Pascale Ruffaldi

Human exposure to allergenic pollens: A comparison between urban and rural areas

BACKGROUND Pollinosis is found more frequently in urban areas than in rural environments. This could be partly related to the different types of pollen exposure in these dissimilar areas. The objective of this study was to compare the distribution of pollen in these environments across an urbanization gradient. METHODS Daily pollen abundances were obtained in France using Hirst-type sensors. Sampling was conducted from January to June in 2003 and 2006 in a rural area, a semi-rural area and in two urban areas, which were characterized by several urbanization criteria. RESULTS Total allergenic pollen abundance was higher in rural and semi-rural areas than in urban areas irrespective of the sampling year. Multivariate analyses showed that pollen exposures differed according to the type of area and were strongly explained by the urbanization gradient. Grass, ash, birch, alder, hornbeam, hazel and plantain pollen quantities exceeded the allergy threshold more often in rural settings than in urban areas. In urban areas, only plane pollen quantities exceeded the allergy threshold more often than in rural areas. CONCLUSIONS Allergenic pollen exposure is higher in rural areas than in urban areas, and the most abundant pollen in each area did not originated from the same taxa. This result should be taken into account in epidemiological studies comparing allergies in rural and urban areas to adapt the panel of pollen extracts for human environmental exposure. In addition, this study highlights that some ornamental trees produce a large number of allergenic pollens and provide new sources of aeroallergens.

Relationship between recent pollen spectra and current vegetation around the cerin peat bog (Ain, France)

Abstract Pollen-vegetation relationships were analysed from moss polster samples along two transects through the major vegetation types of the Cerin peat bog and sorroundings. Vegetation types are presented on a map and by phytosociological analysis. While the pollen frequencies and their relationships to vegetation type of some taxa are similar to those found elsewhere, Betula, Acer and Quercus are distinctively low in their representation, and Carpinus is significantly under-represented. Only those non-arboreal vegetation types with high frequencies of grasses were detectable in the pollen spectra.

Late holocene level fluctuations of the Lake Ilay in Jura, France: sediment and mollusc evidence and climatic implications

The level fluctuations of Lake Ilay, Jura (France) during the last three millennia are reconstructed from sedimentological and malacological analyses of a core that is well-dated by tree-ring, radiocarbon and pollen datings. Changes in sediment facies, in carbonate concretion assemblages and in mollusc assemblages highlight a major lowering phase atc. 1550 BP and minor lowering phases atc. 2800 BP and shortly before AD 1394. Rises in lake level developed during the early Subatlantic and betweenc. 1500 and 1000 BP. These data are in good agreement with other proxy data from higher European and American latitudes. These correlations support the climatic origin of the level fluctuations of the Lake Ilay during the late Holocene. They suggest that the mediaeval climatic optimum is centred rather in the early than the late Middle Age.

Searching for ancient forests: A 2000 year history of land use in northeastern French forests deduced from the pollen compositions of closed depressions

Evidence of the agricultural use, during Roman or Medieval times, of forested areas formerly considered to be ancient, as well as legacies of this former land use on plant biodiversity and soil properties, have encouraged the search for archives of former land use in forests. In central Lorraine (northeastern France), thousands of small closed depressions (CD) on marlstone have been inventoried in forests over the past 150 years, and we hypothesised that these CDs could be used to reconstruct patterns of land use. Closed depressions near the Seille and Sarre valleys were selected and cored for pollen and sediment analyses. Principal Components Analysis (PCA) was used to analyse variations of pollen assemblages during the last two millennia. The history of vegetation changes depicts five main phases. During the Roman period, the region appears to have been primarily covered by grasslands, with some croplands but few forests. All areas were reforested by the end of the Roman period. During the early Medieval period, croplands with grasslands developed in the region, while the late Medieval was characterised by cereal cropping, with especially intense use at sites near the Seille valley, and a lesser extension of grasslands. The present forest cover developed over the past 500 years because of the development of the salt industry in the Seille valley, which required firewood, and the general decrease of agricultural pressure over the past 150 years. Previous investigations had provided evidence of large-scale Roman field systems in the forests covering the limestone plateau and the Vosges foothills on sandstone, areas west and east of the research focus, respectively. These convergent findings suggest that that forests considered to be ‘ancient’ on the basis of historical documents may have been used for pasture or agriculture over extensive periods during the last 2000 years.

Two thousand–year reconstruction of livestock production intensity in France using sediment-archived fecal Bacteroidales and source-specific mitochondrial markers

The reconstruction of past pastoral activities based on microscopic methods (pollen and coprophilous fungal ascospores) does not accurately identify the domestic species involved. In contrast, source-specific DNA markers, commonly employed in water quality microbial source tracking (MST) studies, may represent a promising tool for retrospectively identifying species-specific fecal contamination in sediment deposition. In the present study, molecular methods were used to quantify Bacteroidales and identify ovine and bovine mitochondrial DNA extracted from sediment cores from two forest hollows comprising 2000 years of deposition. The DNA marker abundance was contrasted with the abundance of ascospores and plant-specific pollen throughout the sediment chronosequence. The distribution of DNA markers indicated an agro-pastoral practice transition from pasture/crop production to forested landscape from the second Iron Age/classical Antiquity to the end of the Roman period/modernity, in correlation with microscopic markers. During the second Iron Age/classical Antiquity, hollows were likely used to water herds, whereas during the late Antiquity, low Bacteroidales abundances and the sporadic detection of bovine and ovine DNA markers confirm the progressive afforestation observed using pollen data. For the end of the Roman period and modern times, reforested areas are characterized by the absence of ovine and bovine DNA markers while low Bacteroidales abundances suggest the presence of wild herbivores. The present study has established that in tandem with microscopic methods, sediment-archived fecal-specific bacterial and mitochondrial DNA are extremely useful for reconstructing agricultural practice over timeframes of millennia.