Unraveling the Phenology of the Liana <i>Marcgravia longifolia</i> : Temporal Patterns and Climatic Cues

ABSTRACT Lianas are important providers of food resources in tropical forests, supporting a wide range of animal species. Given their potential to outperform trees under climate change, their significance in trophic networks is likely to increase. Understanding their phenology and its climatic cues is essential for forecasting potential mismatches under future climate scenarios. However, our knowledge remains limited. To help fill this gap, we focused on the phenology of Marcgravia longifolia J. F. Macbr (Marcgraviaceae), a woody endemic Western Amazonian liana, and investigated temporal patterns and climatic factors associated with flower and ripe fruit presence. Ten individuals of M. longifolia were monitored for 84 consecutive months at the Estación Biológica Quebrada Blanco (EBQB) in the Peruvian Amazon. To analyze the timing, synchrony, and seasonality of flower and fruit production, we used circular statistics. To identify the climatic cues of these patterns, we employed Generalized Linear Mixed Models (GLMMs) including climatic variables as potential predictors, such as Photosynthetically Active Radiation (PAR), cloud cover, rainfall, and temperature. Flower presence peaked in August and lasted 36 days, displaying intermediate synchrony. Ripe fruit presence peaked in November and lasted 39 days with high synchrony. Cumulative PAR and cloud cover over the previous 3 and 6 months, respectively, were identified as the main climatic cues for flower and ripe fruit. This study offers valuable insights into the phenology and climatic cues of an understudied plant group, highlighting the importance of PAR and cloud cover in timing reproductive events, in a rainforest characterized by pronounced rainfall seasonality.