Monitoring the pollination of the endangered species Abies pinsapo Boiss.: seasonality, intensity and recent trends

Abies pinsapo Boiss., is an endemic tree species to southern Spain whose pollination has not been studied in detail since its pollen grains have historically been included together with the rest of the Pinaceae species in the same type. However, it is possible to distinguish the pollen of A. pinsapo from the rest based on its size, but no clear references are currently available for fresh pollen. The aim of this study is to establish the size range of fresh pollen of A. pinsapo to characterize the atmospheric seasonality and intensity of this pollen type, as well as the pollination trends of this species in the Sierra de las Nieves National Park during the period 2018-2025 using aerobiological registers. In addition, we have analysed the relationship between meteorological variables and the pollen dispersal of this species. After establishing the size ranges for distinguishing A. pinsapo pollen, we observed that its pollination occurs between March and June. Temperatures and wind speed positively correlated with the airborne pollen concentrations of A. pinsapo, while for the relative humidity negative coefficients were obtained. Besides this, high frequencies of winds blowing from the nearest A. pinsapo forests generally increase the pollen detection. Despite using several trend analysis techniques and considering several main pollen season (MPS) definitions, no significant trends have been detected in the parameters of the MPS studied, except for a single method and MPS combination.