Doctoral Dissertation Research: Human and Climate Influences on Yew (Taxus baccata L.) Population Dynamics in County Cork, Ireland, from 4,000 B.C. to the Present

全球变化研究的一个关键方面是古环境研究，旨在识别过去全球气候和环境变化的形式，特别是自最后一次大陆冰期以来的各个时期。这个博士论文研究项目将确定在过去的6000年里，当人类活动在爱尔兰增加时，影响爱尔兰Youghal教区红豆杉（Taxus baccata L.）种群的因素。凯尔特人将紫杉树视为“高贵的”，认为它是生与死的象征。诺曼人用它作为长弓的原料。该属的所有物种都含有治疗卵巢癌的紫杉醇。紫杉是欧洲最长寿的树种。苏格兰的福廷霍尔紫杉据说有3000年的树龄。爱尔兰的孢粉学分析很广泛，但红豆杉以前的分布和丰度在很大程度上是未知的，因为它的花粉直到最近才被发现。这些特点使它成为一个值得文化和古生态研究的课题。遗憾的是，现在紫杉在爱尔兰已经不常见了。Youghal（在凯尔特语中是eo - chill，意为“紫杉森林”）只剩下几棵存活的紫杉了。这项研究假设红豆杉曾经在爱尔兰很丰富，因为档案中提到的红豆杉森林很常见，地名分析显示，爱尔兰有124个地方以红豆杉命名。Youghal是淡水泥炭地（非常适合进行微化石分析）、宏观化石（杉木树桩森林，适合进行树木年代学分析）和一段记录完好的历史的所在地。古生态学和历史方法将被应用于确定气候（温度和降水）和社会（文化、经济和政治）因素，这些因素导致了Youghal地区紫杉的数量波动，并最终导致其稀少。这些数据应有助于确定，在红豆杉的枯竭方面，人类干预是否比气候变化更重要，其下降程度与人类企业的规模和需求直接相关。该古生态项目将有助于认识全新世物种的减少和多年代际尺度的气候重建。早期古生态学研究者认为植被组合主要受气候变化控制。人们已经认识到，人类活动可能极大地影响这些组合。人类引入了外来动植物与本土物种竞争，并通过砍伐森林和过度杀戮耗尽资源，从而进一步改变了环境。保罗·马丁的闪电战模型表明，由于人类的干预，动物可能在几百年内灭绝。这项研究将有助于确定红豆杉种群是否在类似的时间跨度内枯竭，从而为植物群是否受到人类引起的快速灭绝提供测试。每一个物种减少的案例都是独一无二的。在这种情况下，人们不相信人类的到来导致了这个物种的立即衰落，而是一个具有不同资源感知的新文化群体（诺曼人）的到来。该研究也将有助于全新世气候的重建。对全球变暖的担忧使得全新世气候研究成为必要，以便利用这些数据来模拟未来的气候。孢粉学数据将揭示红豆杉花粉的增加/减少，从而表明气候或人类活动的变化。这些变化将与全球全新世气候数据交叉参考，与其他树木花粉变化进行分析，并与档案数据进行比较。从宏观化石中获取的树木年代学数据将通过树木年轮异常揭示气候条件。它还将补充在花粉剖面中看到的年代事件的微化石数据。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。

A critical facet of research on global change has been paleoenvironmental studies aimed at discerning past forms of global climatic and environmental change, especially in time periods since the last continental glaciation. This doctoral dissertation research project will identify factors that influenced yew tree (Taxus baccata L.) populations in the Irish parish of Youghal over the last 6,000 years, when human activity increased in Ireland. The Celts revered the yew tree as 'noble' and considered it a symbol of life and death. The Normans used it as raw material for the longbow. All species in the genus contain taxol, which has cured ovarian cancer. Yew is the longest-lived tree species in Europe. Scotland's Fortinghall yew is reputed to be 3,000 years old. Palynological analyses in Ireland are extensive, but the yew's former distribution and abundance is largely unknown, because its pollen has only recently been recognized. These qualities make it a worthy subject for cultural and paleoecological research. Regrettably, the yew now is not commonly found in Ireland. Youghal (Eo-chaill in Celtic, meaning 'yew forest') has only a few living yews remaining. This study hypothesizes that yew once was abundant in Ireland, as archival mentions of yew forests are common and toponymic analysis has revealed 124 Irish locations named after the tree. Youghal is home to freshwater peatlands (excellent for microfossil analysis), macrofossils (a forest of yew stumps adequate for dendrochronological analysis), and a well-documented history. Paleoecological and historical methods will be applied to identify climatological (temperature and precipitation) and sociological (cultural, economic, and political) factors that caused population fluctuations, and an eventual rarity, of yews in Youghal. These data should help determine whether human interference has been a more significant factor than climate change in the depletion of the yew, with levels of decline directly related to the scale and needs of human enterprise. This paleoecological project will contribute to knowledge of Holocene species declines and multidecadal scale climate reconstructions. Early paleoecological investigators assumed vegetational assemblages were primarily controlled by climate change. It has been realized that human activity may tremendously influence these assemblages. Humans have introduced exotic flora and fauna to compete with indigenous forms and executed further change by exhausting resources via deforestation and overkill. Paul Martin's Blitzkrieg Model suggests that fauna can become extinct as a result of human interference within a few hundred years. This research should help determine whether yew populations were depleted over a similar timespan, thereby providing a test as to whether flora are subject to human-induced rapid extinction. Every case of species decline is unique. In this case it is not believed that the arrival of humans lead to the immediate decline of this species but the arrival of a new cultural group (the Normans) with a different resource perception. The research will also contribute to Holocene climate reconstruction. Concerns about global warming have necessitated Holocene climate research in order to use the data to model future climates. Palynological data will reveal increases/decreases of yew pollen thus indicating changes in climate or human activity. These changes will be cross referenced with global Holocene climate data, analyzed in terms of other arboreal pollen changes, and compared to archival data. Dendrochronological data retrieved from the macrofossils will reveal climate conditions via tree ring anomalies. It will also complement the microfossil data in terms of dating events seen in the pollen profile. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.