Latitudinal patterns of flowering phenology of three widespread tropical species from public media repositories.

Plant phenology encompasses the study of periodic events in biological life cycles of plants and the influence of seasonal changes in weather and other environmental factors. In order to understand the role of the environment and the changing climate on the life cycle of plants, long-term records are required to establish baselines against which significant future deviations can be discerned. This study aims to analyze the spatial flowering pattern of the plant species -Bombax ceiba, Butea monosperma and Cassia fistula across India, through images uploaded on public media repositories like citizen science portals and social media. Citizen science is rapidly emerging as a reliable source of supplementary scientific information, and can be utilized to understand broad patterns of tree behavior. We found that for all three species, flowering period is longer, and begins earlier in southern latitudes as compared to the northern latitudes. We conclude that publicly available images of flowering trees and citizen science data can be used to supplement existing information on tree phenology across India.