Integrating fossil data, vegetation modelling and genetic analyses of modern tree populations to reconstruct the history of Larix in Europe

拟议项目的目的是通过整合古生态和遗传数据以及空间建模，研究过去气候变化对欧洲落叶松种群的影响。这种回顾性的方法可以帮助评估和校准模型模拟人类引起的气候变化对树木分布。目前的研究与森林树木的一个局限性是，他们没有真正整合，以定量的方式，不同类型的数据，这是典型的显示和分析分开，在这项研究中，我们建议使用统计方法的基础上结合建模来测试假设过去的人口统计和进化历史的树木种群。合并建模将依赖于多位点核DNA信息，古生态数据和单位点遗传数据（来自叶绿体和线粒体）代表有助于构建先验假设的外部信息。这些多个假设，然后将使用信息理论的方法进行比较。树木为此类研究提供了几个优势。特别是，它们留下了丰富的化石记录（bolh宏化石和花粉），可以用来非常精确地重建它们过去的分布。在树木中，落叶落叶松是特别感兴趣的，因为它在最后一个冰河时代的第一个间歇期在欧洲中北部的平原上发挥了重要作用，它仍然在波兰的低地由一组分化的种群代表，其地位尚不清楚，通常被认为是一个不同的亚种（落叶落叶松亚种）。Polonica）。这些低地种群一定经历了与山脉其余部分种群不同的人口统计学历史，后者在晚冰期和全新世期间主要沿沿着海拔梯度扩展。因此，落叶松似乎是一个合适的模式，我们的综合方法。我们将集中在Weichselian和全新世的冰川避难所和范围的变化的位置。预测的古生态学和分子遗传学分析将使详细的推断人口和进化的种群ofthis种，使用精确的定量方法，而不是临时的解释。

The aim of the proposed project is to study the consequences of past climatic changes on European Larix populations by integrating palaeoecological and genetic data as well as spatial modelling. Such retrospective approaches can help evaluate and calibrate models simulating human-induced climate change on tree distribution. A limitation of current studies dealing with forest trees is that they do not truly integrate, in a quantitative way, the different types of data, which are typically displayed and analyzed separately; In this study, we propose to use statistical approaches based on coalescent modelling to test hypotheses for the past demography and evolutionary history of tree populations. The coalescent modelling will rely on multilocus nuclear DNA information, with palaeoecological data and single locus genetic data (from chloroplast and mitochondria) representing extrinsic information that help frame a priori hypotheses. These multiple hypotheses will then be compared using an information theoretic approach. Trees present several advantages for such studies. In particular, they have left an abundant fossil record (bolh macrofossils and pollen) that can be used to reconstruct their past distribution with great precision. Among trees, Larix decidua is of special interest as it played an important role in the plains of north-central Europe during the first interstadials of the last ice age, and it is still represented in the lowlands of Poland by a group of differentiated populations whose status is unclear, often considered as a ditTerent subspecies (Larix decidua subsp. polonica). These lowland populations must have experienced a different demographical history than the populations from the remaining ofthe range, which have mainly expanded along altitudinal gradients during the Late glacial and the Holocene. As a consequence, larch appears to be a suitable model for our integrative approach. We will focus on the location of glacial refugia and range changes during the Weichselian and the Holocene. The projected palaeoecological and molecular genetic analyses will enable detailed inferences on the demography and evolution ofthe populations ofthis species, using precise quantitative approaches instead of adhoc interpretations.