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Indigenous populations of Scots pine are now limited to north-west and central Scotland on the British Isles. However, palaeoecological evidence suggests that Scots pine was much more widely distributed in the past. According to fossil pollen and other plant macrofossil evidence, the species entered south-east England at least 10,000 years ago and expanded across Britain to west Ireland and north Scotland. Approximately 4000 years ago, a widespread decline was observed in pollen frequencies of Scots pine and indigenous populations have become limited to their current localities as a result. The aim of this thesis was to carry out a population genetic analysis of 2 ancient populations of Scots pine using chloroplast microsatellite regions amplified from fossil pollen grains preserved in lake sediment from County Donegal, west Ireland and Loch Maree, west Scotland. Previous ancient DNA analyses have utilised sequencing, but one of the aims of the present study was to develop multiplex chloroplast microsatellite assays for high-resolution genotyping of single pollen grains, in the hope that this method will yield more information than previous attempts using sequencing. A comparative study on 7 extant populations from Scotland was also carried out.

This thesis documents pollen analysis from the Haua Fteah Cave in Cyrenaica, Northeast Libya, in order to reconstruct later Quaternary vegetation and environments in the region.

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This study examined both the present and mid to late Holocene vegetation and eco-limnological characteristics across the latitudinal tree-line region. The study region comprises the tree-line environmental gradient in the central Northwest Territories, Canada north of the city of Yellowknife. The study region is defined in terms of three ecozones, these are the boreal, transitional and tundra ecozones. The modern eco-limnological parameters of the study region were retrieved through a transect of lake surface sediment taken from 57 lake sites. This included pollen and diatom analysis of the lake sediment samples as well as the collection of supplementary data on water chemistry, surrounding vegetation and climatological data. The study was concerned with improving our understanding of mid to late Holocene tree-line dynamics. Two tundra lakes were selected for freeze coring (Horseshoe Lake and Carleton Lake). A chronological framework for the cores was established trough radiocarbon dating and Bayesian age depth modelling, pollen and diatom analysis was then carried out. Through analysis of the pollen record an inferred vegetation history for the study region was developed, interpretation of the diatom record allowed more specific limnological changes to be reconstructed. An integration of the results from the modern surface transect allowed further development of interpretations of the fossil record.

This study undertakes the reconstruction of the late Holocene vegetation of two mountain regions in northern Portugal. High resolution pollen analysis is carried out on sedimentary sequences from both study areas with the aim of obtaining an insight into the occupation and land-use of the study regions, and to assess how these activities contributed to shape the landscape in the past and present. In order to determine when significant changes in vegetation structure occurred, a chronological sequence is obtained for each study sequence through 14C dating and age-modelling. Results are then compared with local archaeological and historical records, and with published climate records from the wider northwestern Iberia region, to determine if observed changes in vegetation were likely caused by human action or climate events.

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Palynomorphs have been recovered from six localities from the type Wenlock and Ludlow series of the Much Wenlock and Ludlow areas in the Welsh Borderland, England. The assemblages contained an abundant and diverse palynoflora and palynofauna constituting elements from both the marine and terrestrial realms. Palynomorphs recovered included acritarchs, prasinophycean algae, chitinozoans and plant sporomorphs associated with scolecodonts and various palynodebris types. The samples were investigated qualitatively, semi-quantitatively, quantitatively and with fully statistical methodology. Acritarchs were recovered from all the samples and exhibited excellent preservation. The acritarchs, prasinophytes and spores are pale yellow to brown in colour, dependent on wall thickness. The chitinozoans and scolecodonts are black while the detrital amorphous organic matter is predominantly yellow/orange. The diversity and absolute abundance of the acritarchs was high throughout the sections from the Coalbrookdale, Much Wenlock Limestone and Lower Elton formations. The effect of lithofacies and palaeoenvironment and palaeoecologial tolerances upon palynomorph assemblages was apparent both in restricted distribution of some species and from lower abundances recorded from the coarse sparitic limestones. The biostratigraphical distribution of the acritarchs and prasinophytes showed that many of the forms recovered belonged to long ranging, cosmopolitan species such as Dictyotidium dictyotum, Duvernaysphaera aranaides, Diexallophasis simplex, Diexallophasis denticulata formgroup, Helosphaeridium pseudodictyum, Leiosphaeridia spp. Michrystridium stellatum, M. inflation, M. salopiense, Multiplicisphaeridium variabile, Salopidium granuliferum, Tasmanites spp. and Quadraditum fantasticum. A number of species with more restricted distributions were also recovered including the biozonal species Dictyotidium amydrum and Eisenackidium wenlockensis . Other species with a more restricted distribution included previously described forms such as Muraticavea wenlockia and Wrensnestia ornata along with a number of new species and genera, which are mostly retained in open nomenclature. Species of the new genus Bellidium were recorded with a distribution throughout the assemblages from the upper Wenlock Series. The distinctive forms defined as new species have potential use as biostratigraphic indicators. Forty-five new species of acritarch have been described systematically.

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