Review of Palaeobotany and Palynology Volume 141, Issues 1-2, August 2006, Pages 203-223 Proxy climate and vegetation changes during the last five millennia in NW Iberia: Pollen and non-pollen palynomorph data from two ombrotrophic peat bogs in the North Western Iberian Peninsula T.M. Mighall, A. Martínez Cortizas, H. Biester and S.E. Turner Abstract Pollen and non-pollen palynomorph data are presented from two radiocarbondated ombrotrophic peat bogs from the Xistral Mountains in the North Western Iberian Peninsula. The results suggest that vegetation changes over the last five millennia are the result of human disturbance and climate change. Four major periods of forest disturbance are recorded: during the Late Neolithic, Metal Ages, Roman period and culminating in the permanent decline of deciduous forests since the Middle Ages, as agriculture and metallurgy intensified. Records of non-pollen palynomorphs, particularly those derived from fungi, proved to be useful indicators of climate change and human activity. Discriminant and cluster analysis suggest that trends in certain pollen and NPP reflect changes in humidity and to a lesser extent temperature. Cyperaceae and Types 18 and 18b increase during more humid, wet phases, whilst Type 306 increases during drier phases. Various ascospores, derived from coprophilous fungi, complement changes in pollen taxa to infer human activity. Keywords: ombrotrophic bog; proxy climate record; pollen; non-pollen palynomorphs; NW Iberia Linking changes in atmospheric dust deposition, vegetation change and human activities in northwest Spain during the last 5300 years Cortizas AM, Mighall T, Pombal XP, Munoz JCN, Varela EP, Rebolo RP HOLOCENE 2005 Volume: 15 Issue: 5 Pages: 698-706 Published: JUL Abstract: A high-resolution, 5300-yr record of pollen and lithogenic elements (K, Ca, Ti, Rb, Sr, Y, Zr) from an ombrotrophic peat bog located in northwest Spain, reveals that the variations in the fluxes of lithogenic elements supplied to the bog by atmospheric deposition were coupled to the evolution of the vegetation of the area. A strong negative correlation exists between the percentage of tree pollen and the concentration of lithogenic elements. For example, the correlation between total tree pollen and Sr concentrations is - 0.94. The main phases of decline of the deciduous forest occurred during known cultural periods (late Neolithic, the Metal Ages, the Roman Period, the Middle Ages and the Industrial period) suggesting a close link between human activities (fires and forest clearances), changes in the vegetation and soil erosion. The flux of lithogenic elements seems to have increased before a significant variation in pollen is detected, which may indicate that changes in soil erosion are reflected earlier than the changes in vegetation in the bog record. Variations in the composition of the deposited dust reflect impacts that occurred at different spatial scales, with local sources dominant in the late Neolithic, the Metal Ages and the Middle Ages, whilst regional sources are more important in the Roman period and the Industrial Revolution. During the prehistoric period, arboreal pollen percentages recovered to their former levels, suggesting that woodland regenerated following a disturbance phase, but for the last 1400 years no significant recovery took place until afforestation with Pines was introduced 200 years ago. While this must be the result of continuous clearances to convert forest into arable land, a cumulative effect on soil degradation must also be implied. Science 7 May 1999: Vol. 284 no. 5416 pp. 939-942 Mercury in a Spanish Peat Bog: Archive of Climate Change and Atmospheric Metal Deposition A. Martı́nez-Cortizas, X. Pontevedra-Pombal, E. Garcı́a-Rodeja, J. C. NóvoaMuñoz and W. Shotyk ABSTRACT A peat core from a bog in northwest Spain provides a record of the net accumulation of atmospheric mercury since 4000 radiocarbon years before the present. It was found that cold climates promoted an enhanced accumulation and the preservation of mercury with low thermal stability, and warm climates were characterized by a lower accumulation and the predominance of mercury with moderate to high thermal stability. This record can be separated into natural and anthropogenic components. The substantial anthropogenic mercury component began ∼2500 radiocarbon years before the present, which is near the time of the onset of mercury mining in Spain. Anthropogenic mercury has dominated the deposition record since the Islamic period (8th to 11th centuries A.D.). The results shown here have implications for the global mercury cycle and also imply that the thermal lability of the accumulated mercury can be used not only to quantify the effects of human activity, but also as a new tool for quantitative paleotemperature reconstruction.