北美许多易发生火灾的生态系统中，历史上的火灾制度已经被打乱了几十年，导致居住在其中的独特物种的减少和消失。本研究将确定实验火制度的影响，对大松豌豆，Chamaecrista keyensis（豆科），豆科草本植物，只发生在松树岩地较低的佛罗里达键。 下键松树岩地是一个火灾依赖的生态系统在佛罗里达，但他们的历史火灾制度尚不清楚。一个正在进行的，由内政部资助的更大的研究，包括实验治疗（夏季燃烧，冬季燃烧，和未燃烧的控制）块的松树罗克兰上的大松树键。 在这个设计是详细的植物种群研究，包括监测土壤种子库动态。 初步结果表明，冬烧处理可能是最有利于维持或增加大松豌豆种群。 这些季节性的火灾处理正在重复，看看这种趋势是否保持。 本研究也将确定大松豌豆种群动态与受火影响的生境变量的关系。这项研究将有助于确定历史火灾制度下，下键松树岩地和他们独特的物种演变。 结果将揭示可能导致当地人口下降和稀有物种灭绝的过程。

In many fire-prone ecosystems of North America, the historical fire regimes have been disrupted for decades, resulting in decline and disappearance of unique species that reside in them. This study will determine the effects of experimental fire regimes on the Big Pine Partridge Pea, Chamaecrista keyensis (Fabaceae), a legume herb that only occurs in pine rocklands of the lower Florida Keys. Lower Keys pine rocklands are one of the fire-dependent ecosystems in Florida, but their historical fire regime is unclear.An ongoing, larger study funded by the Department of the Interior, includes experimental treatments (summer burn, winter burn, and unburned controls) on blocks of pine rockland on Big Pine Key. Within this design are detailed plant population studies, including monitoring soil seed bank dynamics. Preliminary results indicate that the winter burn treatment may be the most beneficial for maintaining or increasing populations of Big Pine Partridge Pea. These seasonal fire treatments are being repeated to see whether this trend holds. This study will also determine the relationship of Big Pine Partridge Pea population dynamics with habitat variables influenced by fire. This research will help to identify the historical fire regimes under which the Lower Keys pine rocklands and their unique species evolved. Results will shed light on the processes that can lead to local population decline and extinction of a rare species.