POTENTIAL IMPACTS OF CLIMATE-CHANGE ON TROPICAL ASIAN FORESTS THROUGHAN INFLUENCE ON PHENOLOGY

Changes in plant phenology will be one of the earliest responses to ra pid global climate change and could potentially have serious consequen ces both for plants and for animals that depend on periodically availa ble plant resources. Phenological patterns are most diverse and least understood in the tropics. In those parts of tropical Asia where low t emperature or drought impose a seasonal rest period, regular annual cy cles of growth and reproduction predominate at the individual, populat ion, and community level. In aseasonal areas, individuals and populati ons show a range of sub- to supra-annual periodicities, with an overal l supra-annual reproductive periodicity at the community level. There is no evidence for photoperiod control of phenology in the Asian tropi cs, and seasonal changes in temperature are a likely factor only near the northern margins. An opportunistic response to water availability is the simplest explanation for most observed patterns where water is seasonally limiting, while the great diversity of phenological pattern s in the aseasonal tropics suggests an equal diversity of controls. Th e robustness of current phenological patterns to high interannual and spatial variability suggests that most plant species will not be serio usly affected by the phenological consequences alone of climate change . However, some individual plant species may suffer, and the consequen ces of changes in plant phenology for flower- and fruit-dependent anim als in fragmented forests could be serious.