Abstract. The vegetation ecology of a paramo cushion mire was studied along four transects. Six local vegetation types were distinguished. Two types are called cushion bogs; one is dominated by Oreobolus cleefii and the other by Plantago rigida. Types 3 and 4 are mire vegetation dominated by bryophytes; one is characterised by Sphagnum sparsum, Breutelia sp. and Campylopus cucullatifolius, the other one is dominated by Lophozia subinflata with Cortaderia sericantha. Vegetation type 5 is dominated by submerged Sphagnum cyclophyllum; type 6 refers to aquatic vegetation with only Equisetum bogotense and algae. The relation between the first four vegetation types and edaphical and hydrological gradients is analysed by means of Canonical Correspondence Analysis (CCA). From the results of CCA it can be concluded that the occurrence of the Oreobolus cleefii type is restricted to areas with a thinner peat layer, a wider distance surface‐anaerobic zone and water table‐anaerobic zone, a higher NO2 concentration and a lower pH. The occurrence of the Plantago rigida type is restricted to a situation with a lower electrical conductivity of the ground water, a lower NO3 and PO4 concentration, and a higher Fe concentration. The occurrence of the Sphagnum type is restricted to places with a higher conductivity of the ground water, a higher NO3 and PO4 concentration, and a lower Fe concentration. The occurrence of the Lophozia subinflata with Cortaderia sericantha type is restricted to a situation with a lower K and Al concentration.

High resolution records oflead and some other elements in Holocene raised bog deposits from the eastern Netherlands were compared with corresponding pollen records for the period 1000Be to AD 1000. Trends in the curves of herbaceous human influence indicators parallel the recorded fluctuations of the aerosol input in the deposit. The chemical records may, in all probability, provide detailed information regarding the combined effects of soil erosion by agriculture (dust emission) and domestic fires in the regions around the bogs. Iron smelting operations may also have been responsible for the emission of aerosols into the atmosphere. The deposition oflead apparently corresponds to periods of agricultural and industrial expansion and depression. Already during periods of high population densities in prehistoric times some 'anthropogenic' aerosols dominated over 'natural' fractions. Relatively high lead levels in excavated prehistoric bones from agricultural societies may be explained by an increased uptake of airborne lead (in soil dust and smoke) via the lungs. Geochemical analysis can provide a more complete historical/prehistorical perspective of anthropogenic influence, especially in combination with palynological records.

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The relation between climatic conditions and type of peatland ecosystem in the different climate zones in Europe is discussed. Special attention is given to the hydrology of raised bogs in the sub-oceanic region. Possible effects of climatic change on such raised bog systems are discussed in terms of changes in water discharge, ground-water table, rate of peat accumulation, and flora and vegetation. It is concluded that future changes, as suggested by the more widely accepted scenarios for climatic change, will seriously disrupt the ecological functioning of these peatland ecosystems, and it is doubtful whether at least the most southerly examples of sub-oceanic raised bogs will at all survive. Finally, suggestions are given for future research on the impact of climatic change on peatland ecosystems.

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