distribution pattern, reproductive biology, Cytotaxonomic study and CONSERVATION of Rafflesia manillana in Mt. Makiling, Laguna, Philippines

We investigated the population of Rafflesia manillana in Mt. Makiling, Laguna, Philippines. Results of field surveys in 2006, 2007 and 2008 and the cytotaxonomic study in 2003 were used to determine the reproductive biology, ecological characteristics and distribution pattern of R. manillana. Problems and effective conservation approaches for the species were also identified. Three subpopulations were located at 436 to 834 m elevation. Rafflesia manillana produced flowers and fruits from March till July, with more male flowers formed compared with female. The cytotaxonomic data confirmed the observed phenology of R. manillana. Mitotic chromosome number was 2n = 22. In Mt. Makiling, compared with Rafflesia in other locations, the threat to R. manillana was caused more by its sex ratio imbalance, unsuccessful pollination and seed dispersal, and habitat disturbances caused by tropical typhoons rather than direct human exploitation. The successful conservation of this species requires information on reproduction and dispersal of R. manillana and the biology of its host plant (Tetrastigma harmandii), which this study attempted to elucidate. Efforts of conservation should focus on the protection and restoration of the habitat of R. manillana which have been damaged by typhoons. An aggressive public awareness programme on the ecological state of Mt. Makiling and R. manillana should be enhanced.