The "desertification" debate surrounding the Karoo Biome of South Africa has recently inspired much research in this region. The preservation of pollen in middens in arid environments from different parts of the world has great potential for the reconstruction of past vegetation. A lodge of the bush karoo rat (Otomys unisulcatus) was excavated near Prince Albert, South Africa, and the high numbers of well-preserved pollen grains was analysed. The vegetation reconstruction suggested that there was a decline in grasses over the whole sequence, while the vegetation experienced several short-term fluctuations throughout the time period. The ages within the lodge were uncertain, although the material is likely to be modern. The palynological analysis appear to be reliable and corresponds relatively well with other studies. The lodges of these species could therefore provide an exciting new source of historical pollen in the arid regions of southern Africa.

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Thesis (Ph. D.)--University of Washington, 1994. / Vita. Includes bibliographical references (leaves).

Thesis (Ph. D.)--University of Western Australia, 2003. / Title from PDF title page (viewed on July 9, 2005). Includes bibliographical references (p. 193-213).

The modern Maya lowlands are covered by a variety of vegetation types, ranging from freshwater swamps, through high "quasi rainforest," to open grasslands, each with its own exploitable potential and effect upon subsistence. Limiting factors such as pests, leaching, and competition would have decreased the potential harvests of prehistoric Mayan agriculture. Several ecologically sound methods, including increased crop diversity, mulching, and quarantine measures, reduce the impact of these limiting factors. Modern Maya agriculture is practiced at such low levels that it evades some limits to its potential productivity. Hypothesized prehistoric systems, such as intensive milpa, ramon cultivation, raised fields, and artificial rain forest, must have reached equilibrium with their biotic, climatic and edaphic environments. Using ethnographic and crop productivity data, with certain assumptions, quantified systems models of prehistoric agriculture have been derived. An ecologically compatible combination of intensive milpa, artificial rain forest, ridged fields, and marsh cultivation theoretically will support over 400 people per square kilometer of upland in the Peten. These data are within the limits of archaeological demographic estimates ranging from 40 to 900 people/km². Principal components analyses of pollen from edaphic and successional gradients serve as modern analogs for statistical comparison with two cores taken in the lake district of central Peten, Guatemala. Results indicate that agricultural activity, not climatic change, caused changes in the prehistoric vegetation. The Maya Classic landscape was an agriculture-dominated regime, with little untouched natural vegetation. Orchards, artificial rain forest and woodlots, although not supported by pollen evidence, may have covered much of the lowlands. The Maya collapse was followed by a general depopulation of the Peten. The Peten-Itza recolonization of the lake district, and the modern population influx appear as two minor agricultural episodes in a largely arboreal Postclassic landscape.

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UK uplands preserve a rich history of human inhabitation and environmental change through standing monuments, archaeological sites, and within peat deposits. Palaeoenvironmental remains within peat can be used to reconstruct environmental histories throughout the Holocene. Small mires in varied topographic locations can allow detailed local landscape reconstruction, setting archaeological sites in environmental context, or building up a picture of the mosaic of changing landscapes through time. Recent moves towards assessing the ecosystem services provided by different landscapes mean that, to make a case for preserving upland peatlands for the palaeoenvironmental remains they preserve, we must be able to demonstrate their archaeological potential or value. This project investigated methods for identifying the extent of this ‘hidden’ resource, as well for assessing its current condition and historic environment value, through the case study of valley, spring and soligenous mires on Exmoor. The lack of known archaeological or material culture remains from upland peatlands in the UK and on Exmoor means that the project focussed solely on the palaeoenvironmental resource. The methods used combined desk-based survey and spatially-extensive walkover survey to assess the overall extent and condition of the palaeoenvironmental resource in mires across Exmoor. Alongside this, a site-based programme of water-table monitoring and coring was undertaken to look at the effects of recent land management practices on the condition of this resource. The results demonstrated that walkover survey and peat depth probing were necessary to define the spatial extent and depth of mires, and assess mire condition. A standardised key was developed to allow the baseline mire condition survey to be repeated. The site-based study demonstrated the negative impact of water-table draw-down on the condition of palaeoenvironmental remains. However, it also demonstrated that a multiproxy approach is necessary to allow the complex palimpsest of the effects of human impact, climate change, and recent damage to mires, to be disentangled. The results of both levels of survey fed into the development of a flexible heritage valuation system for the palaeoenvironmental resource, which highlighted mires with high-potential for future investigation, whilst indicating mires which will require management intervention to prevent further losses to the resource. The datasets provided by this project will be used to identify palaeoenvironmental sampling locations for future archaeological investigations and allow heritage managers to make active contributions to the selection of sites for mire restoration. It provides a baseline survey against which future mire condition monitoring can be compared and which can be extended to other regions. It also offers a dataset against which to test or ‘ground-truth’ new methods for identifying the extent and condition of peatlands using remote-sensed data.

Here is presented a high resolution vegetation model and ecological analysis of an extinct floodplain ecosystem based on the palynology of deposits of the Sagwon Bluffs, northeast Alaska.  This fluvio – lacustrine succession of coal – bearing beds is of Late Palaeocene age and dominated by fine-grained sediment interspersed by coarse sandstones and conglomerates.  Deposition occurred at a latitude of ~ 85° N, but owing to the Palaeocene greenhouse climate, mean annual temperatures as high as 6 - 7°C allowed temperate plant ecosystems to exist.  The palynological dataset has been analysed here using ‘Correspondence Analysis’ (CA) and ‘Fuzzy <i>c</i>-Means Cluster analysis’ (FCM), allowing assessment of proposed ecological groups.  Geochemical analysis has been incorporated using ‘Canonical Correspondence Analysis’ (CCA), demonstrating affiliations of certain taxa to chemical signatures of associated sediments.  These techniques collectively reveal a gymnosperm – dominated floodplain forest with a substantial angiosperm, fern and bryophyte component analogous to modern wooded bogs and riparian swamp forests.  Principal taxa of late seral development include <i>Metasequoia, Taxodium, Sequoia </i>and <i>Nyssa, </i>representing the dominant component of such a forest.  Mid seral floras were characterised by coniferous gymnosperm and broad-leaved angiosperm co-dominance, incorporating <i>Corylus, Alnus, Castanea, Ginkgo </i>and a diversity of Pteridaceous, Polypodiaceous, Osmundaceous and Schizaceaen ferns.  Variably high abundances of <i>Sphagnum-</i>type bryophyte spores suggest extensive peat-forming mires.  The inconsistencies of the ecological structure displayed in the palynological assemblage suggest a dynamic floodplain, however, affected by a changing hydrological and climatic regime.  Climate cooling is considered to have affected the floras concurrent with an increasingly wet floodplain prior to a hypothesised period of mountain building to the south.