Long-term trends in atmospheric Quercus pollen related to climate change in southern Spain: A 25-year perspective

Long-term trends of atmospheric Quercus pollen recorded for 25 years (1995–2019) in southern Spain (Cordoba city, Andalusia region) have been studied to determine the influence climate fluctuations and other anthropogenic factors on Mediterranean oak vegetation areas. Atmospheric analysis revealed different changes reproductive phenology through study period. Pollination intensity showed an average cumulated value Main Pollen Season Integral 12,832 * day/m3, with a high variability among (±SD 8,048) significant rising trend 771 grains per year, being stronger recent (2014–2019). It was remarkable quantity detected out (703 day/m3 ± SD 431), also increasing years. Regarding phenology, results indicated as main species area, ilex subsp. ballota (holm oak), Q. coccifera, faginea suber, presented gradually pollination during spring (from mid-March early June), although lengthening season is observed This phenomenon could be explained by progressive delay suber. factors, decrease rainfall, especially winter autumn recorded, along colder winters but warmer springs, summers, autumns. These were significantly correlated timing intensity. The parameters most affecting those related temperature sunshine. However, total annual negative correlation rainfall. Results show that climatic change, are leading area.