Reproductive phenology and floral visitors in Rhododendron arboreum (Ericaceae) in a temperate forest of Garhwal Himalaya

The study has been conducted in a temperate forest of north-west Himalaya, India at an altitude of 1600-2192 m asl to determine the reproductive phenological shift and the subsequent impact on pollination in Rhododendron arboreum in a temperate Himalayan forest. Phenological study and pollination observations in Rhododendron arboreum were carried out in two reproductive seasons (2016 and 2017) in a mixed broadleaved and conifer temperate forest. Floral morphology of R. arboreum was typically adapted to bird pollination and there was advancement of flowering by 5 days in first flowering and 9 days in termination of flowering in the year 2017 than that of the year 2016. The onset of flowering in R. arboreum was attributed mainly due to the scarcity of winter precipitation regardless of temperature variations. Ornithophily in assistance with entomophily would enhance the reproductive success by stimulating the magnitude of the visits through providing optimum resources.