Pilar Candau

Forecasting olive crop production based on ten consecutive years of monitoring airborne pollen in Andalusia (southern Spain)

This work describes a predictive model for the harvest of olives destined for olive oil, using olive groves in the province of Seville (southern Spain). The study was carried out between 1987 and 1996, monitoring airborne olive pollen with a Cour trap, and using agronomic data (size of harvest expressed in kg/ha) and meteorological observations (rainfall before and after olive pollination, days of rainfall during harvesting, and maximum temperatures during pollination). The data were subjected to simple and multiple regression analysis. Eight equations were obtained, enabling the olive harvest to be forecast with a high degree of reliability: five equations for use at the beginning of July (the end of flowering, and six months before fruit picking), another two at the end of November (immediately before picking), and the remaining one at the end of January, once picking was over.

Olea europaea Airborne Pollen in Southern Spain

BACKGROUND Olea europaea pollen is one of the most abundant constituent pollens in Seville (southern Spain). It is responsible for many documented cases of pollinosis in the area. OBJECTIVE To contribute to the useful knowledge of Olea europaea for allergists. METHODS The number of Olea europaea pollen grains in the atmosphere was recorded during 8 consecutive years (1987-1994), using a Cour collector. RESULTS The concentration of Olea europaea pollen was as high as 250 to 1015 grains/m3 only during 1 or 2 weeks in April and May. Overall annual production of O. europaea pollen alternated between years. The beginning of the main pollination period was related to the mean temperature of the preceding months (February and March). Pollination occurred when the mean temperature in both months was higher than 14 degrees C; conversely it was delayed when the mean temperature was lower. Main pollination period length depended upon both temperature and rainfall during this period: temperatures higher than 19.5 degrees C and absence of rainfall shortened the main pollination period, while lower temperatures (15 to 18 degrees C) together with rainfall rates above 100 mm lengthened it. CONCLUSIONS Climatic variables such as preceding mean temperature and rainfall impact on pollen anthesis of Olea europaea affect onset and duration of pollination. A consideration of yearly cycles of pollen production as well as these variables should allow pollen forecasting.

Airborne grass (Poaceae) pollen in southern Spain. Results of a 10‐year study (1987–96)

This work reports an exhaustive study of the aerobiology of the Gramineae in Seville, Spain, which is typical of coastal Mediterranean areas. Sampling was done with a Cour trap installed on the roof terrace of the School of Pharmacy, Seville, from 1987 to 1996, both inclusive. The climatic pattern of that period was characterized by two exceptionally wet years (1989 and 1996), between which were 5 consecutive years of drought (1990–5). This typieally Mediterranean climate affects grass aerobiology. The annual amounts of total grass pollen are low, never exceeding 25(X) grains/m3. The start, length, and intensity of the pollen season are significantly correlated with preseasonal meteorologic factors (precipitation and temperature), but intraseasonal meteorologic conditions have no effect on the three variables. The relationships are stated by three equations that, while further years of observations are anticipated, can be considered models to forecast the characteristics of the pollen season: the starting date depends on the mean temperatures of January and February, and the length and intensity of the season depend on the rainfall between the beginning of January and the starting date of the season. For the study period, the weekly concentrations (pollen curves) throughout the year showed no typical pattern of variation over the years, so that it was impossible to make mid‐ and long‐term forecasts of the variation in weekly concentration. The most noteworthy aspects of grass pollen curves are a long pollen season, which starts in February or March and lasts until September or October; peaks of higher concentration (>1(K) grains/m3) in May and June, associated with increases in temperature and absence of precipitation; and other peaks in the summer months that may be as high as the spring peaks.

Aeropalynology ofFraxinus (Ash) in an urban area of southwestern Spain

SummaryThe first observations from Huelva (southwestern Iberian Peninsula) on the phenology of Ash, based on an aeropalynological study over three years, are presented. Sampling was carried out with a Cour trap. The beginning of pollination is related to the moment of the lowest average temperature of the year, usually in January. Flowering occurs earlier if there are exceptionally low average temperatures (<10°C) in November. The amount of rainfall in autumn and winter affects the intensity of pollination.

Study of the pollen emissions of Urticaceae, Plantaginaceae and Poaceae at five sites in western Spain

A comparative study is presented of the pollen emissions of Urticaceae, Plantaginaceae and Poaceae, collected during 1995 with Hirst samplers (Burkard or Lanzoni) at five sites in western Spain: two Mediterranean sites located in the south (Huelva and Seville) and three Atlantic sites in the north (Orense, Vigo and Santiago). The annual pollen of Poaceae and Plantaginaceae collected in the Atlantic cities was found to be twice that in the Mediterranean sites, and the total amount of Urticaceae was higher at sites with an urban environment and subject to sea influence (Vigo, Huelva and Seville). At all the sites, the start of the main pollination periods (MPP) took place in the following order: Urticaceae, Plantaginaceae and Poaceae. It was also observed that the MPP of these three pollen types began earlier in Huelva and Seville, where the mean temperatures necessary for the beginning of pollen emissions are recorded very early. Regarding the variation in pollen concentrations throughout the year, Urticaceae presented peaks of maximum concentration in March (Huelva, Seville, Vigo and Orense) and June (Santiago); Plantaginaceae in March (south) and June (north); and Poaceae in May (south) and June–July (north). At northern sites, pollen emissions of Urticaceae and Plantaginaceae continued throughout the summer, while in the south they decreased considerably from May onwards. From the allergenic point of view, the indices of reactivity described for Urticaceae and Poaceae were exceeded more often at northern sites, in particular at Vigo. The meteorological conditions associated with periods of highest pollen emission of these three herbaceous types are a rise in mean temperature, light or absent rainfall, and abundant sunshine. The statistical correlations between pollen emissions and meteorological factors were not well-defined, either for the stations or for all the taxa, although they were clearer for the Atlantic cities and for Urticaceae.

A comparative study of atmospheric pollen concentrations collected with Burkard and Cour samplers, Seville (Spain), 1992–1994

A comparative study has been carried out of the relative efficiency of a Burkard sampler and Cour trap, by taking samples from the air of Seville (SW Spain) for two consecutive years (July 1992 to July 1994). The devices were subjected to identical conditions of installation. 16 specific pollen types were studied either because of their high presence in the regional atmosphere or because of their allergenicity. With both methods, the variations in weekly concentrations throughout the year were analysed. Then the data from the two traps was compared in order to compare the efficiency of the two methods. The Burkard sampler collects 1.42 times more total pollen than the Cour trap. Certain pollen types are found more frequently in the Burkard trap (Casuarina, Mercurialis, Olea, Platanus, Rumex and Urticaceae); some are approximately equal in the two traps (Amaranthaceae/Chenopodiaceae, Cupressaceae, Fraxinus, Pinaceae, Plantago, Poaceae and Quercus); and others are found more frequently in the Cour trap (Art...

Study onPlatanus hispanica Miller pollen content in the air of Seville, southern Spain

The work was carried out using a Cour trap that sampled the air of the city for 8 consecutive years (1987–1994). The pollen ofPlatanus hispanica is the fourth most abundant in the air of Seville (a mean of 11.05% of the total pollen collected). The variation throughout the years in the sum of weekly concentrations ofPlatanus hispanica pollen presents a certain biennial rhythm, in which years of high and low collection of pollen alternate. The starting day of the main pollination period (MPP) is negatively related with the mean of the mean temperatures for February (r=0.73,r2=0.53,P=0.0398) and is earlier (at the beginning of March) when the mean temperature for February is high, and vice versa. The pattern of pollen variation inPlatanus hispanica remains constant through the years—pollen appears abruptly in high weekly concentrations (> 150 grains/m3) in March (sporadically at the beginning of April), with a week of maximum pollen emission (WMPE) in which more than 50% of the annual pollen is collected (in 6 of the 8 years), and a main pollination period (MPP) of 2 or 3 weeks (except in 1989 when it was 5 weeks). In every year (except 1989), weekly mean temperatures increased during the MPP, the duration of which depends on mean temperature and mean rainfall: mean temperatures > 16°C and absence of rainfall shorten the MPP, while lower temperatures and presence of rainfall lengthen it. The meteorological conditions most often found during the WMPE are mean temperatures > 15°C and rainfall absent or almost so.

Airborne fungal spores trend over a highly polluted area of south-west Spain using Cour's trap

SummaryThis investigation was aimed at studying the mycoflora present in Huelva (South West Spain), a highly polluted region. The study was carried out using the Cour trap and it is worth pointing out that the chemical treatment performed following the Cour methodology might destroy a certain percentage of spores. We analyzed the presence and biannual changes (10 April 1989 to 8 April 1991) of fungal spores of three genera, seventeen form genera, and four groups lacking taxonomic category, looking at their morphology: ascospores, basidiospores, and unidentified unicellular and multicellular spores. Special attention was given to agriculturally interesting groups. The results obtained were correlated with meteorological parameters (rainfall, minimum temperature and humidity).

A study on non‐arboreal pollen collected during ten consecutive years in the air of the SW Spain

A Cour trap was used to sample the air of the city of Seville continuously from 1987 to 1996, both inclusive. The most important climatological feature of the period was a prolonged drought, which began in 1990 and reached its severest moment in 1995 after six consecutive years without exceeding the mean annual precipitation for the city. The study was conducted on the 16 pollen types that appeared in amounts greater than 0.05% of the total pollen collected in the ten‐year period: Poaceae, Urticaceae, Plantago Chenopodiaceae‐Amaranthaceae, Asteroideae, Rumex, Mercurialis Brassicaceae, Helianthus Lactucoideae, Typha Cyperaceae, Echium Apiaceae, Artemisia and Leguminoseae. The aspects examined were the possible effect of the drought on the variation, over the years, in the annual total pollen concentrations; the relationship between the non‐arboreal vegetation of the region and the quantitative composition of the pollen spectrum; and the description of the pollen curves (the variation, through the year, in ...

RELATIONSHIP BETWEEN VEGETATION AND POLLEN SPECTRUM IN SOUTHWEST SPAIN

ABSTRACT Weekly variation in airborne pollen composition was studied in three cities located in the SW of the Iberian Peninsula (Cadiz, Huelva, and Seville) from April 1989 to April 1990. These three cities differ in geography, climate, and vegetation. Pollen concentration of Seville was greater and more diverse, with predominance of arboreal pollen (25% of total pollen). Among the ornamental plants, the pollen from ? lat anus sp. and Cupressus sp. was dominant Cadiz and Huelva show a similar pollen spectrum due to their climatic and geographic resemblances. Airborne pollen concentration in Huelva was the lowest (one fifth that in Seville, and half that in Cadiz). Pollen of the herbaceous plants predominates (49% in Cadiz and 45% in Huelv a, of total pollen), while the presence of pollen from ornamental plants was low. The dominant pollen types are Poaceae, followed by Amaranthaceae, Umbelliferae, and Urticaceae. On the other hand, the Olea pollen is the most important of the cultivated plants and the Que...