Climate, phenology, and biotic interactions: a study of ten tree species at University of Peradeniya, Sri Lanka

Abstract

Shifts in climatic factors over time influence phenology and associated biotic interactions in natural and man-made ecosystems. This study investigated the relationship of climatic factors, phenology and biotic interactions in ten selected plant species, namely 𝘗𝘦𝘭𝘵𝘰𝘱𝘩𝘰𝘳𝘶𝘮 𝘱𝘵𝘦𝘳𝘰𝘤𝘢𝘳𝘱𝘶𝘮, 𝘋𝘦𝘭𝘰𝘯𝘪𝘹 𝘳𝘦𝘨𝘪𝘢, 𝘔𝘦𝘴𝘶𝘢 𝘧𝘦𝘳𝘳𝘦𝘢, 𝘛𝘢𝘣𝘦𝘣𝘶𝘪𝘢 𝘳𝘰𝘴𝘦𝘢, 𝘔𝘢𝘤𝘢𝘳𝘢𝘯𝘨𝘢 𝘱𝘦𝘭𝘵𝘢𝘵𝘢, 𝘚𝘱𝘢𝘵𝘩𝘰𝘥𝘦𝘢 𝘤𝘢𝘮𝘱𝘢𝘯𝘶𝘭𝘢𝘵𝘢, 𝘍𝘪𝘭𝘪𝘤𝘪𝘶𝘮 𝘥𝘦𝘤𝘪𝘱𝘪𝘦𝘯𝘴, 𝘑𝘢𝘤𝘢𝘳𝘢𝘯𝘥𝘢 𝘮𝘪𝘮𝘰𝘴𝘪𝘧𝘰𝘭𝘪𝘢, 𝘚𝘢𝘮𝘢𝘯𝘦𝘢 𝘴𝘢𝘮𝘢𝘯, and 𝘔𝘶𝘯𝘵𝘪𝘯𝘨𝘪𝘢 𝘤𝘢𝘭𝘢𝘣𝘶𝘳𝘢 at the Universtity of Peradeniya, Sri Lanka. Ten individuals were sampled from each of the ten selected plant species. The phenological events, including vegetative (flushing) and reproductive (flowering and fruiting) phenophases and biotic interactions (pollination and seed dispersal) associated with them were monitored from January to December 2024. Climatic factors (rainfall and temperature) during the study period were obtained from the Natural Resource Management Centre, Peradeniya. A positive correlation between high rainfall, and the flushing and flowering was recorded for 𝘗𝘦𝘭𝘵𝘰𝘱𝘩𝘰𝘳𝘶𝘮 𝘱𝘵𝘦𝘳𝘰𝘤𝘢𝘳𝘱𝘶𝘮, 𝘋𝘦𝘭𝘰𝘯𝘪𝘹 𝘳𝘦𝘨𝘪𝘢, 𝘔𝘦𝘴𝘶𝘢 𝘧𝘦𝘳𝘳𝘦𝘢, 𝘛𝘢𝘣𝘦𝘣𝘶𝘪𝘢 𝘳𝘰𝘴𝘦𝘢. In contrast, 𝘔𝘢𝘤𝘢𝘳𝘢𝘯𝘨𝘢 𝘱𝘦𝘭𝘵𝘢𝘵𝘢 and 𝘍𝘪𝘭𝘪𝘤𝘪𝘶𝘮 𝘥𝘦𝘤𝘪𝘱𝘪𝘦𝘯𝘴 recorded peak flowering during dry period (mean rainfall 0 mm and mean temperature 26.2 °C), avoiding floral damage due to excessive rainfall. All the tree species were pollinated by insects, except 𝘚𝘱𝘢𝘵𝘩𝘰𝘥𝘦𝘢 𝘤𝘢𝘮𝘱𝘢𝘯𝘶𝘭𝘢𝘵𝘢, which was pollinated by birds. Seeds of 𝘔𝘢𝘤𝘢𝘳𝘢𝘯𝘨𝘢 𝘱𝘦𝘭𝘵𝘢𝘵𝘢, 𝘔𝘶𝘯𝘵𝘪𝘯𝘨𝘪𝘢 𝘤𝘢𝘭𝘢𝘣𝘶𝘳𝘢, 𝘚𝘢𝘮𝘢𝘯𝘦𝘢 𝘴𝘢𝘮𝘢𝘯, and 𝘍𝘪𝘭𝘪𝘤𝘪𝘶𝘮 𝘥𝘦𝘤𝘪𝘦𝘪𝘱𝘪𝘦𝘯𝘴 were dispersed by frugivores. Moreover, the fruiting period of 𝘔𝘦𝘴𝘶𝘢 𝘧𝘦𝘳𝘳𝘦𝘢, 𝘛𝘢𝘣𝘦𝘣𝘶𝘪𝘢 𝘳𝘰𝘴𝘦𝘢, and 𝘋𝘦𝘭𝘰𝘯𝘪𝘹 𝘳𝘦𝘨𝘪𝘢 overlapped with the wet period, ensuring favorable conditions for the seed germination after seed dispersal. High mean monthly rainfall during the wet season (101.8 – 131.5) mm reduced pollinator visits by two folds in 𝘗𝘦𝘭𝘵𝘰𝘱𝘩𝘰𝘳𝘶𝘮 𝘱𝘵𝘦𝘳𝘰𝘤𝘢𝘳𝘱𝘶𝘮 and 𝘔𝘦𝘴𝘶𝘢 𝘧𝘦𝘳𝘳𝘦𝘢 species, emphasising the effect of climate variables on plant-pollinator interactions. Climatic variability plays a pivotal role in shaping phenology and plant-animal interactions, with direct consequences for the reproductive ecology of tree species.