Format: ORAL

Priscilla Muriel1, Gabriel Senz1, Carolina Tovar2

1 Laboratorio de Ecofisiología, Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Ecuador 2 Department of Biodiversity Informatics and Spatial Analysis, Royal Botanical Gardens, Kew, Surrey, UK

Climate warming globally affects plant communities, affecting their distribution, development, productivity and phenological patterns. However, studies of phenological responses to warming in species of equatorial regions are very scarce. In our investigation at Antisana Volcano, Ecuador, we characterized the reproductive phenophases (buds, flowering, and fruiting) of 12 selected plants in high altitude grasslands (pramo) under passive warming using Open Top Chambers (OTC). Objectives included assessing if reproductive seasons coincide among 12 selected pramo species with different growth forms, determining if artificial warming induces phenological shifts, and understanding its impact on reproductive structure abundance. We monitored the phenology of 12 species every 22 days over a year in 23 control plots, and 23 plots under passive warming. We used circular statistics to characterize and compare the phenology of the different species, and we used non-parametric variance analyses to assess if there is a significant phenological shift related to warming for the selected species. Results revealed diverse seasonality patterns, with seasonal, aseasonal, and species with mixed patterns. Seasonal species exhibited a higher abundance of reproductive structures between May and August, indicating a reproductive season, independent of growth form.Contrary to temperate regions, where temperature increase led to earlier flowering and fruiting of many species, we found no significant phenological shift in plants under passive warming in comparison to control.However, significant differences in reproductive structure abundance emerged between control and warming treatments among species, with five producing more structures in control plots and three within chambers. This suggests that warming in equatorial regions may consistently affect the production of reproductive structures in pramo species, instead of their flowering and fruiting seasons, thus potentially altering community composition in the future. The heterogeneous response underscores the urgency of assessing a larger number of species for conservation measures in this highly endemic and diverse region.